[SCSI] libiscsi: Support drivers initiating session removal
[safe/jmp/linux-2.6] / drivers / scsi / iscsi_tcp.c
index 290c1d7..752f428 100644 (file)
 #include <linux/types.h>
 #include <linux/list.h>
 #include <linux/inet.h>
+#include <linux/file.h>
 #include <linux/blkdev.h>
 #include <linux/crypto.h>
 #include <linux/delay.h>
 #include <linux/kfifo.h>
 #include <linux/scatterlist.h>
-#include <linux/mutex.h>
 #include <net/tcp.h>
 #include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_transport_iscsi.h>
@@ -47,7 +48,7 @@ MODULE_AUTHOR("Dmitry Yusupov <dmitry_yus@yahoo.com>, "
              "Alex Aizman <itn780@yahoo.com>");
 MODULE_DESCRIPTION("iSCSI/TCP data-path");
 MODULE_LICENSE("GPL");
-/* #define DEBUG_TCP */
+#undef DEBUG_TCP
 #define DEBUG_ASSERT
 
 #ifdef DEBUG_TCP
@@ -63,200 +64,496 @@ MODULE_LICENSE("GPL");
 #define BUG_ON(expr)
 #endif
 
+static struct scsi_transport_template *iscsi_tcp_scsi_transport;
+static struct scsi_host_template iscsi_sht;
+static struct iscsi_transport iscsi_tcp_transport;
+
 static unsigned int iscsi_max_lun = 512;
 module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
 
+static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
+                                  struct iscsi_segment *segment);
+
+/*
+ * Scatterlist handling: inside the iscsi_segment, we
+ * remember an index into the scatterlist, and set data/size
+ * to the current scatterlist entry. For highmem pages, we
+ * kmap as needed.
+ *
+ * Note that the page is unmapped when we return from
+ * TCP's data_ready handler, so we may end up mapping and
+ * unmapping the same page repeatedly. The whole reason
+ * for this is that we shouldn't keep the page mapped
+ * outside the softirq.
+ */
+
+/**
+ * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
+ * @segment: the buffer object
+ * @sg: scatterlist
+ * @offset: byte offset into that sg entry
+ *
+ * This function sets up the segment so that subsequent
+ * data is copied to the indicated sg entry, at the given
+ * offset.
+ */
 static inline void
-iscsi_buf_init_iov(struct iscsi_buf *ibuf, char *vbuf, int size)
+iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
+                         struct scatterlist *sg, unsigned int offset)
 {
-       ibuf->sg.page = virt_to_page(vbuf);
-       ibuf->sg.offset = offset_in_page(vbuf);
-       ibuf->sg.length = size;
-       ibuf->sent = 0;
-       ibuf->use_sendmsg = 1;
+       segment->sg = sg;
+       segment->sg_offset = offset;
+       segment->size = min(sg->length - offset,
+                           segment->total_size - segment->total_copied);
+       segment->data = NULL;
 }
 
+/**
+ * iscsi_tcp_segment_map - map the current S/G page
+ * @segment: iscsi_segment
+ * @recv: 1 if called from recv path
+ *
+ * We only need to possibly kmap data if scatter lists are being used,
+ * because the iscsi passthrough and internal IO paths will never use high
+ * mem pages.
+ */
 static inline void
-iscsi_buf_init_sg(struct iscsi_buf *ibuf, struct scatterlist *sg)
+iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
 {
-       ibuf->sg.page = sg->page;
-       ibuf->sg.offset = sg->offset;
-       ibuf->sg.length = sg->length;
+       struct scatterlist *sg;
+
+       if (segment->data != NULL || !segment->sg)
+               return;
+
+       sg = segment->sg;
+       BUG_ON(segment->sg_mapped);
+       BUG_ON(sg->length == 0);
+
        /*
-        * Fastpath: sg element fits into single page
+        * If the page count is greater than one it is ok to send
+        * to the network layer's zero copy send path. If not we
+        * have to go the slow sendmsg path. We always map for the
+        * recv path.
         */
-       if (sg->length + sg->offset <= PAGE_SIZE && !PageSlab(sg->page))
-               ibuf->use_sendmsg = 0;
-       else
-               ibuf->use_sendmsg = 1;
-       ibuf->sent = 0;
+       if (page_count(sg_page(sg)) >= 1 && !recv)
+               return;
+
+       debug_tcp("iscsi_tcp_segment_map %s %p\n", recv ? "recv" : "xmit",
+                 segment);
+       segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
+       segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
 }
 
-static inline int
-iscsi_buf_left(struct iscsi_buf *ibuf)
+static inline void
+iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
 {
-       int rc;
+       debug_tcp("iscsi_tcp_segment_unmap %p\n", segment);
 
-       rc = ibuf->sg.length - ibuf->sent;
-       BUG_ON(rc < 0);
-       return rc;
+       if (segment->sg_mapped) {
+               debug_tcp("iscsi_tcp_segment_unmap valid\n");
+               kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
+               segment->sg_mapped = NULL;
+               segment->data = NULL;
+       }
 }
 
+/*
+ * Splice the digest buffer into the buffer
+ */
 static inline void
-iscsi_hdr_digest(struct iscsi_conn *conn, struct iscsi_buf *buf,
-                u8* crc)
+iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
 {
-       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-
-       crypto_digest_digest(tcp_conn->tx_tfm, &buf->sg, 1, crc);
-       buf->sg.length += sizeof(uint32_t);
+       segment->data = digest;
+       segment->digest_len = ISCSI_DIGEST_SIZE;
+       segment->total_size += ISCSI_DIGEST_SIZE;
+       segment->size = ISCSI_DIGEST_SIZE;
+       segment->copied = 0;
+       segment->sg = NULL;
+       segment->hash = NULL;
 }
 
+/**
+ * iscsi_tcp_segment_done - check whether the segment is complete
+ * @segment: iscsi segment to check
+ * @recv: set to one of this is called from the recv path
+ * @copied: number of bytes copied
+ *
+ * Check if we're done receiving this segment. If the receive
+ * buffer is full but we expect more data, move on to the
+ * next entry in the scatterlist.
+ *
+ * If the amount of data we received isn't a multiple of 4,
+ * we will transparently receive the pad bytes, too.
+ *
+ * This function must be re-entrant.
+ */
 static inline int
-iscsi_hdr_extract(struct iscsi_tcp_conn *tcp_conn)
+iscsi_tcp_segment_done(struct iscsi_segment *segment, int recv, unsigned copied)
 {
-       struct sk_buff *skb = tcp_conn->in.skb;
-
-       tcp_conn->in.zero_copy_hdr = 0;
+       static unsigned char padbuf[ISCSI_PAD_LEN];
+       struct scatterlist sg;
+       unsigned int pad;
 
-       if (tcp_conn->in.copy >= tcp_conn->hdr_size &&
-           tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER) {
+       debug_tcp("copied %u %u size %u %s\n", segment->copied, copied,
+                 segment->size, recv ? "recv" : "xmit");
+       if (segment->hash && copied) {
                /*
-                * Zero-copy PDU Header: using connection context
-                * to store header pointer.
+                * If a segment is kmapd we must unmap it before sending
+                * to the crypto layer since that will try to kmap it again.
                 */
-               if (skb_shinfo(skb)->frag_list == NULL &&
-                   !skb_shinfo(skb)->nr_frags) {
-                       tcp_conn->in.hdr = (struct iscsi_hdr *)
-                               ((char*)skb->data + tcp_conn->in.offset);
-                       tcp_conn->in.zero_copy_hdr = 1;
+               iscsi_tcp_segment_unmap(segment);
+
+               if (!segment->data) {
+                       sg_init_table(&sg, 1);
+                       sg_set_page(&sg, sg_page(segment->sg), copied,
+                                   segment->copied + segment->sg_offset +
+                                                       segment->sg->offset);
+               } else
+                       sg_init_one(&sg, segment->data + segment->copied,
+                                   copied);
+               crypto_hash_update(segment->hash, &sg, copied);
+       }
+
+       segment->copied += copied;
+       if (segment->copied < segment->size) {
+               iscsi_tcp_segment_map(segment, recv);
+               return 0;
+       }
+
+       segment->total_copied += segment->copied;
+       segment->copied = 0;
+       segment->size = 0;
+
+       /* Unmap the current scatterlist page, if there is one. */
+       iscsi_tcp_segment_unmap(segment);
+
+       /* Do we have more scatterlist entries? */
+       debug_tcp("total copied %u total size %u\n", segment->total_copied,
+                  segment->total_size);
+       if (segment->total_copied < segment->total_size) {
+               /* Proceed to the next entry in the scatterlist. */
+               iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
+                                         0);
+               iscsi_tcp_segment_map(segment, recv);
+               BUG_ON(segment->size == 0);
+               return 0;
+       }
+
+       /* Do we need to handle padding? */
+       pad = iscsi_padding(segment->total_copied);
+       if (pad != 0) {
+               debug_tcp("consume %d pad bytes\n", pad);
+               segment->total_size += pad;
+               segment->size = pad;
+               segment->data = padbuf;
+               return 0;
+       }
+
+       /*
+        * Set us up for transferring the data digest. hdr digest
+        * is completely handled in hdr done function.
+        */
+       if (segment->hash) {
+               crypto_hash_final(segment->hash, segment->digest);
+               iscsi_tcp_segment_splice_digest(segment,
+                                recv ? segment->recv_digest : segment->digest);
+               return 0;
+       }
+
+       return 1;
+}
+
+/**
+ * iscsi_tcp_xmit_segment - transmit segment
+ * @tcp_conn: the iSCSI TCP connection
+ * @segment: the buffer to transmnit
+ *
+ * This function transmits as much of the buffer as
+ * the network layer will accept, and returns the number of
+ * bytes transmitted.
+ *
+ * If CRC hashing is enabled, the function will compute the
+ * hash as it goes. When the entire segment has been transmitted,
+ * it will retrieve the hash value and send it as well.
+ */
+static int
+iscsi_tcp_xmit_segment(struct iscsi_tcp_conn *tcp_conn,
+                      struct iscsi_segment *segment)
+{
+       struct socket *sk = tcp_conn->sock;
+       unsigned int copied = 0;
+       int r = 0;
+
+       while (!iscsi_tcp_segment_done(segment, 0, r)) {
+               struct scatterlist *sg;
+               unsigned int offset, copy;
+               int flags = 0;
+
+               r = 0;
+               offset = segment->copied;
+               copy = segment->size - offset;
+
+               if (segment->total_copied + segment->size < segment->total_size)
+                       flags |= MSG_MORE;
+
+               /* Use sendpage if we can; else fall back to sendmsg */
+               if (!segment->data) {
+                       sg = segment->sg;
+                       offset += segment->sg_offset + sg->offset;
+                       r = tcp_conn->sendpage(sk, sg_page(sg), offset, copy,
+                                              flags);
                } else {
-                       /* ignoring return code since we checked
-                        * in.copy before */
-                       skb_copy_bits(skb, tcp_conn->in.offset,
-                               &tcp_conn->hdr, tcp_conn->hdr_size);
-                       tcp_conn->in.hdr = &tcp_conn->hdr;
+                       struct msghdr msg = { .msg_flags = flags };
+                       struct kvec iov = {
+                               .iov_base = segment->data + offset,
+                               .iov_len = copy
+                       };
+
+                       r = kernel_sendmsg(sk, &msg, &iov, 1, copy);
                }
-               tcp_conn->in.offset += tcp_conn->hdr_size;
-               tcp_conn->in.copy -= tcp_conn->hdr_size;
-       } else {
-               int hdr_remains;
-               int copylen;
 
-               /*
-                * PDU header scattered across SKB's,
-                * copying it... This'll happen quite rarely.
-                */
+               if (r < 0) {
+                       iscsi_tcp_segment_unmap(segment);
+                       if (copied || r == -EAGAIN)
+                               break;
+                       return r;
+               }
+               copied += r;
+       }
+       return copied;
+}
+
+/**
+ * iscsi_tcp_segment_recv - copy data to segment
+ * @tcp_conn: the iSCSI TCP connection
+ * @segment: the buffer to copy to
+ * @ptr: data pointer
+ * @len: amount of data available
+ *
+ * This function copies up to @len bytes to the
+ * given buffer, and returns the number of bytes
+ * consumed, which can actually be less than @len.
+ *
+ * If hash digest is enabled, the function will update the
+ * hash while copying.
+ * Combining these two operations doesn't buy us a lot (yet),
+ * but in the future we could implement combined copy+crc,
+ * just way we do for network layer checksums.
+ */
+static int
+iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
+                      struct iscsi_segment *segment, const void *ptr,
+                      unsigned int len)
+{
+       unsigned int copy = 0, copied = 0;
+
+       while (!iscsi_tcp_segment_done(segment, 1, copy)) {
+               if (copied == len) {
+                       debug_tcp("iscsi_tcp_segment_recv copied %d bytes\n",
+                                 len);
+                       break;
+               }
+
+               copy = min(len - copied, segment->size - segment->copied);
+               debug_tcp("iscsi_tcp_segment_recv copying %d\n", copy);
+               memcpy(segment->data + segment->copied, ptr + copied, copy);
+               copied += copy;
+       }
+       return copied;
+}
+
+static inline void
+iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
+                     unsigned char digest[ISCSI_DIGEST_SIZE])
+{
+       struct scatterlist sg;
+
+       sg_init_one(&sg, hdr, hdrlen);
+       crypto_hash_digest(hash, &sg, hdrlen, digest);
+}
 
-               if (tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER)
-                       tcp_conn->in.hdr_offset = 0;
+static inline int
+iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
+                     struct iscsi_segment *segment)
+{
+       if (!segment->digest_len)
+               return 1;
 
-               hdr_remains = tcp_conn->hdr_size - tcp_conn->in.hdr_offset;
-               BUG_ON(hdr_remains <= 0);
+       if (memcmp(segment->recv_digest, segment->digest,
+                  segment->digest_len)) {
+               debug_scsi("digest mismatch\n");
+               return 0;
+       }
 
-               copylen = min(tcp_conn->in.copy, hdr_remains);
-               skb_copy_bits(skb, tcp_conn->in.offset,
-                       (char*)&tcp_conn->hdr + tcp_conn->in.hdr_offset,
-                       copylen);
+       return 1;
+}
 
-               debug_tcp("PDU gather offset %d bytes %d in.offset %d "
-                      "in.copy %d\n", tcp_conn->in.hdr_offset, copylen,
-                      tcp_conn->in.offset, tcp_conn->in.copy);
+/*
+ * Helper function to set up segment buffer
+ */
+static inline void
+__iscsi_segment_init(struct iscsi_segment *segment, size_t size,
+                    iscsi_segment_done_fn_t *done, struct hash_desc *hash)
+{
+       memset(segment, 0, sizeof(*segment));
+       segment->total_size = size;
+       segment->done = done;
 
-               tcp_conn->in.offset += copylen;
-               tcp_conn->in.copy -= copylen;
-               if (copylen < hdr_remains)  {
-                       tcp_conn->in_progress = IN_PROGRESS_HEADER_GATHER;
-                       tcp_conn->in.hdr_offset += copylen;
-                       return -EAGAIN;
+       if (hash) {
+               segment->hash = hash;
+               crypto_hash_init(hash);
+       }
+}
+
+static inline void
+iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
+                         size_t size, iscsi_segment_done_fn_t *done,
+                         struct hash_desc *hash)
+{
+       __iscsi_segment_init(segment, size, done, hash);
+       segment->data = data;
+       segment->size = size;
+}
+
+static inline int
+iscsi_segment_seek_sg(struct iscsi_segment *segment,
+                     struct scatterlist *sg_list, unsigned int sg_count,
+                     unsigned int offset, size_t size,
+                     iscsi_segment_done_fn_t *done, struct hash_desc *hash)
+{
+       struct scatterlist *sg;
+       unsigned int i;
+
+       debug_scsi("iscsi_segment_seek_sg offset %u size %llu\n",
+                 offset, size);
+       __iscsi_segment_init(segment, size, done, hash);
+       for_each_sg(sg_list, sg, sg_count, i) {
+               debug_scsi("sg %d, len %u offset %u\n", i, sg->length,
+                          sg->offset);
+               if (offset < sg->length) {
+                       iscsi_tcp_segment_init_sg(segment, sg, offset);
+                       return 0;
                }
-               tcp_conn->in.hdr = &tcp_conn->hdr;
-               tcp_conn->discontiguous_hdr_cnt++;
-               tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
+               offset -= sg->length;
        }
 
+       return ISCSI_ERR_DATA_OFFSET;
+}
+
+/**
+ * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
+ * @tcp_conn: iscsi connection to prep for
+ *
+ * This function always passes NULL for the hash argument, because when this
+ * function is called we do not yet know the final size of the header and want
+ * to delay the digest processing until we know that.
+ */
+static void
+iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
+{
+       debug_tcp("iscsi_tcp_hdr_recv_prep(%p%s)\n", tcp_conn,
+                 tcp_conn->iscsi_conn->hdrdgst_en ? ", digest enabled" : "");
+       iscsi_segment_init_linear(&tcp_conn->in.segment,
+                               tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
+                               iscsi_tcp_hdr_recv_done, NULL);
+}
+
+/*
+ * Handle incoming reply to any other type of command
+ */
+static int
+iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
+                        struct iscsi_segment *segment)
+{
+       struct iscsi_conn *conn = tcp_conn->iscsi_conn;
+       int rc = 0;
+
+       if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
+               return ISCSI_ERR_DATA_DGST;
+
+       rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
+                       conn->data, tcp_conn->in.datalen);
+       if (rc)
+               return rc;
+
+       iscsi_tcp_hdr_recv_prep(tcp_conn);
        return 0;
 }
 
+static void
+iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
+{
+       struct iscsi_conn *conn = tcp_conn->iscsi_conn;
+       struct hash_desc *rx_hash = NULL;
+
+       if (conn->datadgst_en)
+               rx_hash = &tcp_conn->rx_hash;
+
+       iscsi_segment_init_linear(&tcp_conn->in.segment,
+                               conn->data, tcp_conn->in.datalen,
+                               iscsi_tcp_data_recv_done, rx_hash);
+}
+
 /*
  * must be called with session lock
  */
 static void
-iscsi_tcp_cleanup_ctask(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+iscsi_tcp_cleanup_task(struct iscsi_conn *conn, struct iscsi_task *task)
 {
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
+       struct iscsi_tcp_task *tcp_task = task->dd_data;
        struct iscsi_r2t_info *r2t;
-       struct scsi_cmnd *sc;
 
-       /* flush ctask's r2t queues */
-       while (__kfifo_get(tcp_ctask->r2tqueue, (void*)&r2t, sizeof(void*))) {
-               __kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t,
+       /* nothing to do for mgmt tasks */
+       if (!task->sc)
+               return;
+
+       /* flush task's r2t queues */
+       while (__kfifo_get(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
+               __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
                            sizeof(void*));
-               debug_scsi("iscsi_tcp_cleanup_ctask pending r2t dropped\n");
+               debug_scsi("iscsi_tcp_cleanup_task pending r2t dropped\n");
        }
 
-       sc = ctask->sc;
-       if (unlikely(!sc))
-               return;
-
-       tcp_ctask->xmstate = XMSTATE_IDLE;
-       tcp_ctask->r2t = NULL;
+       r2t = tcp_task->r2t;
+       if (r2t != NULL) {
+               __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
+                           sizeof(void*));
+               tcp_task->r2t = NULL;
+       }
 }
 
 /**
- * iscsi_data_rsp - SCSI Data-In Response processing
+ * iscsi_data_in - SCSI Data-In Response processing
  * @conn: iscsi connection
- * @ctask: scsi command task
+ * @task: scsi command task
  **/
 static int
-iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+iscsi_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
 {
-       int rc;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
+       struct iscsi_tcp_task *tcp_task = task->dd_data;
        struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
-       struct iscsi_session *session = conn->session;
        int datasn = be32_to_cpu(rhdr->datasn);
+       unsigned total_in_length = scsi_in(task->sc)->length;
 
-       rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
-       if (rc)
-               return rc;
-       /*
-        * setup Data-In byte counter (gets decremented..)
-        */
-       ctask->data_count = tcp_conn->in.datalen;
-
+       iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
        if (tcp_conn->in.datalen == 0)
                return 0;
 
-       if (ctask->datasn != datasn)
+       if (tcp_task->exp_datasn != datasn) {
+               debug_tcp("%s: task->exp_datasn(%d) != rhdr->datasn(%d)\n",
+                         __func__, tcp_task->exp_datasn, datasn);
                return ISCSI_ERR_DATASN;
+       }
 
-       ctask->datasn++;
+       tcp_task->exp_datasn++;
 
-       tcp_ctask->data_offset = be32_to_cpu(rhdr->offset);
-       if (tcp_ctask->data_offset + tcp_conn->in.datalen > ctask->total_length)
+       tcp_task->data_offset = be32_to_cpu(rhdr->offset);
+       if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
+               debug_tcp("%s: data_offset(%d) + data_len(%d) > total_length_in(%d)\n",
+                         __func__, tcp_task->data_offset,
+                         tcp_conn->in.datalen, total_in_length);
                return ISCSI_ERR_DATA_OFFSET;
-
-       if (rhdr->flags & ISCSI_FLAG_DATA_STATUS) {
-               struct scsi_cmnd *sc = ctask->sc;
-
-               conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
-               if (rhdr->flags & ISCSI_FLAG_DATA_UNDERFLOW) {
-                       int res_count = be32_to_cpu(rhdr->residual_count);
-
-                       if (res_count > 0 &&
-                           res_count <= sc->request_bufflen) {
-                               sc->resid = res_count;
-                               sc->result = (DID_OK << 16) | rhdr->cmd_status;
-                       } else
-                               sc->result = (DID_BAD_TARGET << 16) |
-                                       rhdr->cmd_status;
-               } else if (rhdr->flags & ISCSI_FLAG_DATA_OVERFLOW) {
-                       sc->resid = be32_to_cpu(rhdr->residual_count);
-                       sc->result = (DID_OK << 16) | rhdr->cmd_status;
-               } else
-                       sc->result = (DID_OK << 16) | rhdr->cmd_status;
        }
 
        conn->datain_pdus_cnt++;
@@ -266,7 +563,7 @@ iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
 /**
  * iscsi_solicit_data_init - initialize first Data-Out
  * @conn: iscsi connection
- * @ctask: scsi command task
+ * @task: scsi command task
  * @r2t: R2T info
  *
  * Notes:
@@ -276,11 +573,10 @@ iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
  *     This function is called with connection lock taken.
  **/
 static void
-iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
+iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_task *task,
                        struct iscsi_r2t_info *r2t)
 {
        struct iscsi_data *hdr;
-       struct scsi_cmnd *sc = ctask->sc;
 
        hdr = &r2t->dtask.hdr;
        memset(hdr, 0, sizeof(struct iscsi_data));
@@ -288,8 +584,8 @@ iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
        hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
        r2t->solicit_datasn++;
        hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
-       memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
-       hdr->itt = ctask->hdr->itt;
+       memcpy(hdr->lun, task->hdr->lun, sizeof(hdr->lun));
+       hdr->itt = task->hdr->itt;
        hdr->exp_statsn = r2t->exp_statsn;
        hdr->offset = cpu_to_be32(r2t->data_offset);
        if (r2t->data_length > conn->max_xmit_dlength) {
@@ -304,94 +600,57 @@ iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
        conn->dataout_pdus_cnt++;
 
        r2t->sent = 0;
-
-       iscsi_buf_init_iov(&r2t->headbuf, (char*)hdr,
-                          sizeof(struct iscsi_hdr));
-
-       if (sc->use_sg) {
-               int i, sg_count = 0;
-               struct scatterlist *sg = sc->request_buffer;
-
-               r2t->sg = NULL;
-               for (i = 0; i < sc->use_sg; i++, sg += 1) {
-                       /* FIXME: prefetch ? */
-                       if (sg_count + sg->length > r2t->data_offset) {
-                               int page_offset;
-
-                               /* sg page found! */
-
-                               /* offset within this page */
-                               page_offset = r2t->data_offset - sg_count;
-
-                               /* fill in this buffer */
-                               iscsi_buf_init_sg(&r2t->sendbuf, sg);
-                               r2t->sendbuf.sg.offset += page_offset;
-                               r2t->sendbuf.sg.length -= page_offset;
-
-                               /* xmit logic will continue with next one */
-                               r2t->sg = sg + 1;
-                               break;
-                       }
-                       sg_count += sg->length;
-               }
-               BUG_ON(r2t->sg == NULL);
-       } else {
-               iscsi_buf_init_iov(&r2t->sendbuf,
-                           (char*)sc->request_buffer + r2t->data_offset,
-                           r2t->data_count);
-               r2t->sg = NULL;
-       }
 }
 
 /**
  * iscsi_r2t_rsp - iSCSI R2T Response processing
  * @conn: iscsi connection
- * @ctask: scsi command task
+ * @task: scsi command task
  **/
 static int
-iscsi_r2t_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+iscsi_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
 {
        struct iscsi_r2t_info *r2t;
        struct iscsi_session *session = conn->session;
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
+       struct iscsi_tcp_task *tcp_task = task->dd_data;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
        int r2tsn = be32_to_cpu(rhdr->r2tsn);
        int rc;
 
        if (tcp_conn->in.datalen) {
-               printk(KERN_ERR "iscsi_tcp: invalid R2t with datalen %d\n",
-                      tcp_conn->in.datalen);
+               iscsi_conn_printk(KERN_ERR, conn,
+                                 "invalid R2t with datalen %d\n",
+                                 tcp_conn->in.datalen);
                return ISCSI_ERR_DATALEN;
        }
 
-       if (tcp_ctask->exp_r2tsn && tcp_ctask->exp_r2tsn != r2tsn)
+       if (tcp_task->exp_datasn != r2tsn){
+               debug_tcp("%s: task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
+                         __func__, tcp_task->exp_datasn, r2tsn);
                return ISCSI_ERR_R2TSN;
-
-       rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
-       if (rc)
-               return rc;
-
-       /* FIXME: use R2TSN to detect missing R2T */
+       }
 
        /* fill-in new R2T associated with the task */
-       spin_lock(&session->lock);
-       if (!ctask->sc || ctask->mtask ||
-            session->state != ISCSI_STATE_LOGGED_IN) {
-               printk(KERN_INFO "iscsi_tcp: dropping R2T itt %d in "
-                      "recovery...\n", ctask->itt);
-               spin_unlock(&session->lock);
+       iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
+
+       if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
+               iscsi_conn_printk(KERN_INFO, conn,
+                                 "dropping R2T itt %d in recovery.\n",
+                                 task->itt);
                return 0;
        }
 
-       rc = __kfifo_get(tcp_ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
+       rc = __kfifo_get(tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
        BUG_ON(!rc);
 
        r2t->exp_statsn = rhdr->statsn;
        r2t->data_length = be32_to_cpu(rhdr->data_length);
        if (r2t->data_length == 0) {
-               printk(KERN_ERR "iscsi_tcp: invalid R2T with zero data len\n");
-               spin_unlock(&session->lock);
+               iscsi_conn_printk(KERN_ERR, conn,
+                                 "invalid R2T with zero data len\n");
+               __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
+                           sizeof(void*));
                return ISCSI_ERR_DATALEN;
        }
 
@@ -401,121 +660,159 @@ iscsi_r2t_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
                            r2t->data_length, session->max_burst);
 
        r2t->data_offset = be32_to_cpu(rhdr->data_offset);
-       if (r2t->data_offset + r2t->data_length > ctask->total_length) {
-               spin_unlock(&session->lock);
-               printk(KERN_ERR "iscsi_tcp: invalid R2T with data len %u at "
-                      "offset %u and total length %d\n", r2t->data_length,
-                      r2t->data_offset, ctask->total_length);
+       if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
+               iscsi_conn_printk(KERN_ERR, conn,
+                                 "invalid R2T with data len %u at offset %u "
+                                 "and total length %d\n", r2t->data_length,
+                                 r2t->data_offset, scsi_out(task->sc)->length);
+               __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
+                           sizeof(void*));
                return ISCSI_ERR_DATALEN;
        }
 
        r2t->ttt = rhdr->ttt; /* no flip */
        r2t->solicit_datasn = 0;
 
-       iscsi_solicit_data_init(conn, ctask, r2t);
-
-       tcp_ctask->exp_r2tsn = r2tsn + 1;
-       tcp_ctask->xmstate |= XMSTATE_SOL_HDR;
-       __kfifo_put(tcp_ctask->r2tqueue, (void*)&r2t, sizeof(void*));
-       list_move_tail(&ctask->running, &conn->xmitqueue);
+       iscsi_solicit_data_init(conn, task, r2t);
 
-       scsi_queue_work(session->host, &conn->xmitwork);
+       tcp_task->exp_datasn = r2tsn + 1;
+       __kfifo_put(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
        conn->r2t_pdus_cnt++;
-       spin_unlock(&session->lock);
 
+       iscsi_requeue_task(task);
        return 0;
 }
 
+/*
+ * Handle incoming reply to DataIn command
+ */
 static int
-iscsi_tcp_hdr_recv(struct iscsi_conn *conn)
+iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
+                         struct iscsi_segment *segment)
+{
+       struct iscsi_conn *conn = tcp_conn->iscsi_conn;
+       struct iscsi_hdr *hdr = tcp_conn->in.hdr;
+       int rc;
+
+       if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
+               return ISCSI_ERR_DATA_DGST;
+
+       /* check for non-exceptional status */
+       if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
+               rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
+               if (rc)
+                       return rc;
+       }
+
+       iscsi_tcp_hdr_recv_prep(tcp_conn);
+       return 0;
+}
+
+/**
+ * iscsi_tcp_hdr_dissect - process PDU header
+ * @conn: iSCSI connection
+ * @hdr: PDU header
+ *
+ * This function analyzes the header of the PDU received,
+ * and performs several sanity checks. If the PDU is accompanied
+ * by data, the receive buffer is set up to copy the incoming data
+ * to the correct location.
+ */
+static int
+iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 {
        int rc = 0, opcode, ahslen;
-       struct iscsi_hdr *hdr;
-       struct iscsi_session *session = conn->session;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       uint32_t cdgst, rdgst = 0, itt;
-
-       hdr = tcp_conn->in.hdr;
+       struct iscsi_task *task;
 
        /* verify PDU length */
        tcp_conn->in.datalen = ntoh24(hdr->dlength);
        if (tcp_conn->in.datalen > conn->max_recv_dlength) {
-               printk(KERN_ERR "iscsi_tcp: datalen %d > %d\n",
-                      tcp_conn->in.datalen, conn->max_recv_dlength);
+               iscsi_conn_printk(KERN_ERR, conn,
+                                 "iscsi_tcp: datalen %d > %d\n",
+                                 tcp_conn->in.datalen, conn->max_recv_dlength);
                return ISCSI_ERR_DATALEN;
        }
-       tcp_conn->data_copied = 0;
 
-       /* read AHS */
+       /* Additional header segments. So far, we don't
+        * process additional headers.
+        */
        ahslen = hdr->hlength << 2;
-       tcp_conn->in.offset += ahslen;
-       tcp_conn->in.copy -= ahslen;
-       if (tcp_conn->in.copy < 0) {
-               printk(KERN_ERR "iscsi_tcp: can't handle AHS with length "
-                      "%d bytes\n", ahslen);
-               return ISCSI_ERR_AHSLEN;
-       }
-
-       /* calculate read padding */
-       tcp_conn->in.padding = tcp_conn->in.datalen & (ISCSI_PAD_LEN-1);
-       if (tcp_conn->in.padding) {
-               tcp_conn->in.padding = ISCSI_PAD_LEN - tcp_conn->in.padding;
-               debug_scsi("read padding %d bytes\n", tcp_conn->in.padding);
-       }
-
-       if (conn->hdrdgst_en) {
-               struct scatterlist sg;
-
-               sg_init_one(&sg, (u8 *)hdr,
-                           sizeof(struct iscsi_hdr) + ahslen);
-               crypto_digest_digest(tcp_conn->rx_tfm, &sg, 1, (u8 *)&cdgst);
-               rdgst = *(uint32_t*)((char*)hdr + sizeof(struct iscsi_hdr) +
-                                    ahslen);
-               if (cdgst != rdgst) {
-                       printk(KERN_ERR "iscsi_tcp: hdrdgst error "
-                              "recv 0x%x calc 0x%x\n", rdgst, cdgst);
-                       return ISCSI_ERR_HDR_DGST;
-               }
-       }
 
        opcode = hdr->opcode & ISCSI_OPCODE_MASK;
        /* verify itt (itt encoding: age+cid+itt) */
-       rc = iscsi_verify_itt(conn, hdr, &itt);
-       if (rc == ISCSI_ERR_NO_SCSI_CMD) {
-               tcp_conn->in.datalen = 0; /* force drop */
-               return 0;
-       } else if (rc)
+       rc = iscsi_verify_itt(conn, hdr->itt);
+       if (rc)
                return rc;
 
-       debug_tcp("opcode 0x%x offset %d copy %d ahslen %d datalen %d\n",
-                 opcode, tcp_conn->in.offset, tcp_conn->in.copy,
-                 ahslen, tcp_conn->in.datalen);
+       debug_tcp("opcode 0x%x ahslen %d datalen %d\n",
+                 opcode, ahslen, tcp_conn->in.datalen);
 
        switch(opcode) {
        case ISCSI_OP_SCSI_DATA_IN:
-               tcp_conn->in.ctask = session->cmds[itt];
-               rc = iscsi_data_rsp(conn, tcp_conn->in.ctask);
-               if (rc)
-                       return rc;
-               /* fall through */
-       case ISCSI_OP_SCSI_CMD_RSP:
-               tcp_conn->in.ctask = session->cmds[itt];
-               if (tcp_conn->in.datalen)
-                       goto copy_hdr;
+               spin_lock(&conn->session->lock);
+               task = iscsi_itt_to_ctask(conn, hdr->itt);
+               if (!task)
+                       rc = ISCSI_ERR_BAD_ITT;
+               else
+                       rc = iscsi_data_in(conn, task);
+               if (rc) {
+                       spin_unlock(&conn->session->lock);
+                       break;
+               }
 
-               spin_lock(&session->lock);
+               if (tcp_conn->in.datalen) {
+                       struct iscsi_tcp_task *tcp_task = task->dd_data;
+                       struct hash_desc *rx_hash = NULL;
+                       struct scsi_data_buffer *sdb = scsi_in(task->sc);
+
+                       /*
+                        * Setup copy of Data-In into the Scsi_Cmnd
+                        * Scatterlist case:
+                        * We set up the iscsi_segment to point to the next
+                        * scatterlist entry to copy to. As we go along,
+                        * we move on to the next scatterlist entry and
+                        * update the digest per-entry.
+                        */
+                       if (conn->datadgst_en)
+                               rx_hash = &tcp_conn->rx_hash;
+
+                       debug_tcp("iscsi_tcp_begin_data_in(%p, offset=%d, "
+                                 "datalen=%d)\n", tcp_conn,
+                                 tcp_task->data_offset,
+                                 tcp_conn->in.datalen);
+                       rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
+                                                  sdb->table.sgl,
+                                                  sdb->table.nents,
+                                                  tcp_task->data_offset,
+                                                  tcp_conn->in.datalen,
+                                                  iscsi_tcp_process_data_in,
+                                                  rx_hash);
+                       spin_unlock(&conn->session->lock);
+                       return rc;
+               }
                rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
-               spin_unlock(&session->lock);
+               spin_unlock(&conn->session->lock);
+               break;
+       case ISCSI_OP_SCSI_CMD_RSP:
+               if (tcp_conn->in.datalen) {
+                       iscsi_tcp_data_recv_prep(tcp_conn);
+                       return 0;
+               }
+               rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
                break;
        case ISCSI_OP_R2T:
-               tcp_conn->in.ctask = session->cmds[itt];
-               if (ahslen)
+               spin_lock(&conn->session->lock);
+               task = iscsi_itt_to_ctask(conn, hdr->itt);
+               if (!task)
+                       rc = ISCSI_ERR_BAD_ITT;
+               else if (ahslen)
                        rc = ISCSI_ERR_AHSLEN;
-               else if (tcp_conn->in.ctask->sc->sc_data_direction ==
-                                                               DMA_TO_DEVICE)
-                       rc = iscsi_r2t_rsp(conn, tcp_conn->in.ctask);
+               else if (task->sc->sc_data_direction == DMA_TO_DEVICE)
+                       rc = iscsi_r2t_rsp(conn, task);
                else
                        rc = ISCSI_ERR_PROTO;
+               spin_unlock(&conn->session->lock);
                break;
        case ISCSI_OP_LOGIN_RSP:
        case ISCSI_OP_TEXT_RSP:
@@ -526,18 +823,24 @@ iscsi_tcp_hdr_recv(struct iscsi_conn *conn)
                 * than 8K, but there are no targets that currently do this.
                 * For now we fail until we find a vendor that needs it
                 */
-               if (DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH <
-                   tcp_conn->in.datalen) {
-                       printk(KERN_ERR "iscsi_tcp: received buffer of len %u "
-                             "but conn buffer is only %u (opcode %0x)\n",
-                             tcp_conn->in.datalen,
-                             DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH, opcode);
+               if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
+                       iscsi_conn_printk(KERN_ERR, conn,
+                                         "iscsi_tcp: received buffer of "
+                                         "len %u but conn buffer is only %u "
+                                         "(opcode %0x)\n",
+                                         tcp_conn->in.datalen,
+                                         ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
                        rc = ISCSI_ERR_PROTO;
                        break;
                }
 
-               if (tcp_conn->in.datalen)
-                       goto copy_hdr;
+               /* If there's data coming in with the response,
+                * receive it to the connection's buffer.
+                */
+               if (tcp_conn->in.datalen) {
+                       iscsi_tcp_data_recv_prep(tcp_conn);
+                       return 0;
+               }
        /* fall through */
        case ISCSI_OP_LOGOUT_RSP:
        case ISCSI_OP_NOOP_IN:
@@ -549,453 +852,161 @@ iscsi_tcp_hdr_recv(struct iscsi_conn *conn)
                break;
        }
 
-       return rc;
-
-copy_hdr:
-       /*
-        * if we did zero copy for the header but we will need multiple
-        * skbs to complete the command then we have to copy the header
-        * for later use
-        */
-       if (tcp_conn->in.zero_copy_hdr && tcp_conn->in.copy <=
-          (tcp_conn->in.datalen + tcp_conn->in.padding +
-           (conn->datadgst_en ? 4 : 0))) {
-               debug_tcp("Copying header for later use. in.copy %d in.datalen"
-                         " %d\n", tcp_conn->in.copy, tcp_conn->in.datalen);
-               memcpy(&tcp_conn->hdr, tcp_conn->in.hdr,
-                      sizeof(struct iscsi_hdr));
-               tcp_conn->in.hdr = &tcp_conn->hdr;
-               tcp_conn->in.zero_copy_hdr = 0;
-       }
-       return 0;
-}
-
-/**
- * iscsi_ctask_copy - copy skb bits to the destanation cmd task
- * @conn: iscsi tcp connection
- * @ctask: scsi command task
- * @buf: buffer to copy to
- * @buf_size: size of buffer
- * @offset: offset within the buffer
- *
- * Notes:
- *     The function calls skb_copy_bits() and updates per-connection and
- *     per-cmd byte counters.
- *
- *     Read counters (in bytes):
- *
- *     conn->in.offset         offset within in progress SKB
- *     conn->in.copy           left to copy from in progress SKB
- *                             including padding
- *     conn->in.copied         copied already from in progress SKB
- *     conn->data_copied       copied already from in progress buffer
- *     ctask->sent             total bytes sent up to the MidLayer
- *     ctask->data_count       left to copy from in progress Data-In
- *     buf_left                left to copy from in progress buffer
- **/
-static inline int
-iscsi_ctask_copy(struct iscsi_tcp_conn *tcp_conn, struct iscsi_cmd_task *ctask,
-               void *buf, int buf_size, int offset)
-{
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-       int buf_left = buf_size - (tcp_conn->data_copied + offset);
-       int size = min(tcp_conn->in.copy, buf_left);
-       int rc;
-
-       size = min(size, ctask->data_count);
-
-       debug_tcp("ctask_copy %d bytes at offset %d copied %d\n",
-              size, tcp_conn->in.offset, tcp_conn->in.copied);
-
-       BUG_ON(size <= 0);
-       BUG_ON(tcp_ctask->sent + size > ctask->total_length);
-
-       rc = skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
-                          (char*)buf + (offset + tcp_conn->data_copied), size);
-       /* must fit into skb->len */
-       BUG_ON(rc);
-
-       tcp_conn->in.offset += size;
-       tcp_conn->in.copy -= size;
-       tcp_conn->in.copied += size;
-       tcp_conn->data_copied += size;
-       tcp_ctask->sent += size;
-       ctask->data_count -= size;
-
-       BUG_ON(tcp_conn->in.copy < 0);
-       BUG_ON(ctask->data_count < 0);
-
-       if (buf_size != (tcp_conn->data_copied + offset)) {
-               if (!ctask->data_count) {
-                       BUG_ON(buf_size - tcp_conn->data_copied < 0);
-                       /* done with this PDU */
-                       return buf_size - tcp_conn->data_copied;
-               }
-               return -EAGAIN;
+       if (rc == 0) {
+               /* Anything that comes with data should have
+                * been handled above. */
+               if (tcp_conn->in.datalen)
+                       return ISCSI_ERR_PROTO;
+               iscsi_tcp_hdr_recv_prep(tcp_conn);
        }
 
-       /* done with this buffer or with both - PDU and buffer */
-       tcp_conn->data_copied = 0;
-       return 0;
+       return rc;
 }
 
 /**
- * iscsi_tcp_copy - copy skb bits to the destanation buffer
- * @conn: iscsi tcp connection
+ * iscsi_tcp_hdr_recv_done - process PDU header
  *
- * Notes:
- *     The function calls skb_copy_bits() and updates per-connection
- *     byte counters.
- **/
-static inline int
-iscsi_tcp_copy(struct iscsi_conn *conn)
-{
-       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       int buf_size = tcp_conn->in.datalen;
-       int buf_left = buf_size - tcp_conn->data_copied;
-       int size = min(tcp_conn->in.copy, buf_left);
-       int rc;
-
-       debug_tcp("tcp_copy %d bytes at offset %d copied %d\n",
-              size, tcp_conn->in.offset, tcp_conn->data_copied);
-       BUG_ON(size <= 0);
-
-       rc = skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
-                          (char*)conn->data + tcp_conn->data_copied, size);
-       BUG_ON(rc);
-
-       tcp_conn->in.offset += size;
-       tcp_conn->in.copy -= size;
-       tcp_conn->in.copied += size;
-       tcp_conn->data_copied += size;
-
-       if (buf_size != tcp_conn->data_copied)
-               return -EAGAIN;
-
-       return 0;
-}
-
-static inline void
-partial_sg_digest_update(struct crypto_tfm *tfm, struct scatterlist *sg,
-                        int offset, int length)
-{
-       struct scatterlist temp;
-
-       memcpy(&temp, sg, sizeof(struct scatterlist));
-       temp.offset = offset;
-       temp.length = length;
-       crypto_digest_update(tfm, &temp, 1);
-}
-
-static void
-iscsi_recv_digest_update(struct iscsi_tcp_conn *tcp_conn, char* buf, int len)
-{
-       struct scatterlist tmp;
-
-       sg_init_one(&tmp, buf, len);
-       crypto_digest_update(tcp_conn->data_rx_tfm, &tmp, 1);
-}
-
-static int iscsi_scsi_data_in(struct iscsi_conn *conn)
+ * This is the callback invoked when the PDU header has
+ * been received. If the header is followed by additional
+ * header segments, we go back for more data.
+ */
+static int
+iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
+                       struct iscsi_segment *segment)
 {
-       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       struct iscsi_cmd_task *ctask = tcp_conn->in.ctask;
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-       struct scsi_cmnd *sc = ctask->sc;
-       struct scatterlist *sg;
-       int i, offset, rc = 0;
-
-       BUG_ON((void*)ctask != sc->SCp.ptr);
+       struct iscsi_conn *conn = tcp_conn->iscsi_conn;
+       struct iscsi_hdr *hdr;
 
-       /*
-        * copying Data-In into the Scsi_Cmnd
+       /* Check if there are additional header segments
+        * *prior* to computing the digest, because we
+        * may need to go back to the caller for more.
         */
-       if (!sc->use_sg) {
-               i = ctask->data_count;
-               rc = iscsi_ctask_copy(tcp_conn, ctask, sc->request_buffer,
-                                     sc->request_bufflen,
-                                     tcp_ctask->data_offset);
-               if (rc == -EAGAIN)
-                       return rc;
-               if (conn->datadgst_en)
-                       iscsi_recv_digest_update(tcp_conn, sc->request_buffer,
-                                                i);
-               rc = 0;
-               goto done;
+       hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
+       if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
+               /* Bump the header length - the caller will
+                * just loop around and get the AHS for us, and
+                * call again. */
+               unsigned int ahslen = hdr->hlength << 2;
+
+               /* Make sure we don't overflow */
+               if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
+                       return ISCSI_ERR_AHSLEN;
+
+               segment->total_size += ahslen;
+               segment->size += ahslen;
+               return 0;
        }
 
-       offset = tcp_ctask->data_offset;
-       sg = sc->request_buffer;
-
-       if (tcp_ctask->data_offset)
-               for (i = 0; i < tcp_ctask->sg_count; i++)
-                       offset -= sg[i].length;
-       /* we've passed through partial sg*/
-       if (offset < 0)
-               offset = 0;
-
-       for (i = tcp_ctask->sg_count; i < sc->use_sg; i++) {
-               char *dest;
-
-               dest = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
-               rc = iscsi_ctask_copy(tcp_conn, ctask, dest + sg[i].offset,
-                                     sg[i].length, offset);
-               kunmap_atomic(dest, KM_SOFTIRQ0);
-               if (rc == -EAGAIN)
-                       /* continue with the next SKB/PDU */
-                       return rc;
-               if (!rc) {
-                       if (conn->datadgst_en) {
-                               if (!offset)
-                                       crypto_digest_update(
-                                                       tcp_conn->data_rx_tfm,
-                                                       &sg[i], 1);
-                               else
-                                       partial_sg_digest_update(
-                                                       tcp_conn->data_rx_tfm,
-                                                       &sg[i],
-                                                       sg[i].offset + offset,
-                                                       sg[i].length - offset);
-                       }
-                       offset = 0;
-                       tcp_ctask->sg_count++;
-               }
-
-               if (!ctask->data_count) {
-                       if (rc && conn->datadgst_en)
-                               /*
-                                * data-in is complete, but buffer not...
-                                */
-                               partial_sg_digest_update(tcp_conn->data_rx_tfm,
-                                               &sg[i],
-                                               sg[i].offset, sg[i].length-rc);
-                       rc = 0;
-                       break;
+       /* We're done processing the header. See if we're doing
+        * header digests; if so, set up the recv_digest buffer
+        * and go back for more. */
+       if (conn->hdrdgst_en) {
+               if (segment->digest_len == 0) {
+                       iscsi_tcp_segment_splice_digest(segment,
+                                                       segment->recv_digest);
+                       return 0;
                }
+               iscsi_tcp_dgst_header(&tcp_conn->rx_hash, hdr,
+                                     segment->total_copied - ISCSI_DIGEST_SIZE,
+                                     segment->digest);
 
-               if (!tcp_conn->in.copy)
-                       return -EAGAIN;
-       }
-       BUG_ON(ctask->data_count);
-
-done:
-       /* check for non-exceptional status */
-       if (tcp_conn->in.hdr->flags & ISCSI_FLAG_DATA_STATUS) {
-               debug_scsi("done [sc %lx res %d itt 0x%x flags 0x%x]\n",
-                          (long)sc, sc->result, ctask->itt,
-                          tcp_conn->in.hdr->flags);
-               spin_lock(&conn->session->lock);
-               __iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
-               spin_unlock(&conn->session->lock);
+               if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
+                       return ISCSI_ERR_HDR_DGST;
        }
 
-       return rc;
-}
-
-static int
-iscsi_data_recv(struct iscsi_conn *conn)
-{
-       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       int rc = 0, opcode;
-
-       opcode = tcp_conn->in.hdr->opcode & ISCSI_OPCODE_MASK;
-       switch (opcode) {
-       case ISCSI_OP_SCSI_DATA_IN:
-               rc = iscsi_scsi_data_in(conn);
-               break;
-       case ISCSI_OP_SCSI_CMD_RSP:
-       case ISCSI_OP_TEXT_RSP:
-       case ISCSI_OP_LOGIN_RSP:
-       case ISCSI_OP_ASYNC_EVENT:
-       case ISCSI_OP_REJECT:
-               /*
-                * Collect data segment to the connection's data
-                * placeholder
-                */
-               if (iscsi_tcp_copy(conn)) {
-                       rc = -EAGAIN;
-                       goto exit;
-               }
-
-               rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, conn->data,
-                                       tcp_conn->in.datalen);
-               if (!rc && conn->datadgst_en && opcode != ISCSI_OP_LOGIN_RSP)
-                       iscsi_recv_digest_update(tcp_conn, conn->data,
-                                               tcp_conn->in.datalen);
-               break;
-       default:
-               BUG_ON(1);
-       }
-exit:
-       return rc;
+       tcp_conn->in.hdr = hdr;
+       return iscsi_tcp_hdr_dissect(conn, hdr);
 }
 
 /**
- * iscsi_tcp_data_recv - TCP receive in sendfile fashion
+ * iscsi_tcp_recv - TCP receive in sendfile fashion
  * @rd_desc: read descriptor
  * @skb: socket buffer
  * @offset: offset in skb
  * @len: skb->len - offset
  **/
 static int
-iscsi_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
-               unsigned int offset, size_t len)
+iscsi_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
+              unsigned int offset, size_t len)
 {
-       int rc;
        struct iscsi_conn *conn = rd_desc->arg.data;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       int processed;
-       char pad[ISCSI_PAD_LEN];
-       struct scatterlist sg;
-
-       /*
-        * Save current SKB and its offset in the corresponding
-        * connection context.
-        */
-       tcp_conn->in.copy = skb->len - offset;
-       tcp_conn->in.offset = offset;
-       tcp_conn->in.skb = skb;
-       tcp_conn->in.len = tcp_conn->in.copy;
-       BUG_ON(tcp_conn->in.copy <= 0);
-       debug_tcp("in %d bytes\n", tcp_conn->in.copy);
+       struct iscsi_segment *segment = &tcp_conn->in.segment;
+       struct skb_seq_state seq;
+       unsigned int consumed = 0;
+       int rc = 0;
 
-more:
-       tcp_conn->in.copied = 0;
-       rc = 0;
+       debug_tcp("in %d bytes\n", skb->len - offset);
 
        if (unlikely(conn->suspend_rx)) {
                debug_tcp("conn %d Rx suspended!\n", conn->id);
                return 0;
        }
 
-       if (tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER ||
-           tcp_conn->in_progress == IN_PROGRESS_HEADER_GATHER) {
-               rc = iscsi_hdr_extract(tcp_conn);
-               if (rc) {
-                      if (rc == -EAGAIN)
-                               goto nomore;
-                      else {
-                               iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
-                               return 0;
-                      }
-               }
+       skb_prepare_seq_read(skb, offset, skb->len, &seq);
+       while (1) {
+               unsigned int avail;
+               const u8 *ptr;
 
-               /*
-                * Verify and process incoming PDU header.
-                */
-               rc = iscsi_tcp_hdr_recv(conn);
-               if (!rc && tcp_conn->in.datalen) {
-                       if (conn->datadgst_en) {
-                               BUG_ON(!tcp_conn->data_rx_tfm);
-                               crypto_digest_init(tcp_conn->data_rx_tfm);
-                       }
-                       tcp_conn->in_progress = IN_PROGRESS_DATA_RECV;
-               } else if (rc) {
-                       iscsi_conn_failure(conn, rc);
-                       return 0;
-               }
-       }
-
-       if (tcp_conn->in_progress == IN_PROGRESS_DDIGEST_RECV) {
-               uint32_t recv_digest;
-
-               debug_tcp("extra data_recv offset %d copy %d\n",
-                         tcp_conn->in.offset, tcp_conn->in.copy);
-               skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
-                               &recv_digest, 4);
-               tcp_conn->in.offset += 4;
-               tcp_conn->in.copy -= 4;
-               if (recv_digest != tcp_conn->in.datadgst) {
-                       debug_tcp("iscsi_tcp: data digest error!"
-                                 "0x%x != 0x%x\n", recv_digest,
-                                 tcp_conn->in.datadgst);
-                       iscsi_conn_failure(conn, ISCSI_ERR_DATA_DGST);
-                       return 0;
-               } else {
-                       debug_tcp("iscsi_tcp: data digest match!"
-                                 "0x%x == 0x%x\n", recv_digest,
-                                 tcp_conn->in.datadgst);
-                       tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
-               }
-       }
-
-       if (tcp_conn->in_progress == IN_PROGRESS_DATA_RECV &&
-          tcp_conn->in.copy) {
-
-               debug_tcp("data_recv offset %d copy %d\n",
-                      tcp_conn->in.offset, tcp_conn->in.copy);
-
-               rc = iscsi_data_recv(conn);
-               if (rc) {
-                       if (rc == -EAGAIN)
-                               goto again;
-                       iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
-                       return 0;
+               avail = skb_seq_read(consumed, &ptr, &seq);
+               if (avail == 0) {
+                       debug_tcp("no more data avail. Consumed %d\n",
+                                 consumed);
+                       break;
                }
-               tcp_conn->in.copy -= tcp_conn->in.padding;
-               tcp_conn->in.offset += tcp_conn->in.padding;
-               if (conn->datadgst_en) {
-                       if (tcp_conn->in.padding) {
-                               debug_tcp("padding -> %d\n",
-                                         tcp_conn->in.padding);
-                               memset(pad, 0, tcp_conn->in.padding);
-                               sg_init_one(&sg, pad, tcp_conn->in.padding);
-                               crypto_digest_update(tcp_conn->data_rx_tfm,
-                                                    &sg, 1);
+               BUG_ON(segment->copied >= segment->size);
+
+               debug_tcp("skb %p ptr=%p avail=%u\n", skb, ptr, avail);
+               rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
+               BUG_ON(rc == 0);
+               consumed += rc;
+
+               if (segment->total_copied >= segment->total_size) {
+                       debug_tcp("segment done\n");
+                       rc = segment->done(tcp_conn, segment);
+                       if (rc != 0) {
+                               skb_abort_seq_read(&seq);
+                               goto error;
                        }
-                       crypto_digest_final(tcp_conn->data_rx_tfm,
-                                           (u8 *) & tcp_conn->in.datadgst);
-                       debug_tcp("rx digest 0x%x\n", tcp_conn->in.datadgst);
-                       tcp_conn->in_progress = IN_PROGRESS_DDIGEST_RECV;
-               } else
-                       tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
-       }
-
-       debug_tcp("f, processed %d from out of %d padding %d\n",
-              tcp_conn->in.offset - offset, (int)len, tcp_conn->in.padding);
-       BUG_ON(tcp_conn->in.offset - offset > len);
 
-       if (tcp_conn->in.offset - offset != len) {
-               debug_tcp("continue to process %d bytes\n",
-                      (int)len - (tcp_conn->in.offset - offset));
-               goto more;
+                       /* The done() functions sets up the
+                        * next segment. */
+               }
        }
+       skb_abort_seq_read(&seq);
+       conn->rxdata_octets += consumed;
+       return consumed;
 
-nomore:
-       processed = tcp_conn->in.offset - offset;
-       BUG_ON(processed == 0);
-       return processed;
-
-again:
-       processed = tcp_conn->in.offset - offset;
-       debug_tcp("c, processed %d from out of %d rd_desc_cnt %d\n",
-                 processed, (int)len, (int)rd_desc->count);
-       BUG_ON(processed == 0);
-       BUG_ON(processed > len);
-
-       conn->rxdata_octets += processed;
-       return processed;
+error:
+       debug_tcp("Error receiving PDU, errno=%d\n", rc);
+       iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+       return 0;
 }
 
 static void
 iscsi_tcp_data_ready(struct sock *sk, int flag)
 {
        struct iscsi_conn *conn = sk->sk_user_data;
+       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        read_descriptor_t rd_desc;
 
        read_lock(&sk->sk_callback_lock);
 
        /*
-        * Use rd_desc to pass 'conn' to iscsi_tcp_data_recv.
+        * Use rd_desc to pass 'conn' to iscsi_tcp_recv.
         * We set count to 1 because we want the network layer to
-        * hand us all the skbs that are available. iscsi_tcp_data_recv
+        * hand us all the skbs that are available. iscsi_tcp_recv
         * handled pdus that cross buffers or pdus that still need data.
         */
        rd_desc.arg.data = conn;
        rd_desc.count = 1;
-       tcp_read_sock(sk, &rd_desc, iscsi_tcp_data_recv);
+       tcp_read_sock(sk, &rd_desc, iscsi_tcp_recv);
 
        read_unlock(&sk->sk_callback_lock);
+
+       /* If we had to (atomically) map a highmem page,
+        * unmap it now. */
+       iscsi_tcp_segment_unmap(&tcp_conn->in.segment);
 }
 
 static void
@@ -1075,666 +1086,390 @@ iscsi_conn_restore_callbacks(struct iscsi_tcp_conn *tcp_conn)
 }
 
 /**
- * iscsi_send - generic send routine
- * @sk: kernel's socket
- * @buf: buffer to write from
- * @size: actual size to write
- * @flags: socket's flags
- */
-static inline int
-iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags)
-{
-       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       struct socket *sk = tcp_conn->sock;
-       int offset = buf->sg.offset + buf->sent, res;
-
-       /*
-        * if we got use_sg=0 or are sending something we kmallocd
-        * then we did not have to do kmap (kmap returns page_address)
-        *
-        * if we got use_sg > 0, but had to drop down, we do not
-        * set clustering so this should only happen for that
-        * slab case.
-        */
-       if (buf->use_sendmsg)
-               res = sock_no_sendpage(sk, buf->sg.page, offset, size, flags);
-       else
-               res = tcp_conn->sendpage(sk, buf->sg.page, offset, size, flags);
-
-       if (res >= 0) {
-               conn->txdata_octets += res;
-               buf->sent += res;
-               return res;
-       }
-
-       tcp_conn->sendpage_failures_cnt++;
-       if (res == -EAGAIN)
-               res = -ENOBUFS;
-       else
-               iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
-       return res;
-}
-
-/**
- * iscsi_sendhdr - send PDU Header via tcp_sendpage()
- * @conn: iscsi connection
- * @buf: buffer to write from
- * @datalen: lenght of data to be sent after the header
- *
- * Notes:
- *     (Tx, Fast Path)
- **/
-static inline int
-iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen)
-{
-       int flags = 0; /* MSG_DONTWAIT; */
-       int res, size;
-
-       size = buf->sg.length - buf->sent;
-       BUG_ON(buf->sent + size > buf->sg.length);
-       if (buf->sent + size != buf->sg.length || datalen)
-               flags |= MSG_MORE;
-
-       res = iscsi_send(conn, buf, size, flags);
-       debug_tcp("sendhdr %d bytes, sent %d res %d\n", size, buf->sent, res);
-       if (res >= 0) {
-               if (size != res)
-                       return -EAGAIN;
-               return 0;
-       }
-
-       return res;
-}
-
-/**
- * iscsi_sendpage - send one page of iSCSI Data-Out.
- * @conn: iscsi connection
- * @buf: buffer to write from
- * @count: remaining data
- * @sent: number of bytes sent
- *
- * Notes:
- *     (Tx, Fast Path)
- **/
-static inline int
-iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,
-              int *count, int *sent)
-{
-       int flags = 0; /* MSG_DONTWAIT; */
-       int res, size;
-
-       size = buf->sg.length - buf->sent;
-       BUG_ON(buf->sent + size > buf->sg.length);
-       if (size > *count)
-               size = *count;
-       if (buf->sent + size != buf->sg.length || *count != size)
-               flags |= MSG_MORE;
-
-       res = iscsi_send(conn, buf, size, flags);
-       debug_tcp("sendpage: %d bytes, sent %d left %d sent %d res %d\n",
-                 size, buf->sent, *count, *sent, res);
-       if (res >= 0) {
-               *count -= res;
-               *sent += res;
-               if (size != res)
-                       return -EAGAIN;
-               return 0;
-       }
-
-       return res;
-}
-
-static inline void
-iscsi_data_digest_init(struct iscsi_tcp_conn *tcp_conn,
-                     struct iscsi_tcp_cmd_task *tcp_ctask)
-{
-       crypto_digest_init(tcp_conn->data_tx_tfm);
-       tcp_ctask->digest_count = 4;
-}
-
-/**
- * iscsi_solicit_data_cont - initialize next Data-Out
- * @conn: iscsi connection
- * @ctask: scsi command task
- * @r2t: R2T info
- * @left: bytes left to transfer
- *
- * Notes:
- *     Initialize next Data-Out within this R2T sequence and continue
- *     to process next Scatter-Gather element(if any) of this SCSI command.
- *
- *     Called under connection lock.
- **/
-static void
-iscsi_solicit_data_cont(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
-                       struct iscsi_r2t_info *r2t, int left)
-{
-       struct iscsi_data *hdr;
-       struct scsi_cmnd *sc = ctask->sc;
-       int new_offset;
-
-       hdr = &r2t->dtask.hdr;
-       memset(hdr, 0, sizeof(struct iscsi_data));
-       hdr->ttt = r2t->ttt;
-       hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
-       r2t->solicit_datasn++;
-       hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
-       memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
-       hdr->itt = ctask->hdr->itt;
-       hdr->exp_statsn = r2t->exp_statsn;
-       new_offset = r2t->data_offset + r2t->sent;
-       hdr->offset = cpu_to_be32(new_offset);
-       if (left > conn->max_xmit_dlength) {
-               hton24(hdr->dlength, conn->max_xmit_dlength);
-               r2t->data_count = conn->max_xmit_dlength;
-       } else {
-               hton24(hdr->dlength, left);
-               r2t->data_count = left;
-               hdr->flags = ISCSI_FLAG_CMD_FINAL;
-       }
-       conn->dataout_pdus_cnt++;
-
-       iscsi_buf_init_iov(&r2t->headbuf, (char*)hdr,
-                          sizeof(struct iscsi_hdr));
-
-       if (iscsi_buf_left(&r2t->sendbuf))
-               return;
-
-       if (sc->use_sg) {
-               iscsi_buf_init_sg(&r2t->sendbuf, r2t->sg);
-               r2t->sg += 1;
-       } else {
-               iscsi_buf_init_iov(&r2t->sendbuf,
-                           (char*)sc->request_buffer + new_offset,
-                           r2t->data_count);
-               r2t->sg = NULL;
-       }
-}
-
-static void iscsi_set_padding(struct iscsi_tcp_cmd_task *tcp_ctask,
-                             unsigned long len)
-{
-       tcp_ctask->pad_count = len & (ISCSI_PAD_LEN - 1);
-       if (!tcp_ctask->pad_count)
-               return;
-
-       tcp_ctask->pad_count = ISCSI_PAD_LEN - tcp_ctask->pad_count;
-       debug_scsi("write padding %d bytes\n", tcp_ctask->pad_count);
-       tcp_ctask->xmstate |= XMSTATE_W_PAD;
-}
-
-/**
- * iscsi_tcp_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
- * @conn: iscsi connection
- * @ctask: scsi command task
- * @sc: scsi command
- **/
-static void
-iscsi_tcp_cmd_init(struct iscsi_cmd_task *ctask)
-{
-       struct scsi_cmnd *sc = ctask->sc;
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-
-       BUG_ON(__kfifo_len(tcp_ctask->r2tqueue));
-
-       tcp_ctask->sent = 0;
-       tcp_ctask->sg_count = 0;
-
-       if (sc->sc_data_direction == DMA_TO_DEVICE) {
-               tcp_ctask->xmstate = XMSTATE_W_HDR;
-               tcp_ctask->exp_r2tsn = 0;
-               BUG_ON(ctask->total_length == 0);
-
-               if (sc->use_sg) {
-                       struct scatterlist *sg = sc->request_buffer;
-
-                       iscsi_buf_init_sg(&tcp_ctask->sendbuf, sg);
-                       tcp_ctask->sg = sg + 1;
-                       tcp_ctask->bad_sg = sg + sc->use_sg;
-               } else {
-                       iscsi_buf_init_iov(&tcp_ctask->sendbuf,
-                                          sc->request_buffer,
-                                          sc->request_bufflen);
-                       tcp_ctask->sg = NULL;
-                       tcp_ctask->bad_sg = NULL;
-               }
-               debug_scsi("cmd [itt 0x%x total %d imm_data %d "
-                          "unsol count %d, unsol offset %d]\n",
-                          ctask->itt, ctask->total_length, ctask->imm_count,
-                          ctask->unsol_count, ctask->unsol_offset);
-       } else
-               tcp_ctask->xmstate = XMSTATE_R_HDR;
-
-       iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)ctask->hdr,
-                           sizeof(struct iscsi_hdr));
-}
-
-/**
- * iscsi_tcp_mtask_xmit - xmit management(immediate) task
- * @conn: iscsi connection
- * @mtask: task management task
- *
- * Notes:
- *     The function can return -EAGAIN in which case caller must
- *     call it again later, or recover. '0' return code means successful
- *     xmit.
- *
- *     Management xmit state machine consists of two states:
- *             IN_PROGRESS_IMM_HEAD - PDU Header xmit in progress
- *             IN_PROGRESS_IMM_DATA - PDU Data xmit in progress
+ * iscsi_xmit - TCP transmit
  **/
 static int
-iscsi_tcp_mtask_xmit(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask)
+iscsi_xmit(struct iscsi_conn *conn)
 {
-       struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
-       int rc;
+       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+       struct iscsi_segment *segment = &tcp_conn->out.segment;
+       unsigned int consumed = 0;
+       int rc = 0;
 
-       debug_scsi("mtask deq [cid %d state %x itt 0x%x]\n",
-               conn->id, tcp_mtask->xmstate, mtask->itt);
-
-       if (tcp_mtask->xmstate & XMSTATE_IMM_HDR) {
-               tcp_mtask->xmstate &= ~XMSTATE_IMM_HDR;
-               if (mtask->data_count)
-                       tcp_mtask->xmstate |= XMSTATE_IMM_DATA;
-               if (conn->c_stage != ISCSI_CONN_INITIAL_STAGE &&
-                   conn->stop_stage != STOP_CONN_RECOVER &&
-                   conn->hdrdgst_en)
-                       iscsi_hdr_digest(conn, &tcp_mtask->headbuf,
-                                       (u8*)tcp_mtask->hdrext);
-               rc = iscsi_sendhdr(conn, &tcp_mtask->headbuf,
-                                  mtask->data_count);
-               if (rc) {
-                       tcp_mtask->xmstate |= XMSTATE_IMM_HDR;
-                       if (mtask->data_count)
-                               tcp_mtask->xmstate &= ~XMSTATE_IMM_DATA;
-                       return rc;
-               }
-       }
+       while (1) {
+               rc = iscsi_tcp_xmit_segment(tcp_conn, segment);
+               if (rc < 0)
+                       goto error;
+               if (rc == 0)
+                       break;
 
-       if (tcp_mtask->xmstate & XMSTATE_IMM_DATA) {
-               BUG_ON(!mtask->data_count);
-               tcp_mtask->xmstate &= ~XMSTATE_IMM_DATA;
-               /* FIXME: implement.
-                * Virtual buffer could be spreaded across multiple pages...
-                */
-               do {
-                       int rc;
-
-                       rc = iscsi_sendpage(conn, &tcp_mtask->sendbuf,
-                                       &mtask->data_count, &tcp_mtask->sent);
-                       if (rc) {
-                               tcp_mtask->xmstate |= XMSTATE_IMM_DATA;
-                               return rc;
+               consumed += rc;
+
+               if (segment->total_copied >= segment->total_size) {
+                       if (segment->done != NULL) {
+                               rc = segment->done(tcp_conn, segment);
+                               if (rc < 0)
+                                       goto error;
                        }
-               } while (mtask->data_count);
+               }
        }
 
-       BUG_ON(tcp_mtask->xmstate != XMSTATE_IDLE);
-       if (mtask->hdr->itt == cpu_to_be32(ISCSI_RESERVED_TAG)) {
-               struct iscsi_session *session = conn->session;
+       debug_tcp("xmit %d bytes\n", consumed);
 
-               spin_lock_bh(&session->lock);
-               list_del(&conn->mtask->running);
-               __kfifo_put(session->mgmtpool.queue, (void*)&conn->mtask,
-                           sizeof(void*));
-               spin_unlock_bh(&session->lock);
-       }
-       return 0;
+       conn->txdata_octets += consumed;
+       return consumed;
+
+error:
+       /* Transmit error. We could initiate error recovery
+        * here. */
+       debug_tcp("Error sending PDU, errno=%d\n", rc);
+       iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+       return rc;
 }
 
+/**
+ * iscsi_tcp_xmit_qlen - return the number of bytes queued for xmit
+ */
 static inline int
-iscsi_send_read_hdr(struct iscsi_conn *conn,
-                   struct iscsi_tcp_cmd_task *tcp_ctask)
+iscsi_tcp_xmit_qlen(struct iscsi_conn *conn)
 {
-       int rc;
+       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+       struct iscsi_segment *segment = &tcp_conn->out.segment;
 
-       tcp_ctask->xmstate &= ~XMSTATE_R_HDR;
-       if (conn->hdrdgst_en)
-               iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
-                                (u8*)tcp_ctask->hdrext);
-       rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, 0);
-       if (!rc) {
-               BUG_ON(tcp_ctask->xmstate != XMSTATE_IDLE);
-               return 0; /* wait for Data-In */
-       }
-       tcp_ctask->xmstate |= XMSTATE_R_HDR;
-       return rc;
+       return segment->total_copied - segment->total_size;
 }
 
 static inline int
-iscsi_send_write_hdr(struct iscsi_conn *conn,
-                    struct iscsi_cmd_task *ctask)
+iscsi_tcp_flush(struct iscsi_conn *conn)
 {
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
        int rc;
 
-       tcp_ctask->xmstate &= ~XMSTATE_W_HDR;
-       if (conn->hdrdgst_en)
-               iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
-                                (u8*)tcp_ctask->hdrext);
-       rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->imm_count);
-       if (rc) {
-               tcp_ctask->xmstate |= XMSTATE_W_HDR;
-               return rc;
-       }
-
-       if (ctask->imm_count) {
-               tcp_ctask->xmstate |= XMSTATE_IMM_DATA;
-               iscsi_set_padding(tcp_ctask, ctask->imm_count);
-
-               if (ctask->conn->datadgst_en) {
-                       iscsi_data_digest_init(ctask->conn->dd_data, tcp_ctask);
-                       tcp_ctask->immdigest = 0;
-               }
+       while (iscsi_tcp_xmit_qlen(conn)) {
+               rc = iscsi_xmit(conn);
+               if (rc == 0)
+                       return -EAGAIN;
+               if (rc < 0)
+                       return rc;
        }
 
-       if (ctask->unsol_count)
-               tcp_ctask->xmstate |= XMSTATE_UNS_HDR | XMSTATE_UNS_INIT;
        return 0;
 }
 
+/*
+ * This is called when we're done sending the header.
+ * Simply copy the data_segment to the send segment, and return.
+ */
 static int
-iscsi_send_padding(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+iscsi_tcp_send_hdr_done(struct iscsi_tcp_conn *tcp_conn,
+                       struct iscsi_segment *segment)
 {
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       int sent = 0, rc;
-
-       if (tcp_ctask->xmstate & XMSTATE_W_PAD) {
-               iscsi_buf_init_iov(&tcp_ctask->sendbuf, (char*)&tcp_ctask->pad,
-                                  tcp_ctask->pad_count);
-               if (conn->datadgst_en)
-                       crypto_digest_update(tcp_conn->data_tx_tfm,
-                                            &tcp_ctask->sendbuf.sg, 1);
-       } else if (!(tcp_ctask->xmstate & XMSTATE_W_RESEND_PAD))
-               return 0;
-
-       tcp_ctask->xmstate &= ~XMSTATE_W_PAD;
-       tcp_ctask->xmstate &= ~XMSTATE_W_RESEND_PAD;
-       debug_scsi("sending %d pad bytes for itt 0x%x\n",
-                  tcp_ctask->pad_count, ctask->itt);
-       rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf, &tcp_ctask->pad_count,
-                          &sent);
-       if (rc) {
-               debug_scsi("padding send failed %d\n", rc);
-               tcp_ctask->xmstate |= XMSTATE_W_RESEND_PAD;
-       }
-       return rc;
+       tcp_conn->out.segment = tcp_conn->out.data_segment;
+       debug_tcp("Header done. Next segment size %u total_size %u\n",
+                 tcp_conn->out.segment.size, tcp_conn->out.segment.total_size);
+       return 0;
 }
 
-static int
-iscsi_send_digest(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
-                       struct iscsi_buf *buf, uint32_t *digest)
+static void
+iscsi_tcp_send_hdr_prep(struct iscsi_conn *conn, void *hdr, size_t hdrlen)
 {
-       struct iscsi_tcp_cmd_task *tcp_ctask;
-       struct iscsi_tcp_conn *tcp_conn;
-       int rc, sent = 0;
+       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 
-       if (!conn->datadgst_en)
-               return 0;
+       debug_tcp("%s(%p%s)\n", __func__, tcp_conn,
+                       conn->hdrdgst_en? ", digest enabled" : "");
 
-       tcp_ctask = ctask->dd_data;
-       tcp_conn = conn->dd_data;
+       /* Clear the data segment - needs to be filled in by the
+        * caller using iscsi_tcp_send_data_prep() */
+       memset(&tcp_conn->out.data_segment, 0, sizeof(struct iscsi_segment));
 
-       if (!(tcp_ctask->xmstate & XMSTATE_W_RESEND_DATA_DIGEST)) {
-               crypto_digest_final(tcp_conn->data_tx_tfm, (u8*)digest);
-               iscsi_buf_init_iov(buf, (char*)digest, 4);
-       }
-       tcp_ctask->xmstate &= ~XMSTATE_W_RESEND_DATA_DIGEST;
-
-       rc = iscsi_sendpage(conn, buf, &tcp_ctask->digest_count, &sent);
-       if (!rc)
-               debug_scsi("sent digest 0x%x for itt 0x%x\n", *digest,
-                         ctask->itt);
-       else {
-               debug_scsi("sending digest 0x%x failed for itt 0x%x!\n",
-                         *digest, ctask->itt);
-               tcp_ctask->xmstate |= XMSTATE_W_RESEND_DATA_DIGEST;
+       /* If header digest is enabled, compute the CRC and
+        * place the digest into the same buffer. We make
+        * sure that both iscsi_tcp_task and mtask have
+        * sufficient room.
+        */
+       if (conn->hdrdgst_en) {
+               iscsi_tcp_dgst_header(&tcp_conn->tx_hash, hdr, hdrlen,
+                                     hdr + hdrlen);
+               hdrlen += ISCSI_DIGEST_SIZE;
        }
-       return rc;
+
+       /* Remember header pointer for later, when we need
+        * to decide whether there's a payload to go along
+        * with the header. */
+       tcp_conn->out.hdr = hdr;
+
+       iscsi_segment_init_linear(&tcp_conn->out.segment, hdr, hdrlen,
+                               iscsi_tcp_send_hdr_done, NULL);
 }
 
+/*
+ * Prepare the send buffer for the payload data.
+ * Padding and checksumming will all be taken care
+ * of by the iscsi_segment routines.
+ */
 static int
-iscsi_send_data(struct iscsi_cmd_task *ctask, struct iscsi_buf *sendbuf,
-               struct scatterlist **sg, int *sent, int *count,
-               struct iscsi_buf *digestbuf, uint32_t *digest)
+iscsi_tcp_send_data_prep(struct iscsi_conn *conn, struct scatterlist *sg,
+                        unsigned int count, unsigned int offset,
+                        unsigned int len)
 {
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-       struct iscsi_conn *conn = ctask->conn;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       int rc, buf_sent, offset;
-
-       while (*count) {
-               buf_sent = 0;
-               offset = sendbuf->sent;
-
-               rc = iscsi_sendpage(conn, sendbuf, count, &buf_sent);
-               *sent = *sent + buf_sent;
-               if (buf_sent && conn->datadgst_en)
-                       partial_sg_digest_update(tcp_conn->data_tx_tfm,
-                               &sendbuf->sg, sendbuf->sg.offset + offset,
-                               buf_sent);
-               if (!iscsi_buf_left(sendbuf) && *sg != tcp_ctask->bad_sg) {
-                       iscsi_buf_init_sg(sendbuf, *sg);
-                       *sg = *sg + 1;
-               }
+       struct hash_desc *tx_hash = NULL;
+       unsigned int hdr_spec_len;
 
-               if (rc)
-                       return rc;
-       }
+       debug_tcp("%s(%p, offset=%d, datalen=%d%s)\n", __func__,
+                       tcp_conn, offset, len,
+                       conn->datadgst_en? ", digest enabled" : "");
 
-       rc = iscsi_send_padding(conn, ctask);
-       if (rc)
-               return rc;
+       /* Make sure the datalen matches what the caller
+          said he would send. */
+       hdr_spec_len = ntoh24(tcp_conn->out.hdr->dlength);
+       WARN_ON(iscsi_padded(len) != iscsi_padded(hdr_spec_len));
 
-       return iscsi_send_digest(conn, ctask, digestbuf, digest);
+       if (conn->datadgst_en)
+               tx_hash = &tcp_conn->tx_hash;
+
+       return iscsi_segment_seek_sg(&tcp_conn->out.data_segment,
+                                  sg, count, offset, len,
+                                  NULL, tx_hash);
 }
 
-static int
-iscsi_send_unsol_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+static void
+iscsi_tcp_send_linear_data_prepare(struct iscsi_conn *conn, void *data,
+                                  size_t len)
 {
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-       struct iscsi_data_task *dtask;
-       int rc;
+       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+       struct hash_desc *tx_hash = NULL;
+       unsigned int hdr_spec_len;
 
-       tcp_ctask->xmstate |= XMSTATE_UNS_DATA;
-       if (tcp_ctask->xmstate & XMSTATE_UNS_INIT) {
-               dtask = &tcp_ctask->unsol_dtask;
-
-               iscsi_prep_unsolicit_data_pdu(ctask, &dtask->hdr);
-               iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)&dtask->hdr,
-                                  sizeof(struct iscsi_hdr));
-               if (conn->hdrdgst_en)
-                       iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
-                                       (u8*)dtask->hdrext);
-               if (conn->datadgst_en) {
-                       iscsi_data_digest_init(ctask->conn->dd_data, tcp_ctask);
-                       dtask->digest = 0;
-               }
+       debug_tcp("%s(%p, datalen=%d%s)\n", __func__, tcp_conn, len,
+                 conn->datadgst_en? ", digest enabled" : "");
 
-               tcp_ctask->xmstate &= ~XMSTATE_UNS_INIT;
-               iscsi_set_padding(tcp_ctask, ctask->data_count);
-       }
+       /* Make sure the datalen matches what the caller
+          said he would send. */
+       hdr_spec_len = ntoh24(tcp_conn->out.hdr->dlength);
+       WARN_ON(iscsi_padded(len) != iscsi_padded(hdr_spec_len));
 
-       rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->data_count);
-       if (rc) {
-               tcp_ctask->xmstate &= ~XMSTATE_UNS_DATA;
-               tcp_ctask->xmstate |= XMSTATE_UNS_HDR;
-               return rc;
-       }
+       if (conn->datadgst_en)
+               tx_hash = &tcp_conn->tx_hash;
 
-       debug_scsi("uns dout [itt 0x%x dlen %d sent %d]\n",
-                  ctask->itt, ctask->unsol_count, tcp_ctask->sent);
-       return 0;
+       iscsi_segment_init_linear(&tcp_conn->out.data_segment,
+                               data, len, NULL, tx_hash);
 }
 
+/**
+ * iscsi_solicit_data_cont - initialize next Data-Out
+ * @conn: iscsi connection
+ * @task: scsi command task
+ * @r2t: R2T info
+ * @left: bytes left to transfer
+ *
+ * Notes:
+ *     Initialize next Data-Out within this R2T sequence and continue
+ *     to process next Scatter-Gather element(if any) of this SCSI command.
+ *
+ *     Called under connection lock.
+ **/
 static int
-iscsi_send_unsol_pdu(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+iscsi_solicit_data_cont(struct iscsi_conn *conn, struct iscsi_task *task,
+                       struct iscsi_r2t_info *r2t)
 {
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-       int rc;
+       struct iscsi_data *hdr;
+       int new_offset, left;
 
-       if (tcp_ctask->xmstate & XMSTATE_UNS_HDR) {
-               BUG_ON(!ctask->unsol_count);
-               tcp_ctask->xmstate &= ~XMSTATE_UNS_HDR;
-send_hdr:
-               rc = iscsi_send_unsol_hdr(conn, ctask);
-               if (rc)
-                       return rc;
+       BUG_ON(r2t->data_length - r2t->sent < 0);
+       left = r2t->data_length - r2t->sent;
+       if (left == 0)
+               return 0;
+
+       hdr = &r2t->dtask.hdr;
+       memset(hdr, 0, sizeof(struct iscsi_data));
+       hdr->ttt = r2t->ttt;
+       hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
+       r2t->solicit_datasn++;
+       hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
+       memcpy(hdr->lun, task->hdr->lun, sizeof(hdr->lun));
+       hdr->itt = task->hdr->itt;
+       hdr->exp_statsn = r2t->exp_statsn;
+       new_offset = r2t->data_offset + r2t->sent;
+       hdr->offset = cpu_to_be32(new_offset);
+       if (left > conn->max_xmit_dlength) {
+               hton24(hdr->dlength, conn->max_xmit_dlength);
+               r2t->data_count = conn->max_xmit_dlength;
+       } else {
+               hton24(hdr->dlength, left);
+               r2t->data_count = left;
+               hdr->flags = ISCSI_FLAG_CMD_FINAL;
        }
 
-       if (tcp_ctask->xmstate & XMSTATE_UNS_DATA) {
-               struct iscsi_data_task *dtask = &tcp_ctask->unsol_dtask;
-               int start = tcp_ctask->sent;
+       conn->dataout_pdus_cnt++;
+       return 1;
+}
 
-               rc = iscsi_send_data(ctask, &tcp_ctask->sendbuf, &tcp_ctask->sg,
-                                    &tcp_ctask->sent, &ctask->data_count,
-                                    &dtask->digestbuf, &dtask->digest);
-               ctask->unsol_count -= tcp_ctask->sent - start;
-               if (rc)
-                       return rc;
-               tcp_ctask->xmstate &= ~XMSTATE_UNS_DATA;
+/**
+ * iscsi_tcp_task - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
+ * @conn: iscsi connection
+ * @task: scsi command task
+ * @sc: scsi command
+ **/
+static int
+iscsi_tcp_task_init(struct iscsi_task *task)
+{
+       struct iscsi_tcp_task *tcp_task = task->dd_data;
+       struct iscsi_conn *conn = task->conn;
+       struct scsi_cmnd *sc = task->sc;
+       int err;
+
+       if (!sc) {
                /*
-                * Done with the Data-Out. Next, check if we need
-                * to send another unsolicited Data-Out.
+                * mgmt tasks do not have a scatterlist since they come
+                * in from the iscsi interface.
                 */
-               if (ctask->unsol_count) {
-                       debug_scsi("sending more uns\n");
-                       tcp_ctask->xmstate |= XMSTATE_UNS_INIT;
-                       goto send_hdr;
-               }
+               debug_scsi("mtask deq [cid %d itt 0x%x]\n", conn->id,
+                          task->itt);
+
+               /* Prepare PDU, optionally w/ immediate data */
+               iscsi_tcp_send_hdr_prep(conn, task->hdr, sizeof(*task->hdr));
+
+               /* If we have immediate data, attach a payload */
+               if (task->data_count)
+                       iscsi_tcp_send_linear_data_prepare(conn, task->data,
+                                                          task->data_count);
+               return 0;
        }
+
+       BUG_ON(__kfifo_len(tcp_task->r2tqueue));
+       tcp_task->sent = 0;
+       tcp_task->exp_datasn = 0;
+
+       /* Prepare PDU, optionally w/ immediate data */
+       debug_scsi("task deq [cid %d itt 0x%x imm %d unsol %d]\n",
+                   conn->id, task->itt, task->imm_count,
+                   task->unsol_count);
+       iscsi_tcp_send_hdr_prep(conn, task->hdr, task->hdr_len);
+
+       if (!task->imm_count)
+               return 0;
+
+       /* If we have immediate data, attach a payload */
+       err = iscsi_tcp_send_data_prep(conn, scsi_out(sc)->table.sgl,
+                                      scsi_out(sc)->table.nents,
+                                      0, task->imm_count);
+       if (err)
+               return err;
+       tcp_task->sent += task->imm_count;
+       task->imm_count = 0;
        return 0;
 }
 
-static int iscsi_send_sol_pdu(struct iscsi_conn *conn,
-                             struct iscsi_cmd_task *ctask)
+/*
+ * iscsi_tcp_task_xmit - xmit normal PDU task
+ * @task: iscsi command task
+ *
+ * We're expected to return 0 when everything was transmitted succesfully,
+ * -EAGAIN if there's still data in the queue, or != 0 for any other kind
+ * of error.
+ */
+static int
+iscsi_tcp_task_xmit(struct iscsi_task *task)
 {
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-       struct iscsi_session *session = conn->session;
-       struct iscsi_r2t_info *r2t;
-       struct iscsi_data_task *dtask;
-       int left, rc;
-
-       if (tcp_ctask->xmstate & XMSTATE_SOL_HDR) {
-               tcp_ctask->xmstate &= ~XMSTATE_SOL_HDR;
-               tcp_ctask->xmstate |= XMSTATE_SOL_DATA;
-               if (!tcp_ctask->r2t)
-                       __kfifo_get(tcp_ctask->r2tqueue, (void*)&tcp_ctask->r2t,
-                                   sizeof(void*));
-send_hdr:
-               r2t = tcp_ctask->r2t;
-               dtask = &r2t->dtask;
+       struct iscsi_conn *conn = task->conn;
+       struct iscsi_tcp_task *tcp_task = task->dd_data;
+       struct scsi_cmnd *sc = task->sc;
+       struct scsi_data_buffer *sdb;
+       int rc = 0;
 
-               if (conn->hdrdgst_en)
-                       iscsi_hdr_digest(conn, &r2t->headbuf,
-                                       (u8*)dtask->hdrext);
+flush:
+       /* Flush any pending data first. */
+       rc = iscsi_tcp_flush(conn);
+       if (rc < 0)
+               return rc;
 
-               if (conn->datadgst_en) {
-                       iscsi_data_digest_init(conn->dd_data, tcp_ctask);
-                       dtask->digest = 0;
-               }
+       /* mgmt command */
+       if (!sc) {
+               if (task->hdr->itt == RESERVED_ITT)
+                       iscsi_put_task(task);
+               return 0;
+       }
 
-               rc = iscsi_sendhdr(conn, &r2t->headbuf, r2t->data_count);
-               if (rc) {
-                       tcp_ctask->xmstate &= ~XMSTATE_SOL_DATA;
-                       tcp_ctask->xmstate |= XMSTATE_SOL_HDR;
-                       return rc;
-               }
+       /* Are we done already? */
+       if (sc->sc_data_direction != DMA_TO_DEVICE)
+               return 0;
 
-               iscsi_set_padding(tcp_ctask, r2t->data_count);
-               debug_scsi("sol dout [dsn %d itt 0x%x dlen %d sent %d]\n",
-                       r2t->solicit_datasn - 1, ctask->itt, r2t->data_count,
-                       r2t->sent);
-       }
+       sdb = scsi_out(sc);
+       if (task->unsol_count != 0) {
+               struct iscsi_data *hdr = &tcp_task->unsol_dtask.hdr;
+
+               /* Prepare a header for the unsolicited PDU.
+                * The amount of data we want to send will be
+                * in task->data_count.
+                * FIXME: return the data count instead.
+                */
+               iscsi_prep_unsolicit_data_pdu(task, hdr);
 
-       if (tcp_ctask->xmstate & XMSTATE_SOL_DATA) {
-               r2t = tcp_ctask->r2t;
-               dtask = &r2t->dtask;
+               debug_tcp("unsol dout [itt 0x%x doff %d dlen %d]\n",
+                               task->itt, tcp_task->sent, task->data_count);
 
-               rc = iscsi_send_data(ctask, &r2t->sendbuf, &r2t->sg,
-                                    &r2t->sent, &r2t->data_count,
-                                    &dtask->digestbuf, &dtask->digest);
+               iscsi_tcp_send_hdr_prep(conn, hdr, sizeof(*hdr));
+               rc = iscsi_tcp_send_data_prep(conn, sdb->table.sgl,
+                                             sdb->table.nents, tcp_task->sent,
+                                             task->data_count);
                if (rc)
-                       return rc;
-               tcp_ctask->xmstate &= ~XMSTATE_SOL_DATA;
+                       goto fail;
+               tcp_task->sent += task->data_count;
+               task->unsol_count -= task->data_count;
+               goto flush;
+       } else {
+               struct iscsi_session *session = conn->session;
+               struct iscsi_r2t_info *r2t;
 
-               /*
-                * Done with this Data-Out. Next, check if we have
-                * to send another Data-Out for this R2T.
+               /* All unsolicited PDUs sent. Check for solicited PDUs.
                 */
-               BUG_ON(r2t->data_length - r2t->sent < 0);
-               left = r2t->data_length - r2t->sent;
-               if (left) {
-                       iscsi_solicit_data_cont(conn, ctask, r2t, left);
-                       tcp_ctask->xmstate |= XMSTATE_SOL_DATA;
-                       tcp_ctask->xmstate &= ~XMSTATE_SOL_HDR;
-                       goto send_hdr;
+               spin_lock_bh(&session->lock);
+               r2t = tcp_task->r2t;
+               if (r2t != NULL) {
+                       /* Continue with this R2T? */
+                       if (!iscsi_solicit_data_cont(conn, task, r2t)) {
+                               debug_scsi("  done with r2t %p\n", r2t);
+
+                               __kfifo_put(tcp_task->r2tpool.queue,
+                                           (void*)&r2t, sizeof(void*));
+                               tcp_task->r2t = r2t = NULL;
+                       }
                }
 
-               /*
-                * Done with this R2T. Check if there are more
-                * outstanding R2Ts ready to be processed.
-                */
-               spin_lock_bh(&session->lock);
-               tcp_ctask->r2t = NULL;
-               __kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t,
-                           sizeof(void*));
-               if (__kfifo_get(tcp_ctask->r2tqueue, (void*)&r2t,
-                               sizeof(void*))) {
-                       tcp_ctask->r2t = r2t;
-                       tcp_ctask->xmstate |= XMSTATE_SOL_DATA;
-                       tcp_ctask->xmstate &= ~XMSTATE_SOL_HDR;
-                       spin_unlock_bh(&session->lock);
-                       goto send_hdr;
+               if (r2t == NULL) {
+                       __kfifo_get(tcp_task->r2tqueue, (void*)&tcp_task->r2t,
+                                   sizeof(void*));
+                       r2t = tcp_task->r2t;
                }
                spin_unlock_bh(&session->lock);
-       }
-       return 0;
-}
-
-static int
-iscsi_tcp_ctask_xmit(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
-{
-       struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-       int rc = 0;
-
-       debug_scsi("ctask deq [cid %d xmstate %x itt 0x%x]\n",
-               conn->id, tcp_ctask->xmstate, ctask->itt);
 
-       /*
-        * serialize with TMF AbortTask
-        */
-       if (ctask->mtask)
-               return rc;
+               /* Waiting for more R2Ts to arrive. */
+               if (r2t == NULL) {
+                       debug_tcp("no R2Ts yet\n");
+                       return 0;
+               }
 
-       if (tcp_ctask->xmstate & XMSTATE_R_HDR)
-               return iscsi_send_read_hdr(conn, tcp_ctask);
+               debug_scsi("sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
+                       r2t, r2t->solicit_datasn - 1, task->itt,
+                       r2t->data_offset + r2t->sent, r2t->data_count);
 
-       if (tcp_ctask->xmstate & XMSTATE_W_HDR) {
-               rc = iscsi_send_write_hdr(conn, ctask);
-               if (rc)
-                       return rc;
-       }
+               iscsi_tcp_send_hdr_prep(conn, &r2t->dtask.hdr,
+                                       sizeof(struct iscsi_hdr));
 
-       if (tcp_ctask->xmstate & XMSTATE_IMM_DATA) {
-               rc = iscsi_send_data(ctask, &tcp_ctask->sendbuf, &tcp_ctask->sg,
-                                    &tcp_ctask->sent, &ctask->imm_count,
-                                    &tcp_ctask->immbuf, &tcp_ctask->immdigest);
+               rc = iscsi_tcp_send_data_prep(conn, sdb->table.sgl,
+                                             sdb->table.nents,
+                                             r2t->data_offset + r2t->sent,
+                                             r2t->data_count);
                if (rc)
-                       return rc;
-               tcp_ctask->xmstate &= ~XMSTATE_IMM_DATA;
+                       goto fail;
+               tcp_task->sent += r2t->data_count;
+               r2t->sent += r2t->data_count;
+               goto flush;
        }
-
-       rc = iscsi_send_unsol_pdu(conn, ctask);
-       if (rc)
-               return rc;
-
-       rc = iscsi_send_sol_pdu(conn, ctask);
-       if (rc)
-               return rc;
-
-       return rc;
+       return 0;
+fail:
+       iscsi_conn_failure(conn, rc);
+       return -EIO;
 }
 
 static struct iscsi_cls_conn *
@@ -1744,7 +1479,7 @@ iscsi_tcp_conn_create(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
        struct iscsi_cls_conn *cls_conn;
        struct iscsi_tcp_conn *tcp_conn;
 
-       cls_conn = iscsi_conn_setup(cls_session, conn_idx);
+       cls_conn = iscsi_conn_setup(cls_session, sizeof(*tcp_conn), conn_idx);
        if (!cls_conn)
                return NULL;
        conn = cls_conn->dd_data;
@@ -1752,21 +1487,33 @@ iscsi_tcp_conn_create(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
         * due to strange issues with iser these are not set
         * in iscsi_conn_setup
         */
-       conn->max_recv_dlength = DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH;
+       conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
 
-       tcp_conn = kzalloc(sizeof(*tcp_conn), GFP_KERNEL);
-       if (!tcp_conn)
-               goto tcp_conn_alloc_fail;
-
-       conn->dd_data = tcp_conn;
+       tcp_conn = conn->dd_data;
        tcp_conn->iscsi_conn = conn;
-       tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
-       /* initial operational parameters */
-       tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
+
+       tcp_conn->tx_hash.tfm = crypto_alloc_hash("crc32c", 0,
+                                                 CRYPTO_ALG_ASYNC);
+       tcp_conn->tx_hash.flags = 0;
+       if (IS_ERR(tcp_conn->tx_hash.tfm))
+               goto free_conn;
+
+       tcp_conn->rx_hash.tfm = crypto_alloc_hash("crc32c", 0,
+                                                 CRYPTO_ALG_ASYNC);
+       tcp_conn->rx_hash.flags = 0;
+       if (IS_ERR(tcp_conn->rx_hash.tfm))
+               goto free_tx_tfm;
 
        return cls_conn;
 
-tcp_conn_alloc_fail:
+free_tx_tfm:
+       crypto_free_hash(tcp_conn->tx_hash.tfm);
+free_conn:
+       iscsi_conn_printk(KERN_ERR, conn,
+                         "Could not create connection due to crc32c "
+                         "loading error. Make sure the crc32c "
+                         "module is built as a module or into the "
+                         "kernel\n");
        iscsi_conn_teardown(cls_conn);
        return NULL;
 }
@@ -1774,18 +1521,21 @@ tcp_conn_alloc_fail:
 static void
 iscsi_tcp_release_conn(struct iscsi_conn *conn)
 {
+       struct iscsi_session *session = conn->session;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+       struct socket *sock = tcp_conn->sock;
 
-       if (!tcp_conn->sock)
+       if (!sock)
                return;
 
-       sock_hold(tcp_conn->sock->sk);
+       sock_hold(sock->sk);
        iscsi_conn_restore_callbacks(tcp_conn);
-       sock_put(tcp_conn->sock->sk);
+       sock_put(sock->sk);
 
-       sock_release(tcp_conn->sock);
+       spin_lock_bh(&session->lock);
        tcp_conn->sock = NULL;
-       conn->recv_lock = NULL;
+       spin_unlock_bh(&session->lock);
+       sockfd_put(sock);
 }
 
 static void
@@ -1793,43 +1543,86 @@ iscsi_tcp_conn_destroy(struct iscsi_cls_conn *cls_conn)
 {
        struct iscsi_conn *conn = cls_conn->dd_data;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       int digest = 0;
-
-       if (conn->hdrdgst_en || conn->datadgst_en)
-               digest = 1;
 
        iscsi_tcp_release_conn(conn);
-       iscsi_conn_teardown(cls_conn);
 
-       /* now free tcp_conn */
-       if (digest) {
-               if (tcp_conn->tx_tfm)
-                       crypto_free_tfm(tcp_conn->tx_tfm);
-               if (tcp_conn->rx_tfm)
-                       crypto_free_tfm(tcp_conn->rx_tfm);
-               if (tcp_conn->data_tx_tfm)
-                       crypto_free_tfm(tcp_conn->data_tx_tfm);
-               if (tcp_conn->data_rx_tfm)
-                       crypto_free_tfm(tcp_conn->data_rx_tfm);
-       }
+       if (tcp_conn->tx_hash.tfm)
+               crypto_free_hash(tcp_conn->tx_hash.tfm);
+       if (tcp_conn->rx_hash.tfm)
+               crypto_free_hash(tcp_conn->rx_hash.tfm);
 
-       kfree(tcp_conn);
+       iscsi_conn_teardown(cls_conn);
 }
 
 static void
 iscsi_tcp_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
 {
        struct iscsi_conn *conn = cls_conn->dd_data;
+       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+
+       /* userspace may have goofed up and not bound us */
+       if (!tcp_conn->sock)
+               return;
+       /*
+        * Make sure our recv side is stopped.
+        * Older tools called conn stop before ep_disconnect
+        * so IO could still be coming in.
+        */
+       write_lock_bh(&tcp_conn->sock->sk->sk_callback_lock);
+       set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
+       write_unlock_bh(&tcp_conn->sock->sk->sk_callback_lock);
 
        iscsi_conn_stop(cls_conn, flag);
        iscsi_tcp_release_conn(conn);
 }
 
+static int iscsi_tcp_get_addr(struct iscsi_conn *conn, struct socket *sock,
+                             char *buf, int *port,
+                             int (*getname)(struct socket *, struct sockaddr *,
+                                       int *addrlen))
+{
+       struct sockaddr_storage *addr;
+       struct sockaddr_in6 *sin6;
+       struct sockaddr_in *sin;
+       int rc = 0, len;
+
+       addr = kmalloc(sizeof(*addr), GFP_KERNEL);
+       if (!addr)
+               return -ENOMEM;
+
+       if (getname(sock, (struct sockaddr *) addr, &len)) {
+               rc = -ENODEV;
+               goto free_addr;
+       }
+
+       switch (addr->ss_family) {
+       case AF_INET:
+               sin = (struct sockaddr_in *)addr;
+               spin_lock_bh(&conn->session->lock);
+               sprintf(buf, NIPQUAD_FMT, NIPQUAD(sin->sin_addr.s_addr));
+               *port = be16_to_cpu(sin->sin_port);
+               spin_unlock_bh(&conn->session->lock);
+               break;
+       case AF_INET6:
+               sin6 = (struct sockaddr_in6 *)addr;
+               spin_lock_bh(&conn->session->lock);
+               sprintf(buf, NIP6_FMT, NIP6(sin6->sin6_addr));
+               *port = be16_to_cpu(sin6->sin6_port);
+               spin_unlock_bh(&conn->session->lock);
+               break;
+       }
+free_addr:
+       kfree(addr);
+       return rc;
+}
+
 static int
 iscsi_tcp_conn_bind(struct iscsi_cls_session *cls_session,
                    struct iscsi_cls_conn *cls_conn, uint64_t transport_eph,
                    int is_leading)
 {
+       struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
+       struct iscsi_host *ihost = shost_priv(shost);
        struct iscsi_conn *conn = cls_conn->dd_data;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct sock *sk;
@@ -1839,13 +1632,28 @@ iscsi_tcp_conn_bind(struct iscsi_cls_session *cls_session,
        /* lookup for existing socket */
        sock = sockfd_lookup((int)transport_eph, &err);
        if (!sock) {
-               printk(KERN_ERR "iscsi_tcp: sockfd_lookup failed %d\n", err);
+               iscsi_conn_printk(KERN_ERR, conn,
+                                 "sockfd_lookup failed %d\n", err);
                return -EEXIST;
        }
+       /*
+        * copy these values now because if we drop the session
+        * userspace may still want to query the values since we will
+        * be using them for the reconnect
+        */
+       err = iscsi_tcp_get_addr(conn, sock, conn->portal_address,
+                                &conn->portal_port, kernel_getpeername);
+       if (err)
+               goto free_socket;
+
+       err = iscsi_tcp_get_addr(conn, sock, ihost->local_address,
+                               &ihost->local_port, kernel_getsockname);
+       if (err)
+               goto free_socket;
 
        err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
        if (err)
-               return err;
+               goto free_socket;
 
        /* bind iSCSI connection and socket */
        tcp_conn->sock = sock;
@@ -1856,38 +1664,17 @@ iscsi_tcp_conn_bind(struct iscsi_cls_session *cls_session,
        sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
        sk->sk_allocation = GFP_ATOMIC;
 
-       /* FIXME: disable Nagle's algorithm */
-
-       /*
-        * Intercept TCP callbacks for sendfile like receive
-        * processing.
-        */
-       conn->recv_lock = &sk->sk_callback_lock;
        iscsi_conn_set_callbacks(conn);
        tcp_conn->sendpage = tcp_conn->sock->ops->sendpage;
        /*
         * set receive state machine into initial state
         */
-       tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
-
+       iscsi_tcp_hdr_recv_prep(tcp_conn);
        return 0;
-}
-
-/* called with host lock */
-static void
-iscsi_tcp_mgmt_init(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask,
-                   char *data, uint32_t data_size)
-{
-       struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
-
-       iscsi_buf_init_iov(&tcp_mtask->headbuf, (char*)mtask->hdr,
-                          sizeof(struct iscsi_hdr));
-       tcp_mtask->xmstate = XMSTATE_IMM_HDR;
-       tcp_mtask->sent = 0;
 
-       if (mtask->data_count)
-               iscsi_buf_init_iov(&tcp_mtask->sendbuf, (char*)mtask->data,
-                                   mtask->data_count);
+free_socket:
+       sockfd_put(sock);
+       return err;
 }
 
 static int
@@ -1900,8 +1687,8 @@ iscsi_r2tpool_alloc(struct iscsi_session *session)
         * initialize per-task: R2T pool and xmit queue
         */
        for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
-               struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
-               struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
+               struct iscsi_task *task = session->cmds[cmd_i];
+               struct iscsi_tcp_task *tcp_task = task->dd_data;
 
                /*
                 * pre-allocated x4 as much r2ts to handle race when
@@ -1910,18 +1697,16 @@ iscsi_r2tpool_alloc(struct iscsi_session *session)
                 */
 
                /* R2T pool */
-               if (iscsi_pool_init(&tcp_ctask->r2tpool, session->max_r2t * 4,
-                                   (void***)&tcp_ctask->r2ts,
+               if (iscsi_pool_init(&tcp_task->r2tpool, session->max_r2t * 4, NULL,
                                    sizeof(struct iscsi_r2t_info))) {
                        goto r2t_alloc_fail;
                }
 
                /* R2T xmit queue */
-               tcp_ctask->r2tqueue = kfifo_alloc(
+               tcp_task->r2tqueue = kfifo_alloc(
                      session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
-               if (tcp_ctask->r2tqueue == ERR_PTR(-ENOMEM)) {
-                       iscsi_pool_free(&tcp_ctask->r2tpool,
-                                       (void**)tcp_ctask->r2ts);
+               if (tcp_task->r2tqueue == ERR_PTR(-ENOMEM)) {
+                       iscsi_pool_free(&tcp_task->r2tpool);
                        goto r2t_alloc_fail;
                }
        }
@@ -1930,12 +1715,11 @@ iscsi_r2tpool_alloc(struct iscsi_session *session)
 
 r2t_alloc_fail:
        for (i = 0; i < cmd_i; i++) {
-               struct iscsi_cmd_task *ctask = session->cmds[i];
-               struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
+               struct iscsi_task *task = session->cmds[i];
+               struct iscsi_tcp_task *tcp_task = task->dd_data;
 
-               kfifo_free(tcp_ctask->r2tqueue);
-               iscsi_pool_free(&tcp_ctask->r2tpool,
-                               (void**)tcp_ctask->r2ts);
+               kfifo_free(tcp_task->r2tqueue);
+               iscsi_pool_free(&tcp_task->r2tpool);
        }
        return -ENOMEM;
 }
@@ -1946,12 +1730,11 @@ iscsi_r2tpool_free(struct iscsi_session *session)
        int i;
 
        for (i = 0; i < session->cmds_max; i++) {
-               struct iscsi_cmd_task *ctask = session->cmds[i];
-               struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
+               struct iscsi_task *task = session->cmds[i];
+               struct iscsi_tcp_task *tcp_task = task->dd_data;
 
-               kfifo_free(tcp_ctask->r2tqueue);
-               iscsi_pool_free(&tcp_ctask->r2tpool,
-                               (void**)tcp_ctask->r2ts);
+               kfifo_free(tcp_task->r2tqueue);
+               iscsi_pool_free(&tcp_task->r2tpool);
        }
 }
 
@@ -1967,60 +1750,20 @@ iscsi_conn_set_param(struct iscsi_cls_conn *cls_conn, enum iscsi_param param,
        switch(param) {
        case ISCSI_PARAM_HDRDGST_EN:
                iscsi_set_param(cls_conn, param, buf, buflen);
-               tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
-               if (conn->hdrdgst_en) {
-                       tcp_conn->hdr_size += sizeof(__u32);
-                       if (!tcp_conn->tx_tfm)
-                               tcp_conn->tx_tfm = crypto_alloc_tfm("crc32c",
-                                                                   0);
-                       if (!tcp_conn->tx_tfm)
-                               return -ENOMEM;
-                       if (!tcp_conn->rx_tfm)
-                               tcp_conn->rx_tfm = crypto_alloc_tfm("crc32c",
-                                                                   0);
-                       if (!tcp_conn->rx_tfm) {
-                               crypto_free_tfm(tcp_conn->tx_tfm);
-                               return -ENOMEM;
-                       }
-               } else {
-                       if (tcp_conn->tx_tfm)
-                               crypto_free_tfm(tcp_conn->tx_tfm);
-                       if (tcp_conn->rx_tfm)
-                               crypto_free_tfm(tcp_conn->rx_tfm);
-               }
                break;
        case ISCSI_PARAM_DATADGST_EN:
                iscsi_set_param(cls_conn, param, buf, buflen);
-               if (conn->datadgst_en) {
-                       if (!tcp_conn->data_tx_tfm)
-                               tcp_conn->data_tx_tfm =
-                                   crypto_alloc_tfm("crc32c", 0);
-                       if (!tcp_conn->data_tx_tfm)
-                               return -ENOMEM;
-                       if (!tcp_conn->data_rx_tfm)
-                               tcp_conn->data_rx_tfm =
-                                   crypto_alloc_tfm("crc32c", 0);
-                       if (!tcp_conn->data_rx_tfm) {
-                               crypto_free_tfm(tcp_conn->data_tx_tfm);
-                               return -ENOMEM;
-                       }
-               } else {
-                       if (tcp_conn->data_tx_tfm)
-                               crypto_free_tfm(tcp_conn->data_tx_tfm);
-                       if (tcp_conn->data_rx_tfm)
-                               crypto_free_tfm(tcp_conn->data_rx_tfm);
-               }
                tcp_conn->sendpage = conn->datadgst_en ?
                        sock_no_sendpage : tcp_conn->sock->ops->sendpage;
                break;
        case ISCSI_PARAM_MAX_R2T:
                sscanf(buf, "%d", &value);
-               if (session->max_r2t == roundup_pow_of_two(value))
+               if (value <= 0 || !is_power_of_2(value))
+                       return -EINVAL;
+               if (session->max_r2t == value)
                        break;
                iscsi_r2tpool_free(session);
                iscsi_set_param(cls_conn, param, buf, buflen);
-               if (session->max_r2t & (session->max_r2t - 1))
-                       session->max_r2t = roundup_pow_of_two(session->max_r2t);
                if (iscsi_r2tpool_alloc(session))
                        return -ENOMEM;
                break;
@@ -2036,43 +1779,18 @@ iscsi_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
                         enum iscsi_param param, char *buf)
 {
        struct iscsi_conn *conn = cls_conn->dd_data;
-       struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
-       struct inet_sock *inet;
-       struct ipv6_pinfo *np;
-       struct sock *sk;
        int len;
 
        switch(param) {
        case ISCSI_PARAM_CONN_PORT:
-               mutex_lock(&conn->xmitmutex);
-               if (!tcp_conn->sock) {
-                       mutex_unlock(&conn->xmitmutex);
-                       return -EINVAL;
-               }
-
-               inet = inet_sk(tcp_conn->sock->sk);
-               len = sprintf(buf, "%hu\n", be16_to_cpu(inet->dport));
-               mutex_unlock(&conn->xmitmutex);
+               spin_lock_bh(&conn->session->lock);
+               len = sprintf(buf, "%hu\n", conn->portal_port);
+               spin_unlock_bh(&conn->session->lock);
                break;
        case ISCSI_PARAM_CONN_ADDRESS:
-               mutex_lock(&conn->xmitmutex);
-               if (!tcp_conn->sock) {
-                       mutex_unlock(&conn->xmitmutex);
-                       return -EINVAL;
-               }
-
-               sk = tcp_conn->sock->sk;
-               if (sk->sk_family == PF_INET) {
-                       inet = inet_sk(sk);
-                       len = sprintf(buf, "%u.%u.%u.%u\n",
-                                     NIPQUAD(inet->daddr));
-               } else {
-                       np = inet6_sk(sk);
-                       len = sprintf(buf,
-                               "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
-                               NIP6(np->daddr));
-               }
-               mutex_unlock(&conn->xmitmutex);
+               spin_lock_bh(&conn->session->lock);
+               len = sprintf(buf, "%s\n", conn->portal_address);
+               spin_unlock_bh(&conn->session->lock);
                break;
        default:
                return iscsi_conn_get_param(cls_conn, param, buf);
@@ -2106,64 +1824,94 @@ iscsi_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *stats)
 }
 
 static struct iscsi_cls_session *
-iscsi_tcp_session_create(struct iscsi_transport *iscsit,
-                        struct scsi_transport_template *scsit,
-                        uint32_t initial_cmdsn, uint32_t *hostno)
+iscsi_tcp_session_create(struct iscsi_endpoint *ep, uint16_t cmds_max,
+                        uint16_t qdepth, uint32_t initial_cmdsn,
+                        uint32_t *hostno)
 {
        struct iscsi_cls_session *cls_session;
        struct iscsi_session *session;
-       uint32_t hn;
+       struct Scsi_Host *shost;
        int cmd_i;
 
-       cls_session = iscsi_session_setup(iscsit, scsit,
-                                        sizeof(struct iscsi_tcp_cmd_task),
-                                        sizeof(struct iscsi_tcp_mgmt_task),
-                                        initial_cmdsn, &hn);
-       if (!cls_session)
+       if (ep) {
+               printk(KERN_ERR "iscsi_tcp: invalid ep %p.\n", ep);
                return NULL;
-       *hostno = hn;
-
-       session = class_to_transport_session(cls_session);
-       for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
-               struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
-               struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
-
-               ctask->hdr = &tcp_ctask->hdr;
        }
 
-       for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {
-               struct iscsi_mgmt_task *mtask = session->mgmt_cmds[cmd_i];
-               struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
+       shost = iscsi_host_alloc(&iscsi_sht, 0, qdepth);
+       if (!shost)
+               return NULL;
+       shost->transportt = iscsi_tcp_scsi_transport;
+       shost->max_lun = iscsi_max_lun;
+       shost->max_id = 0;
+       shost->max_channel = 0;
+       shost->max_cmd_len = SCSI_MAX_VARLEN_CDB_SIZE;
+
+       if (iscsi_host_add(shost, NULL))
+               goto free_host;
+       *hostno = shost->host_no;
+
+       cls_session = iscsi_session_setup(&iscsi_tcp_transport, shost, cmds_max,
+                                         sizeof(struct iscsi_tcp_task),
+                                         initial_cmdsn, 0);
+       if (!cls_session)
+               goto remove_host;
+       session = cls_session->dd_data;
 
-               mtask->hdr = &tcp_mtask->hdr;
-       }
+       shost->can_queue = session->scsi_cmds_max;
+       for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
+               struct iscsi_task *task = session->cmds[cmd_i];
+               struct iscsi_tcp_task *tcp_task = task->dd_data;
 
-       if (iscsi_r2tpool_alloc(class_to_transport_session(cls_session)))
-               goto r2tpool_alloc_fail;
+               task->hdr = &tcp_task->hdr.cmd_hdr;
+               task->hdr_max = sizeof(tcp_task->hdr) - ISCSI_DIGEST_SIZE;
+       }
 
+       if (iscsi_r2tpool_alloc(session))
+               goto remove_session;
        return cls_session;
 
-r2tpool_alloc_fail:
+remove_session:
        iscsi_session_teardown(cls_session);
+remove_host:
+       iscsi_host_remove(shost);
+free_host:
+       iscsi_host_free(shost);
        return NULL;
 }
 
 static void iscsi_tcp_session_destroy(struct iscsi_cls_session *cls_session)
 {
-       iscsi_r2tpool_free(class_to_transport_session(cls_session));
+       struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
+
+       iscsi_r2tpool_free(cls_session->dd_data);
        iscsi_session_teardown(cls_session);
+
+       iscsi_host_remove(shost);
+       iscsi_host_free(shost);
+}
+
+static int iscsi_tcp_slave_configure(struct scsi_device *sdev)
+{
+       blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_ANY);
+       blk_queue_dma_alignment(sdev->request_queue, 0);
+       return 0;
 }
 
 static struct scsi_host_template iscsi_sht = {
+       .module                 = THIS_MODULE,
        .name                   = "iSCSI Initiator over TCP/IP",
        .queuecommand           = iscsi_queuecommand,
        .change_queue_depth     = iscsi_change_queue_depth,
-       .can_queue              = ISCSI_XMIT_CMDS_MAX - 1,
-       .sg_tablesize           = ISCSI_SG_TABLESIZE,
+       .can_queue              = ISCSI_DEF_XMIT_CMDS_MAX - 1,
+       .sg_tablesize           = 4096,
+       .max_sectors            = 0xFFFF,
        .cmd_per_lun            = ISCSI_DEF_CMD_PER_LUN,
        .eh_abort_handler       = iscsi_eh_abort,
+       .eh_device_reset_handler= iscsi_eh_device_reset,
        .eh_host_reset_handler  = iscsi_eh_host_reset,
        .use_clustering         = DISABLE_CLUSTERING,
+       .slave_configure        = iscsi_tcp_slave_configure,
        .proc_name              = "iscsi_tcp",
        .this_id                = -1,
 };
@@ -2190,12 +1938,16 @@ static struct iscsi_transport iscsi_tcp_transport = {
                                  ISCSI_EXP_STATSN |
                                  ISCSI_PERSISTENT_PORT |
                                  ISCSI_PERSISTENT_ADDRESS |
-                                 ISCSI_TARGET_NAME |
-                                 ISCSI_TPGT,
-       .host_template          = &iscsi_sht,
-       .conndata_size          = sizeof(struct iscsi_conn),
-       .max_conn               = 1,
-       .max_cmd_len            = ISCSI_TCP_MAX_CMD_LEN,
+                                 ISCSI_TARGET_NAME | ISCSI_TPGT |
+                                 ISCSI_USERNAME | ISCSI_PASSWORD |
+                                 ISCSI_USERNAME_IN | ISCSI_PASSWORD_IN |
+                                 ISCSI_FAST_ABORT | ISCSI_ABORT_TMO |
+                                 ISCSI_LU_RESET_TMO |
+                                 ISCSI_PING_TMO | ISCSI_RECV_TMO |
+                                 ISCSI_IFACE_NAME | ISCSI_INITIATOR_NAME,
+       .host_param_mask        = ISCSI_HOST_HWADDRESS | ISCSI_HOST_IPADDRESS |
+                                 ISCSI_HOST_INITIATOR_NAME |
+                                 ISCSI_HOST_NETDEV_NAME,
        /* session management */
        .create_session         = iscsi_tcp_session_create,
        .destroy_session        = iscsi_tcp_session_destroy,
@@ -2208,14 +1960,15 @@ static struct iscsi_transport iscsi_tcp_transport = {
        .get_session_param      = iscsi_session_get_param,
        .start_conn             = iscsi_conn_start,
        .stop_conn              = iscsi_tcp_conn_stop,
+       /* iscsi host params */
+       .get_host_param         = iscsi_host_get_param,
+       .set_host_param         = iscsi_host_set_param,
        /* IO */
        .send_pdu               = iscsi_conn_send_pdu,
        .get_stats              = iscsi_conn_get_stats,
-       .init_cmd_task          = iscsi_tcp_cmd_init,
-       .init_mgmt_task         = iscsi_tcp_mgmt_init,
-       .xmit_cmd_task          = iscsi_tcp_ctask_xmit,
-       .xmit_mgmt_task         = iscsi_tcp_mtask_xmit,
-       .cleanup_cmd_task       = iscsi_tcp_cleanup_ctask,
+       .init_task              = iscsi_tcp_task_init,
+       .xmit_task              = iscsi_tcp_task_xmit,
+       .cleanup_task           = iscsi_tcp_cleanup_task,
        /* recovery */
        .session_recovery_timedout = iscsi_session_recovery_timedout,
 };
@@ -2228,9 +1981,10 @@ iscsi_tcp_init(void)
                       iscsi_max_lun);
                return -EINVAL;
        }
-       iscsi_tcp_transport.max_lun = iscsi_max_lun;
 
-       if (!iscsi_register_transport(&iscsi_tcp_transport))
+       iscsi_tcp_scsi_transport = iscsi_register_transport(
+                                                       &iscsi_tcp_transport);
+       if (!iscsi_tcp_scsi_transport)
                return -ENODEV;
 
        return 0;