[SCSI] libiscsi: allow drivers to modify the itt sent to the target

bnx2i and cxgb3i need to encode LLD info in the itt so that
the firmware/hardware can process the pdu. This patch allows
the LLDs to encode info in the task->hdr->itt that they
setup in the alloc_pdu callout (any resources that are allocated
can be freed with the pdu in the cleanup_task callout). If
the LLD encodes info in the itt they should implement a
parse_pdu_itt callout. If parse_pdu_itt is not implemented
libiscsi will do the right thing for the LLD.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index c1bb740..6c4034b 100644 (file)
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -222,12 +222,14 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
        struct scsi_cmnd *sc = task->sc;
        struct iscsi_cmd *hdr;
        unsigned hdrlength, cmd_len;
+       itt_t itt;
        int rc;
 
        rc = conn->session->tt->alloc_pdu(task);
        if (rc)
                return rc;
        hdr = (struct iscsi_cmd *) task->hdr;
+       itt = hdr->itt;
        memset(hdr, 0, sizeof(*hdr));
 
        task->hdr_len = 0;
@@ -238,7 +240,11 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
        hdr->flags = ISCSI_ATTR_SIMPLE;
        int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
        memcpy(task->lun, hdr->lun, sizeof(task->lun));
-       hdr->itt = task->hdr_itt = build_itt(task->itt, session->age);
+       if (session->tt->parse_pdu_itt)
+               hdr->itt = task->hdr_itt = itt;
+       else
+               hdr->itt = task->hdr_itt = build_itt(task->itt,
+                                                    task->conn->session->age);
        hdr->cmdsn = task->cmdsn = cpu_to_be32(session->cmdsn);
        session->cmdsn++;
        hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
@@ -457,7 +463,6 @@ static int iscsi_prep_mgmt_task(struct iscsi_conn *conn,
         */
        nop->cmdsn = cpu_to_be32(session->cmdsn);
        if (hdr->itt != RESERVED_ITT) {
-               hdr->itt = build_itt(task->itt, session->age);
                /*
                 * TODO: We always use immediate, so we never hit this.
                 * If we start to send tmfs or nops as non-immediate then
@@ -490,6 +495,7 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 {
        struct iscsi_session *session = conn->session;
        struct iscsi_task *task;
+       itt_t itt;
 
        if (session->state == ISCSI_STATE_TERMINATE)
                return NULL;
@@ -531,9 +537,18 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                                 "pdu for mgmt task.\n");
                goto requeue_task;
        }
+       itt = task->hdr->itt;
        task->hdr_len = sizeof(struct iscsi_hdr);
-
        memcpy(task->hdr, hdr, sizeof(struct iscsi_hdr));
+
+       if (hdr->itt != RESERVED_ITT) {
+               if (session->tt->parse_pdu_itt)
+                       task->hdr->itt = itt;
+               else
+                       task->hdr->itt = build_itt(task->itt,
+                                                  task->conn->session->age);
+       }
+
        INIT_LIST_HEAD(&task->running);
        list_add_tail(&task->running, &conn->mgmtqueue);
 
@@ -745,7 +760,6 @@ static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 {
        struct iscsi_reject *reject = (struct iscsi_reject *)hdr;
        struct iscsi_hdr rejected_pdu;
-       uint32_t itt;
 
        conn->exp_statsn = be32_to_cpu(reject->statsn) + 1;
 
@@ -755,10 +769,9 @@ static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 
                if (ntoh24(reject->dlength) >= sizeof(struct iscsi_hdr)) {
                        memcpy(&rejected_pdu, data, sizeof(struct iscsi_hdr));
-                       itt = get_itt(rejected_pdu.itt);
                        iscsi_conn_printk(KERN_ERR, conn,
-                                         "itt 0x%x had pdu (op 0x%x) rejected "
-                                         "due to DataDigest error.\n", itt,
+                                         "pdu (op 0x%x) rejected "
+                                         "due to DataDigest error.\n",
                                          rejected_pdu.opcode);
                }
        }
@@ -778,12 +791,15 @@ static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 static struct iscsi_task *iscsi_itt_to_task(struct iscsi_conn *conn, itt_t itt)
 {
        struct iscsi_session *session = conn->session;
-       uint32_t i;
+       int i;
 
        if (itt == RESERVED_ITT)
                return NULL;
 
-       i = get_itt(itt);
+       if (session->tt->parse_pdu_itt)
+               session->tt->parse_pdu_itt(conn, itt, &i, NULL);
+       else
+               i = get_itt(itt);
        if (i >= session->cmds_max)
                return NULL;
 
@@ -958,20 +974,25 @@ EXPORT_SYMBOL_GPL(iscsi_complete_pdu);
 int iscsi_verify_itt(struct iscsi_conn *conn, itt_t itt)
 {
        struct iscsi_session *session = conn->session;
-       uint32_t i;
+       int age = 0, i = 0;
 
        if (itt == RESERVED_ITT)
                return 0;
 
-       if (((__force u32)itt & ISCSI_AGE_MASK) !=
-           (session->age << ISCSI_AGE_SHIFT)) {
+       if (session->tt->parse_pdu_itt)
+               session->tt->parse_pdu_itt(conn, itt, &i, &age);
+       else {
+               i = get_itt(itt);
+               age = ((__force u32)itt >> ISCSI_AGE_SHIFT) & ISCSI_AGE_MASK;
+       }
+
+       if (age != session->age) {
                iscsi_conn_printk(KERN_ERR, conn,
                                  "received itt %x expected session age (%x)\n",
                                  (__force u32)itt, session->age);
                return ISCSI_ERR_BAD_ITT;
        }
 
-       i = get_itt(itt);
        if (i >= session->cmds_max) {
                iscsi_conn_printk(KERN_ERR, conn,
                                  "received invalid itt index %u (max cmds "

diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 5150057..7360e19 100644 (file)
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -30,6 +30,7 @@
 #include <linux/workqueue.h>
 #include <scsi/iscsi_proto.h>
 #include <scsi/iscsi_if.h>
+#include <scsi/scsi_transport_iscsi.h>
 
 struct scsi_transport_template;
 struct scsi_host_template;
@@ -70,12 +71,12 @@ enum {
 /* Connection suspend "bit" */
 #define ISCSI_SUSPEND_BIT              1
 
-#define ISCSI_ITT_MASK                 (0x1fff)
+#define ISCSI_ITT_MASK                 0x1fff
 #define ISCSI_TOTAL_CMDS_MAX           4096
 /* this must be a power of two greater than ISCSI_MGMT_CMDS_MAX */
 #define ISCSI_TOTAL_CMDS_MIN           16
 #define ISCSI_AGE_SHIFT                        28
-#define ISCSI_AGE_MASK                 (0xf << ISCSI_AGE_SHIFT)
+#define ISCSI_AGE_MASK                 0xf
 
 #define ISCSI_ADDRESS_BUF_LEN          64
 

diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
index c928234..e13cb20 100644 (file)
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -122,6 +122,9 @@ struct iscsi_transport {
        int (*xmit_pdu) (struct iscsi_task *task);
        int (*init_pdu) (struct iscsi_task *task, unsigned int offset,
                         unsigned int count);
+       void (*parse_pdu_itt) (struct iscsi_conn *conn, itt_t itt,
+                              int *index, int *age);
+
        void (*session_recovery_timedout) (struct iscsi_cls_session *session);
        struct iscsi_endpoint *(*ep_connect) (struct sockaddr *dst_addr,
                                              int non_blocking);