[SCSI] tgt: use scsi_init_io instead of scsi_alloc_sgtable

If we export scsi_init_io()/scsi_release_buffers() instead of
scsi_{alloc,free}_sgtable() from scsi_lib than tgt code is much more
insulated from scsi_lib changes. As a bonus it will also gain bidi
capability when it comes.

[jejb: rebase on to sg_table and fix up rejections]

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 7c4c889..69fd621 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -746,7 +746,7 @@ static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
        return mempool_alloc(sgp->pool, gfp_mask);
 }
 
-int scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
+static int scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 {
        int ret;
 
@@ -762,15 +762,11 @@ int scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
        return ret;
 }
 
-EXPORT_SYMBOL(scsi_alloc_sgtable);
-
-void scsi_free_sgtable(struct scsi_cmnd *cmd)
+static void scsi_free_sgtable(struct scsi_cmnd *cmd)
 {
        __sg_free_table(&cmd->sg_table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
 }
 
-EXPORT_SYMBOL(scsi_free_sgtable);
-
 /*
  * Function:    scsi_release_buffers()
  *
@@ -788,7 +784,7 @@ EXPORT_SYMBOL(scsi_free_sgtable);
  *             the scatter-gather table, and potentially any bounce
  *             buffers.
  */
-static void scsi_release_buffers(struct scsi_cmnd *cmd)
+void scsi_release_buffers(struct scsi_cmnd *cmd)
 {
        if (cmd->use_sg)
                scsi_free_sgtable(cmd);
@@ -800,6 +796,7 @@ static void scsi_release_buffers(struct scsi_cmnd *cmd)
        cmd->request_buffer = NULL;
        cmd->request_bufflen = 0;
 }
+EXPORT_SYMBOL(scsi_release_buffers);
 
 /*
  * Function:    scsi_io_completion()
@@ -1001,7 +998,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
  * Returns:     0 on success
  *             BLKPREP_DEFER if the failure is retryable
  */
-static int scsi_init_io(struct scsi_cmnd *cmd)
+int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 {
        struct request     *req = cmd->request;
        int                count;
@@ -1016,7 +1013,7 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
        /*
         * If sg table allocation fails, requeue request later.
         */
-       if (unlikely(scsi_alloc_sgtable(cmd, GFP_ATOMIC))) {
+       if (unlikely(scsi_alloc_sgtable(cmd, gfp_mask))) {
                scsi_unprep_request(req);
                return BLKPREP_DEFER;
        }
@@ -1036,6 +1033,7 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
        cmd->use_sg = count;
        return BLKPREP_OK;
 }
+EXPORT_SYMBOL(scsi_init_io);
 
 static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
                struct request *req)
@@ -1081,7 +1079,7 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 
                BUG_ON(!req->nr_phys_segments);
 
-               ret = scsi_init_io(cmd);
+               ret = scsi_init_io(cmd, GFP_ATOMIC);
                if (unlikely(ret))
                        return ret;
        } else {
@@ -1132,7 +1130,7 @@ int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
        if (unlikely(!cmd))
                return BLKPREP_DEFER;
 
-       return scsi_init_io(cmd);
+       return scsi_init_io(cmd, GFP_ATOMIC);
 }
 EXPORT_SYMBOL(scsi_setup_fs_cmnd);
 

diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c
index 01e03f3..91630ba 100644 (file)
--- a/drivers/scsi/scsi_tgt_lib.c
+++ b/drivers/scsi/scsi_tgt_lib.c
@@ -331,8 +331,7 @@ static void scsi_tgt_cmd_done(struct scsi_cmnd *cmd)
 
        scsi_tgt_uspace_send_status(cmd, tcmd->itn_id, tcmd->tag);
 
-       if (scsi_sglist(cmd))
-               scsi_free_sgtable(cmd);
+       scsi_release_buffers(cmd);
 
        queue_work(scsi_tgtd, &tcmd->work);
 }
@@ -353,25 +352,6 @@ static int scsi_tgt_transfer_response(struct scsi_cmnd *cmd)
        return 0;
 }
 
-static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask)
-{
-       struct request *rq = cmd->request;
-       int count;
-
-       cmd->use_sg = rq->nr_phys_segments;
-       if (scsi_alloc_sgtable(cmd, gfp_mask))
-               return -ENOMEM;
-
-       cmd->request_bufflen = rq->data_len;
-
-       dprintk("cmd %p cnt %d %lu\n", cmd, scsi_sg_count(cmd),
-               rq_data_dir(rq));
-       count = blk_rq_map_sg(rq->q, rq, scsi_sglist(cmd));
-       BUG_ON(count > cmd->use_sg);
-       cmd->use_sg = count;
-       return 0;
-}
-
 /* TODO: test this crap and replace bio_map_user with new interface maybe */
 static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd,
                               unsigned long uaddr, unsigned int len, int rw)
@@ -397,9 +377,11 @@ static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd,
        }
 
        tcmd->bio = rq->bio;
-       err = scsi_tgt_init_cmd(cmd, GFP_KERNEL);
-       if (err)
+       err = scsi_init_io(cmd, GFP_KERNEL);
+       if (err) {
+               scsi_release_buffers(cmd);
                goto unmap_rq;
+       }
 
        return 0;
 

diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index a457fca..09d44f9 100644 (file)
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -127,8 +127,8 @@ extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
                                 size_t *offset, size_t *len);
 extern void scsi_kunmap_atomic_sg(void *virt);
 
-extern int scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
-extern void scsi_free_sgtable(struct scsi_cmnd *);
+extern int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask);
+extern void scsi_release_buffers(struct scsi_cmnd *cmd);
 
 extern int scsi_dma_map(struct scsi_cmnd *cmd);
 extern void scsi_dma_unmap(struct scsi_cmnd *cmd);