3 files changed, 38 insertions, 144 deletions

diff --git a/drivers/scsi/ide-scsi.c b/drivers/scsi/ide-scsi.c
index 02e91893064..db8bc20539e 100644
--- a/drivers/scsi/ide-scsi.c
+++ b/drivers/scsi/ide-scsi.c
@@ -919,8 +919,8 @@ static int idescsi_eh_reset (struct scsi_cmnd *cmd)
         }
 
         /* kill current request */
-        blkdev_dequeue_request(req);
-        end_that_request_last(req, 0);
+        if (__blk_end_request(req, -EIO, 0))
+                BUG();
         if (blk_sense_request(req))
                 kfree(scsi->pc->buffer);
         kfree(scsi->pc);
@@ -929,8 +929,8 @@ static int idescsi_eh_reset (struct scsi_cmnd *cmd)
 
         /* now nuke the drive queue */
         while ((req = elv_next_request(drive->queue))) {
-                blkdev_dequeue_request(req);
-                end_that_request_last(req, 0);
+                if (__blk_end_request(req, -EIO, 0))
+                        BUG();
         }
 
         HWGROUP(drive)->rq = NULL;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 4cf902efbdb..7c4c889c522 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -634,7 +634,7 @@ void scsi_run_host_queues(struct Scsi_Host *shost)
  *              of upper level post-processing and scsi_io_completion).
  *
  * Arguments:   cmd      - command that is complete.
- *              uptodate - 1 if I/O indicates success, <= 0 for I/O error.
+ *              error    - 0 if I/O indicates success, < 0 for I/O error.
  *              bytes    - number of bytes of completed I/O
  *              requeue  - indicates whether we should requeue leftovers.
  *
@@ -649,26 +649,25 @@ void scsi_run_host_queues(struct Scsi_Host *shost)
  *              at some point during this call.
  * Notes:       If cmd was requeued, upon return it will be a stale pointer.
  */
-static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate,
+static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
                                           int bytes, int requeue)
 {
         struct request_queue *q = cmd->device->request_queue;
         struct request *req = cmd->request;
-        unsigned long flags;
 
         /*
          * If there are blocks left over at the end, set up the command
          * to queue the remainder of them.
          */
-        if (end_that_request_chunk(req, uptodate, bytes)) {
+        if (blk_end_request(req, error, bytes)) {
                 int leftover = (req->hard_nr_sectors << 9);
 
                 if (blk_pc_request(req))
                         leftover = req->data_len;
 
                 /* kill remainder if no retrys */
-                if (!uptodate && blk_noretry_request(req))
-                        end_that_request_chunk(req, 0, leftover);
+                if (error && blk_noretry_request(req))
+                        blk_end_request(req, error, leftover);
                 else {
                         if (requeue) {
                                 /*
@@ -683,14 +682,6 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate,
                 }
         }
 
-        add_disk_randomness(req->rq_disk);
-
-        spin_lock_irqsave(q->queue_lock, flags);
-        if (blk_rq_tagged(req))
-                blk_queue_end_tag(q, req);
-        end_that_request_last(req, uptodate);
-        spin_unlock_irqrestore(q->queue_lock, flags);
-
         /*
          * This will goose the queue request function at the end, so we don't
          * need to worry about launching another command.
@@ -739,138 +730,43 @@ static inline unsigned int scsi_sgtable_index(unsigned short nents)
         return index;
 }
 
-struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
+static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
 {
         struct scsi_host_sg_pool *sgp;
-        struct scatterlist *sgl, *prev, *ret;
-        unsigned int index;
-        int this, left;
-
-        BUG_ON(!cmd->use_sg);
-
-        left = cmd->use_sg;
-        ret = prev = NULL;
-        do {
-                this = left;
-                if (this > SCSI_MAX_SG_SEGMENTS) {
-                        this = SCSI_MAX_SG_SEGMENTS - 1;
-                        index = SG_MEMPOOL_NR - 1;
-                } else
-                        index = scsi_sgtable_index(this);
-
-                left -= this;
 
-                sgp = scsi_sg_pools + index;
-
-                sgl = mempool_alloc(sgp->pool, gfp_mask);
-                if (unlikely(!sgl))
-                        goto enomem;
+        sgp = scsi_sg_pools + scsi_sgtable_index(nents);
+        mempool_free(sgl, sgp->pool);
+}
 
-                sg_init_table(sgl, sgp->size);
+static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
+{
+        struct scsi_host_sg_pool *sgp;
 
-                /*
-                 * first loop through, set initial index and return value
-                 */
-                if (!ret)
-                        ret = sgl;
+        sgp = scsi_sg_pools + scsi_sgtable_index(nents);
+        return mempool_alloc(sgp->pool, gfp_mask);
+}
 
-                /*
-                 * chain previous sglist, if any. we know the previous
-                 * sglist must be the biggest one, or we would not have
-                 * ended up doing another loop.
-                 */
-                if (prev)
-                        sg_chain(prev, SCSI_MAX_SG_SEGMENTS, sgl);
+int scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
+{
+        int ret;
 
-                /*
-                 * if we have nothing left, mark the last segment as
-                 * end-of-list
-                 */
-                if (!left)
-                        sg_mark_end(&sgl[this - 1]);
+        BUG_ON(!cmd->use_sg);
 
-                /*
-                 * don't allow subsequent mempool allocs to sleep, it would
-                 * violate the mempool principle.
-                 */
-                gfp_mask &= ~__GFP_WAIT;
-                gfp_mask |= __GFP_HIGH;
-                prev = sgl;
-        } while (left);
+        ret = __sg_alloc_table(&cmd->sg_table, cmd->use_sg,
+                               SCSI_MAX_SG_SEGMENTS, gfp_mask, scsi_sg_alloc);
+        if (unlikely(ret))
+                __sg_free_table(&cmd->sg_table, SCSI_MAX_SG_SEGMENTS,
+                                scsi_sg_free);
 
-        /*
-         * ->use_sg may get modified after dma mapping has potentially
-         * shrunk the number of segments, so keep a copy of it for free.
-         */
-        cmd->__use_sg = cmd->use_sg;
+        cmd->request_buffer = cmd->sg_table.sgl;
         return ret;
-enomem:
-        if (ret) {
-                /*
-                 * Free entries chained off ret. Since we were trying to
-                 * allocate another sglist, we know that all entries are of
-                 * the max size.
-                 */
-                sgp = scsi_sg_pools + SG_MEMPOOL_NR - 1;
-                prev = ret;
-                ret = &ret[SCSI_MAX_SG_SEGMENTS - 1];
-
-                while ((sgl = sg_chain_ptr(ret)) != NULL) {
-                        ret = &sgl[SCSI_MAX_SG_SEGMENTS - 1];
-                        mempool_free(sgl, sgp->pool);
-                }
-
-                mempool_free(prev, sgp->pool);
-        }
-        return NULL;
 }
 
 EXPORT_SYMBOL(scsi_alloc_sgtable);
 
 void scsi_free_sgtable(struct scsi_cmnd *cmd)
 {
-        struct scatterlist *sgl = cmd->request_buffer;
-        struct scsi_host_sg_pool *sgp;
-
-        /*
-         * if this is the biggest size sglist, check if we have
-         * chained parts we need to free
-         */
-        if (cmd->__use_sg > SCSI_MAX_SG_SEGMENTS) {
-                unsigned short this, left;
-                struct scatterlist *next;
-                unsigned int index;
-
-                left = cmd->__use_sg - (SCSI_MAX_SG_SEGMENTS - 1);
-                next = sg_chain_ptr(&sgl[SCSI_MAX_SG_SEGMENTS - 1]);
-                while (left && next) {
-                        sgl = next;
-                        this = left;
-                        if (this > SCSI_MAX_SG_SEGMENTS) {
-                                this = SCSI_MAX_SG_SEGMENTS - 1;
-                                index = SG_MEMPOOL_NR - 1;
-                        } else
-                                index = scsi_sgtable_index(this);
-
-                        left -= this;
-
-                        sgp = scsi_sg_pools + index;
-
-                        if (left)
-                                next = sg_chain_ptr(&sgl[sgp->size - 1]);
-
-                        mempool_free(sgl, sgp->pool);
-                }
-
-                /*
-                 * Restore original, will be freed below
-                 */
-                sgl = cmd->request_buffer;
-                sgp = scsi_sg_pools + SG_MEMPOOL_NR - 1;
-        } else
-                sgp = scsi_sg_pools + scsi_sgtable_index(cmd->__use_sg);
-
-        mempool_free(sgl, sgp->pool);
+        __sg_free_table(&cmd->sg_table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
 }
 
 EXPORT_SYMBOL(scsi_free_sgtable);
@@ -987,7 +883,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
          * are leftovers and there is some kind of error
          * (result != 0), retry the rest.
          */
-        if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL)
+        if (scsi_end_request(cmd, 0, good_bytes, result == 0) == NULL)
                 return;
 
         /* good_bytes = 0, or (inclusive) there were leftovers and
@@ -1001,7 +897,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                                  * and quietly refuse further access.
                                  */
                                 cmd->device->changed = 1;
-                                scsi_end_request(cmd, 0, this_count, 1);
+                                scsi_end_request(cmd, -EIO, this_count, 1);
                                 return;
                         } else {
                                 /* Must have been a power glitch, or a
@@ -1033,7 +929,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                                 scsi_requeue_command(q, cmd);
                                 return;
                         } else {
-                                scsi_end_request(cmd, 0, this_count, 1);
+                                scsi_end_request(cmd, -EIO, this_count, 1);
                                 return;
                         }
                         break;
@@ -1061,7 +957,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                                                          "Device not ready",
                                                          &sshdr);
 
-                        scsi_end_request(cmd, 0, this_count, 1);
+                        scsi_end_request(cmd, -EIO, this_count, 1);
                         return;
                 case VOLUME_OVERFLOW:
                         if (!(req->cmd_flags & REQ_QUIET)) {
@@ -1071,7 +967,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                                 scsi_print_sense("", cmd);
                         }
                         /* See SSC3rXX or current. */
-                        scsi_end_request(cmd, 0, this_count, 1);
+                        scsi_end_request(cmd, -EIO, this_count, 1);
                         return;
                 default:
                         break;
@@ -1092,7 +988,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                                 scsi_print_sense("", cmd);
                 }
         }
-        scsi_end_request(cmd, 0, this_count, !result);
+        scsi_end_request(cmd, -EIO, this_count, !result);
 }
 
 /*
@@ -1120,8 +1016,7 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
         /*
          * If sg table allocation fails, requeue request later.
          */
-        cmd->request_buffer = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
-        if (unlikely(!cmd->request_buffer)) {
+        if (unlikely(scsi_alloc_sgtable(cmd, GFP_ATOMIC))) {
                 scsi_unprep_request(req);
                 return BLKPREP_DEFER;
         }
diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c
index 93ece8f4e5d..01e03f3f6ff 100644
--- a/drivers/scsi/scsi_tgt_lib.c
+++ b/drivers/scsi/scsi_tgt_lib.c
@@ -359,8 +359,7 @@ static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask)
         int count;
 
         cmd->use_sg = rq->nr_phys_segments;
-        cmd->request_buffer = scsi_alloc_sgtable(cmd, gfp_mask);
-        if (!cmd->request_buffer)
+        if (scsi_alloc_sgtable(cmd, gfp_mask))
                 return -ENOMEM;
 
         cmd->request_bufflen = rq->data_len;