[SCSI] make scsi_queue_insert() use blk_requeue_request()

scsi_queue_insert() used to use blk_insert_request() for requeueing
requests.  This depends on the unobvious behavior of
blk_insert_request() setting REQ_SPECIAL and REQ_SOFTBARRIER when
requeueing.  This patch makes scsi_queue_insert() use
blk_requeue_request().  As REQ_SPECIAL means special requests and
REQ_SOFTBARRIER is automatically handled by blk layer now, no flag
needs to be set.

Note that scsi_queue_insert() now calls scsi_run_queue() itself, and
the prototype of the function is added right above
scsi_queue_insert().  This is temporary, as later requeue path
consolidation patchset removes scsi_queue_insert().  By adding
temporary prototype, we can do away with unnecessarily moving
functions.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 14 insertions, 5 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0b33e4f1a51..c3bb28c3fee 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -96,6 +96,8 @@ int scsi_insert_special_req(struct scsi_request *sreq, int at_head)
         return 0;
 }
 
+static void scsi_run_queue(struct request_queue *q);
+
 /*
  * Function:    scsi_queue_insert()
  *
@@ -119,6 +121,8 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 {
         struct Scsi_Host *host = cmd->device->host;
         struct scsi_device *device = cmd->device;
+        struct request_queue *q = device->request_queue;
+        unsigned long flags;
 
         SCSI_LOG_MLQUEUE(1,
                  printk("Inserting command %p into mlqueue\n", cmd));
@@ -160,17 +164,22 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
         scsi_device_unbusy(device);
 
         /*
-         * Insert this command at the head of the queue for it's device.
-         * It will go before all other commands that are already in the queue.
+         * Requeue this command.  It will go before all other commands
+         * that are already in the queue.
          *
          * NOTE: there is magic here about the way the queue is plugged if
          * we have no outstanding commands.
          * 
-         * Although this *doesn't* plug the queue, it does call the request
+         * Although we *don't* plug the queue, we call the request
          * function.  The SCSI request function detects the blocked condition
          * and plugs the queue appropriately.
-         */
-        blk_insert_request(device->request_queue, cmd->request, 1, cmd, 1);
+         */
+        spin_lock_irqsave(q->queue_lock, flags);
+        blk_requeue_request(q, cmd->request);
+        spin_unlock_irqrestore(q->queue_lock, flags);
+
+        scsi_run_queue(q);
+
         return 0;
 }