Avoid a spurious device get/put cycle by using scsi_put_command and folding
scsi_unprep_request into scsi_requeue_command.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/scsi/scsi_lib.c | 35 +++--------------------------------
1 file changed, 3 insertions(+), 32 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 91ca414..9350691 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -75,29 +75,6 @@ struct kmem_cache *scsi_sdb_cache;
*/
#define SCSI_QUEUE_DELAY 3
-/*
- * Function: scsi_unprep_request()
- *
- * Purpose: Remove all preparation done for a request, including its
- * associated scsi_cmnd, so that it can be requeued.
- *
- * Arguments: req - request to unprepare
- *
- * Lock status: Assumed that no locks are held upon entry.
- *
- * Returns: Nothing.
- */
-static void scsi_unprep_request(struct request *req)
-{
- struct scsi_cmnd *cmd = req->special;
-
- blk_unprep_request(req);
- req->special = NULL;
-
- scsi_put_command(cmd);
- put_device(&cmd->device->sdev_gendev);
-}
-
/**
* __scsi_queue_insert - private queue insertion
* @cmd: The SCSI command being requeued
@@ -503,16 +480,10 @@ static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
struct request *req = cmd->request;
unsigned long flags;
- /*
- * We need to hold a reference on the device to avoid the queue being
- * killed after the unlock and before scsi_run_queue is invoked which
- * may happen because scsi_unprep_request() puts the command which
- * releases its reference on the device.
- */
- get_device(&sdev->sdev_gendev);
-
spin_lock_irqsave(q->queue_lock, flags);
- scsi_unprep_request(req);
+ blk_unprep_request(req);
+ req->special = NULL;
+ scsi_put_command(cmd);
blk_requeue_request(q, req);
spin_unlock_irqrestore(q->queue_lock, flags);
--
1.7.10.4
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