[PATCH 6/9] scsi: remove a useless get/put_device pair in scsi_requeue_command

Christoph Hellwig
2014-02-20T22:23:58Z

[-- Attachment #1: 0006-scsi-remove-a-useless-get-put_device-pair-in-scsi_re.patch --]
[-- Type: text/plain, Size: 1907 bytes --]

Avoid a spurious device get/put pair by cleaning up scsi_requeue_command
and folding scsi_unprep_request into it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hannes Reinecke <hare@suse.de>
---
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