From: Christoph Hellwig <hch@infradead.org>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: linux-scsi@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>
Subject: [PATCH 5/6] scsi: remove a useless get/put_device pair in scsi_next_command
Date: Thu, 06 Feb 2014 10:43:11 -0800 [thread overview]
Message-ID: <20140206184418.063744285@bombadil.infradead.org> (raw)
In-Reply-To: 20140206184306.997538898@bombadil.infradead.org
[-- Attachment #1: 0005-scsi-remove-a-useless-get-put_device-pair-in-scsi_ne.patch --]
[-- Type: text/plain, Size: 1008 bytes --]
From: Bart Van Assche <bvanassche@acm.org>
Eliminate a get_device() / put_device() pair from scsi_next_command().
Both are atomic operations hence removing these slightly improves
performance.
[hch: slight changes due to different context]
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/scsi/scsi_lib.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 7d35678..91ca414 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -526,14 +526,9 @@ void scsi_next_command(struct scsi_cmnd *cmd)
struct scsi_device *sdev = cmd->device;
struct request_queue *q = sdev->request_queue;
- /* need to hold a reference on the device before we let go of the cmd */
- get_device(&sdev->sdev_gendev);
-
scsi_put_command(cmd);
- put_device(&sdev->sdev_gendev);
scsi_run_queue(q);
- /* ok to remove device now */
put_device(&sdev->sdev_gendev);
}
--
1.7.10.4
next prev parent reply other threads:[~2014-02-06 18:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-06 18:43 [PATCH 0/6] first batch of SCSI data path micro-optimizations Christoph Hellwig
2014-02-06 18:43 ` [PATCH 1/6] scsi: avoid useless free_list lock roundtrips Christoph Hellwig
2014-02-12 10:53 ` Hannes Reinecke
2014-02-06 18:43 ` [PATCH 2/6] scsi: avoid taking host_lock in scsi_run_queue unless nessecary Christoph Hellwig
2014-02-12 11:08 ` Hannes Reinecke
2014-02-12 15:52 ` Christoph Hellwig
2014-02-06 18:43 ` [PATCH 3/6] scsi: do not manipulate device reference counts in scsi_get/put_command Christoph Hellwig
2014-02-12 11:37 ` Hannes Reinecke
2014-02-12 15:58 ` Christoph Hellwig
2014-02-06 18:43 ` [PATCH 4/6] scsi: remove a useless get/put_device pair in scsi_request_fn Christoph Hellwig
2014-02-12 11:38 ` Hannes Reinecke
2014-02-06 18:43 ` Christoph Hellwig [this message]
2014-02-12 11:39 ` [PATCH 5/6] scsi: remove a useless get/put_device pair in scsi_next_command Hannes Reinecke
2014-02-06 18:43 ` [PATCH 6/6] scsi: remove a useless get/put_device pair in scsi_requeue_command Christoph Hellwig
2014-02-12 11:40 ` Hannes Reinecke
2014-02-12 15:58 ` Christoph Hellwig
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