From: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Thu, 1 Dec 2011 02:18:33 +0000 (-0800)
Subject: target: Remove extra se_device->execute_task_lock access in fast path
X-Git-Tag: v3.3-rc1~7^2~3
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4d2300ccffd22d1d0213b6a8e4d685eb6ca069c0;p=pandora-kernel.git

target: Remove extra se_device->execute_task_lock access in fast path

This patch makes __transport_execute_tasks() perform the addition of
tasks to dev->execute_task_list via __transport_add_tasks_from_cmd()
while holding dev->execute_task_lock during normal I/O fast path
submission.

It effectively removes the unnecessary re-acquire of dev->execute_task_lock
during transport_execute_tasks() -> transport_add_tasks_from_cmd() ahead
of calling  __transport_execute_tasks() to queue tasks for the passed
*se_cmd descriptor.

(v2: Re-add goto check_depth usage for multi-task submission for now..)

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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