From: Lai Jiangshan <laijs@cn.fujitsu.com>
Date: Sat, 4 Oct 2008 20:51:15 +0000 (+0400)
Subject: [PATCH] signal, procfs: some lock_task_sighand() users do not need rcu_read_lock()
X-Git-Tag: v2.6.28-rc1~608^2~3
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a6bebbc87a8c16eabb6bd5c6fd2d994be0236fba;p=pandora-kernel.git

[PATCH] signal, procfs: some lock_task_sighand() users do not need rcu_read_lock()

lock_task_sighand() make sure task->sighand is being protected,
so we do not need rcu_read_lock().
[ exec() will get task->sighand->siglock before change task->sighand! ]

But code using rcu_read_lock() _just_ to protect lock_task_sighand()
only appear in procfs. (and some code in procfs use lock_task_sighand()
without such redundant protection.)

Other subsystem may put lock_task_sighand() into rcu_read_lock()
critical region, but these rcu_read_lock() are used for protecting
"for_each_process()", "find_task_by_vpid()" etc. , not for protecting
lock_task_sighand().

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
[ok from Oleg]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

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