tree 3e617ca49063f3a12c982da5d6c687882a1b4070
parent 53167a3ef23df561d898dee636f3393e9fba937c
author Lai Jiangshan <laijs@cn.fujitsu.com> 1223153475 +0400
committer Alexey Dobriyan <adobriyan@gmail.com> 1223597937 +0400

[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>