tree 6406beef9e8f60f7fb920c9100bdf2d60639289f
parent 50875788a1d4a3f662a27ed13cd05282d835939a
author Frederic Weisbecker <fweisbec@gmail.com> 1381506071 +0200
committer Frederic Weisbecker <fweisbec@gmail.com> 1386604431 +0100

posix-timers: Use sighand lock instead of tasklist_lock on timer deletion

Timer deletion doesn't need the tasklist lock.
We need to protect against:

* concurrent access to the lists p->cputime_expires and
  p->sighand->cputime_expires

* task reaping that may also delete the timer list entry

* timer firing

We already hold the timer lock which protects us against concurrent
timer firing.

The rest only need the targets sighand to be locked.
So hold it and drop the use of tasklist_lock there.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>