From: Oleg Nesterov Date: Wed, 30 Apr 2008 07:52:37 +0000 (-0700) Subject: lock_task_sighand: add rcu lock/unlock X-Git-Tag: v2.6.26-rc1~309 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=1406f2d321bae5ac5ff729dcb773336d9c05ec74;p=linux-2.6-omap-h63xx.git lock_task_sighand: add rcu lock/unlock Most of the callers of lock_task_sighand() doesn't actually need rcu_lock(). lock_task_sighand() needs it only to safely play with tsk->sighand, it can take the lock itself. Signed-off-by: Oleg Nesterov Cc: "Eric W. Biederman" Cc: "Paul E. McKenney" Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/signal.c b/kernel/signal.c index 29aca40be33..4a45bac2c63 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -971,13 +971,11 @@ int __fatal_signal_pending(struct task_struct *tsk) } EXPORT_SYMBOL(__fatal_signal_pending); -/* - * Must be called under rcu_read_lock() or with tasklist_lock read-held. - */ struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags) { struct sighand_struct *sighand; + rcu_read_lock(); for (;;) { sighand = rcu_dereference(tsk->sighand); if (unlikely(sighand == NULL)) @@ -988,6 +986,7 @@ struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long break; spin_unlock_irqrestore(&sighand->siglock, *flags); } + rcu_read_unlock(); return sighand; }