From 10f02d1c59e55f529140dda3a92f0099d748451c Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Sat, 21 May 2005 17:50:15 +0200 Subject: [PATCH] spin_unlock_bh() and preempt_check_resched() In _spin_unlock_bh(lock): do { \ _raw_spin_unlock(lock); \ preempt_enable(); \ local_bh_enable(); \ __release(lock); \ } while (0) there is no reason for using preempt_enable() instead of a simple preempt_enable_no_resched() Since we know bottom halves are disabled, preempt_schedule() will always return at once (preempt_count!=0), and hence preempt_check_resched() is useless here... This fixes it by using "preempt_enable_no_resched()" instead of the "preempt_enable()", and thus avoids the useless preempt_check_resched() just before re-enabling bottom halves. Signed-off-by: Samuel Thibault Signed-off-by: Linus Torvalds --- kernel/spinlock.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/spinlock.c b/kernel/spinlock.c index e15ed17863f..0c3f9d8bbe1 100644 --- a/kernel/spinlock.c +++ b/kernel/spinlock.c @@ -294,7 +294,7 @@ EXPORT_SYMBOL(_spin_unlock_irq); void __lockfunc _spin_unlock_bh(spinlock_t *lock) { _raw_spin_unlock(lock); - preempt_enable(); + preempt_enable_no_resched(); local_bh_enable(); } EXPORT_SYMBOL(_spin_unlock_bh); @@ -318,7 +318,7 @@ EXPORT_SYMBOL(_read_unlock_irq); void __lockfunc _read_unlock_bh(rwlock_t *lock) { _raw_read_unlock(lock); - preempt_enable(); + preempt_enable_no_resched(); local_bh_enable(); } EXPORT_SYMBOL(_read_unlock_bh); @@ -342,7 +342,7 @@ EXPORT_SYMBOL(_write_unlock_irq); void __lockfunc _write_unlock_bh(rwlock_t *lock) { _raw_write_unlock(lock); - preempt_enable(); + preempt_enable_no_resched(); local_bh_enable(); } EXPORT_SYMBOL(_write_unlock_bh); @@ -354,7 +354,7 @@ int __lockfunc _spin_trylock_bh(spinlock_t *lock) if (_raw_spin_trylock(lock)) return 1; - preempt_enable(); + preempt_enable_no_resched(); local_bh_enable(); return 0; } -- cgit v1.2.3