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 --- include/linux/spinlock.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index e895f3eaf53a..d6ba068719b6 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -248,7 +248,7 @@ typedef struct { #define _spin_trylock_bh(lock) ({preempt_disable(); local_bh_disable(); \ _raw_spin_trylock(lock) ? \ - 1 : ({preempt_enable(); local_bh_enable(); 0;});}) + 1 : ({preempt_enable_no_resched(); local_bh_enable(); 0;});}) #define _spin_lock(lock) \ do { \ @@ -383,7 +383,7 @@ do { \ #define _spin_unlock_bh(lock) \ do { \ _raw_spin_unlock(lock); \ - preempt_enable(); \ + preempt_enable_no_resched(); \ local_bh_enable(); \ __release(lock); \ } while (0) @@ -391,7 +391,7 @@ do { \ #define _write_unlock_bh(lock) \ do { \ _raw_write_unlock(lock); \ - preempt_enable(); \ + preempt_enable_no_resched(); \ local_bh_enable(); \ __release(lock); \ } while (0) @@ -423,8 +423,8 @@ do { \ #define _read_unlock_bh(lock) \ do { \ _raw_read_unlock(lock); \ + preempt_enable_no_resched(); \ local_bh_enable(); \ - preempt_enable(); \ __release(lock); \ } while (0) -- cgit v1.2.3-59-g8ed1b