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| author | Samuel Thibault <samuel.thibault@labri.fr> | 2005-05-21 17:50:15 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-05-21 10:46:48 -0700 |
| commit | 10f02d1c59e55f529140dda3a92f0099d748451c (patch) | |
| tree | 6b5a5804503401624171aff65b09ff022a9f0103 /include/linux/spinlock.h | |
| parent | 9636273dae265b9354b861b373cd43cd76a6d0fe (diff) | |
| download | lwn-10f02d1c59e55f529140dda3a92f0099d748451c.tar.gz lwn-10f02d1c59e55f529140dda3a92f0099d748451c.zip | |
[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 <samuel.thibault@ens-lyon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/spinlock.h')
| -rw-r--r-- | include/linux/spinlock.h | 8 |
1 files changed, 4 insertions, 4 deletions
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) |