Commit-ID: 5a41344a3d83ef2c08e40bfce1efa5795def9b82
Gitweb: http://git.kernel.org/tip/5a41344a3d83ef2c08e40bfce1efa5795def9b82
Author: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
AuthorDate: Thu, 29 Nov 2012 16:46:02 +0800
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Thu, 7 Feb 2013 15:06:25 -0800
srcu: Simplify __srcu_read_unlock() via this_cpu_dec()
This commit replaces disabling of preemption and decrement of a per-CPU
variable with this_cpu_dec(), which avoids preemption disabling on x86
and shortens the code on all platforms.
Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/srcu.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/kernel/srcu.c b/kernel/srcu.c
index 2b85982..c9d003b 100644
--- a/kernel/srcu.c
+++ b/kernel/srcu.c
@@ -321,10 +321,8 @@ EXPORT_SYMBOL_GPL(__srcu_read_lock);
*/
void __srcu_read_unlock(struct srcu_struct *sp, int idx)
{
- preempt_disable();
smp_mb(); /* C */ /* Avoid leaking the critical section. */
- ACCESS_ONCE(this_cpu_ptr(sp->per_cpu_ref)->c[idx]) -= 1;
- preempt_enable();
+ this_cpu_dec(sp->per_cpu_ref->c[idx]);
}
EXPORT_SYMBOL_GPL(__srcu_read_unlock);
--
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