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authorLai Jiangshan <laijs@cn.fujitsu.com>2012-11-29 12:46:02 +0400
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-02-08 03:06:25 +0400
commit5a41344a3d83ef2c08e40bfce1efa5795def9b82 (patch)
tree123d0fa065a35bb7de384edb5e753ec28beee7b0
parent0351096eb0584ba927a00a37e18be7af135250c3 (diff)
downloadlinux-5a41344a3d83ef2c08e40bfce1efa5795def9b82.tar.xz
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@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--kernel/srcu.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/kernel/srcu.c b/kernel/srcu.c
index 2b859828cdc3..c9d003bc6c49 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);