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Commit 5a41344a authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Paul E. McKenney
Browse files

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: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 0351096e

kernel/srcu.c

+1 −3
Original line number Diff line number Diff line
@@ -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);