From 944ce9af4767ca085d465e4add69df11a8faa9ef Mon Sep 17 00:00:00 2001
From: Lai Jiangshan <laijs@cn.fujitsu.com>
Date: Wed, 22 Feb 2012 16:43:55 -0800
Subject: [PATCH] rcu: Flip ->completed only once per SRCU grace period

This is an optimization of the SRCU grace period.  To guard against
preempted readers with old values of the counter, it suffices to scan the
old counters once more, then flip ->completed only one time.  The reason
this works is that the old readers must have incremented the old set of
counters (if they have not yet incremented, then their critical section
starts after this grace period, so they may be safely ignored).

This commit therefore optimizes the second flip out in favor of a simple
rescan.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
Reading git-format-patch failed