[PATCH 5/5] md/raid1: update next_resync under resync_lock.

[NeilBrown <neilb@suse.de>]

raise_barrier() uses next_resync as part of its calculations, so it
really should be updated first, instead of afterwards.

next_resync is always used under  resync_lock so update it under
resync lock to, just before it is used.  That is safest.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid1.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 08a6989fcff6..53e163d31750 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -827,7 +827,7 @@ static void flush_pending_writes(struct r1conf *conf)
  *    there is no normal IO happeing.  It must arrange to call
  *    lower_barrier when the particular background IO completes.
  */
-static void raise_barrier(struct r1conf *conf)
+static void raise_barrier(struct r1conf *conf, sector_t sector_nr)
 {
 	spin_lock_irq(&conf->resync_lock);
 
@@ -837,6 +837,7 @@ static void raise_barrier(struct r1conf *conf)
 
 	/* block any new IO from starting */
 	conf->barrier++;
+	conf->next_resync = sector_nr;
 
 	/* For these conditions we must wait:
 	 * A: while the array is in frozen state
@@ -2542,9 +2543,8 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
 
 	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
 	r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
-	raise_barrier(conf);
 
-	conf->next_resync = sector_nr;
+	raise_barrier(conf, sector_nr);
 
 	rcu_read_lock();
 	/*