md: move suspend_hi/lo handling into core md code

responding to ->suspend_lo and ->suspend_hi is similar
to responding to ->suspended.  It is best to wait in
the common core code without incrementing ->active_io.
This allows mddev_suspend()/mddev_resume() to work while
requests are waiting for suspend_lo/hi to change.
This is will be important after a subsequent patch
which uses mddev_suspend() to synchronize updating for
suspend_lo/hi.

So move the code for testing suspend_lo/hi out of raid1.c
and raid5.c, and place it in md.c

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index efdabd3..fb56ef79 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1310,11 +1310,9 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 	 */
 
 
-	if ((bio_end_sector(bio) > mddev->suspend_lo &&
-	    bio->bi_iter.bi_sector < mddev->suspend_hi) ||
-	    (mddev_is_clustered(mddev) &&
+	if (mddev_is_clustered(mddev) &&
 	     md_cluster_ops->area_resyncing(mddev, WRITE,
-		     bio->bi_iter.bi_sector, bio_end_sector(bio)))) {
+		     bio->bi_iter.bi_sector, bio_end_sector(bio))) {
 
 		/*
 		 * As the suspend_* range is controlled by userspace, we want
@@ -1325,12 +1323,10 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 			sigset_t full, old;
 			prepare_to_wait(&conf->wait_barrier,
 					&w, TASK_INTERRUPTIBLE);
-			if ((bio_end_sector(bio) <= mddev->suspend_lo ||
-			     bio->bi_iter.bi_sector >= mddev->suspend_hi) &&
-			    (!mddev_is_clustered(mddev) ||
-			     !md_cluster_ops->area_resyncing(mddev, WRITE,
+			if (!mddev_is_clustered(mddev) ||
+			    !md_cluster_ops->area_resyncing(mddev, WRITE,
 							bio->bi_iter.bi_sector,
-							bio_end_sector(bio))))
+							bio_end_sector(bio)))
 				break;
 			sigfillset(&full);
 			sigprocmask(SIG_BLOCK, &full, &old);