md/raid5: suspend shouldn't affect read requests.

md allows write to regions on an array to be suspended temporarily.
This allows user-space to participate is aspects of reshape.
In particular, data can be copied with not risk of a race.
We should not be blocking read requests though, so don't.

Cc: stable@kernel.org
Signed-off-by: NNeilBrown <neilb@suse.de>

drivers/md/raid5.c

@@ -3702,7 +3702,8 @@ static int make_request(struct request_queue *q, struct bio * bi)
 			/* FIXME what if we get a false positive because these
 			 * are being updated.
 			 */
-			if (logical_sector >= mddev->suspend_lo &&
+			if (bio_data_dir(bi) == WRITE &&
+			    logical_sector >= mddev->suspend_lo &&
 			    logical_sector < mddev->suspend_hi) {
 				release_stripe(sh);
 				schedule();