From: Yu Kuai <yukuai3@huawei.com>

Faulty rdev should never be accessed anymore, hence there is no point to
wait for bad block to be acknowledged in this case while handling write
request.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Tested-by: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
---
 drivers/md/raid10.c | 40 ++++++++++++++++++----------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index f3bf1116794a..ff73db2f6c41 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1285,9 +1285,9 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
 
 static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio)
 {
-	int i;
 	struct r10conf *conf = mddev->private;
 	struct md_rdev *blocked_rdev;
+	int i;
 
 retry_wait:
 	blocked_rdev = NULL;
@@ -1295,40 +1295,36 @@ static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio)
 		struct md_rdev *rdev, *rrdev;
 
 		rdev = conf->mirrors[i].rdev;
-		rrdev = conf->mirrors[i].replacement;
-		if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
-			atomic_inc(&rdev->nr_pending);
-			blocked_rdev = rdev;
-			break;
-		}
-		if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) {
-			atomic_inc(&rrdev->nr_pending);
-			blocked_rdev = rrdev;
-			break;
-		}
-
-		if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
+		if (rdev) {
 			sector_t dev_sector = r10_bio->devs[i].addr;
 
 			/*
 			 * Discard request doesn't care the write result
 			 * so it doesn't need to wait blocked disk here.
 			 */
-			if (!r10_bio->sectors)
-				continue;
-
-			if (rdev_has_badblock(rdev, dev_sector,
-					      r10_bio->sectors) < 0) {
+			if (test_bit(WriteErrorSeen, &rdev->flags) &&
+			    r10_bio->sectors &&
+			    rdev_has_badblock(rdev, dev_sector,
+					      r10_bio->sectors) < 0)
 				/*
-				 * Mustn't write here until the bad block
-				 * is acknowledged
+				 * Mustn't write here until the bad
+				 * block is acknowledged
 				 */
-				atomic_inc(&rdev->nr_pending);
 				set_bit(BlockedBadBlocks, &rdev->flags);
+
+			if (rdev_blocked(rdev)) {
 				blocked_rdev = rdev;
+				atomic_inc(&rdev->nr_pending);
 				break;
 			}
 		}
+
+		rrdev = conf->mirrors[i].replacement;
+		if (rrdev && rdev_blocked(rrdev)) {
+			atomic_inc(&rrdev->nr_pending);
+			blocked_rdev = rrdev;
+			break;
+		}
 	}
 
 	if (unlikely(blocked_rdev)) {
-- 
2.39.2