[PATCH v4 6/6] md/raid10: Handle bio_split() errors

[John Garry <john.g.garry@xxxxxxxxxx>]

Add proper bio_split() error handling. For any error, call
raid_end_bio_io() and return. Except for discard, where we end the bio
directly.

Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
---
 drivers/md/raid10.c | 47 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index ff73db2f6c41..8c7f5daa073a 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1159,6 +1159,7 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
 	int slot = r10_bio->read_slot;
 	struct md_rdev *err_rdev = NULL;
 	gfp_t gfp = GFP_NOIO;
+	int error;
 
 	if (slot >= 0 && r10_bio->devs[slot].rdev) {
 		/*
@@ -1206,6 +1207,10 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
 	if (max_sectors < bio_sectors(bio)) {
 		struct bio *split = bio_split(bio, max_sectors,
 					      gfp, &conf->bio_split);
+		if (IS_ERR(split)) {
+			error = PTR_ERR(split);
+			goto err_handle;
+		}
 		bio_chain(split, bio);
 		allow_barrier(conf);
 		submit_bio_noacct(bio);
@@ -1236,6 +1241,11 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
 	mddev_trace_remap(mddev, read_bio, r10_bio->sector);
 	submit_bio_noacct(read_bio);
 	return;
+err_handle:
+	atomic_dec(&rdev->nr_pending);
+	bio->bi_status = errno_to_blk_status(error);
+	set_bit(R10BIO_Uptodate, &r10_bio->state);
+	raid_end_bio_io(r10_bio);
 }
 
 static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
@@ -1343,9 +1353,10 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
 				 struct r10bio *r10_bio)
 {
 	struct r10conf *conf = mddev->private;
-	int i;
+	int i, k;
 	sector_t sectors;
 	int max_sectors;
+	int error;
 
 	if ((mddev_is_clustered(mddev) &&
 	     md_cluster_ops->area_resyncing(mddev, WRITE,
@@ -1478,6 +1489,10 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
 	if (r10_bio->sectors < bio_sectors(bio)) {
 		struct bio *split = bio_split(bio, r10_bio->sectors,
 					      GFP_NOIO, &conf->bio_split);
+		if (IS_ERR(split)) {
+			error = PTR_ERR(split);
+			goto err_handle;
+		}
 		bio_chain(split, bio);
 		allow_barrier(conf);
 		submit_bio_noacct(bio);
@@ -1499,6 +1514,26 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
 			raid10_write_one_disk(mddev, r10_bio, bio, true, i);
 	}
 	one_write_done(r10_bio);
+	return;
+err_handle:
+	for (k = 0;  k < i; k++) {
+		int d = r10_bio->devs[k].devnum;
+		struct md_rdev *rdev = conf->mirrors[d].rdev;
+		struct md_rdev *rrdev = conf->mirrors[d].replacement;
+
+		if (r10_bio->devs[k].bio) {
+			rdev_dec_pending(rdev, mddev);
+			r10_bio->devs[k].bio = NULL;
+		}
+		if (r10_bio->devs[k].repl_bio) {
+			rdev_dec_pending(rrdev, mddev);
+			r10_bio->devs[k].repl_bio = NULL;
+		}
+	}
+
+	bio->bi_status = errno_to_blk_status(error);
+	set_bit(R10BIO_Uptodate, &r10_bio->state);
+	raid_end_bio_io(r10_bio);
 }
 
 static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
@@ -1640,6 +1675,11 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
 	if (remainder) {
 		split_size = stripe_size - remainder;
 		split = bio_split(bio, split_size, GFP_NOIO, &conf->bio_split);
+		if (IS_ERR(split)) {
+			bio->bi_status = errno_to_blk_status(PTR_ERR(split));
+			bio_endio(bio);
+			return 0;
+		}
 		bio_chain(split, bio);
 		allow_barrier(conf);
 		/* Resend the fist split part */
@@ -1650,6 +1690,11 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
 	if (remainder) {
 		split_size = bio_sectors(bio) - remainder;
 		split = bio_split(bio, split_size, GFP_NOIO, &conf->bio_split);
+		if (IS_ERR(split)) {
+			bio->bi_status = errno_to_blk_status(PTR_ERR(split));
+			bio_endio(bio);
+			return 0;
+		}
 		bio_chain(split, bio);
 		allow_barrier(conf);
 		/* Resend the second split part */
-- 
2.31.1