Patch "md/raid0: Factor out helper for mapping and submitting a bio" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    md/raid0: Factor out helper for mapping and submitting a bio

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     md-raid0-factor-out-helper-for-mapping-and-submittin.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit da1f7d3469f673c0dccb01008658a7b858ed0199
Author: Jan Kara <jack@xxxxxxx>
Date:   Mon Aug 14 11:27:07 2023 +0200

    md/raid0: Factor out helper for mapping and submitting a bio
    
    [ Upstream commit af50e20afb401cc203bd2a9ff62ece0ae4976103 ]
    
    Factor out helper function for mapping and submitting a bio out of
    raid0_make_request(). We will use it later for submitting both parts of
    a split bio.
    
    Signed-off-by: Jan Kara <jack@xxxxxxx>
    Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230814092720.3931-1-jack@xxxxxxx
    Signed-off-by: Song Liu <song@xxxxxxxxxx>
    Stable-dep-of: 319ff40a5427 ("md/raid0: Fix performance regression for large sequential writes")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 6917d72c18132..eca0022588c6d 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -570,54 +570,21 @@ static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
 	bio_endio(bio);
 }
 
-static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
+static void raid0_map_submit_bio(struct mddev *mddev, struct bio *bio)
 {
 	struct r0conf *conf = mddev->private;
 	struct strip_zone *zone;
 	struct md_rdev *tmp_dev;
-	sector_t bio_sector;
-	sector_t sector;
-	sector_t orig_sector;
-	unsigned chunk_sects;
-	unsigned sectors;
-
-	if (unlikely(bio->bi_opf & REQ_PREFLUSH)
-	    && md_flush_request(mddev, bio))
-		return true;
-
-	if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
-		raid0_handle_discard(mddev, bio);
-		return true;
-	}
-
-	bio_sector = bio->bi_iter.bi_sector;
-	sector = bio_sector;
-	chunk_sects = mddev->chunk_sectors;
-
-	sectors = chunk_sects -
-		(likely(is_power_of_2(chunk_sects))
-		 ? (sector & (chunk_sects-1))
-		 : sector_div(sector, chunk_sects));
-
-	/* Restore due to sector_div */
-	sector = bio_sector;
-
-	if (sectors < bio_sectors(bio)) {
-		struct bio *split = bio_split(bio, sectors, GFP_NOIO,
-					      &mddev->bio_set);
-		bio_chain(split, bio);
-		submit_bio_noacct(bio);
-		bio = split;
-	}
+	sector_t bio_sector = bio->bi_iter.bi_sector;
+	sector_t sector = bio_sector;
 
 	if (bio->bi_pool != &mddev->bio_set)
 		md_account_bio(mddev, &bio);
 
-	orig_sector = sector;
 	zone = find_zone(mddev->private, &sector);
 	switch (conf->layout) {
 	case RAID0_ORIG_LAYOUT:
-		tmp_dev = map_sector(mddev, zone, orig_sector, &sector);
+		tmp_dev = map_sector(mddev, zone, bio_sector, &sector);
 		break;
 	case RAID0_ALT_MULTIZONE_LAYOUT:
 		tmp_dev = map_sector(mddev, zone, sector, &sector);
@@ -625,13 +592,13 @@ static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
 	default:
 		WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev));
 		bio_io_error(bio);
-		return true;
+		return;
 	}
 
 	if (unlikely(is_rdev_broken(tmp_dev))) {
 		bio_io_error(bio);
 		md_error(mddev, tmp_dev);
-		return true;
+		return;
 	}
 
 	bio_set_dev(bio, tmp_dev->bdev);
@@ -644,6 +611,40 @@ static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
 	mddev_check_writesame(mddev, bio);
 	mddev_check_write_zeroes(mddev, bio);
 	submit_bio_noacct(bio);
+}
+
+static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
+{
+	sector_t sector;
+	unsigned chunk_sects;
+	unsigned sectors;
+
+	if (unlikely(bio->bi_opf & REQ_PREFLUSH)
+	    && md_flush_request(mddev, bio))
+		return true;
+
+	if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
+		raid0_handle_discard(mddev, bio);
+		return true;
+	}
+
+	sector = bio->bi_iter.bi_sector;
+	chunk_sects = mddev->chunk_sectors;
+
+	sectors = chunk_sects -
+		(likely(is_power_of_2(chunk_sects))
+		 ? (sector & (chunk_sects-1))
+		 : sector_div(sector, chunk_sects));
+
+	if (sectors < bio_sectors(bio)) {
+		struct bio *split = bio_split(bio, sectors, GFP_NOIO,
+					      &mddev->bio_set);
+		bio_chain(split, bio);
+		submit_bio_noacct(bio);
+		bio = split;
+	}
+
+	raid0_map_submit_bio(mddev, bio);
 	return true;
 }