md/raid0: fix up bio splitting.

raid0_make_request() should use a private bio_set rather than the
shared fs_bio_set, which is only meant for filesystems to use.

raid0_make_request() shouldn't loop around using the bio_set
multiple times as that can deadlock.

So use mddev->bio_set and pass the tail to generic_make_request()
instead of looping on it.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 56f70c3ad37c08f9df68fe990b186316141e0c48..e777e48f55f61a8f6d7944301926776115eea0c5 100644 (file)
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -462,52 +462,53 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio)
 {
        struct strip_zone *zone;
        struct md_rdev *tmp_dev;
-       struct bio *split;
+       sector_t bio_sector;
+       sector_t sector;
+       unsigned chunk_sects;
+       unsigned sectors;
 
        if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
                md_flush_request(mddev, bio);
                return;
        }
 
-       do {
-               sector_t bio_sector = bio->bi_iter.bi_sector;
-               sector_t sector = bio_sector;
-               unsigned chunk_sects = mddev->chunk_sectors;
+       bio_sector = bio->bi_iter.bi_sector;
+       sector = bio_sector;
+       chunk_sects = mddev->chunk_sectors;
 
-               unsigned sectors = chunk_sects -
-                       (likely(is_power_of_2(chunk_sects))
-                        ? (sector & (chunk_sects-1))
-                        : sector_div(sector, chunk_sects));
+       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;
+       /* Restore due to sector_div */
+       sector = bio_sector;
 
-               if (sectors < bio_sectors(bio)) {
-                       split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set);
-                       bio_chain(split, bio);
-               } else {
-                       split = bio;
-               }
+       if (sectors < bio_sectors(bio)) {
+               struct bio *split = bio_split(bio, sectors, GFP_NOIO, mddev->bio_set);
+               bio_chain(split, bio);
+               generic_make_request(bio);
+               bio = split;
+       }
 
-               zone = find_zone(mddev->private, &sector);
-               tmp_dev = map_sector(mddev, zone, sector, &sector);
-               split->bi_bdev = tmp_dev->bdev;
-               split->bi_iter.bi_sector = sector + zone->dev_start +
-                       tmp_dev->data_offset;
-
-               if (unlikely((bio_op(split) == REQ_OP_DISCARD) &&
-                        !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {
-                       /* Just ignore it */
-                       bio_endio(split);
-               } else {
-                       if (mddev->gendisk)
-                               trace_block_bio_remap(bdev_get_queue(split->bi_bdev),
-                                                     split, disk_devt(mddev->gendisk),
-                                                     bio_sector);
-                       mddev_check_writesame(mddev, split);
-                       generic_make_request(split);
-               }
-       } while (split != bio);
+       zone = find_zone(mddev->private, &sector);
+       tmp_dev = map_sector(mddev, zone, sector, &sector);
+       bio->bi_bdev = tmp_dev->bdev;
+       bio->bi_iter.bi_sector = sector + zone->dev_start +
+               tmp_dev->data_offset;
+
+       if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
+                    !blk_queue_discard(bdev_get_queue(bio->bi_bdev)))) {
+               /* Just ignore it */
+               bio_endio(bio);
+       } else {
+               if (mddev->gendisk)
+                       trace_block_bio_remap(bdev_get_queue(bio->bi_bdev),
+                                             bio, disk_devt(mddev->gendisk),
+                                             bio_sector);
+               mddev_check_writesame(mddev, bio);
+               generic_make_request(bio);
+       }
 }
 
 static void raid0_status(struct seq_file *seq, struct mddev *mddev)