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authorNeilBrown <neilb@suse.com>2017-04-05 14:05:51 +1000
committerShaohua Li <shli@fb.com>2017-04-11 10:17:55 -0700
commit868f604b1de2ddbdcf194d7792a0d91d7da719c1 (patch)
tree24e4e2bee699aa4195a469cbb109327976c68173 /drivers/md
parentdd7a8f5dee81ffb1794df1103f07c63fd4f1d766 (diff)
md/linear: improve bio splitting.
linear_make_request() uses fs_bio_set, which is meant for filesystems to use, and loops, possible allocating from the same bio set multiple times. These behaviors can theoretically cause deadlocks, though as linear requests are hardly ever split, it is unlikely in practice. Change to use mddev->bio_set - otherwise unused for linear, and submit the tail of a split request to generic_make_request() for it to handle. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/linear.c73
1 files changed, 34 insertions, 39 deletions
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 3e38e0207a3e..f16316fbf658 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -249,53 +249,48 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio)
{
char b[BDEVNAME_SIZE];
struct dev_info *tmp_dev;
- struct bio *split;
sector_t start_sector, end_sector, data_offset;
+ sector_t bio_sector = bio->bi_iter.bi_sector;
if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
md_flush_request(mddev, bio);
return;
}
- do {
- sector_t bio_sector = bio->bi_iter.bi_sector;
- tmp_dev = which_dev(mddev, bio_sector);
- start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
- end_sector = tmp_dev->end_sector;
- data_offset = tmp_dev->rdev->data_offset;
- bio->bi_bdev = tmp_dev->rdev->bdev;
-
- if (unlikely(bio_sector >= end_sector ||
- bio_sector < start_sector))
- goto out_of_bounds;
-
- if (unlikely(bio_end_sector(bio) > end_sector)) {
- /* This bio crosses a device boundary, so we have to
- * split it.
- */
- split = bio_split(bio, end_sector - bio_sector,
- GFP_NOIO, fs_bio_set);
- bio_chain(split, bio);
- } else {
- split = bio;
- }
+ tmp_dev = which_dev(mddev, bio_sector);
+ start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
+ end_sector = tmp_dev->end_sector;
+ data_offset = tmp_dev->rdev->data_offset;
+
+ if (unlikely(bio_sector >= end_sector ||
+ bio_sector < start_sector))
+ goto out_of_bounds;
+
+ if (unlikely(bio_end_sector(bio) > end_sector)) {
+ /* This bio crosses a device boundary, so we have to split it */
+ struct bio *split = bio_split(bio, end_sector - bio_sector,
+ GFP_NOIO, mddev->bio_set);
+ bio_chain(split, bio);
+ generic_make_request(bio);
+ bio = split;
+ }
- split->bi_iter.bi_sector = split->bi_iter.bi_sector -
- start_sector + 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);
+ bio->bi_bdev = tmp_dev->rdev->bdev;
+ bio->bi_iter.bi_sector = bio->bi_iter.bi_sector -
+ start_sector + 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);
+ }
return;
out_of_bounds: