From: NeilBrown <neilb@suse.com>
To: Shaohua Li <shli@kernel.org>
Cc: linux-raid@vger.kernel.org
Subject: [md PATCH 09/10] md/linear: improve bio splitting.
Date: Wed, 05 Apr 2017 14:05:51 +1000 [thread overview]
Message-ID: <149136515137.25893.12381990673581871748.stgit@noble> (raw)
In-Reply-To: <149136485390.25893.1797855041954158826.stgit@noble>
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>
---
drivers/md/linear.c | 75 ++++++++++++++++++++++++---------------------------
1 file changed, 36 insertions(+), 39 deletions(-)
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 3e38e0207a3e..d67105a15a39 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -249,53 +249,50 @@ 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:
next prev parent reply other threads:[~2017-04-05 4:05 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-05 4:05 [md PATCH 00/10] Simplify bio splitting and related code NeilBrown
2017-04-05 4:05 ` [md PATCH 02/10] md/raid1: simplify alloc_behind_master_bio() NeilBrown
2017-04-05 4:05 ` [md PATCH 03/10] Revert "block: introduce bio_copy_data_partial" NeilBrown
2017-04-05 4:05 ` [md PATCH 01/10] md/raid1: simplify the splitting of requests NeilBrown
2017-04-05 4:05 ` [md PATCH 04/10] md/raid1: simplify handle_read_error() NeilBrown
2017-04-05 4:05 ` [md PATCH 06/10] md/raid10: simplify the splitting of requests NeilBrown
2017-04-05 4:05 ` [md PATCH 10/10] md/raid0: fix up bio splitting NeilBrown
2017-04-05 4:05 ` [md PATCH 05/10] md/raid1: factor out flush_bio_list() NeilBrown
2017-04-05 4:05 ` [md PATCH 08/10] md/raid5: make chunk_aligned_read() split bios more cleanly NeilBrown
2017-04-05 22:15 ` kbuild test robot
2017-04-06 0:13 ` NeilBrown
2017-04-05 4:05 ` [md PATCH 07/10] md/raid10: simplify handle_read_error() NeilBrown
2017-04-05 4:05 ` NeilBrown [this message]
2017-04-11 17:01 ` [md PATCH 00/10] Simplify bio splitting and related code Shaohua Li
2017-04-11 23:27 ` NeilBrown
2017-04-12 2:51 ` Shaohua Li
2017-04-20 1:37 ` NeilBrown
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