[PATCH 03/10] block: add a blk_next_discard_bio helper

Christoph Hellwig
2024-03-07T15:12:08Z

This factors the guts of __blkdev_issue_discard into a helper that can
be used by callers avoid the fatal_signal_pending check and to generally
simplify the bio handling.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-lib.c | 41 ++++++++++++++++++++++++-----------------
include/linux/blkdev.h | 2 ++
2 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 50923508a32466..4f2d52210b129c 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -55,28 +55,35 @@ static void await_bio_chain(struct bio *bio)
blk_wait_io(&done);
}

+bool blk_next_discard_bio(struct block_device *bdev, struct bio **biop,
+ sector_t *sector, sector_t *nr_sects, gfp_t gfp_mask)
+{
+ sector_t bio_sects = min(*nr_sects, bio_discard_limit(bdev, *sector));
+
+ if (!bio_sects)
+ return false;
+
+ *biop = blk_next_bio(*biop, bdev, 0, REQ_OP_DISCARD, gfp_mask);
+ (*biop)->bi_iter.bi_sector = *sector;
+ (*biop)->bi_iter.bi_size = bio_sects << SECTOR_SHIFT;
+ *sector += bio_sects;
+ *nr_sects -= bio_sects;
+ /*
+ * We can loop for a long time in here if someone does full device
+ * discards (like mkfs). Be nice and allow us to schedule out to avoid
+ * softlocking if preempt is disabled.
+ */
+ cond_resched();
+ return true;
+}
+EXPORT_SYMBOL_GPL(blk_next_discard_bio);
+
int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct bio **biop)
{
struct bio *bio = *biop;

- while (nr_sects) {
- sector_t req_sects =
- min(nr_sects, bio_discard_limit(bdev, sector));
-
- bio = blk_next_bio(bio, bdev, 0, REQ_OP_DISCARD, gfp_mask);
- bio->bi_iter.bi_sector = sector;
- bio->bi_iter.bi_size = req_sects << 9;
- sector += req_sects;
- nr_sects -= req_sects;
-
- /*
- * We can loop for a long time in here, if someone does
- * full device discards (like mkfs). Be nice and allow
- * us to schedule out to avoid softlocking if preempt
- * is disabled.
- */
- cond_resched();
+ while (blk_next_discard_bio(bdev, &bio, &sector, &nr_sects, gfp_mask)) {
if (fatal_signal_pending(current)) {
await_bio_chain(bio);
return -EINTR;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a9a0bd6cac4aff..b87cd889008291 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1059,6 +1059,8 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask);
int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct bio **biop);
+bool blk_next_discard_bio(struct block_device *bdev, struct bio **biop,
+ sector_t *sector, sector_t *nr_sects, gfp_t gfp_mask);
int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp);

--
2.39.2