github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-27 01:32:21 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

dm-bufio: fix wrong count calculation in dm_bufio_issue_discard

Browse Source 
block_to_sector converts a block number to a sector number and adds
c->start to the result. It is inappropriate to use this function for
converting the number of blocks to a number to sectors because c->start
would be incorrectly added to the result.

Luckily, the only target that uses dm_bufio_issue_discard is dm-ebs,
which sets c->start to 0, so this bug is latent.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Fixes: 6fbeb0048e ("dm bufio: implement discard")
Cc: stable@vger.kernel.org
This commit is contained in:
Mikulas Patocka 2026-07-10 18:32:49 +02:00
parent 8ec4d9c5a5
commit 422f1d4f14
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/md/dm-bufio.c
View File

@ -2238,7 +2238,9 @@ int dm_bufio_issue_discard(struct dm_bufio_client *c, sector_t block, sector_t c
struct dm_io_region io_reg = {
.bdev = c->bdev,
.sector = block_to_sector(c, block),
.count = block_to_sector(c, count),
.count = likely(c->sectors_per_block_bits >= 0) ?
count << c->sectors_per_block_bits :
count * (c->block_size >> SECTOR_SHIFT),
};
if (WARN_ON_ONCE(dm_bufio_in_request()))