shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-05 18:41:58 +09:00
Code Issues Packages Projects Releases Wiki Activity

dm-bufio: align write boundary on physical block size

Browse Source 
commit d0ac06ae53be0cdb61f5fe6b62d25d3317c51657 upstream.

There may be devices with physical block size larger than 4k.

If dm-bufio sends I/O that is not aligned on physical block size,
performance is degraded.

The 4k minimum alignment limit is there because some SSDs report logical
and physical block size 512 despite having 4k internally - so dm-bufio
shouldn't send I/Os not aligned on 4k boundary, because they perform
badly (the SSD does read-modify-write for them).

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mikulas Patocka
2025-10-20 14:48:13 +02:00
committed by Greg Kroah-Hartman
parent 34f6abd6e4
commit 2b0b703a34
1 changed files with 6 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/md/dm-bufio.c
View File

@@ -1375,7 +1375,7 @@ static void submit_io(struct dm_buffer *b, enum req_op op,
{
unsigned int n_sectors;
sector_t sector;
unsigned int offset, end;
unsigned int offset, end, align;
b->end_io = end_io;
@@ -1389,9 +1389,11 @@ static void submit_io(struct dm_buffer *b, enum req_op op,
b->c->write_callback(b);
offset = b->write_start;
end = b->write_end;
offset &= -DM_BUFIO_WRITE_ALIGN;
end += DM_BUFIO_WRITE_ALIGN - 1;
end &= -DM_BUFIO_WRITE_ALIGN;
align = max(DM_BUFIO_WRITE_ALIGN,
bdev_physical_block_size(b->c->bdev));
offset &= -align;
end += align - 1;
end &= -align;
if (unlikely(end > b->c->block_size))
end = b->c->block_size;