This is a note to let you know that I've just added the patch titled
dm: revert 8f50e358153d ("dm: limit the max bio size as BIO_MAX_PAGES * PAGE_SIZE")
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-revert-8f50e358153d-dm-limit-the-max-bio-size-as-bio_max_pages-page_size.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 75ae193626de3238ca5fb895868ec91c94e63b1b Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Date: Thu, 21 Mar 2019 16:46:12 -0400
Subject: dm: revert 8f50e358153d ("dm: limit the max bio size as BIO_MAX_PAGES * PAGE_SIZE")
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
commit 75ae193626de3238ca5fb895868ec91c94e63b1b upstream.
The limit was already incorporated to dm-crypt with commit 4e870e948fba
("dm crypt: fix error with too large bios"), so we don't need to apply
it globally to all targets. The quantity BIO_MAX_PAGES * PAGE_SIZE is
wrong anyway because the variable ti->max_io_len it is supposed to be in
the units of 512-byte sectors not in bytes.
Reduction of the limit to 1048576 sectors could even cause data
corruption in rare cases - suppose that we have a dm-striped device with
stripe size 768MiB. The target will call dm_set_target_max_io_len with
the value 1572864. The buggy code would reduce it to 1048576. Now, the
dm-core will errorneously split the bios on 1048576-sector boundary
insetad of 1572864-sector boundary and pass these stripe-crossing bios
to the striped target.
Cc: stable@xxxxxxxxxxxxxxx # v4.16+
Fixes: 8f50e358153d ("dm: limit the max bio size as BIO_MAX_PAGES * PAGE_SIZE")
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Acked-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1007,15 +1007,7 @@ int dm_set_target_max_io_len(struct dm_t
return -EINVAL;
}
- /*
- * BIO based queue uses its own splitting. When multipage bvecs
- * is switched on, size of the incoming bio may be too big to
- * be handled in some targets, such as crypt.
- *
- * When these targets are ready for the big bio, we can remove
- * the limit.
- */
- ti->max_io_len = min_t(uint32_t, len, BIO_MAX_PAGES * PAGE_SIZE);
+ ti->max_io_len = (uint32_t) len;
return 0;
}
Patches currently in stable-queue which might be from mpatocka@xxxxxxxxxx are
queue-4.19/dm-integrity-change-memcmp-to-strncmp-in-dm_integrity_ctr.patch
queue-4.19/dm-integrity-fix-deadlock-with-overlapping-i-o.patch
queue-4.19/dm-revert-8f50e358153d-dm-limit-the-max-bio-size-as-bio_max_pages-page_size.patch
