tree 2d90f9196beeb6fc12fe2d3917b780f063733838
parent 91e630d9ae6de6f740ef7c8176736eb55366833e
author Mikulas Patocka <mpatocka@redhat.com> 1472589522 -0400
committer Mike Snitzer <snitzer@redhat.com> 1472600651 -0400

dm crypt: fix error with too large bios

When dm-crypt processes writes, it allocates a new bio in
crypt_alloc_buffer().  The bio is allocated from a bio set and it can
have at most BIO_MAX_PAGES vector entries, however the incoming bio can be
larger (e.g. if it was allocated by bcache).  If the incoming bio is
larger, bio_alloc_bioset() fails and an error is returned.

To avoid the error, we test for a too large bio in the function
crypt_map() and use dm_accept_partial_bio() to split the bio.
dm_accept_partial_bio() trims the current bio to the desired size and
asks DM core to send another bio with the rest of the data.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v3.16+