tree d40a2f0aa45427a66d024ce1b29ea7cb24cc770e
parent 91212507f93778c09d4c1335207b6f4b995f5ad1
author Milan Broz <mbroz@redhat.com> 1197555370 +0000
committer Alasdair G Kergon <agk@redhat.com> 1198171933 +0000

dm crypt: use bio_add_page

Fix possible max_phys_segments violation in cloned dm-crypt bio.

In write operation dm-crypt needs to allocate new bio request
and run crypto operation on this clone. Cloned request has always
the same size, but number of physical segments can be increased
and violate max_phys_segments restriction.

This can lead to data corruption and serious hardware malfunction.
This was observed when using XFS over dm-crypt and at least
two HBA controller drivers (arcmsr, cciss) recently.

Fix it by using bio_add_page() call (which tests for other
restrictions too) instead of constructing own biovec.

All versions of dm-crypt are affected by this bug.

Cc: stable@kernel.org
Cc:  dm-crypt@saout.de
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>