Commits
Joe Thornber committed 1c220c69ce0
dm: fix casting bug in dm_merge_bvec()
dm_merge_bvec() was originally added in f6fccb ("dm: introduce
merge_bvec_fn"). In that commit a value in sectors is converted to
bytes using << 9, and then assigned to an int. This code made
assumptions about the value of BIO_MAX_SECTORS.
A later commit 148e51 ("dm: improve documentation and code clarity in
dm_merge_bvec") was meant to have no functional change but it removed
the use of BIO_MAX_SECTORS in favor of using queue_max_sectors(). At
this point the cast from sector_t to int resulted in a zero value. The
fallout being dm_merge_bvec() would only allow a single page to be added
to a bio.
This interim fix is minimal for the benefit of stable@ because the more
comprehensive cleanup of passing a sector_t to all DM targets' merge
function will impact quite a few DM targets.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.19+