4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Jens Axboe <[email protected]> commit af097f5d199e2aa3ab3ef777f0716e487b8f7b08 upstream. Don't build discards bigger than what the user asked for, if the user decided to limit the size by writing to 'discard_max_bytes'. Reviewed-by: Darrick J. Wong <[email protected]> Reviewed-by: Omar Sandoval <[email protected]> Signed-off-by: Jens Axboe <[email protected]> Signed-off-by: Sudip Mukherjee <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- block/blk-lib.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -81,8 +81,14 @@ int blkdev_issue_discard(struct block_de break; } - /* Make sure bi_size doesn't overflow */ - req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9); + /* + * Issue in chunks of the user defined max discard setting, + * ensuring that bi_size doesn't overflow + */ + req_sects = min_t(sector_t, nr_sects, + q->limits.max_discard_sectors); + if (req_sects > UINT_MAX >> 9) + req_sects = UINT_MAX >> 9; /* * If splitting a request, and the next starting sector would be
