block: don't honor chunk sizes for data-less IO

We don't need to honor chunk sizes for IO that doesn't carry any
data.

Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Jens Axboe 2015-05-29 13:11:32 -06:00
parent beefa6ba7b
commit e548ca4ee4

View File

@ -903,7 +903,7 @@ static inline unsigned int blk_rq_get_max_sectors(struct request *rq)
if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC))
return q->limits.max_hw_sectors;
if (!q->limits.chunk_sectors)
if (!q->limits.chunk_sectors || (rq->cmd_flags & REQ_DISCARD))
return blk_queue_get_max_sectors(q, rq->cmd_flags);
return min(blk_max_size_offset(q, blk_rq_pos(rq)),