From: Mike Snitzer X-Patchwork-Id: 114064 Propagate REQ_DISCARD in cmd_flags when cloning a discard request. Skip blk_rq_check_limits's existing checks for discard requests because discard limits will have already been checked in blkdev_issue_discard. Signed-off-by: Mike Snitzer Cc: Jens Axboe Cc: Christoph Hellwig Cc: Kiyoshi Ueda Reviewed-by: Christoph Hellwig --- block/blk-core.c | 5 +++++ block/blk-core.c | 5 +++++ 1 file changed, 5 insertions(+) -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel Index: linux/block/blk-core.c =================================================================== --- linux.orig/block/blk-core.c +++ linux/block/blk-core.c @@ -1628,6 +1628,9 @@ EXPORT_SYMBOL(submit_bio); */ int blk_rq_check_limits(struct request_queue *q, struct request *rq) { + if (rq->cmd_flags & REQ_DISCARD) + return 0; + if (blk_rq_sectors(rq) > queue_max_sectors(q) || blk_rq_bytes(rq) > queue_max_hw_sectors(q) << 9) { printk(KERN_ERR "%s: over max size limit.\n", __func__); @@ -2450,6 +2453,8 @@ static void __blk_rq_prep_clone(struct r { dst->cpu = src->cpu; dst->cmd_flags = (rq_data_dir(src) | REQ_NOMERGE); + if (src->cmd_flags & REQ_DISCARD) + dst->cmd_flags |= REQ_DISCARD; dst->cmd_type = src->cmd_type; dst->__sector = blk_rq_pos(src); dst->__data_len = blk_rq_bytes(src);