Commit db0a2e00 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block: clear drain buffer if draining for write command 



Clear drain buffer before chaining if the command in question is a
write.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 2fb98e84

block/blk-merge.c

+3 −0
Original line number Diff line number Diff line
@@ -221,6 +221,9 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, 
	} /* segments in rq */



	if (q->dma_drain_size && q->dma_drain_needed(rq)) {

		if (rq->cmd_flags & REQ_RW)

			memset(q->dma_drain_buffer, 0, q->dma_drain_size);



		sg->page_link &= ~0x02;

		sg = sg_next(sg);

		sg_set_page(sg, virt_to_page(q->dma_drain_buffer),