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Commit fe2cb290 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

loop: zero-fill bio on the submitting cpu 



In thruth I've just audited which blk-mq drivers don't currently have a
complete callback, but I think this change is at least borderline useful.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 17d5363b

drivers/block/loop.c

+14 −16
Original line number Diff line number Diff line
@@ -445,32 +445,27 @@ static int lo_req_flush(struct loop_device *lo, struct request *rq) 
	return ret;

}



static inline void handle_partial_read(struct loop_cmd *cmd, long bytes)

static void lo_complete_rq(struct request *rq)

{

	if (bytes < 0 || op_is_write(req_op(cmd->rq)))

		return;

	struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);



	if (unlikely(bytes < blk_rq_bytes(cmd->rq))) {

	if (unlikely(req_op(cmd->rq) == REQ_OP_READ && cmd->use_aio &&

		     cmd->ret >= 0 && cmd->ret < blk_rq_bytes(cmd->rq))) {

		struct bio *bio = cmd->rq->bio;



		bio_advance(bio, bytes);

		bio_advance(bio, cmd->ret);

		zero_fill_bio(bio);

	}



	blk_mq_end_request(rq, cmd->ret < 0 ? -EIO : 0);

}



static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2)

{

	struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb);

	struct request *rq = cmd->rq;



	handle_partial_read(cmd, ret);



	if (ret > 0)

		ret = 0;

	else if (ret < 0)

		ret = -EIO;



	blk_mq_complete_request(rq, ret);

	cmd->ret = ret;

	blk_mq_complete_request(cmd->rq, 0);

}



static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
@@ -1688,8 +1683,10 @@ static void loop_handle_cmd(struct loop_cmd *cmd) 
	ret = do_req_filebacked(lo, cmd->rq);

 failed:

	/* complete non-aio request */

	if (!cmd->use_aio || ret)

		blk_mq_complete_request(cmd->rq, ret ? -EIO : 0);

	if (!cmd->use_aio || ret) {

		cmd->ret = ret ? -EIO : 0;

		blk_mq_complete_request(cmd->rq, 0);

	}

}



static void loop_queue_work(struct kthread_work *work)
@@ -1715,6 +1712,7 @@ static int loop_init_request(void *data, struct request *rq, 
static const struct blk_mq_ops loop_mq_ops = {

	.queue_rq       = loop_queue_rq,

	.init_request	= loop_init_request,

	.complete	= lo_complete_rq,

};



static int loop_add(struct loop_device **l, int i)

drivers/block/loop.h

+1 −0
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ struct loop_cmd { 
	struct request *rq;

	struct list_head list;

	bool use_aio;           /* use AIO interface to handle I/O */

	long ret;

	struct kiocb iocb;

};