On Fri, Apr 13, 2018 at 04:30:35PM -0600, Jens Axboe wrote:
> We can always get at the request from the payload, no need to store
> a pointer to it.
>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> drivers/block/loop.c | 36 +++++++++++++++++++-----------------
> drivers/block/loop.h | 1 -
> 2 files changed, 19 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index c9d04497a415..8b2fde2109fc 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -452,9 +452,9 @@ static void lo_complete_rq(struct request *rq)
> {
> struct loop_cmd *cmd = blk_mq_rq_to_pdu(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;
> + if (unlikely(req_op(rq) == REQ_OP_READ && cmd->use_aio &&
> + cmd->ret >= 0 && cmd->ret < blk_rq_bytes(rq))) {
> + struct bio *bio = rq->bio;
>
> bio_advance(bio, cmd->ret);
> zero_fill_bio(bio);
> @@ -465,11 +465,13 @@ static void lo_complete_rq(struct request *rq)
>
> static void lo_rw_aio_do_completion(struct loop_cmd *cmd)
> {
> + struct request *rq = blk_mq_rq_from_pdu(cmd);
> +
> if (!atomic_dec_and_test(&cmd->ref))
> return;
> kfree(cmd->bvec);
> cmd->bvec = NULL;
> - blk_mq_complete_request(cmd->rq);
> + blk_mq_complete_request(rq);
> }
>
> static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2)
> @@ -487,7 +489,7 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
> {
> struct iov_iter iter;
> struct bio_vec *bvec;
> - struct request *rq = cmd->rq;
> + struct request *rq = blk_mq_rq_from_pdu(cmd);
> struct bio *bio = rq->bio;
> struct file *file = lo->lo_backing_file;
> unsigned int offset;
> @@ -1702,15 +1704,16 @@ EXPORT_SYMBOL(loop_unregister_transfer);
> static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
> const struct blk_mq_queue_data *bd)
> {
> - struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
> - struct loop_device *lo = cmd->rq->q->queuedata;
> + struct request *rq = bd->rq;
> + struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
> + struct loop_device *lo = rq->q->queuedata;
>
> - blk_mq_start_request(bd->rq);
> + blk_mq_start_request(rq);
>
> if (lo->lo_state != Lo_bound)
> return BLK_STS_IOERR;
>
> - switch (req_op(cmd->rq)) {
> + switch (req_op(rq)) {
> case REQ_OP_FLUSH:
> case REQ_OP_DISCARD:
> case REQ_OP_WRITE_ZEROES:
> @@ -1723,8 +1726,8 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
>
> /* always use the first bio's css */
> #ifdef CONFIG_BLK_CGROUP
> - if (cmd->use_aio && cmd->rq->bio && cmd->rq->bio->bi_css) {
> - cmd->css = cmd->rq->bio->bi_css;
> + if (cmd->use_aio && rq->bio && rq->bio->bi_css) {
> + cmd->css = rq->bio->bi_css;
> css_get(cmd->css);
> } else
> #endif
> @@ -1736,8 +1739,9 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
>
> static void loop_handle_cmd(struct loop_cmd *cmd)
> {
> - const bool write = op_is_write(req_op(cmd->rq));
> - struct loop_device *lo = cmd->rq->q->queuedata;
> + struct request *rq = blk_mq_rq_from_pdu(cmd);
> + const bool write = op_is_write(req_op(rq));
> + struct loop_device *lo = rq->q->queuedata;
> int ret = 0;
>
> if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) {
> @@ -1745,12 +1749,12 @@ static void loop_handle_cmd(struct loop_cmd *cmd)
> goto failed;
> }
>
> - ret = do_req_filebacked(lo, cmd->rq);
> + ret = do_req_filebacked(lo, rq);
> failed:
> /* complete non-aio request */
> if (!cmd->use_aio || ret) {
> cmd->ret = ret ? -EIO : 0;
> - blk_mq_complete_request(cmd->rq);
> + blk_mq_complete_request(rq);
> }
> }
>
> @@ -1767,9 +1771,7 @@ static int loop_init_request(struct blk_mq_tag_set *set, struct request *rq,
> {
> struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
>
> - cmd->rq = rq;
> kthread_init_work(&cmd->work, loop_queue_work);
> -
> return 0;
> }
>
> diff --git a/drivers/block/loop.h b/drivers/block/loop.h
> index 0f45416e4fcf..b78de9879f4f 100644
> --- a/drivers/block/loop.h
> +++ b/drivers/block/loop.h
> @@ -66,7 +66,6 @@ struct loop_device {
>
> struct loop_cmd {
> struct kthread_work work;
> - struct request *rq;
> bool use_aio; /* use AIO interface to handle I/O */
> atomic_t ref; /* only for aio */
> long ret;
> --
> 2.7.4
>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
--
Ming
