On Mon, Nov 26, 2018 at 09:35:55AM -0700, Jens Axboe wrote:
> If we are issuing a list of requests, we know if we're at the last one.
> If we fail issuing, ensure that we call ->commits_rqs() to flush any
> potential previous requests.
One comment below, otherwise
Reviewed-by: Omar Sandoval <osandov@xxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> block/blk-core.c | 2 +-
> block/blk-mq.c | 32 ++++++++++++++++++++++++--------
> block/blk-mq.h | 2 +-
> 3 files changed, 26 insertions(+), 10 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index c9758d185357..808a65d23f1a 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1334,7 +1334,7 @@ blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *
> * bypass a potential scheduler on the bottom device for
> * insert.
> */
> - return blk_mq_request_issue_directly(rq);
> + return blk_mq_request_issue_directly(rq, true);
> }
> EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 6a249bf6ed00..0a12cec0b426 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1260,6 +1260,14 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
> if (!list_empty(list)) {
> bool needs_restart;
>
> + /*
> + * If we didn't flush the entire list, we could have told
> + * the driver there was more coming, but that turned out to
> + * be a lie.
> + */
> + if (q->mq_ops->commit_rqs)
> + q->mq_ops->commit_rqs(hctx);
> +
This hunk seems like it should go with the patch adding commit_rqs.
> spin_lock(&hctx->lock);
> list_splice_init(list, &hctx->dispatch);
> spin_unlock(&hctx->lock);
> @@ -1736,12 +1744,12 @@ static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq)
>
> static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
> struct request *rq,
> - blk_qc_t *cookie)
> + blk_qc_t *cookie, bool last)
> {
> struct request_queue *q = rq->q;
> struct blk_mq_queue_data bd = {
> .rq = rq,
> - .last = true,
> + .last = last,
> };
> blk_qc_t new_cookie;
> blk_status_t ret;
> @@ -1776,7 +1784,7 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
> static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
> struct request *rq,
> blk_qc_t *cookie,
> - bool bypass_insert)
> + bool bypass_insert, bool last)
> {
> struct request_queue *q = rq->q;
> bool run_queue = true;
> @@ -1805,7 +1813,7 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
> goto insert;
> }
>
> - return __blk_mq_issue_directly(hctx, rq, cookie);
> + return __blk_mq_issue_directly(hctx, rq, cookie, last);
> insert:
> if (bypass_insert)
> return BLK_STS_RESOURCE;
> @@ -1824,7 +1832,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
>
> hctx_lock(hctx, &srcu_idx);
>
> - ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false);
> + ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false, true);
> if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
> blk_mq_sched_insert_request(rq, false, true, false);
> else if (ret != BLK_STS_OK)
> @@ -1833,7 +1841,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
> hctx_unlock(hctx, srcu_idx);
> }
>
> -blk_status_t blk_mq_request_issue_directly(struct request *rq)
> +blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
> {
> blk_status_t ret;
> int srcu_idx;
> @@ -1841,7 +1849,7 @@ blk_status_t blk_mq_request_issue_directly(struct request *rq)
> struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
>
> hctx_lock(hctx, &srcu_idx);
> - ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true);
> + ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true, last);
> hctx_unlock(hctx, srcu_idx);
>
> return ret;
> @@ -1856,7 +1864,7 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
> queuelist);
>
> list_del_init(&rq->queuelist);
> - ret = blk_mq_request_issue_directly(rq);
> + ret = blk_mq_request_issue_directly(rq, list_empty(list));
> if (ret != BLK_STS_OK) {
> if (ret == BLK_STS_RESOURCE ||
> ret == BLK_STS_DEV_RESOURCE) {
> @@ -1866,6 +1874,14 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
> blk_mq_end_request(rq, ret);
> }
> }
> +
> + /*
> + * If we didn't flush the entire list, we could have told
> + * the driver there was more coming, but that turned out to
> + * be a lie.
> + */
> + if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs)
> + hctx->queue->mq_ops->commit_rqs(hctx);
> }
>
> static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
> diff --git a/block/blk-mq.h b/block/blk-mq.h
> index 9ae8e9f8f8b1..7291e5379358 100644
> --- a/block/blk-mq.h
> +++ b/block/blk-mq.h
> @@ -69,7 +69,7 @@ void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
> struct list_head *list);
>
> /* Used by blk_insert_cloned_request() to issue request directly */
> -blk_status_t blk_mq_request_issue_directly(struct request *rq);
> +blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last);
> void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
> struct list_head *list);
>
> --
> 2.17.1
>
