It is not necessary to issue request directly with bypass 'true'
in blk_mq_sched_insert_requests and handle the non-issued requests
itself. Just set bypass to 'false' and let blk_mq_try_issue_directly
handle them totally. Remove the blk_rq_can_direct_dispatch check,
because blk_mq_try_issue_directly can handle it well.
With respect to commit_rqs hook, we only need to care about the last
request's result. If it is inserted, invoke commit_rqs. We identify
the actual result of blk_mq_try_issue_directly with outputed cookie.
Signed-off-by: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx>
---
block/blk-mq-sched.c | 8 +++-----
block/blk-mq.c | 25 ++++++++-----------------
include/linux/blk_types.h | 1 +
3 files changed, 12 insertions(+), 22 deletions(-)
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index f096d898..5b4d52d 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -417,12 +417,10 @@ void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx,
* busy in case of 'none' scheduler, and this way may save
* us one extra enqueue & dequeue to sw queue.
*/
- if (!hctx->dispatch_busy && !e && !run_queue_async) {
+ if (!hctx->dispatch_busy && !e && !run_queue_async)
blk_mq_try_issue_list_directly(hctx, list);
- if (list_empty(list))
- return;
- }
- blk_mq_insert_requests(hctx, ctx, list);
+ else
+ blk_mq_insert_requests(hctx, ctx, list);
}
blk_mq_run_hw_queue(hctx, run_queue_async);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index fe92e52..0dfa269 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1899,32 +1899,23 @@ 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)
{
+ blk_qc_t cookie = BLK_QC_T_INVALID;
+
while (!list_empty(list)) {
- blk_status_t ret;
struct request *rq = list_first_entry(list, struct request,
queuelist);
- if (!blk_rq_can_direct_dispatch(rq))
- break;
-
list_del_init(&rq->queuelist);
- 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) {
- list_add(&rq->queuelist, list);
- break;
- }
- blk_mq_end_request(rq, ret);
- }
+ blk_mq_try_issue_directly(hctx, rq, &cookie, false,
+ list_empty(list));
}
/*
- * 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.
+ * cookie is set to a valid value only when reqeust is issued successfully.
+ * We only need to care about the last request's result, if it is inserted,
+ * kick the hardware with commit_rqs hook.
*/
- if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs)
+ if ((cookie == BLK_QC_T_INVALID) && hctx->queue->mq_ops->commit_rqs)
hctx->queue->mq_ops->commit_rqs(hctx);
}
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index c0ba1a0..a0a467a41 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -414,6 +414,7 @@ static inline int op_stat_group(unsigned int op)
}
typedef unsigned int blk_qc_t;
+#define BLK_QC_T_INVALID -2U
#define BLK_QC_T_NONE -1U
#define BLK_QC_T_SHIFT 16
#define BLK_QC_T_INTERNAL (1U << 31)
--
2.7.4
