Refactor the hybrid polling logic by moving the request lookup into a
helper, and the check if hybrid polling is enabled into blk_poll, and
then merging blk_mq_poll_hybrid and blk_mq_poll_hybrid_sleep into a
single function.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/blk-mq.c | 65 +++++++++++++++++++-------------------------------
1 file changed, 25 insertions(+), 40 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3dde5e7b2251..15a8bfd27aa2 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -69,6 +69,14 @@ static inline struct blk_mq_hw_ctx *blk_qc_to_hctx(struct request_queue *q,
return q->queue_hw_ctx[(qc & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT];
}
+static inline struct request *blk_qc_to_rq(struct blk_mq_hw_ctx *hctx,
+ blk_qc_t qc)
+{
+ if (blk_qc_t_is_internal(qc))
+ return blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(qc));
+ return blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(qc));
+}
+
/*
* Check if any of the ctx, dispatch list or elevator
* have pending work in this hardware queue.
@@ -3781,15 +3789,20 @@ static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
return ret;
}
-static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
- struct request *rq)
+static bool blk_mq_poll_hybrid(struct request_queue *q, blk_qc_t qc)
{
+ struct blk_mq_hw_ctx *hctx = blk_qc_to_hctx(q, qc);
+ struct request *rq = blk_qc_to_rq(hctx, qc);
struct hrtimer_sleeper hs;
enum hrtimer_mode mode;
unsigned int nsecs;
ktime_t kt;
- if (rq->rq_flags & RQF_MQ_POLL_SLEPT)
+ /*
+ * If a request has completed on queue that uses an I/O scheduler, we
+ * won't get back a request from blk_qc_to_rq.
+ */
+ if (!rq || (rq->rq_flags & RQF_MQ_POLL_SLEPT))
return false;
/*
@@ -3834,31 +3847,6 @@ static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
return true;
}
-static bool blk_mq_poll_hybrid(struct request_queue *q,
- struct blk_mq_hw_ctx *hctx, blk_qc_t cookie)
-{
- struct request *rq;
-
- if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
- return false;
-
- if (!blk_qc_t_is_internal(cookie))
- rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie));
- else {
- rq = blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(cookie));
- /*
- * With scheduling, if the request has completed, we'll
- * get a NULL return here, as we clear the sched tag when
- * that happens. The request still remains valid, like always,
- * so we should be safe with just the NULL check.
- */
- if (!rq)
- return false;
- }
-
- return blk_mq_poll_hybrid_sleep(q, rq);
-}
-
static int blk_mq_poll_classic(struct request_queue *q, blk_qc_t qc, bool spin)
{
struct blk_mq_hw_ctx *hctx = blk_qc_to_hctx(q, qc);
@@ -3906,8 +3894,6 @@ static int blk_mq_poll_classic(struct request_queue *q, blk_qc_t qc, bool spin)
*/
int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
{
- struct blk_mq_hw_ctx *hctx;
-
if (!blk_qc_t_valid(cookie) ||
!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
return 0;
@@ -3915,18 +3901,17 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
if (current->plug)
blk_flush_plug_list(current->plug, false);
- hctx = blk_qc_to_hctx(q, cookie);
-
/*
- * If we sleep, have the caller restart the poll loop to reset
- * the state. Like for the other success return cases, the
- * caller is responsible for checking if the IO completed. If
- * the IO isn't complete, we'll get called again and will go
- * straight to the busy poll loop. If specified not to spin,
- * we also should not sleep.
+ * If we sleep, have the caller restart the poll loop to reset the
+ * state. Like for the other success return cases, the caller is
+ * responsible for checking if the IO completed. If the IO isn't
+ * complete, we'll get called again and will go straight to the busy
+ * poll loop. If specified not to spin, we also should not sleep.
*/
- if (spin && blk_mq_poll_hybrid(q, hctx, cookie))
- return 1;
+ if (spin && q->poll_nsec != BLK_MQ_POLL_CLASSIC) {
+ if (blk_mq_poll_hybrid(q, cookie))
+ return 1;
+ }
return blk_mq_poll_classic(q, cookie, spin);
}
EXPORT_SYMBOL_GPL(blk_poll);
--
2.30.1
