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From: Jens Axboe <axboe@kernel.dk>
To: linux-block@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 07/11] block: have ->poll_fn() return number of entries polled
Date: Tue, 13 Nov 2018 08:42:29 -0700	[thread overview]
Message-ID: <20181113154233.15256-8-axboe@kernel.dk> (raw)
In-Reply-To: <20181113154233.15256-1-axboe@kernel.dk>

We currently only really support sync poll, ie poll with 1
IO in flight. This prepares us for supporting async poll.

Note that the returned value isn't necessarily 100% accurate.
If poll races with IRQ completion, we assume that the fact
that the task is now runnable means we found at least one
entry. In reality it could be more than 1, or not even 1.
This is fine, the caller will just need to take this into
account.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 block/blk-mq.c                | 18 +++++++++---------
 drivers/nvme/host/multipath.c |  4 ++--
 include/linux/blkdev.h        |  2 +-
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6e0cb6adfc90..f8c2e6544903 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -38,7 +38,7 @@
 #include "blk-mq-sched.h"
 #include "blk-rq-qos.h"
 
-static bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie);
+static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie);
 static void blk_mq_poll_stats_start(struct request_queue *q);
 static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
 
@@ -3305,7 +3305,7 @@ static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
 	return true;
 }
 
-static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq)
+static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq)
 {
 	struct request_queue *q = hctx->queue;
 	long state;
@@ -3318,7 +3318,7 @@ static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq)
 	 * straight to the busy poll loop.
 	 */
 	if (blk_mq_poll_hybrid_sleep(q, hctx, rq))
-		return true;
+		return 1;
 
 	hctx->poll_considered++;
 
@@ -3332,30 +3332,30 @@ static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq)
 		if (ret > 0) {
 			hctx->poll_success++;
 			set_current_state(TASK_RUNNING);
-			return true;
+			return ret;
 		}
 
 		if (signal_pending_state(state, current))
 			set_current_state(TASK_RUNNING);
 
 		if (current->state == TASK_RUNNING)
-			return true;
+			return 1;
 		if (ret < 0)
 			break;
 		cpu_relax();
 	}
 
 	__set_current_state(TASK_RUNNING);
-	return false;
+	return 0;
 }
 
-static bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
+static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
 {
 	struct blk_mq_hw_ctx *hctx;
 	struct request *rq;
 
 	if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
-		return false;
+		return 0;
 
 	hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
 	if (!blk_qc_t_is_internal(cookie))
@@ -3369,7 +3369,7 @@ static bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
 		 * so we should be safe with just the NULL check.
 		 */
 		if (!rq)
-			return false;
+			return 0;
 	}
 
 	return __blk_mq_poll(hctx, rq);
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 5e3cc8c59a39..0484c1f9c8ce 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -220,11 +220,11 @@ static blk_qc_t nvme_ns_head_make_request(struct request_queue *q,
 	return ret;
 }
 
-static bool nvme_ns_head_poll(struct request_queue *q, blk_qc_t qc)
+static int nvme_ns_head_poll(struct request_queue *q, blk_qc_t qc)
 {
 	struct nvme_ns_head *head = q->queuedata;
 	struct nvme_ns *ns;
-	bool found = false;
+	int found = 0;
 	int srcu_idx;
 
 	srcu_idx = srcu_read_lock(&head->srcu);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d1ef8cbbea04..b2af6c68b78d 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -287,7 +287,7 @@ static inline unsigned short req_get_ioprio(struct request *req)
 struct blk_queue_ctx;
 
 typedef blk_qc_t (make_request_fn) (struct request_queue *q, struct bio *bio);
-typedef bool (poll_q_fn) (struct request_queue *q, blk_qc_t);
+typedef int (poll_q_fn) (struct request_queue *q, blk_qc_t);
 
 struct bio_vec;
 typedef int (dma_drain_needed_fn)(struct request *);
-- 
2.17.1


  parent reply	other threads:[~2018-11-13 15:42 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-13 15:42 [PATCHSET v2 0/11] Various block optimizations Jens Axboe
2018-11-13 15:42 ` [PATCH 01/11] nvme: don't disable local ints for polled queue Jens Axboe
2018-11-13 15:42   ` Jens Axboe
2018-11-13 15:42 ` [PATCH 02/11] block: add queue_is_mq() helper Jens Axboe
2018-11-14 15:23   ` Christoph Hellwig
2018-11-13 15:42 ` [PATCH 03/11] blk-mq: embed blk_mq_ops directly in the request queue Jens Axboe
2018-11-13 15:42 ` [PATCH 04/11] blk-rq-qos: inline check for q->rq_qos functions Jens Axboe
2018-11-13 15:42 ` [PATCH 05/11] block: avoid ordered task state change for polled IO Jens Axboe
2018-11-14  2:29   ` jianchao.wang
2018-11-14  2:35     ` Jens Axboe
2018-11-13 15:42 ` [PATCH 06/11] block: add polled wakeup task helper Jens Axboe
2018-11-13 15:52   ` Keith Busch
2018-11-13 15:58     ` Jens Axboe
2018-11-13 16:59       ` Jens Axboe
2018-11-13 15:42 ` Jens Axboe [this message]
2018-11-13 15:42 ` [PATCH 08/11] blk-mq: when polling for IO, look for any completion Jens Axboe
2018-11-13 15:42 ` [PATCH 09/11] block: make blk_poll() take a parameter on whether to spin or not Jens Axboe
2018-11-13 15:42 ` [PATCH 10/11] block: for async O_DIRECT, mark us as polling if asked to Jens Axboe
2018-11-13 15:42 ` [PATCH 11/11] block: don't plug for aio/O_DIRECT HIPRI IO Jens Axboe

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