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Mon, 08 Feb 2021 03:52:50 -0500 X-MC-Unique: kbyAghp6Ohu7ugxIiNBNNQ-1 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R501e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04400; MF=jefflexu@linux.alibaba.com; NM=1; PH=DS; RN=8; SR=0; TI=SMTPD_---0UO9so9N_1612774367 Received: from localhost(mailfrom:jefflexu@linux.alibaba.com fp:SMTPD_---0UO9so9N_1612774367) by smtp.aliyun-inc.com(127.0.0.1); Mon, 08 Feb 2021 16:52:47 +0800 From: Jeffle Xu To: snitzer@redhat.com, axboe@kernel.dk Date: Mon, 8 Feb 2021 16:52:35 +0800 Message-Id: <20210208085243.82367-4-jefflexu@linux.alibaba.com> In-Reply-To: <20210208085243.82367-1-jefflexu@linux.alibaba.com> References: <20210208085243.82367-1-jefflexu@linux.alibaba.com> MIME-Version: 1.0 X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Mimecast-Bulk-Signature: yes X-Mimecast-Spam-Signature: bulk X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-loop: dm-devel@redhat.com X-Mailman-Approved-At: Wed, 17 Feb 2021 10:31:26 -0500 Cc: caspar@linux.alibaba.com, hch@lst.de, linux-block@vger.kernel.org, joseph.qi@linux.alibaba.com, dm-devel@redhat.com, io-uring@vger.kernel.org Subject: [dm-devel] [PATCH v3 03/11] block: add poll method to support bio-based IO polling X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com ->poll_fn was introduced in commit ea435e1b9392 ("block: add a poll_fn callback to struct request_queue") to support bio-based queues such as nvme multipath, but was later removed in commit 529262d56dbe ("block: remove ->poll_fn"). Given commit c62b37d96b6e ("block: move ->make_request_fn to struct block_device_operations") restore the possibility of bio-based IO polling support by adding an ->poll method to gendisk->fops. Make blk_mq_poll() specific to blk-mq, while blk_bio_poll() is originally a copy from blk_mq_poll(), and is specific to bio-based polling. Signed-off-by: Jeffle Xu --- block/blk-core.c | 58 ++++++++++++++++++++++++++++++++++++++++++ block/blk-mq.c | 22 +--------------- include/linux/blk-mq.h | 1 + include/linux/blkdev.h | 1 + 4 files changed, 61 insertions(+), 21 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 7663a9b94b80..37aa513da5f2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1132,6 +1132,64 @@ blk_qc_t submit_bio(struct bio *bio) } EXPORT_SYMBOL(submit_bio); + +static int blk_bio_poll(struct request_queue *q, blk_qc_t cookie, bool spin) +{ + long state; + struct gendisk *disk = queue_to_disk(q); + + state = current->state; + do { + int ret; + + ret = disk->fops->poll(q, cookie); + if (ret > 0) { + __set_current_state(TASK_RUNNING); + return ret; + } + + if (signal_pending_state(state, current)) + __set_current_state(TASK_RUNNING); + + if (current->state == TASK_RUNNING) + return 1; + if (ret < 0 || !spin) + break; + cpu_relax(); + } while (!need_resched()); + + __set_current_state(TASK_RUNNING); + return 0; +} + +/** + * blk_poll - poll for IO completions + * @q: the queue + * @cookie: cookie passed back at IO submission time + * @spin: whether to spin for completions + * + * Description: + * Poll for completions on the passed in queue. Returns number of + * completed entries found. If @spin is true, then blk_poll will continue + * looping until at least one completion is found, unless the task is + * otherwise marked running (or we need to reschedule). + */ +int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) +{ + if (!blk_qc_t_valid(cookie) || + !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) + return 0; + + if (current->plug) + blk_flush_plug_list(current->plug, false); + + if (queue_is_mq(q)) + return blk_mq_poll(q, cookie, spin); + else + return blk_bio_poll(q, cookie, spin); +} +EXPORT_SYMBOL_GPL(blk_poll); + /** * blk_cloned_rq_check_limits - Helper function to check a cloned request * for the new queue limits diff --git a/block/blk-mq.c b/block/blk-mq.c index f285a9123a8b..c18bc23834a0 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3826,30 +3826,11 @@ static bool blk_mq_poll_hybrid(struct request_queue *q, return blk_mq_poll_hybrid_sleep(q, rq); } -/** - * blk_poll - poll for IO completions - * @q: the queue - * @cookie: cookie passed back at IO submission time - * @spin: whether to spin for completions - * - * Description: - * Poll for completions on the passed in queue. Returns number of - * completed entries found. If @spin is true, then blk_poll will continue - * looping until at least one completion is found, unless the task is - * otherwise marked running (or we need to reschedule). - */ -int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) +int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin) { struct blk_mq_hw_ctx *hctx; long state; - if (!blk_qc_t_valid(cookie) || - !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) - return 0; - - if (current->plug) - blk_flush_plug_list(current->plug, false); - hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)]; /* @@ -3891,7 +3872,6 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) __set_current_state(TASK_RUNNING); return 0; } -EXPORT_SYMBOL_GPL(blk_poll); unsigned int blk_mq_rq_cpu(struct request *rq) { diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index d705b174d346..adc789d5888e 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -607,6 +607,7 @@ static inline void blk_rq_bio_prep(struct request *rq, struct bio *bio, } blk_qc_t blk_mq_submit_bio(struct bio *bio); +int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin); void blk_mq_hctx_set_fq_lock_class(struct blk_mq_hw_ctx *hctx, struct lock_class_key *key); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 2a802e011a95..ebe16f55cba4 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1853,6 +1853,7 @@ static inline void blk_ksm_unregister(struct request_queue *q) { } struct block_device_operations { blk_qc_t (*submit_bio) (struct bio *bio); + int (*poll)(struct request_queue *q, blk_qc_t cookie); int (*open) (struct block_device *, fmode_t); void (*release) (struct gendisk *, fmode_t); int (*rw_page)(struct block_device *, sector_t, struct page *, unsigned int);