From: Ming Lei <ming.lei@redhat.com> To: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>, Jeffle Xu <jefflexu@linux.alibaba.com>, Mike Snitzer <snitzer@redhat.com>, dm-devel@redhat.com Subject: [RFC PATCH 10/11] block: add poll_capable method to support bio-based IO polling Date: Tue, 16 Mar 2021 11:15:22 +0800 [thread overview] Message-ID: <20210316031523.864506-11-ming.lei@redhat.com> (raw) In-Reply-To: <20210316031523.864506-1-ming.lei@redhat.com> From: Jeffle Xu <jefflexu@linux.alibaba.com> This method can be used to check if bio-based device supports IO polling or not. For mq devices, checking for hw queue in polling mode is adequate, while the sanity check shall be implementation specific for bio-based devices. For example, dm device needs to check if all underlying devices are capable of IO polling. Though bio-based device may have done the sanity check during the device initialization phase, cacheing the result of this sanity check (such as by cacheing in the queue_flags) may not work. Because for dm devices, users could change the state of the underlying devices through '/sys/block/<dev>/io_poll', bypassing the dm device above. In this case, the cached result of the very beginning sanity check could be out-of-date. Thus the sanity check needs to be done every time 'io_poll' is to be modified. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> --- block/blk-sysfs.c | 14 +++++++++++--- include/linux/blkdev.h | 1 + 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 0f4f0c8a7825..367c1d9a55c6 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -426,9 +426,17 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page, unsigned long poll_on; ssize_t ret; - if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL || - !q->tag_set->map[HCTX_TYPE_POLL].nr_queues) - return -EINVAL; + if (queue_is_mq(q)) { + if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL || + !q->tag_set->map[HCTX_TYPE_POLL].nr_queues) + return -EINVAL; + } else { + struct gendisk *disk = queue_to_disk(q); + + if (!disk->fops->poll_capable || + !disk->fops->poll_capable(disk)) + return -EINVAL; + } ret = queue_var_store(&poll_on, page, count); if (ret < 0) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index bfab74b45f15..a46f975f2a2f 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1881,6 +1881,7 @@ struct block_device_operations { int (*report_zones)(struct gendisk *, sector_t sector, unsigned int nr_zones, report_zones_cb cb, void *data); char *(*devnode)(struct gendisk *disk, umode_t *mode); + bool (*poll_capable)(struct gendisk *disk); struct module *owner; const struct pr_ops *pr_ops; }; -- 2.29.2
WARNING: multiple messages have this Message-ID (diff)
From: Ming Lei <ming.lei@redhat.com> To: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org, Jeffle Xu <jefflexu@linux.alibaba.com>, dm-devel@redhat.com, Christoph Hellwig <hch@lst.de>, Mike Snitzer <snitzer@redhat.com> Subject: [dm-devel] [RFC PATCH 10/11] block: add poll_capable method to support bio-based IO polling Date: Tue, 16 Mar 2021 11:15:22 +0800 [thread overview] Message-ID: <20210316031523.864506-11-ming.lei@redhat.com> (raw) In-Reply-To: <20210316031523.864506-1-ming.lei@redhat.com> From: Jeffle Xu <jefflexu@linux.alibaba.com> This method can be used to check if bio-based device supports IO polling or not. For mq devices, checking for hw queue in polling mode is adequate, while the sanity check shall be implementation specific for bio-based devices. For example, dm device needs to check if all underlying devices are capable of IO polling. Though bio-based device may have done the sanity check during the device initialization phase, cacheing the result of this sanity check (such as by cacheing in the queue_flags) may not work. Because for dm devices, users could change the state of the underlying devices through '/sys/block/<dev>/io_poll', bypassing the dm device above. In this case, the cached result of the very beginning sanity check could be out-of-date. Thus the sanity check needs to be done every time 'io_poll' is to be modified. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> --- block/blk-sysfs.c | 14 +++++++++++--- include/linux/blkdev.h | 1 + 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 0f4f0c8a7825..367c1d9a55c6 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -426,9 +426,17 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page, unsigned long poll_on; ssize_t ret; - if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL || - !q->tag_set->map[HCTX_TYPE_POLL].nr_queues) - return -EINVAL; + if (queue_is_mq(q)) { + if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL || + !q->tag_set->map[HCTX_TYPE_POLL].nr_queues) + return -EINVAL; + } else { + struct gendisk *disk = queue_to_disk(q); + + if (!disk->fops->poll_capable || + !disk->fops->poll_capable(disk)) + return -EINVAL; + } ret = queue_var_store(&poll_on, page, count); if (ret < 0) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index bfab74b45f15..a46f975f2a2f 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1881,6 +1881,7 @@ struct block_device_operations { int (*report_zones)(struct gendisk *, sector_t sector, unsigned int nr_zones, report_zones_cb cb, void *data); char *(*devnode)(struct gendisk *disk, umode_t *mode); + bool (*poll_capable)(struct gendisk *disk); struct module *owner; const struct pr_ops *pr_ops; }; -- 2.29.2 -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel
next prev parent reply other threads:[~2021-03-16 3:20 UTC|newest] Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-16 3:15 [RFC PATCH 00/11] block: support bio based io polling Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 3:15 ` [RFC PATCH 01/11] block: add helper of blk_queue_poll Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 3:26 ` Chaitanya Kulkarni 2021-03-16 3:26 ` [dm-devel] " Chaitanya Kulkarni 2021-03-16 3:15 ` [RFC PATCH 02/11] block: add one helper to free io_context Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 3:15 ` [RFC PATCH 03/11] block: add helper of blk_create_io_context Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 3:15 ` [RFC PATCH 04/11] block: create io poll context for submission and poll task Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 3:15 ` [RFC PATCH 05/11] block: add req flag of REQ_TAG Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 3:15 ` [RFC PATCH 06/11] block: add new field into 'struct bvec_iter' Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 3:15 ` [RFC PATCH 07/11] block/mq: extract one helper function polling hw queue Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 3:15 ` [RFC PATCH 08/11] block: use per-task poll context to implement bio based io poll Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 6:46 ` JeffleXu 2021-03-16 6:46 ` [dm-devel] " JeffleXu 2021-03-16 7:17 ` Ming Lei 2021-03-16 7:17 ` [dm-devel] " Ming Lei 2021-03-16 8:52 ` JeffleXu 2021-03-16 8:52 ` [dm-devel] " JeffleXu 2021-03-17 2:54 ` Ming Lei 2021-03-17 2:54 ` [dm-devel] " Ming Lei 2021-03-17 3:53 ` JeffleXu 2021-03-17 3:53 ` [dm-devel] " JeffleXu 2021-03-17 6:54 ` Ming Lei 2021-03-17 6:54 ` [dm-devel] " Ming Lei 2021-03-16 11:00 ` JeffleXu 2021-03-16 11:00 ` [dm-devel] " JeffleXu 2021-03-17 3:38 ` Ming Lei 2021-03-17 3:38 ` [dm-devel] " Ming Lei 2021-03-17 3:49 ` JeffleXu 2021-03-17 3:49 ` [dm-devel] " JeffleXu 2021-03-17 7:19 ` Ming Lei 2021-03-17 7:19 ` [dm-devel] " Ming Lei 2021-03-18 14:51 ` Mike Snitzer 2021-03-18 14:51 ` [dm-devel] " Mike Snitzer 2021-03-16 3:15 ` [RFC PATCH 09/11] block: add queue_to_disk() to get gendisk from request_queue Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei 2021-03-16 3:15 ` Ming Lei [this message] 2021-03-16 3:15 ` [dm-devel] [RFC PATCH 10/11] block: add poll_capable method to support bio-based IO polling Ming Lei 2021-03-16 3:15 ` [RFC PATCH 11/11] dm: support IO polling for bio-based dm device Ming Lei 2021-03-16 3:15 ` [dm-devel] " Ming Lei
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