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>, Mike Snitzer <snitzer@redhat.com>, dm-devel@redhat.com, Hannes Reinecke <hare@suse.de> Subject: [PATCH V4 11/12] block: add poll_capable method to support bio-based IO polling Date: Mon, 29 Mar 2021 23:26:21 +0800 [thread overview] Message-ID: <20210329152622.173035-12-ming.lei@redhat.com> (raw) In-Reply-To: <20210329152622.173035-1-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 In this case, the cached result of the very beginning sanity check could be out-of-date.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 db3268d41274..c8e7e4af66cb 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, Mike Snitzer <snitzer@redhat.com> Subject: [dm-devel] [PATCH V4 11/12] block: add poll_capable method to support bio-based IO polling Date: Mon, 29 Mar 2021 23:26:21 +0800 [thread overview] Message-ID: <20210329152622.173035-12-ming.lei@redhat.com> (raw) In-Reply-To: <20210329152622.173035-1-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 db3268d41274..c8e7e4af66cb 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:[~2021-03-29 15:28 UTC|newest] Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-29 15:26 [PATCH V4 00/12] block: support bio based io polling Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-29 15:26 ` [PATCH V4 01/12] block: add helper of blk_queue_poll Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-29 15:26 ` [PATCH V4 02/12] block: add one helper to free io_context Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-29 15:26 ` [PATCH V4 03/12] block: create io poll context for submission and poll task Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-30 3:54 ` JeffleXu 2021-03-30 3:54 ` [dm-devel] " JeffleXu 2021-03-30 6:17 ` Hannes Reinecke 2021-03-30 6:17 ` [dm-devel] " Hannes Reinecke 2021-03-29 15:26 ` [PATCH V4 04/12] block: add req flag of REQ_POLL_CTX Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-30 6:19 ` Hannes Reinecke 2021-03-30 6:19 ` [dm-devel] " Hannes Reinecke 2021-03-29 15:26 ` [PATCH V4 05/12] block: add new field into 'struct bvec_iter' Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-29 15:26 ` [PATCH V4 06/12] block/mq: extract one helper function polling hw queue Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-29 15:26 ` [PATCH V4 07/12] block: prepare for supporting bio_list via other link Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-29 15:26 ` [PATCH V4 08/12] block: use per-task poll context to implement bio based io polling Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-30 3:52 ` JeffleXu 2021-03-30 3:52 ` [dm-devel] " JeffleXu 2021-03-30 6:40 ` Hannes Reinecke 2021-03-30 6:40 ` [dm-devel] " Hannes Reinecke 2021-03-30 8:32 ` Ming Lei 2021-03-30 8:32 ` [dm-devel] " Ming Lei 2021-03-29 15:26 ` [PATCH V4 09/12] blk-mq: limit hw queues to be polled in each blk_poll() Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-30 3:53 ` JeffleXu 2021-03-30 3:53 ` [dm-devel] " JeffleXu 2021-03-29 15:26 ` [PATCH V4 10/12] block: add queue_to_disk() to get gendisk from request_queue Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-30 6:27 ` Hannes Reinecke 2021-03-30 6:27 ` [dm-devel] " Hannes Reinecke 2021-03-29 15:26 ` Ming Lei [this message] 2021-03-29 15:26 ` [dm-devel] [PATCH V4 11/12] block: add poll_capable method to support bio-based IO polling Ming Lei 2021-03-30 6:26 ` Hannes Reinecke 2021-03-30 6:26 ` [dm-devel] " Hannes Reinecke 2021-03-30 6:50 ` JeffleXu 2021-03-30 6:50 ` [dm-devel] " JeffleXu 2021-03-30 8:49 ` Ming Lei 2021-03-30 8:49 ` [dm-devel] " Ming Lei 2021-03-29 15:26 ` [PATCH V4 12/12] dm: support IO polling for bio-based dm device Ming Lei 2021-03-29 15:26 ` [dm-devel] " Ming Lei 2021-03-30 6:40 ` Hannes Reinecke 2021-03-30 6:40 ` [dm-devel] " Hannes Reinecke
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