[PATCH V6 11/12] block: allow to control FLAG_POLL via sysfs for bio poll capable queue
From: Ming Lei <hidden>
Date: 2021-04-22 12:23:04
Also in:
dm-devel
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Prepare for supporting bio based io polling. If one disk is capable of bio polling, we allow user to control FLAG_POLL via sysfs. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <redacted> --- block/blk-sysfs.c | 14 ++++++++++++-- include/linux/genhd.h | 2 ++ 2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index fed4981b1f7a..3620db390658 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c@@ -430,9 +430,14 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page, { unsigned long poll_on; ssize_t ret; + struct gendisk *disk = queue_to_disk(q); - if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL || - !q->tag_set->map[HCTX_TYPE_POLL].nr_queues) + if (!queue_is_mq(q) && !(disk->flags & GENHD_FL_CAP_BIO_POLL)) + return -EINVAL; + + if (queue_is_mq(q) && (!q->tag_set || + q->tag_set->nr_maps <= HCTX_TYPE_POLL || + !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)) return -EINVAL; ret = queue_var_store(&poll_on, page, count);
@@ -442,6 +447,11 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page, if (poll_on) { blk_queue_flag_set(QUEUE_FLAG_POLL, q); } else { + /* + * For bio queue, it is safe to just freeze bio submission + * activity because we don't read FLAG_POLL after bio is + * submitted. + */ blk_mq_freeze_queue(q); blk_queue_flag_clear(QUEUE_FLAG_POLL, q); blk_mq_unfreeze_queue(q);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 7e9660ea967d..e5ae77cba853 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h@@ -104,6 +104,8 @@ struct partition_meta_info { #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE 0x0100 #define GENHD_FL_NO_PART_SCAN 0x0200 #define GENHD_FL_HIDDEN 0x0400 +/* only valid for bio based disk */ +#define GENHD_FL_CAP_BIO_POLL 0x0800 enum { DISK_EVENT_MEDIA_CHANGE = 1 << 0, /* media changed */
--
2.29.2