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 <[email protected]> Signed-off-by: Ming Lei <[email protected]> --- 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 -- dm-devel mailing list [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
