6.16-stable review patch. If anyone has any objections, please let me know.
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From: Damien Le Moal dlemoal@kernel.org
commit f70291411ba20d50008db90a6f0731efac27872c upstream.
In preparation for fixing device mapper zone write handling, introduce the inline helper function bio_needs_zone_write_plugging() to test if a BIO requires handling through zone write plugging using the function blk_zone_plug_bio(). This function returns true for any write (op_is_write(bio) == true) operation directed at a zoned block device using zone write plugging, that is, a block device with a disk that has a zone write plug hash table.
This helper allows simplifying the check on entry to blk_zone_plug_bio() and used in to protect calls to it for blk-mq devices and DM devices.
Fixes: f211268ed1f9 ("dm: Use the block layer zone append emulation") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal dlemoal@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20250625093327.548866-3-dlemoal@kernel.org Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/blk-mq.c | 6 +++-- block/blk-zoned.c | 20 ----------------- drivers/md/dm.c | 4 ++- include/linux/blkdev.h | 55 +++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 63 insertions(+), 22 deletions(-)
--- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3169,8 +3169,10 @@ void blk_mq_submit_bio(struct bio *bio) if (blk_mq_attempt_bio_merge(q, bio, nr_segs)) goto queue_exit;
- if (blk_queue_is_zoned(q) && blk_zone_plug_bio(bio, nr_segs)) - goto queue_exit; + if (bio_needs_zone_write_plugging(bio)) { + if (blk_zone_plug_bio(bio, nr_segs)) + goto queue_exit; + }
new_request: if (rq) { --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -1116,25 +1116,7 @@ bool blk_zone_plug_bio(struct bio *bio, { struct block_device *bdev = bio->bi_bdev;
- if (!bdev->bd_disk->zone_wplugs_hash) - return false; - - /* - * If the BIO already has the plugging flag set, then it was already - * handled through this path and this is a submission from the zone - * plug bio submit work. - */ - if (bio_flagged(bio, BIO_ZONE_WRITE_PLUGGING)) - return false; - - /* - * We do not need to do anything special for empty flush BIOs, e.g - * BIOs such as issued by blkdev_issue_flush(). The is because it is - * the responsibility of the user to first wait for the completion of - * write operations for flush to have any effect on the persistence of - * the written data. - */ - if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) + if (WARN_ON_ONCE(!bdev->bd_disk->zone_wplugs_hash)) return false;
/* --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1788,7 +1788,9 @@ static inline bool dm_zone_bio_needs_spl } static inline bool dm_zone_plug_bio(struct mapped_device *md, struct bio *bio) { - return dm_emulate_zone_append(md) && blk_zone_plug_bio(bio, 0); + if (!bio_needs_zone_write_plugging(bio)) + return false; + return blk_zone_plug_bio(bio, 0); }
static blk_status_t __send_zone_reset_all_emulated(struct clone_info *ci, --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -842,6 +842,55 @@ static inline unsigned int disk_nr_zones { return disk->nr_zones; } + +/** + * bio_needs_zone_write_plugging - Check if a BIO needs to be handled with zone + * write plugging + * @bio: The BIO being submitted + * + * Return true whenever @bio execution needs to be handled through zone + * write plugging (using blk_zone_plug_bio()). Return false otherwise. + */ +static inline bool bio_needs_zone_write_plugging(struct bio *bio) +{ + enum req_op op = bio_op(bio); + + /* + * Only zoned block devices have a zone write plug hash table. But not + * all of them have one (e.g. DM devices may not need one). + */ + if (!bio->bi_bdev->bd_disk->zone_wplugs_hash) + return false; + + /* Only write operations need zone write plugging. */ + if (!op_is_write(op)) + return false; + + /* Ignore empty flush */ + if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) + return false; + + /* Ignore BIOs that already have been handled by zone write plugging. */ + if (bio_flagged(bio, BIO_ZONE_WRITE_PLUGGING)) + return false; + + /* + * All zone write operations must be handled through zone write plugging + * using blk_zone_plug_bio(). + */ + switch (op) { + case REQ_OP_ZONE_APPEND: + case REQ_OP_WRITE: + case REQ_OP_WRITE_ZEROES: + case REQ_OP_ZONE_FINISH: + case REQ_OP_ZONE_RESET: + case REQ_OP_ZONE_RESET_ALL: + return true; + default: + return false; + } +} + bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs);
/** @@ -871,6 +920,12 @@ static inline unsigned int disk_nr_zones { return 0; } + +static inline bool bio_needs_zone_write_plugging(struct bio *bio) +{ + return false; +} + static inline bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs) { return false;