Commit f7029141 authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
Browse files

block: Introduce bio_needs_zone_write_plugging() 



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: f211268e ("dm: Use the block layer zone append emulation")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250625093327.548866-3-dlemoal@kernel.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3f66ccba

block/blk-mq.c

+4 −2
Original line number Diff line number Diff line
@@ -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))

	if (bio_needs_zone_write_plugging(bio)) {

		if (blk_zone_plug_bio(bio, nr_segs))

			goto queue_exit;

	}



new_request:

	if (rq) {

block/blk-zoned.c

+1 −19
Original line number Diff line number Diff line
@@ -1116,25 +1116,7 @@ bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs) 
{

	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;



	/*

drivers/md/dm.c

+3 −1
Original line number Diff line number Diff line
@@ -1788,7 +1788,9 @@ static inline bool dm_zone_bio_needs_split(struct mapped_device *md, 
}

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,

include/linux/blkdev.h

+55 −0
Original line number Diff line number Diff line
@@ -837,6 +837,55 @@ static inline unsigned int disk_nr_zones(struct gendisk *disk) 
{

	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);



/**
@@ -866,6 +915,12 @@ static inline unsigned int disk_nr_zones(struct gendisk *disk) 
{

	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;