Commit 9e78c38a authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
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block: Hold a reference on zone write plugs to schedule submission 



Since a zone write plug BIO work is a field of struct blk_zone_wplug, we
must ensure that a zone write plug is never freed when its BIO
submission work is queued or running. Do this by holding a reference on
the zone write plug when the submission work is scheduled for execution
with queue_work() and releasing the reference at the end of the
execution of the work function blk_zone_wplug_bio_work().
The helper function disk_zone_wplug_schedule_bio_work() is introduced to
get a reference on a zone write plug and queue its work. This helper is
used in disk_zone_wplug_unplug_bio() and disk_zone_wplug_handle_error().

Fixes: dd291d77 ("block: Introduce zone write plugging")
Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-6-dlemoal@kernel.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 19aad274

block/blk-zoned.c

+21 −5
Original line number Diff line number Diff line
@@ -1132,6 +1132,19 @@ bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs) 
}

EXPORT_SYMBOL_GPL(blk_zone_plug_bio);



static void disk_zone_wplug_schedule_bio_work(struct gendisk *disk,

					      struct blk_zone_wplug *zwplug)

{

	/*

	 * Take a reference on the zone write plug and schedule the submission

	 * of the next plugged BIO. blk_zone_wplug_bio_work() will release the

	 * reference we take here.

	 */

	WARN_ON_ONCE(!(zwplug->flags & BLK_ZONE_WPLUG_PLUGGED));

	atomic_inc(&zwplug->ref);

	queue_work(disk->zone_wplugs_wq, &zwplug->bio_work);

}



static void disk_zone_wplug_unplug_bio(struct gendisk *disk,

				       struct blk_zone_wplug *zwplug)

{
@@ -1151,8 +1164,8 @@ static void disk_zone_wplug_unplug_bio(struct gendisk *disk, 


	/* Schedule submission of the next plugged BIO if we have one. */

	if (!bio_list_empty(&zwplug->bio_list)) {

		disk_zone_wplug_schedule_bio_work(disk, zwplug);

		spin_unlock_irqrestore(&zwplug->lock, flags);

		queue_work(disk->zone_wplugs_wq, &zwplug->bio_work);

		return;

	}
@@ -1252,14 +1265,14 @@ static void blk_zone_wplug_bio_work(struct work_struct *work) 
	if (!bio) {

		zwplug->flags &= ~BLK_ZONE_WPLUG_PLUGGED;

		spin_unlock_irqrestore(&zwplug->lock, flags);

		return;

		goto put_zwplug;

	}



	if (!blk_zone_wplug_prepare_bio(zwplug, bio)) {

		/* Error recovery will decide what to do with the BIO. */

		bio_list_add_head(&zwplug->bio_list, bio);

		spin_unlock_irqrestore(&zwplug->lock, flags);

		return;

		goto put_zwplug;

	}



	spin_unlock_irqrestore(&zwplug->lock, flags);
@@ -1275,6 +1288,10 @@ static void blk_zone_wplug_bio_work(struct work_struct *work) 
	 */

	if (bdev->bd_has_submit_bio)

		blk_queue_exit(bdev->bd_disk->queue);



put_zwplug:

	/* Drop the reference we took in disk_zone_wplug_schedule_bio_work(). */

	disk_put_zone_wplug(zwplug);

}



static unsigned int blk_zone_wp_offset(struct blk_zone *zone)
@@ -1354,8 +1371,7 @@ static void disk_zone_wplug_handle_error(struct gendisk *disk, 


	/* Restart BIO submission if we still have any BIO left. */

	if (!bio_list_empty(&zwplug->bio_list)) {

		WARN_ON_ONCE(!(zwplug->flags & BLK_ZONE_WPLUG_PLUGGED));

		queue_work(disk->zone_wplugs_wq, &zwplug->bio_work);

		disk_zone_wplug_schedule_bio_work(disk, zwplug);

		goto unlock;

	}