Commit bba4322e authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
Browse files

block: freeze queue when updating zone resources 



Modify disk_update_zone_resources() to freeze the device queue before
updating the number of zones, zone capacity and other zone related
resources. The locking order resulting from the call to
queue_limits_commit_update_frozen() is preserved, that is, the queue
limits lock is first taken by calling queue_limits_start_update() before
freezing the queue, and the queue is unfrozen after executing
queue_limits_commit_update(), which replaces the call to
queue_limits_commit_update_frozen().

This change ensures that there are no in-flights I/Os when the zone
resources are updated due to a zone revalidation. In case of error when
the limits are applied, directly call disk_free_zone_resources() from
disk_update_zone_resources() while the disk queue is still frozen to
avoid needing to freeze & unfreeze the queue again in
blk_revalidate_disk_zones(), thus simplifying that function code a
little.

Fixes: 0b83c86b ("block: Prevent potential deadlock in blk_revalidate_disk_zones()")
Cc: stable@vger.kernel.org
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>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent efae226c

block/blk-zoned.c

+24 −18
Original line number Diff line number Diff line
@@ -1557,8 +1557,13 @@ static int disk_update_zone_resources(struct gendisk *disk, 
{

	struct request_queue *q = disk->queue;

	unsigned int nr_seq_zones, nr_conv_zones;

	unsigned int pool_size;

	unsigned int pool_size, memflags;

	struct queue_limits lim;

	int ret = 0;



	lim = queue_limits_start_update(q);



	memflags = blk_mq_freeze_queue(q);



	disk->nr_zones = args->nr_zones;

	disk->zone_capacity = args->zone_capacity;
@@ -1568,11 +1573,10 @@ static int disk_update_zone_resources(struct gendisk *disk, 
	if (nr_conv_zones >= disk->nr_zones) {

		pr_warn("%s: Invalid number of conventional zones %u / %u\n",

			disk->disk_name, nr_conv_zones, disk->nr_zones);

		return -ENODEV;

		ret = -ENODEV;

		goto unfreeze;

	}



	lim = queue_limits_start_update(q);



	/*

	 * Some devices can advertize zone resource limits that are larger than

	 * the number of sequential zones of the zoned block device, e.g. a
@@ -1609,7 +1613,15 @@ static int disk_update_zone_resources(struct gendisk *disk, 
	}



commit:

	return queue_limits_commit_update_frozen(q, &lim);

	ret = queue_limits_commit_update(q, &lim);



unfreeze:

	if (ret)

		disk_free_zone_resources(disk);



	blk_mq_unfreeze_queue(q, memflags);



	return ret;

}



static int blk_revalidate_conv_zone(struct blk_zone *zone, unsigned int idx,
@@ -1774,7 +1786,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk) 
	sector_t zone_sectors = q->limits.chunk_sectors;

	sector_t capacity = get_capacity(disk);

	struct blk_revalidate_zone_args args = { };

	unsigned int noio_flag;

	unsigned int memflags, noio_flag;

	int ret = -ENOMEM;



	if (WARN_ON_ONCE(!blk_queue_is_zoned(q)))
@@ -1824,20 +1836,14 @@ int blk_revalidate_disk_zones(struct gendisk *disk) 
		ret = -ENODEV;

	}



	/*

	 * Set the new disk zone parameters only once the queue is frozen and

	 * all I/Os are completed.

	 */

	if (ret > 0)

		ret = disk_update_zone_resources(disk, &args);

	else

		return disk_update_zone_resources(disk, &args);



	pr_warn("%s: failed to revalidate zones\n", disk->disk_name);

	if (ret) {

		unsigned int memflags = blk_mq_freeze_queue(q);



	memflags = blk_mq_freeze_queue(q);

	disk_free_zone_resources(disk);

	blk_mq_unfreeze_queue(q, memflags);

	}



	return ret;

}