Commit 35bc10b2 authored by Kanchan Joshi's avatar Kanchan Joshi Committed by Jens Axboe
Browse files

null_blk: synchronization fix for zoned device 



Parallel write,read,zone-mgmt operations accessing/altering zone state
and write-pointer may get into race. Avoid the situation by using a new
spinlock for zoned device.
Concurrent zone-appends (on a zone) returning same write-pointer issue
is also avoided using this lock.

Cc: stable@vger.kernel.org
Fixes: e0489ed5 ("null_blk: Support REQ_OP_ZONE_APPEND")
Signed-off-by: default avatarKanchan Joshi <joshi.k@samsung.com>
Reviewed-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f255c19b

drivers/block/null_blk.h

+1 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ struct nullb_device { 
	unsigned int nr_zones_closed;

	struct blk_zone *zones;

	sector_t zone_size_sects;

	spinlock_t zone_lock;



	unsigned long size; /* device size in MB */

	unsigned long completion_nsec; /* time in ns to complete a request */

drivers/block/null_blk_zoned.c

+18 −4
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q) 
	if (!dev->zones)

		return -ENOMEM;



	spin_lock_init(&dev->zone_lock);

	if (dev->zone_nr_conv >= dev->nr_zones) {

		dev->zone_nr_conv = dev->nr_zones - 1;

		pr_info("changed the number of conventional zones to %u",
@@ -149,8 +150,11 @@ int null_report_zones(struct gendisk *disk, sector_t sector, 
		 * So use a local copy to avoid corruption of the device zone

		 * array.

		 */

		spin_lock_irq(&dev->zone_lock);

		memcpy(&zone, &dev->zones[first_zone + i],

		       sizeof(struct blk_zone));

		spin_unlock_irq(&dev->zone_lock);



		error = cb(&zone, i, data);

		if (error)

			return error;
@@ -499,18 +503,28 @@ static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_opf op, 
blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd, enum req_opf op,

				    sector_t sector, sector_t nr_sectors)

{

	blk_status_t sts;

	struct nullb_device *dev = cmd->nq->dev;



	spin_lock_irq(&dev->zone_lock);

	switch (op) {

	case REQ_OP_WRITE:

		return null_zone_write(cmd, sector, nr_sectors, false);

		sts = null_zone_write(cmd, sector, nr_sectors, false);

		break;

	case REQ_OP_ZONE_APPEND:

		return null_zone_write(cmd, sector, nr_sectors, true);

		sts = null_zone_write(cmd, sector, nr_sectors, true);

		break;

	case REQ_OP_ZONE_RESET:

	case REQ_OP_ZONE_RESET_ALL:

	case REQ_OP_ZONE_OPEN:

	case REQ_OP_ZONE_CLOSE:

	case REQ_OP_ZONE_FINISH:

		return null_zone_mgmt(cmd, op, sector);

		sts = null_zone_mgmt(cmd, op, sector);

		break;

	default:

		return null_process_cmd(cmd, op, sector, nr_sectors);

		sts = null_process_cmd(cmd, op, sector, nr_sectors);

	}

	spin_unlock_irq(&dev->zone_lock);



	return sts;

}

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