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null_blk: synchronization fix for zoned device

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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: e0489ed5da ("null_blk: Support REQ_OP_ZONE_APPEND")
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Kanchan Joshi 2020-09-28 15:25:49 +05:30 committed by Jens Axboe
parent f255c19b3a
commit 35bc10b2ea
2 changed files with 19 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/block/null_blk.h
View File

@ -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 */

22
drivers/block/null_blk_zoned.c
View File

@ -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;
}