block: freeze queue when updating zone resources

[ Upstream commit bba4322e3f303b2d656e748be758320b567f046f ]

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: 0b83c86b444a ("block: Prevent potential deadlock in blk_revalidate_disk_zones()")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[ adapted blk_mq_freeze_queue/unfreeze_queue calls to single-argument void API ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 60ba23d205808fb663ea171465bb34d184958d28..aac5ae9292b60a5248b1fcc1fa7f078d272d9b9b 100644 (file)
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -1514,6 +1514,11 @@ static int disk_update_zone_resources(struct gendisk *disk,
        unsigned int nr_seq_zones, nr_conv_zones;
        unsigned int pool_size;
        struct queue_limits lim;
+       int ret = 0;
+
+       lim = queue_limits_start_update(q);
+
+       blk_mq_freeze_queue(q);
 
        disk->nr_zones = args->nr_zones;
        disk->zone_capacity = args->zone_capacity;
@@ -1523,11 +1528,10 @@ 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
@@ -1564,7 +1568,15 @@ 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);
+
+       return ret;
 }
 
 static int blk_revalidate_conv_zone(struct blk_zone *zone, unsigned int idx,
@@ -1785,19 +1797,14 @@ 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
-               pr_warn("%s: failed to revalidate zones\n", disk->disk_name);
-       if (ret) {
-               blk_mq_freeze_queue(q);
-               disk_free_zone_resources(disk);
-               blk_mq_unfreeze_queue(q);
-       }
+               return disk_update_zone_resources(disk, &args);
+
+       pr_warn("%s: failed to revalidate zones\n", disk->disk_name);
+
+       blk_mq_freeze_queue(q);
+       disk_free_zone_resources(disk);
+       blk_mq_unfreeze_queue(q);
 
        return ret;
 }