[PATCH V4 5/9] null_blk: free zones array on device power-off

[Zizhi Wo]

From: Zizhi Wo <wozizhi@xxxxxxxxxx>

null_init_zoned_dev() allocates dev->zones when a zoned device is powered
on, but null_del_dev() never frees it on power-off; dev->zones is only
freed later in null_free_dev(), when the configfs directory is removed. If
the device is powered off and then on again, null_init_zoned_dev()
allocates a new array and overwrites the dev->zones pointer, leaking the
previous allocation each power cycle.

Free dev->zones in null_del_dev() via null_free_zoned_dev() to solve it.
And calling null_del_dev() in null_free_dev() is no longer necessary
because every caller already invokes null_del_dev() first: via
nullb_group_drop_item() before nullb_device_release(), in the
null_add_dev() error path of null_create_dev(), and in null_destroy_dev().
Remove the redundant call.

Fixes: ca4b2a011948 ("null_blk: add zone support")
Signed-off-by: Zizhi Wo <wozizhi@xxxxxxxxxx>
---
 drivers/block/null_blk/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index df85189f0b69..a75989220a2f 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -834,11 +834,10 @@ static struct nullb_device *null_alloc_dev(void)
 static void null_free_dev(struct nullb_device *dev)
 {
 	if (!dev)
 		return;
 
-	null_free_zoned_dev(dev);
 	badblocks_exit(&dev->badblocks);
 	kfree(dev);
 }
 
 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
@@ -1775,10 +1774,11 @@ static void null_del_dev(struct nullb *nullb)
 		atomic_long_set(&nullb->cur_bytes, LONG_MAX);
 		blk_mq_start_stopped_hw_queues(nullb->q, true);
 	}
 
 	put_disk(nullb->disk);
+	null_free_zoned_dev(dev);
 	if (nullb->tag_set == &nullb->__tag_set)
 		blk_mq_free_tag_set(nullb->tag_set);
 	kfree(nullb->queues);
 	if (null_cache_active(nullb))
 		null_free_device_storage(nullb->dev, true);
-- 
2.52.0