[PATCH 2/2] null_blk: fix race and oops at removing device with bandwidth limit

[Konstantin Khlebnikov]

Function null_del_dev should disable throttling before canceling timer,
otherwise timer could be restarted by null_handle_cmd().

Remove bump of cur_bytes - without NULLB_DEV_FL_THROTTLED it has no effect.

Fixes: eff2c4f10873 ("nullb: bandwidth control")
Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
---
 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 15925b355965..2d4ba7b05e2f 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1398,8 +1398,8 @@ static void null_del_dev(struct nullb *nullb)
        del_gendisk(nullb->disk);
 
        if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
+               clear_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags);
                hrtimer_cancel(&nullb->bw_timer);
-               atomic_long_set(&nullb->cur_bytes, LONG_MAX);
                null_restart_queue_async(nullb);
        }