path: root/lib
diff options
authorMing Lei <ming.lei@redhat.com>2019-01-15 11:59:52 +0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-01-15 16:29:57 +1200
commitfe76fc6aaf538df27708ffa3e5d549a6c8e16142 (patch)
tree4fda8ebbcb82694899a476026684951e25d9b853 /lib
parent3719876809e745b9db5293d418600c194bbf5c23 (diff)
sbitmap: Protect swap_lock from hardirq
Because we may call blk_mq_get_driver_tag() directly from blk_mq_dispatch_rq_list() without holding any lock, then HARDIRQ may come and the above DEADLOCK is triggered. Commit ab53dcfb3e7b ("sbitmap: Protect swap_lock from hardirq") tries to fix this issue by using 'spin_lock_bh', which isn't enough because we complete request from hardirq context direclty in case of multiqueue. Cc: Clark Williams <williams@redhat.com> Fixes: ab53dcfb3e7b ("sbitmap: Protect swap_lock from hardirq") Cc: Jens Axboe <axboe@kernel.dk> Cc: Ming Lei <ming.lei@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
1 files changed, 3 insertions, 2 deletions
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 864354000e04..5b382c1244ed 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -27,8 +27,9 @@ static inline bool sbitmap_deferred_clear(struct sbitmap *sb, int index)
unsigned long mask, val;
bool ret = false;
+ unsigned long flags;
- spin_lock_bh(&sb->map[index].swap_lock);
+ spin_lock_irqsave(&sb->map[index].swap_lock, flags);
if (!sb->map[index].cleared)
goto out_unlock;
@@ -49,7 +50,7 @@ static inline bool sbitmap_deferred_clear(struct sbitmap *sb, int index)
ret = true;
- spin_unlock_bh(&sb->map[index].swap_lock);
+ spin_unlock_irqrestore(&sb->map[index].swap_lock, flags);
return ret;