tracing: Fix a possible race when disabling buffered events

[platform/kernel/linux-starfive.git] / kernel / trace / blktrace.c

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 5743be5..d5d9451 100644 (file)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -729,14 +729,10 @@ EXPORT_SYMBOL_GPL(blk_trace_startstop);
  **/
 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 {
-       struct request_queue *q;
+       struct request_queue *q = bdev_get_queue(bdev);
        int ret, start = 0;
        char b[BDEVNAME_SIZE];
 
-       q = bdev_get_queue(bdev);
-       if (!q)
-               return -ENXIO;
-
        mutex_lock(&q->debugfs_mutex);
 
        switch (cmd) {