diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index d5d94510afd3..ce5a1ed01d64 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -320,14 +320,16 @@ static void blk_trace_free(struct request_queue *q, struct blk_trace *bt) * under 'q->debugfs_dir', thus lookup and remove them. */ if (!bt->dir) { - debugfs_lookup_and_remove("dropped", q->debugfs_dir); - debugfs_lookup_and_remove("msg", q->debugfs_dir); + struct dentry *debugfs_dir = q ? q->debugfs_dir : bt->debugfs_dir; + + debugfs_lookup_and_remove("dropped", debugfs_dir); + debugfs_lookup_and_remove("msg", debugfs_dir); } else { debugfs_remove(bt->dir); } free_percpu(bt->sequence); free_percpu(bt->msg_data); - kfree(bt); + kfree_rcu(bt); } static void get_probe_ref(void) @@ -377,12 +379,25 @@ static int blk_trace_stop(struct blk_trace *bt) return 0; } +static void blk_trace_rcu_free(struct rcu_head *rcu) +{ + struct blk_trace *bt; + + bt = container_of(rcu, struct blk_trace, rcu); + if (bt) { + blk_trace_free(NULL, bt); + put_probe_ref(); + } +} + static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt) { blk_trace_stop(bt); - synchronize_rcu(); - blk_trace_free(q, bt); - put_probe_ref(); + if (!bt->dir) + bt->debugfs_dir = q->debugfs_dir; + mutex_unlock(&q->debugfs_mutex); + call_rcu(&bt->rcu, blk_trace_rcu_free); + mutex_lock(&q->debugfs_mutex); } static int __blk_trace_remove(struct request_queue *q) diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h index 122c62e561fc..4920c201bd12 100644 --- a/include/linux/blktrace_api.h +++ b/include/linux/blktrace_api.h @@ -26,6 +26,8 @@ struct blk_trace { struct dentry *dir; struct list_head running_list; atomic_t dropped; + struct dentry *debugfs_dir; + struct rcu_head rcu; }; extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);