blktrace: remove debugfs file dentries from struct blk_trace

These debugfs dentries do not need to be saved for anything as the whole
directory and everything in it is properly cleaned up when the parent
directory is removed.  So remove them from struct blk_trace and don't
save them when created as it's not necessary.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

include/linux/blktrace_api.h

@@ -23,8 +23,6 @@ struct blk_trace {
 	u32 pid;
 	u32 dev;
 	struct dentry *dir;
-	struct dentry *dropped_file;
-	struct dentry *msg_file;
 	struct list_head running_list;
 	atomic_t dropped;
 };

kernel/trace/blktrace.c

@@ -311,8 +311,6 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
 
 static void blk_trace_free(struct blk_trace *bt)
 {
-	debugfs_remove(bt->msg_file);
-	debugfs_remove(bt->dropped_file);
 	relay_close(bt->rchan);
 	debugfs_remove(bt->dir);
 	free_percpu(bt->sequence);
@@ -544,10 +542,8 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	INIT_LIST_HEAD(&bt->running_list);
 
 	ret = -EIO;
-	bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
-					       &blk_dropped_fops);
-
-	bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
+	debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
+	debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
 
 	bt->rchan = relay_open("trace", dir, buts->buf_size,
 				buts->buf_nr, &blk_relay_callbacks, bt);