From 6ac93117ab009d3901ed5d3d0f79056eb5fc0afd Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Tue, 31 Jan 2017 14:53:22 -0800 Subject: [PATCH] blktrace: use existing disk debugfs directory We may already have a directory to put the blktrace stuff in if 1. The disk uses blk-mq 2. CONFIG_BLK_DEBUG_FS is enabled 3. We are tracing the whole disk and not a partition Instead of hardcoding this very specific case, let's use the new debugfs_lookup(). If the directory exists, we use it, otherwise we create one and clean it up later. Fixes: 07e4fead45e6 ("blk-mq: create debugfs directory tree") Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe --- kernel/trace/blktrace.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 8cea91d248d98..b2058a7f94bd8 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -470,12 +470,12 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, if (!blk_debugfs_root) goto err; - dir = debugfs_create_dir(buts->name, blk_debugfs_root); - + dir = debugfs_lookup(buts->name, blk_debugfs_root); + if (!dir) + bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root); if (!dir) goto err; - bt->dir = dir; bt->dev = dev; atomic_set(&bt->dropped, 0); INIT_LIST_HEAD(&bt->running_list); @@ -517,9 +517,12 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, if (atomic_inc_return(&blk_probes_ref) == 1) blk_register_tracepoints(); - return 0; + ret = 0; err: - blk_trace_free(bt); + if (dir && !bt->dir) + dput(dir); + if (ret) + blk_trace_free(bt); return ret; }