[PATCH 6/6] blktrace: use existing disk debugfs directory
From: Omar Sandoval <osandov@osandov.com>
Date: 2017-01-31 23:01:06
Subsystem:
block layer, the rest, tracing · Maintainers:
Jens Axboe, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
From: Omar Sandoval <redacted>
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 <redacted>
---
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 38052f625a0f..cc9d23692a35 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; }
--
2.11.0