From: Liu Bo bo.liu@linux.alibaba.com
commit e1a413245a564683697a3d02ec197b72cf009b89 upstream.
Since @blk_debugfs_root couldn't be configured dynamically, we can save a few memory allocation if it's not there.
Signed-off-by: Liu Bo bo.liu@linux.alibaba.com Signed-off-by: Jens Axboe axboe@kernel.dk [bwh: Cherry-picked for 4.14 to ease backporting a later fix] Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/blktrace.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -498,6 +498,9 @@ static int do_blk_trace_setup(struct req if (!buts->buf_size || !buts->buf_nr) return -EINVAL;
+ if (!blk_debugfs_root) + return -ENOENT; + strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
@@ -532,9 +535,6 @@ static int do_blk_trace_setup(struct req
ret = -ENOENT;
- if (!blk_debugfs_root) - goto err; - dir = debugfs_lookup(buts->name, blk_debugfs_root); if (!dir) bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);