On Thu, Feb 21, 2019 at 09:23:09AM +0100, Michal Hocko wrote: > On Thu 21-02-19 12:01:30, Yue Hu wrote: > > From: Yue Hu <huyue2@xxxxxxxxxx> > > > > If debugfs_create_dir() failed, the following debugfs_create_file() > > will be meanless since it depends on non-NULL tmp dentry and it will > > only waste CPU resource. > > The file will be created in the debugfs root. But, more importantly. > Greg (CCed now) is working on removing the failure paths because he > believes they do not really matter for debugfs and they make code more > ugly. More importantly a check for NULL is not correct because you > get ERR_PTR after recent changes IIRC. > > > > > Signed-off-by: Yue Hu <huyue2@xxxxxxxxxx> > > --- > > mm/cma_debug.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/mm/cma_debug.c b/mm/cma_debug.c > > index 2c2c869..3e9d984 100644 > > --- a/mm/cma_debug.c > > +++ b/mm/cma_debug.c > > @@ -169,6 +169,8 @@ static void cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry) > > scnprintf(name, sizeof(name), "cma-%s", cma->name); > > > > tmp = debugfs_create_dir(name, root_dentry); > > + if (!tmp) > > + return; Ick, yes, this patch isn't ok, I've been doing lots of work to rip these checks out :) Thanks for catching this Michal. greg k-h
