Re: [PATCH] mm/memblock: validate the creation of debugfs files

Andrew Morton
2015-08-15T07:38:17Z

On Sat, 15 Aug 2015 13:26:36 +0600 Alexander Kuleshov <kuleshovmail@gmail.com> wrote:

> Hello Andrew,
>
> On 08-14-15, Andrew Morton wrote:
> > On Sat, 15 Aug 2015 01:03:31 +0600 Alexander Kuleshov <kuleshovmail@gmail.com> wrote:
> >
> > > Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
> >
> > There's no changelog.
>
> Yes, will add it if there will be sense in the patch.
>
> >
> > Why? Ignoring the debugfs API return values is standard practice.
> >
>
> Yes, but I saw many places where this practice is applicable (for example
> in the kernel/kprobes and etc.), besides this, the memblock API is used
> mostly at early stage, so we will have some output if something going wrong.

The debugfs error-handling rules are something Greg cooked up after one
too many beers. I've never understood them, but maybe I continue to
miss the point.

Yes, I agree that if memblock's debugfs_create_file() fails, we want to
know about it because something needs fixing. But that's true of
all(?) debugfs_create_file callsites, so it's a bit silly to add
warnings to them all. Why not put the warning into
debugfs_create_file() itself? And add a debugfs_create_file_no_warn()
if there are callsites which have reason to go it alone. Or add a
debugfs_create_file_warn() wrapper.