linux-kernel - Re: [PATCH] x86: mce: no need to check return value of debugfs

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Date:   Wed, 12 Jun 2019 17:47:30 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Tony Luck <tony.luck@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Pu Wen <puwen@...on.cn>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: mce: no need to check return value of
 debugfs_create functions

On Wed, Jun 12, 2019 at 05:41:22PM +0200, Greg Kroah-Hartman wrote:
> On Wed, Jun 12, 2019 at 05:18:56PM +0200, Borislav Petkov wrote:
> > On Wed, Jun 12, 2019 at 05:15:31PM +0200, Greg Kroah-Hartman wrote:
> > > When calling debugfs functions, there is no need to ever check the
> > > return value.  The function can work or not, but the code logic should
> > > never do something different based on this.
> > > 
> > > Cc: Thomas Gleixner <tglx@...utronix.de>
> > > Cc: Ingo Molnar <mingo@...hat.com>
> > > Cc: Borislav Petkov <bp@...en8.de>
> > > Cc: "H. Peter Anvin" <hpa@...or.com>
> > > Cc: <x86@...nel.org>
> > > Cc: Tony Luck <tony.luck@...el.com>
> > > Cc: Vishal Verma <vishal.l.verma@...el.com>
> > > Cc: Pu Wen <puwen@...on.cn>
> > > Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> > > ---
> > >  arch/x86/kernel/cpu/mce/core.c     | 16 +++++---------
> > >  arch/x86/kernel/cpu/mce/inject.c   | 34 +++++-------------------------
> > >  arch/x86/kernel/cpu/mce/severity.c | 14 +++---------
> > >  3 files changed, 13 insertions(+), 51 deletions(-)
> > 
> > I think I'm having a deja-vu:
> > 
> > https://lkml.kernel.org/r/20190122215326.GM26587@zn.tnic
> 
> Ah, I thought I had sent this out before...
> 
> Anyway, I'll fix this up, but really, you will not have a debugfs file
> fail creation unless the system is totally out of memory...

Promise? :-P

I mean, I don't mind getting rid of all that error handling getting in
the way of the code but we'll leave the injector in a half-init state if
the allocation fails.

I guess I can take this and see what breaks. If it does, we can always
revert it...

Btw, is your aim to make debugfs_create_file() return void or you're
just doing some cleanups?

-- 
Regards/Gruss,
    Boris.

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