linux-kernel - Re: [GIT PULL] kbuild updates for v4.7-rc1

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Message-ID: <CA+55aFzQ4oe6cT5xf=3xT1d6ji2L_her8AmJxpsixFw_GavDvg@mail.gmail.com>
Date:	Fri, 27 May 2016 13:20:29 -0700
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	Michal Marek <mmarek@...e.com>,
	Макс Жуков 
	<mussitantesmortem@...il.com>, nicolas.ferre@...el.com,
	Nicolas Pitre <nicolas.pitre@...aro.org>,
	robert.jarzmik@...e.fr, yamada.masahiro@...ionext.com,
	Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Bob Peterson <rpeterso@...hat.com>
Subject: Re: [GIT PULL] kbuild updates for v4.7-rc1

On Fri, May 27, 2016 at 1:04 PM, Arnd Bergmann <arnd@...db.de> wrote:
>
> In fact, the patch that I have in my private tree that was hiding the
> warning for me on x86 is one that removes all instances of IS_ERR_VALUE()
> with arguments other than 'unsigned long', see http://pastebin.com/uYa2mkgC
> for reference.

Please just send me that patch, we need to do this (and then add a
cast to pointer (and back to unsigned long) in IS_ERR_VALUE() so that
we get warnings for when that macro is mis-used.

I didn't look at the details of your patch, but I did look at several
IS_ERR_VALUE() uses in the standard kernel, and they were basically
all wrong. Even the ones that used it for the rigth reason (vm_brk()
that returns a pointer or an error in an "unsigned long") had actively
screwed up and truncated that (correct) unsigned long value to "int"
before doing the IS_ERR_VALUE(), which made it all wrong again.

And the other users just looked entirely bogus, and were all just
"zero or negative error code" that has nothing to do with
IS_ERR_VALUE(). The code should just check against zero, not use that
macro that was designed for something different.

                Linus