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From: Arnd Bergmann <arnd@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Russell King - ARM Linux admin <linux@armlinux.org.uk>,
	linux-toolchains@vger.kernel.org,
	Mark Rutland <mark.rutland@arm.com>,
	"Theodore Ts'o" <tytso@mit.edu>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	Ext4 Developers List <linux-ext4@vger.kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: Aarch64 EXT4FS inode checksum failures - seems to be weak memory ordering issues
Date: Fri, 8 Jan 2021 21:22:18 +0100	[thread overview]
Message-ID: <CAK8P3a2w2u8pcQJue3OveDckJNkGmwzVdfOM-VEXShQEw8EOzw@mail.gmail.com> (raw)
In-Reply-To: <CAHk-=whnKkj5CSbj-uG_MVVUsPZ6ppd_MFhZf_kpXDkh2MAVRA@mail.gmail.com>

On Fri, Jan 8, 2021 at 9:02 PM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Fri, Jan 8, 2021 at 1:27 AM Will Deacon <will@kernel.org> wrote:
> >
> > On Fri, Jan 08, 2021 at 10:21:54AM +0100, Peter Zijlstra wrote:
> > > On Thu, Jan 07, 2021 at 10:20:38PM +0100, Arnd Bergmann wrote:
> > > > On Thu, Jan 7, 2021 at 2:37 PM Russell King - ARM Linux admin
>
> I appreciate Arnd pointing out "--std=gnu11", though. What are the
> actual relevant language improvements?
>
> Variable declarations in for-loops is the only one I can think of. I
> think that would clean up some code (and some macros), but might not
> be compelling on its own.

I think that was the main one, as most of --std=c11 is already part
of --std=gnu89 as a gnu extension. There were a few things that
came up with clang porting, as clang is somewhat closer to gnu11
than to gnu89, but I don't remember exactly what that was.

I would still like to improve READ_ONCE()/get_user()/cmpxchg()
further using __auto_type and _Generic where possible, but I think
that was already supported in gcc-4.9, and does not require gcc-5.

       Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Theodore Ts'o <tytso@mit.edu>,
	Peter Zijlstra <peterz@infradead.org>,
	Russell King - ARM Linux admin <linux@armlinux.org.uk>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	linux-toolchains@vger.kernel.org,
	Ext4 Developers List <linux-ext4@vger.kernel.org>,
	Will Deacon <will@kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: Aarch64 EXT4FS inode checksum failures - seems to be weak memory ordering issues
Date: Fri, 8 Jan 2021 21:22:18 +0100	[thread overview]
Message-ID: <CAK8P3a2w2u8pcQJue3OveDckJNkGmwzVdfOM-VEXShQEw8EOzw@mail.gmail.com> (raw)
In-Reply-To: <CAHk-=whnKkj5CSbj-uG_MVVUsPZ6ppd_MFhZf_kpXDkh2MAVRA@mail.gmail.com>

On Fri, Jan 8, 2021 at 9:02 PM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Fri, Jan 8, 2021 at 1:27 AM Will Deacon <will@kernel.org> wrote:
> >
> > On Fri, Jan 08, 2021 at 10:21:54AM +0100, Peter Zijlstra wrote:
> > > On Thu, Jan 07, 2021 at 10:20:38PM +0100, Arnd Bergmann wrote:
> > > > On Thu, Jan 7, 2021 at 2:37 PM Russell King - ARM Linux admin
>
> I appreciate Arnd pointing out "--std=gnu11", though. What are the
> actual relevant language improvements?
>
> Variable declarations in for-loops is the only one I can think of. I
> think that would clean up some code (and some macros), but might not
> be compelling on its own.

I think that was the main one, as most of --std=c11 is already part
of --std=gnu89 as a gnu extension. There were a few things that
came up with clang porting, as clang is somewhat closer to gnu11
than to gnu89, but I don't remember exactly what that was.

I would still like to improve READ_ONCE()/get_user()/cmpxchg()
further using __auto_type and _Generic where possible, but I think
that was already supported in gcc-4.9, and does not require gcc-5.

       Arnd

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-01-08 20:23 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-05 15:47 Aarch64 EXT4FS inode checksum failures - seems to be weak memory ordering issues Russell King - ARM Linux admin
2021-01-05 15:47 ` Russell King - ARM Linux admin
2021-01-05 18:27 ` Darrick J. Wong
2021-01-05 18:27   ` Darrick J. Wong
2021-01-05 19:50   ` Russell King - ARM Linux admin
2021-01-05 19:50     ` Russell King - ARM Linux admin
2021-01-06 11:53 ` Mark Rutland
2021-01-06 11:53   ` Mark Rutland
2021-01-06 12:13   ` Russell King - ARM Linux admin
2021-01-06 12:13     ` Russell King - ARM Linux admin
2021-01-06 13:52   ` Russell King - ARM Linux admin
2021-01-06 17:20     ` Will Deacon
2021-01-06 17:20       ` Will Deacon
2021-01-06 17:46       ` Russell King - ARM Linux admin
2021-01-06 17:46         ` Russell King - ARM Linux admin
2021-01-06 21:04       ` Arnd Bergmann
2021-01-06 21:04         ` Arnd Bergmann
2021-01-06 22:00         ` Arnd Bergmann
2021-01-06 22:00           ` Arnd Bergmann
2021-01-06 22:32       ` Russell King - ARM Linux admin
2021-01-06 22:32         ` Russell King - ARM Linux admin
2021-01-07 11:18         ` Russell King - ARM Linux admin
2021-01-07 11:18           ` Russell King - ARM Linux admin
2021-01-07 12:45           ` Russell King - ARM Linux admin
2021-01-07 12:45             ` Russell King - ARM Linux admin
2021-01-07 13:16             ` Arnd Bergmann
2021-01-07 13:16               ` Arnd Bergmann
2021-01-07 13:37               ` Russell King - ARM Linux admin
2021-01-07 13:37                 ` Russell King - ARM Linux admin
2021-01-07 16:27                 ` Theodore Ts'o
2021-01-07 16:27                   ` Theodore Ts'o
2021-01-07 17:00                   ` Florian Weimer
2021-01-07 17:00                     ` Florian Weimer
2021-01-07 21:48                   ` Arnd Bergmann
2021-01-07 21:48                     ` Arnd Bergmann
2021-01-07 22:14                     ` Russell King - ARM Linux admin
2021-01-07 22:14                       ` Russell King - ARM Linux admin
2021-01-07 22:41                       ` Eric Biggers
2021-01-07 22:41                         ` Eric Biggers
2021-01-08  8:21                         ` Ard Biesheuvel
2021-01-08  8:21                           ` Ard Biesheuvel
2021-01-07 22:27                     ` Eric Biggers
2021-01-07 22:27                       ` Eric Biggers
2021-01-07 23:53                       ` Darrick J. Wong
2021-01-07 23:53                         ` Darrick J. Wong
2021-01-08  8:05                         ` Arnd Bergmann
2021-01-08  8:05                           ` Arnd Bergmann
2021-01-08  9:13                   ` Peter Zijlstra
2021-01-08  9:13                     ` Peter Zijlstra
2021-01-08 10:31                   ` Pavel Machek
2021-01-08 10:31                     ` Pavel Machek
2021-01-07 21:20                 ` Arnd Bergmann
2021-01-07 21:20                   ` Arnd Bergmann
2021-01-08  9:21                   ` Peter Zijlstra
2021-01-08  9:21                     ` Peter Zijlstra
2021-01-08  9:26                     ` Will Deacon
2021-01-08  9:26                       ` Will Deacon
2021-01-08 20:02                       ` Linus Torvalds
2021-01-08 20:02                         ` Linus Torvalds
2021-01-08 20:22                         ` Arnd Bergmann [this message]
2021-01-08 20:22                           ` Arnd Bergmann
2021-01-08 21:20                           ` Nick Desaulniers
2021-01-08 21:20                             ` Nick Desaulniers
2021-01-08 20:29                         ` Russell King - ARM Linux admin
2021-01-08 20:29                           ` Russell King - ARM Linux admin
2021-01-12 13:20                         ` Lukas Wunner
2021-01-12 13:31                           ` Florian Weimer
2021-01-12 13:31                             ` Florian Weimer
2021-01-12 13:46                             ` David Laight
2021-01-12 13:46                               ` David Laight
2021-01-12 17:28                           ` Linus Torvalds
2021-01-12 17:28                             ` Linus Torvalds
2021-01-14 13:13                             ` Lukas Wunner

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