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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Lukas Wunner <lukas@wunner.de>
Cc: Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Arnd Bergmann <arnd@kernel.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: Tue, 12 Jan 2021 09:28:32 -0800	[thread overview]
Message-ID: <CAHk-=wiHaVWUKQ9wvHe5D=JrV3MDehfRi_FL7KXGbi6=S7=jUA@mail.gmail.com> (raw)
In-Reply-To: <20210112132049.GA26096@wunner.de>

On Tue, Jan 12, 2021 at 5:20 AM Lukas Wunner <lukas@wunner.de> wrote:
>
> > 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.
>
> Anonymous structs/unions.  I used to have a use case for that in
> struct efi_dev_path in include/linux/efi.h, but Ard Biesheuvel
> refactored it in a gnu89-compatible way for v5.7 with db8952e7094f.

We use anonymous structs/unions extensively and all over the place already.

We've had a couple of special cases where some versions of gcc didn't
do things right iirc (it was something like "nested anonymous struct"
or similar), but those weren't actually about the feature itself.

Was it perhaps the nested case you were thinking of? If so, I think
that's not really a --std=gun11 thing, it's more of a "certain
versions of gcc didn't do it at all".

               Linus

WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Lukas Wunner <lukas@wunner.de>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Arnd Bergmann <arnd@kernel.org>, 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: Tue, 12 Jan 2021 09:28:32 -0800	[thread overview]
Message-ID: <CAHk-=wiHaVWUKQ9wvHe5D=JrV3MDehfRi_FL7KXGbi6=S7=jUA@mail.gmail.com> (raw)
In-Reply-To: <20210112132049.GA26096@wunner.de>

On Tue, Jan 12, 2021 at 5:20 AM Lukas Wunner <lukas@wunner.de> wrote:
>
> > 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.
>
> Anonymous structs/unions.  I used to have a use case for that in
> struct efi_dev_path in include/linux/efi.h, but Ard Biesheuvel
> refactored it in a gnu89-compatible way for v5.7 with db8952e7094f.

We use anonymous structs/unions extensively and all over the place already.

We've had a couple of special cases where some versions of gcc didn't
do things right iirc (it was something like "nested anonymous struct"
or similar), but those weren't actually about the feature itself.

Was it perhaps the nested case you were thinking of? If so, I think
that's not really a --std=gun11 thing, it's more of a "certain
versions of gcc didn't do it at all".

               Linus

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

  parent reply	other threads:[~2021-01-12 17:29 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
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 [this message]
2021-01-12 17:28                             ` Linus Torvalds
2021-01-14 13:13                             ` Lukas Wunner

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