Re: Aarch64 EXT4FS inode checksum failures - seems to be weak memory ordering issues

Arnd Bergmann
2021-01-08T20:23:18Z

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