From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: Implement 1-,2- byte smp_load_acquire and smp_store_release
Date: Mon, 20 Apr 2015 17:13:57 +0100 [thread overview]
Message-ID: <20150420161357.GE1504@arm.com> (raw)
In-Reply-To: <CA+55aFwgG0pNwp3ywOsaEfeArD43MoJ9VLbUYQ8DCKN30=mLOA@mail.gmail.com>
On Mon, Apr 20, 2015 at 05:08:37PM +0100, Linus Torvalds wrote:
> On Mon, Apr 20, 2015 at 8:45 AM, Andrey Ryabinin <a.ryabinin@samsung.com> wrote:
> >
> > Commit 8053871d0f7f ("smp: Fix smp_call_function_single_async() locking")
> > started to use smp_load_acquire() to load 2-bytes csd->flags.
> > That crashes arm64 kernel during the boot.
>
> Ahh. I don't disagree with your patch, but we should just make
> csd->flags be an "int" regardless of this issue.
>
> There is absolutely no reason to try to use 16-bit words. It doesn't
> save us any space (alignment), and it's just a *bad* idea to depend on
> any kind of atomicity of 16-bit entities. Bytes, yes. Words, yes. But
> 16-bit half-words? There's no point.
>
> So I'll make it "unsigned int" instead of "u16".
>
> But as said, the ARM64 patch definitely is a good idea regardless.
Sounds good to me and means I can leave the pull for a day or two to see
if any other arm64 fixes queue up.
Will
next prev parent reply other threads:[~2015-04-20 16:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-20 15:45 [PATCH] arm64: Implement 1-,2- byte smp_load_acquire and smp_store_release Andrey Ryabinin
2015-04-20 15:48 ` Will Deacon
2015-04-20 16:09 ` Paul E. McKenney
2015-04-20 16:08 ` [PATCH] arm64: Implement 1-, 2- " Linus Torvalds
2015-04-20 16:13 ` Will Deacon [this message]
2015-04-20 16:08 ` [PATCH] arm64: Implement 1-,2- " Paul E. McKenney
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