From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@ozlabs.org
Cc: peterz@infradead.org, xinhui.pan@linux.vnet.ibm.com
Subject: Re: powerpc: Fix __cmpxchg() to take a volatile ptr again
Date: Mon, 28 Nov 2016 23:15:17 +1100 (AEDT) [thread overview]
Message-ID: <3tS5Gs6KZYz9vFt@ozlabs.org> (raw)
In-Reply-To: <1480043229-2363-1-git-send-email-mpe@ellerman.id.au>
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On Fri, 2016-11-25 at 03:07:09 UTC, Michael Ellerman wrote:
> In commit d0563a1297e2 ("powerpc: Implement {cmp}xchg for u8 and u16")
> we removed the volatile from __cmpxchg().
>
> This is leading to warnings such as:
>
> drivers/gpu/drm/drm_lock.c: In function ‘drm_lock_take’:
> arch/powerpc/include/asm/cmpxchg.h:484:37: warning: passing argument 1
> of ‘__cmpxchg’ discards ‘volatile’ qualifier from pointer target
> (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
>
> There doesn't seem to be consensus across architectures whether the
> argument is volatile or not, so at least for now put the volatile back.
>
> Fixes: d0563a1297e2 ("powerpc: Implement {cmp}xchg for u8 and u16")
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Applied to powerpc next.
https://git.kernel.org/powerpc/c/da58b23cb976ab83a80d358102e139
cheers
prev parent reply other threads:[~2016-11-28 12:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-25 3:07 [PATCH] powerpc: Fix __cmpxchg() to take a volatile ptr again Michael Ellerman
2016-11-25 4:26 ` Pan Xinhui
2016-11-28 12:15 ` Michael Ellerman [this message]
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