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Subject: Re: [PATCH v3 3/3] mm/armv6: work around armv6 cmpxchg support issue
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Anshuman Khandual <anshuman.khandual@arm.com>,
        David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Baolin Wang <baolin.wang@linux.alibaba.com>,
        Russell King <linux@armlinux.org.uk>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
References: <1598928612-68996-1-git-send-email-alex.shi@linux.alibaba.com>
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 <ffa89b09-995a-77d8-03c6-2c1234a5474a@linux.alibaba.com>
 <20200901131749.GL14765@casper.infradead.org>
From:   Alex Shi <alex.shi@linux.alibaba.com>
Message-ID: <5c6020c8-2fdd-13ef-0e83-bea3b32364af@linux.alibaba.com>
Date:   Thu, 3 Sep 2020 14:47:13 +0800
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?? 2020/9/1 ????9:17, Matthew Wilcox д??:
> On Tue, Sep 01, 2020 at 02:30:51PM +0800, Alex Shi wrote:
>> seems there are couples archs can not do cmpxchg1
>> So update the patch here. And it's easy to fix if more arch issue find here.
> 
>> +/*
>> + * cmpxchg only support 32-bits operands on the following archs ARMv6, SPARC32
>> + * sh2, XTENSA.
>> + */
>> +#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_SH2) || \
>> +	defined(CONFIG_SPARC32) || defined(CONFIG_XTENSA)
> 
> Looks like we need a HAVE_CMPXCHG_BYTE in Kconfig to parallel
> HAVE_CMPXCHG_DOUBLE.
> 

Thanks for reminder! Compare the HAVE_CMPXCHG_BYTE, NO_CMPXCHG_BYTE would be
better for less code change. 

I will send the v4 for a bit more change on patch 2.

Thanks!
Alex