Date:   Thu, 16 Feb 2023 23:02:09 +0800
From:   Baoquan He <bhe@redhat.com>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        akpm@linux-foundation.org, christophe.leroy@csgroup.eu,
        hch@infradead.org, agordeev@linux.ibm.com,
        wangkefeng.wang@huawei.com, schnelle@linux.ibm.com,
        David.Laight@aculab.com, shorne@gmail.com, arnd@arndb.de,
        "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
        Helge Deller <deller@gmx.de>, linux-parisc@vger.kernel.org
Subject: Re: [PATCH v4 12/16] parisc: mm: Convert to GENERIC_IOREMAP
Message-ID: <Y+5Fcc6wsbr0qmoN@MiWiFi-R3L-srv>
References: <20230216123419.461016-1-bhe@redhat.com>
 <20230216123419.461016-13-bhe@redhat.com>
 <Y+40p3oegc2Of9w2@casper.infradead.org>
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On 02/16/23 at 01:50pm, Matthew Wilcox wrote:
> On Thu, Feb 16, 2023 at 08:34:15PM +0800, Baoquan He wrote:
> > Meanwhile, add macro ARCH_HAS_IOREMAP_WC since the added ioremap_wc()
> > will conflict with the one in include/asm-generic/iomap.h, then an
> > compiling error is seen:
> 

Thanks for reviewing.

> Huh?  ARCH_HAS_IOREMAP_WC comes up nowhere else in this patchset, and
> the current definition of ioremap_wc() is guarded by an ifndef ioremap_wc

Because another patch of powerpc has got ARCH_HAS_IOREMAP_WC in the
existed code.

> 
> > +#define ioremap_wc(addr, size)  \
> > +	ioremap_prot((addr), (size), _PAGE_IOREMAP)
> 
> This should be enough all by itself.

It's not if including asm-generic/iomap.h. The ARCH_HAS_IOREMAP_xx is to
avoid redefinition there.

include/asm-generic/iomap.h:
----
#ifndef ARCH_HAS_IOREMAP_WC
#define ioremap_wc ioremap
#endif

>