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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Mon, 4 Jan 2021 19:50:39 -0800
Message-ID: <CAPcyv4jPwk_xjeVjv0LhXr_d9+dbcEDJ_YOF+qrX97e_CE8yRA@mail.gmail.com>
Subject: Re: [PATCH v2] fs/dax: include <asm/page.h> to fix build error on ARC
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        kernel test robot <lkp@intel.com>,
        Vineet Gupta <vgupta@synopsys.com>,
        linux-snps-arc@lists.infradead.org,
        Vineet Gupta <vgupts@synopsys.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        linux-nvdimm <linux-nvdimm@lists.01.org>
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On Mon, Jan 4, 2021 at 7:47 PM Randy Dunlap <rdunlap@infradead.org> wrote:
>
> On 1/4/21 12:13 PM, Dan Williams wrote:
> > On Thu, Dec 31, 2020 at 8:29 PM Randy Dunlap <rdunlap@infradead.org> wrote:
> >>
> >> fs/dax.c uses copy_user_page() but ARC does not provide that interface,
> >> resulting in a build error.
> >>
> >> Provide copy_user_page() in <asm/page.h> (beside copy_page()) and
> >> add <asm/page.h> to fs/dax.c to fix the build error.
> >>
> >> ../fs/dax.c: In function 'copy_cow_page_dax':
> >> ../fs/dax.c:702:2: error: implicit declaration of function 'copy_user_page'; did you mean 'copy_to_user_page'? [-Werror=implicit-function-declaration]
> >>
> >> Fixes: cccbce671582 ("filesystem-dax: convert to dax_direct_access()")
> >> Reported-by: kernel test robot <lkp@intel.com>
> >> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> >> Cc: Vineet Gupta <vgupta@synopsys.com>
> >> Cc: linux-snps-arc@lists.infradead.org
> >> Cc: Dan Williams <dan.j.williams@intel.com>
> >> Acked-by: Vineet Gupta <vgupts@synopsys.com>
> >> Cc: Andrew Morton <akpm@linux-foundation.org>
> >> Cc: Matthew Wilcox <willy@infradead.org>
> >> Cc: Jan Kara <jack@suse.cz>
> >> Cc: linux-fsdevel@vger.kernel.org
> >> Cc: linux-nvdimm@lists.01.org
> >> ---
> >> v2: rebase, add more Cc:
> >>
> >>  arch/arc/include/asm/page.h |    1 +
> >>  fs/dax.c                    |    1 +
> >>  2 files changed, 2 insertions(+)
> >>
> >> --- lnx-511-rc1.orig/fs/dax.c
> >> +++ lnx-511-rc1/fs/dax.c
> >> @@ -25,6 +25,7 @@
> >>  #include <linux/sizes.h>
> >>  #include <linux/mmu_notifier.h>
> >>  #include <linux/iomap.h>
> >> +#include <asm/page.h>
> >
> > I would expect this to come from one of the linux/ includes like
> > linux/mm.h. asm/ headers are implementation linux/ headers are api.
> >
> > Once you drop that then the subject of this patch can just be "arc:
> > add a copy_user_page() implementation", and handled by the arc
> > maintainer (or I can take it with Vineet's ack).
>
> Got it. Thanks.
> Vineet is copied. I expect that he will take the v3 patch.
>
> >>  #include <asm/pgalloc.h>
> >
> > Yes, this one should have a linux/ api header to front it, but that's
> > a cleanup for another day.
>
> That line is only part of the contextual diff in this patch.
> I guess you are just commenting in general, along with your earlier
> paragraph.

Yes, I was prefetching a "...hey, but, there's an asm/ include right
below this one?"