Re: [PATCH v2] fs/dax: include <asm/page.h> to fix build error on ARC

From: Randy Dunlap <rdunlap@infradead.org>
To: Dan Williams <dan.j.williams@intel.com>
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>
Subject: Re: [PATCH v2] fs/dax: include <asm/page.h> to fix build error on ARC
Date: Mon, 4 Jan 2021 19:41:48 -0800	[thread overview]
Message-ID: <f7803685-e255-7cfe-5259-e2a7dc5ab581@infradead.org> (raw)
In-Reply-To: <CAPcyv4jAiqyFg_BUHh_bJRG-BqzvOwthykijRapB_8i6VtwTmQ@mail.gmail.com>

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.

>>
>>  #define CREATE_TRACE_POINTS
>> --- lnx-511-rc1.orig/arch/arc/include/asm/page.h
>> +++ lnx-511-rc1/arch/arc/include/asm/page.h
>> @@ -10,6 +10,7 @@
>>  #ifndef __ASSEMBLY__
>>
>>  #define clear_page(paddr)              memset((paddr), 0, PAGE_SIZE)
>> +#define copy_user_page(to, from, vaddr, pg)    copy_page(to, from)
>>  #define copy_page(to, from)            memcpy((to), (from), PAGE_SIZE)
>>
>>  struct vm_area_struct;

-- 
~Randy
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