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From: Al Viro <viro@zeniv.linux.org.uk>
To: Randy Dunlap <rdunlap@infradead.org>
Cc: 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@vger.kernel.org, linux-nvdimm@lists.01.org
Subject: Re: [PATCH v2] fs/dax: include <asm/page.h> to fix build error on ARC
Date: Tue, 5 Jan 2021 04:17:38 +0000	[thread overview]
Message-ID: <20210105041738.GS3579531@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20210101042914.5313-1-rdunlap@infradead.org>

On Thu, Dec 31, 2020 at 08:29:14PM -0800, Randy Dunlap 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]

Could somebody explain what the force-cast is doing in there?
I mean, the call is
        copy_user_page(vto, (void __force *)kaddr, vaddr, to);
kaddr is a local variable there, declared as void *; AFAICS, that
had been pure cargo-cult since
commit 7a9eb20666317794d0279843fbd091af93907780
Author: Dan Williams <dan.j.williams@intel.com>
Date:   Fri Jun 3 18:06:47 2016 -0700

    pmem: kill __pmem address space

I mean, it's been more than 4 years, time to bury that body...
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      parent reply	other threads:[~2021-01-05  4:18 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-01  4:29 [PATCH v2] fs/dax: include <asm/page.h> to fix build error on ARC Randy Dunlap
2021-01-04 16:12 ` Ira Weiny
2021-01-04 20:13 ` Dan Williams
2021-01-04 20:16   ` Matthew Wilcox
2021-01-05  3:41   ` Randy Dunlap
2021-01-05  3:50     ` Dan Williams
2021-01-05  4:17 ` Al Viro [this message]

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