Re: drivers/media/common/videobuf2/videobuf2-dma-contig.c:509:5: error: implicit declaration of function '__pfn_to_phys'

[Mike Rapoport <rppt@linux.ibm.com>]

On Thu, Feb 11, 2021 at 10:03:54PM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   291009f656e8eaebbdfd3a8d99f6b190a9ce9deb
> commit: 4bfc848e0981fcd35db00fe1c6581560689f6dc7 m68k/mm: enable use of generic memory_model.h for !DISCONTIGMEM
> date:   8 weeks ago
> config: m68k-randconfig-r021-20210211 (attached as .config)
> compiler: m68k-linux-gcc (GCC) 9.3.0
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4bfc848e0981fcd35db00fe1c6581560689f6dc7
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout 4bfc848e0981fcd35db00fe1c6581560689f6dc7
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All errors (new ones prefixed by >>):
> 
>    drivers/media/common/videobuf2/videobuf2-dma-contig.c: In function 'vb2_dc_get_userptr':
> >> drivers/media/common/videobuf2/videobuf2-dma-contig.c:509:5: error: implicit declaration of function '__pfn_to_phys' [-Werror=implicit-function-declaration]
>      509 |     __pfn_to_phys(nums[0]), size, buf->dma_dir, 0);
>          |     ^~~~~~~~~~~~~
>    cc1: some warnings being treated as errors

Here is the fix:

From 9709296dbfb627b99defc2c152e1b2d264cf5b86 Mon Sep 17 00:00:00 2001
From: Mike Rapoport <rppt@linux.ibm.com>
Date: Fri, 12 Feb 2021 01:12:15 +0200
Subject: [PATCH] m68k: make __pfn_to_phys() and __phys_to_pfn() available for !MMU

Recent changes that obsoleted DISCONTIGMEM on m68k switched the MMU variant
to use generic definitions of __pfn_to_phys() and __phys_to_pfn(), but
missed the !MMU variant which caused a build failure:

All errors (new ones prefixed by >>):

   drivers/media/common/videobuf2/videobuf2-dma-contig.c: In function 'vb2_dc_get_userptr':
>> drivers/media/common/videobuf2/videobuf2-dma-contig.c:509:5: error: implicit declaration of function '__pfn_to_phys' [-Werror=implicit-function-declaration]
     509 |     __pfn_to_phys(nums[0]), size, buf->dma_dir, 0);
         |     ^~~~~~~~~~~~~
   cc1: some warnings being treated as errors

Enable __pfn_to_phys() and __phys_to_pfn() on !MMU builds.

Fixes: 4bfc848e0981 ("m68k/mm: enable use of generic memory_model.h for !DISCONTIGMEM")
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
---
 arch/m68k/include/asm/page.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/m68k/include/asm/page.h b/arch/m68k/include/asm/page.h
index 6116d7094292..97087dd3ca6d 100644
--- a/arch/m68k/include/asm/page.h
+++ b/arch/m68k/include/asm/page.h
@@ -62,7 +62,7 @@ extern unsigned long _ramend;
 #include <asm/page_no.h>
 #endif
 
-#ifdef CONFIG_DISCONTIGMEM
+#if !defined(CONFIG_MMU) || defined(CONFIG_DISCONTIGMEM)
 #define __phys_to_pfn(paddr)	((unsigned long)((paddr) >> PAGE_SHIFT))
 #define __pfn_to_phys(pfn)	PFN_PHYS(pfn)
 #endif
-- 
2.28.0