Re: [PATCH 2/2] mm: fix undefined reference to `.kernel_map_pages' on PPC builds

From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
To: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	josh@joshtriplett.org, Kim Phillips <kim.phillips@freescale.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Minchan Kim <minchan@kernel.org>, Rik van Riel <riel@redhat.com>,
	Sasha Levin <sasha.levin@oracle.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Konstantin Khlebnikov <k.khlebnikov@samsung.com>,
	Jens Axboe <axboe@fb.com>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH 2/2] mm: fix undefined reference to `.kernel_map_pages' on PPC builds
Date: Tue, 27 Jan 2015 16:56:53 +0900	[thread overview]
Message-ID: <20150127075653.GA11358@js1304-P5Q-DELUXE> (raw)
In-Reply-To: <20150122014550.GA21444@js1304-P5Q-DELUXE>

On Thu, Jan 22, 2015 at 10:45:51AM +0900, Joonsoo Kim wrote:
> On Wed, Jan 21, 2015 at 09:57:59PM +0900, Akinobu Mita wrote:
> > 2015-01-21 9:07 GMT+09:00 Andrew Morton <akpm@linux-foundation.org>:
> > > On Tue, 20 Jan 2015 15:01:50 -0800 josh@joshtriplett.org wrote:
> > >
> > >> On Tue, Jan 20, 2015 at 02:02:00PM -0600, Kim Phillips wrote:
> > >> > It's possible to configure DEBUG_PAGEALLOC without PAGE_POISONING on
> > >> > ppc.  Fix building the generic kernel_map_pages() implementation in
> > >> > this case:
> > >> >
> > >> >   LD      init/built-in.o
> > >> > mm/built-in.o: In function `free_pages_prepare':
> > >> > mm/page_alloc.c:770: undefined reference to `.kernel_map_pages'
> > >> > mm/built-in.o: In function `prep_new_page':
> > >> > mm/page_alloc.c:933: undefined reference to `.kernel_map_pages'
> > >> > mm/built-in.o: In function `map_pages':
> > >> > mm/compaction.c:61: undefined reference to `.kernel_map_pages'
> > >> > make: *** [vmlinux] Error 1
> > 
> > kernel_map_pages() is static inline function since commit 031bc5743f15
> > ("mm/debug-pagealloc: make debug-pagealloc boottime configurable").
> > 
> > But there is old declaration in 'arch/powerpc/include/asm/cacheflush.h'.
> > Removing it or changing s/kernel_map_pages/__kernel_map_pages/ in this
> > header file or something can fix this problem?
> > 
> > The architecture which has ARCH_SUPPORTS_DEBUG_PAGEALLOC
> > including PPC should not build mm/debug-pagealloc.o
> 
> Yes, architecture with ARCH_SUPPORTS_DEBUG_PAGEALLOC should not build
> mm/debug-pagealloc.o. I attach the patch to remove old declaration.
> I hope it will fix Kim's problem.
> 
> -------------->8------------------
> >From 7cb9d1ed8a785df152cb8934e187031c8ebd1bb2 Mon Sep 17 00:00:00 2001
> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Date: Thu, 22 Jan 2015 10:28:58 +0900
> Subject: [PATCH] mm/debug_pagealloc: fix build failure on ppc and some other
>  archs
> 
> Kim Phillips reported following build failure.
> 
>   LD      init/built-in.o
>   mm/built-in.o: In function `free_pages_prepare':
>   mm/page_alloc.c:770: undefined reference to `.kernel_map_pages'
>   mm/built-in.o: In function `prep_new_page':
>   mm/page_alloc.c:933: undefined reference to `.kernel_map_pages'
>   mm/built-in.o: In function `map_pages':
>   mm/compaction.c:61: undefined reference to `.kernel_map_pages'
>   make: *** [vmlinux] Error 1
> 
> Reason for this problem is that commit 031bc5743f15
> ("mm/debug-pagealloc: make debug-pagealloc boottime configurable") forgot
> to remove old declaration of kernel_map_pages() in some architectures.
> This patch removes them to fix build failure.
> 
> Reported-by: Kim Phillips <kim.phillips@freescale.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Hello, Andrew.

Could you take this patch?
This patch is also needed to fix build failure.

Thanks.