Re: [PATCH] fix build error when CONFIG_SWAP is not set

[Geert Uytterhoeven]

On Mon, Jan 24, 2011 at 22:07, Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
> On Mon, Jan 24, 2011 at 12:44:12PM -0800, Andrew Morton wrote:
>> On Mon, 24 Jan 2011 22:30:46 +0300
>> Sergei Shtylyov <sshtylyov@xxxxxxxxxx> wrote:
>> > Yoichi Yuasa wrote:
>> >
>> > > In file included from
>> > > linux-2.6/arch/mips/include/asm/tlb.h:21,
>> > > Â Â Â Â Â Â Â Â Âfrom mm/pgtable-generic.c:9:
>> > > include/asm-generic/tlb.h: In function 'tlb_flush_mmu':
>> > > include/asm-generic/tlb.h:76: error: implicit declaration of function
>> > > 'release_pages'
>> > > include/asm-generic/tlb.h: In function 'tlb_remove_page':
>> > > include/asm-generic/tlb.h:105: error: implicit declaration of function
>> > > 'page_cache_release'
>> > > make[1]: *** [mm/pgtable-generic.o] Error 1
>> > >
>> > > Signed-off-by: Yoichi Yuasa <yuasa@xxxxxxxxxxxxxx>
>> > [...]
>> >
>> > > diff --git a/include/linux/swap.h b/include/linux/swap.h
>> > > index 4d55932..92c1be6 100644
>> > > --- a/include/linux/swap.h
>> > > +++ b/include/linux/swap.h
>> > > @@ -8,6 +8,7 @@
>> > > Â#include <linux/memcontrol.h>
>> > > Â#include <linux/sched.h>
>> > > Â#include <linux/node.h>
>> > > +#include <linux/pagemap.h>
>> >
>> > Â Â Hm, if the errors are in <asm-generic/tlb.h>, why add #include in
>> > <linux/swap.h>?
>> >
>>
>> The build error is caused by macros which are defined in swap.h.
>>
>> I worry about the effects of the patch - I don't know which of swap.h
>> and pagemap.h is the "innermost" header file. ÂThere's potential for
>> new build errors due to strange inclusion graphs.
>>
>> err, there's also this, in swap.h:
>>
>> /* only sparc can not include linux/pagemap.h in this file
>> Â* so leave page_cache_release and release_pages undeclared... */

Yeah, I noticed this too a while ago, when trying to get m68k
allnoconfig "working".
Was wondering whether this was still true...

> I just checked.
> sparc32 with a defconfig barfed out like this:
> ÂCC Â Â Âarch/sparc/kernel/traps_32.o
> In file included from /home/sam/kernel/linux-2.6.git/include/linux/pagemap.h:7:0,
> Â Â Â Â Â Â Â Â from /home/sam/kernel/linux-2.6.git/include/linux/swap.h:11,
> Â Â Â Â Â Â Â Â from /home/sam/kernel/linux-2.6.git/arch/sparc/include/asm/pgtable_32.h:15,
> Â Â Â Â Â Â Â Â from /home/sam/kernel/linux-2.6.git/arch/sparc/include/asm/pgtable.h:6,
> Â Â Â Â Â Â Â Â from /home/sam/kernel/linux-2.6.git/arch/sparc/kernel/traps_32.c:23:
> /home/sam/kernel/linux-2.6.git/include/linux/mm.h: In function 'is_vmalloc_addr':
> /home/sam/kernel/linux-2.6.git/include/linux/mm.h:301:17: error: 'VMALLOC_START' undeclared (first use in this function)
> /home/sam/kernel/linux-2.6.git/include/linux/mm.h:301:17: note: each undeclared identifier is reported only once for each function it appears in
> /home/sam/kernel/linux-2.6.git/include/linux/mm.h:301:41: error: 'VMALLOC_END' undeclared (first use in this function)
> /home/sam/kernel/linux-2.6.git/include/linux/mm.h: In function 'maybe_mkwrite':
> /home/sam/kernel/linux-2.6.git/include/linux/mm.h:483:3: error: implicit declaration of function 'pte_mkwrite'
>
> When I removed the include it could build again.

... and so it is. Good to know, thanks for checking!

Gr{oetje,eeting}s,

            Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
             Â Â -- Linus Torvalds
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