Re: m68k build failures in -next: undefined reference to `arch_dma_prep_coherent'

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Christoph Hellwig <hch@lst.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	linux-m68k <linux-m68k@lists.linux-m68k.org>
Subject: Re: m68k build failures in -next: undefined reference to `arch_dma_prep_coherent'
Date: Mon, 8 Jul 2019 21:13:02 +0200	[thread overview]
Message-ID: <CAMuHMdUnSqKHA7EN1S8U7eBODs4gi-raw4P3FxnR_afhb2Zd5g@mail.gmail.com> (raw)
In-Reply-To: <20190708170647.GA12313@roeck-us.net>

Hi Günter,

On Mon, Jul 8, 2019 at 7:06 PM Guenter Roeck <linux@roeck-us.net> wrote:
> I see the following build error in -next:
>
> kernel/dma/direct.o: In function `dma_direct_alloc_pages':
> direct.c:(.text+0x4d8): undefined reference to `arch_dma_prep_coherent'
>
> Example: m68k:allnoconfig.
>
> Bisect log is ambiguous and points to the merge of m68k/for-next into
> -next. Yet, I think the problem is with commit 69878ef47562 ("m68k:
> Implement arch_dma_prep_coherent()") which is supposed to introduce
> the function. The problem is likely that arch_dma_prep_coherent()
> is only declared if CONFIG_MMU is enabled, but it is called from code
> outside CONFIG_MMU.

Thanks, one more thing to fix in m68k-allnoconfig (did it really build
before?)...

Given you say "example", does it fail in real configs, too?

Thanks again!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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.
                                -- Linus Torvalds