On Wed, Nov 17, 2021 at 2:22 AM Matthew Wilcox [off-list ref] wrote:

On Mon, Nov 15, 2021 at 10:33:01PM -0800, Christoph Hellwig wrote:

quoted

I see how this works no, but it is pretty horrible.  Why not something
simple like the patch below?  If/when an architecture actually
wants to override flush_dcache_folio we can find out how to best do
it:

I'll stick this one into -next and see if anything blows up:

From 14f55de74c68a3eb058cfdbf81414148b9bdaac7 Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: Sat, 6 Nov 2021 17:13:35 -0400
Subject: [PATCH] Add linux/cacheflush.h

Many architectures do not include asm-generic/cacheflush.h, so turn
the includes on their head and add linux/cacheflush.h which includes
asm/cacheflush.h.

Move the flush_dcache_folio() declaration from asm-generic/cacheflush.h
to linux/cacheflush.h and change linux/highmem.h to include
linux/cacheflush.h instead of asm/cacheflush.h so that all necessary
places will see flush_dcache_folio().

More functions should have their default implementations moved in the
future, but those are for follow-on patches.  This fixes csky, sparc and
sparc64 which were missed in the commit which added flush_dcache_folio().

Fixes: 08b0b0059bf1 ("mm: Add flush_dcache_folio()")
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

 arch/m68k/include/asm/cacheflush_mm.h |  1 -

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

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