Re: [PATCH v2 01/28] csky,sparc: Declare flush_dcache_folio()

[Christoph Hellwig]

On Mon, Nov 08, 2021 at 04:05:24AM +0000, Matthew Wilcox (Oracle) wrote:
> These architectures do not include asm-generic/cacheflush.h so need
> to declare it themselves.

In mainline mm/util.c implements flush_dcache_folio unless
ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO is set.  So I think you need to
define that for csky and sparc.