Re: flush_dcache_page vs kunmap_local

[Russell King (Oracle)]

On Thu, Nov 04, 2021 at 06:04:45PM +0000, Catalin Marinas wrote:
> The cachetlb.rst doc states the two cases where flush_dcache_page()
> should be called:
> 
> 1. After writing to a page cache page (that's what we need on arm64 for
>    the I-cache).
> 
> 2. Before reading from a page cache page and user mappings potentially
>    exist. I think arm32 ensures the D-cache user aliases are coherent
>    with the kernel one (added rmk to confirm).

Yes, where necessary, we flush the user aliases in flush_dcache_page().

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