Re: [PATCH] mm/highmem: Align-down to page the address for kunmap_flush_on_unmap()

[Matthew Wilcox]

On Thu, Jan 26, 2023 at 03:33:46PM +0100, Fabio M. De Francesco wrote:
> If ARCH_HAS_FLUSH_ON_KUNMAP is defined (PA-RISC case), __kunmap_local()
> calls kunmap_flush_on_unmap(). The latter currently flushes the wrong
> address (as confirmed by Matthew Wilcox and Helge Deller). Al Viro
> proposed to call kunmap_flush_on_unmap() on an aligned-down to page
> address in order to fix this issue. Consensus has been reached on this
> solution.
> 
> Therefore, if ARCH_HAS_FLUSH_ON_KUNMAP is defined, call
> kunmap_flush_on_unmap() on an aligned-down to page address computed with
> the PTR_ALIGN_DOWN() macro.

You missed a spot.  Sent the version I've had in my tree for a few days.