Messages in this thread | | | Date | Thu, 26 Jan 2023 20:49:43 +0000 | From | Matthew Wilcox <> | Subject | Re: [PATCH] mm/highmem: Align-down to page the address for kunmap_flush_on_unmap() |
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On Thu, Jan 26, 2023 at 09:37:08PM +0100, Helge Deller wrote: > > This 'fixes' looks correct to me. I don't know how many folks are running > > highmem with parisc but if they are I am sure they would appreciate the > > extra knowledge. > > It seems nobody is running highmem on parisc, because it can't be enabled. > AFAICS, it's not in any parisc related Kconfig file.
But this isn't being used for highmem on parisc; it's being used for cache coherency.
> > I do wonder if this should be cc'ed to stable to ensure it gets > > backported? Helge do you think there is a need for that? > > For correctness I think it's nevertheless good to backport it.
I cc'd stable on my version of this patch, and included a Fixes tag to indicate how far back to backport it.
> That would be another possibility: > > diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h > index 0bdee6724132..ce5d1f8a23bd 100644 > --- a/arch/parisc/include/asm/cacheflush.h > +++ b/arch/parisc/include/asm/cacheflush.h > @@ -77,6 +77,7 @@ void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned lon > #define ARCH_HAS_FLUSH_ON_KUNMAP > static inline void kunmap_flush_on_unmap(const void *addr) > { > + addr = PTR_ALIGN_DOWN(addr, PAGE_SIZE);
I considered that, but thought it a shame to do it here when all the other users are passing in a page-aligned address.
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