Re: [PATCH v3 1/3] mm, powerpc: use vma_kernel_pagesize() in vma_mmu_pagesize()

[Michael Ellerman <mpe@ellerman.id.au>]

Dan Williams <dan.j.williams@intel.com> writes:

> The current powerpc definition of vma_mmu_pagesize() open codes looking
> up the page size via hstate. It is identical to the generic
> vma_kernel_pagesize() implementation.
>
> Now, vma_kernel_pagesize() is growing support for determining the
> page size of Device-DAX vmas in addition to the existing Hugetlbfs page
> size determination.
>
> Ideally, if the powerpc vma_mmu_pagesize() used vma_kernel_pagesize() it
> would automatically benefit from any new vma-type support that is added
> to vma_kernel_pagesize(). However, the powerpc vma_mmu_pagesize() is
> prevented from calling vma_kernel_pagesize() due to a circular header
> dependency that requires vma_mmu_pagesize() to be defined before
> including <linux/hugetlb.h>.
>
> Break this circular dependency by defining the default
> vma_mmu_pagesize() as a __weak symbol to be overridden by the powerpc
> version.
>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  arch/powerpc/include/asm/hugetlb.h |    6 ------
>  arch/powerpc/mm/hugetlbpage.c      |    5 +----
>  mm/hugetlb.c                       |    8 +++-----
>  3 files changed, 4 insertions(+), 15 deletions(-)

This looks OK to me. I was worried switching to a weak symbol would mean
it doesn't get inlined, but it's not inlined today anyway!

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

cheers

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