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mm, powerpc: use vma_kernel_pagesize() in vma_mmu_pagesize()

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Patch series "mm, smaps: MMUPageSize for device-dax", v3.

Similar to commit 31383c6865a5 ("mm, hugetlbfs: introduce ->split() to
vm_operations_struct") here is another occasion where we want
special-case hugetlbfs/hstate enabling to also apply to device-dax.

This prompts the question what other hstate conversions we might do
beyond ->split() and ->pagesize(), but this appears to be the last of
the usages of hstate_vma() in generic/non-hugetlbfs specific code paths.

This patch (of 3):

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.

Link: http://lkml.kernel.org/r/151996254179.27922.2213728278535578744.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Jane Chu <jane.chu@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dan Williams 2018-04-05 16:24:21 -07:00 committed by Linus Torvalds
parent 2923117b71
commit 09135cc594
3 changed files with 4 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/powerpc/include/asm/hugetlb.h
View File

@ -117,12 +117,6 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
unsigned long end, unsigned long floor,
unsigned long ceiling);
/*
* The version of vma_mmu_pagesize() in arch/powerpc/mm/hugetlbpage.c needs
* to override the version in mm/hugetlb.c
*/
#define vma_mmu_pagesize vma_mmu_pagesize
/*
* If the arch doesn't supply something else, assume that hugepage
* size aligned regions are ok without further preparation.

5
arch/powerpc/mm/hugetlbpage.c
View File

@ -568,10 +568,7 @@ unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
if (!radix_enabled())
return 1UL << mmu_psize_to_shift(psize);
#endif
if (!is_vm_hugetlb_page(vma))
return PAGE_SIZE;
return huge_page_size(hstate_vma(vma));
return vma_kernel_pagesize(vma);
}
static inline bool is_power_of_4(unsigned long x)

8
mm/hugetlb.c
View File

@ -651,15 +651,13 @@ EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
/*
* Return the page size being used by the MMU to back a VMA. In the majority
* of cases, the page size used by the kernel matches the MMU size. On
* architectures where it differs, an architecture-specific version of this
* function is required.
* architectures where it differs, an architecture-specific 'strong'
* version of this symbol is required.
*/
#ifndef vma_mmu_pagesize
unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
{
return vma_kernel_pagesize(vma);
}
#endif
/*
* Flags for MAP_PRIVATE reservations. These are stored in the bottom