From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm, powerpc: use vma_kernel_pagesize() in vma_mmu_pagesize()
Patch series "mm, smaps: MMUPageSize for device-dax", v3.
Similar to 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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Jane Chu <jane.chu@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/hugetlb.h | 6 ------
arch/powerpc/mm/hugetlbpage.c | 5 +----
mm/hugetlb.c | 8 +++-----
3 files changed, 4 insertions(+), 15 deletions(-)
diff -puN arch/powerpc/include/asm/hugetlb.h~mm-powerpc-use-vma_kernel_pagesize-in-vma_mmu_pagesize arch/powerpc/include/asm/hugetlb.h
--- a/arch/powerpc/include/asm/hugetlb.h~mm-powerpc-use-vma_kernel_pagesize-in-vma_mmu_pagesize
+++ a/arch/powerpc/include/asm/hugetlb.h
@@ -118,12 +118,6 @@ void hugetlb_free_pgd_range(struct mmu_g
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.
*/
diff -puN arch/powerpc/mm/hugetlbpage.c~mm-powerpc-use-vma_kernel_pagesize-in-vma_mmu_pagesize arch/powerpc/mm/hugetlbpage.c
--- a/arch/powerpc/mm/hugetlbpage.c~mm-powerpc-use-vma_kernel_pagesize-in-vma_mmu_pagesize
+++ a/arch/powerpc/mm/hugetlbpage.c
@@ -568,10 +568,7 @@ unsigned long vma_mmu_pagesize(struct vm
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)
diff -puN mm/hugetlb.c~mm-powerpc-use-vma_kernel_pagesize-in-vma_mmu_pagesize mm/hugetlb.c
--- a/mm/hugetlb.c~mm-powerpc-use-vma_kernel_pagesize-in-vma_mmu_pagesize
+++ a/mm/hugetlb.c
@@ -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
_
--
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