x86: mm: Remove x86 version of huge_pmd_share.

The huge_pmd_share code has been copied over to mm/hugetlb.c to
make it accessible to other architectures.

Remove the x86 copy of the huge_pmd_share code and enable the
ARCH_WANT_HUGE_PMD_SHARE config flag. That way we reference the
general one.

Signed-off-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 685692c94f051a8a7ad582442efcc3fa11173332..476f786c11e94091f41a42e59e49df0b2e5b7216 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -207,6 +207,9 @@ config ARCH_HIBERNATION_POSSIBLE
 config ARCH_SUSPEND_POSSIBLE
        def_bool y
 
+config ARCH_WANT_HUGE_PMD_SHARE
+       def_bool y
+
 config ZONE_DMA32
        bool
        default X86_64

diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index ae1aa71d0115f8ef2509e8ae4a1789385446df18..7e522a3599722b72d3b54ff139eb23d93b774f0c 100644 (file)
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -16,126 +16,6 @@
 #include <asm/tlbflush.h>
 #include <asm/pgalloc.h>
 
-static unsigned long page_table_shareable(struct vm_area_struct *svma,
-                               struct vm_area_struct *vma,
-                               unsigned long addr, pgoff_t idx)
-{
-       unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
-                               svma->vm_start;
-       unsigned long sbase = saddr & PUD_MASK;
-       unsigned long s_end = sbase + PUD_SIZE;
-
-       /* Allow segments to share if only one is marked locked */
-       unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
-       unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
-
-       /*
-        * match the virtual addresses, permission and the alignment of the
-        * page table page.
-        */
-       if (pmd_index(addr) != pmd_index(saddr) ||
-           vm_flags != svm_flags ||
-           sbase < svma->vm_start || svma->vm_end < s_end)
-               return 0;
-
-       return saddr;
-}
-
-static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
-{
-       unsigned long base = addr & PUD_MASK;
-       unsigned long end = base + PUD_SIZE;
-
-       /*
-        * check on proper vm_flags and page table alignment
-        */
-       if (vma->vm_flags & VM_MAYSHARE &&
-           vma->vm_start <= base && end <= vma->vm_end)
-               return 1;
-       return 0;
-}
-
-/*
- * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
- * and returns the corresponding pte. While this is not necessary for the
- * !shared pmd case because we can allocate the pmd later as well, it makes the
- * code much cleaner. pmd allocation is essential for the shared case because
- * pud has to be populated inside the same i_mmap_mutex section - otherwise
- * racing tasks could either miss the sharing (see huge_pte_offset) or select a
- * bad pmd for sharing.
- */
-static pte_t *
-huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
-{
-       struct vm_area_struct *vma = find_vma(mm, addr);
-       struct address_space *mapping = vma->vm_file->f_mapping;
-       pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
-                       vma->vm_pgoff;
-       struct vm_area_struct *svma;
-       unsigned long saddr;
-       pte_t *spte = NULL;
-       pte_t *pte;
-
-       if (!vma_shareable(vma, addr))
-               return (pte_t *)pmd_alloc(mm, pud, addr);
-
-       mutex_lock(&mapping->i_mmap_mutex);
-       vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
-               if (svma == vma)
-                       continue;
-
-               saddr = page_table_shareable(svma, vma, addr, idx);
-               if (saddr) {
-                       spte = huge_pte_offset(svma->vm_mm, saddr);
-                       if (spte) {
-                               get_page(virt_to_page(spte));
-                               break;
-                       }
-               }
-       }
-
-       if (!spte)
-               goto out;
-
-       spin_lock(&mm->page_table_lock);
-       if (pud_none(*pud))
-               pud_populate(mm, pud, (pmd_t *)((unsigned long)spte & PAGE_MASK));
-       else
-               put_page(virt_to_page(spte));
-       spin_unlock(&mm->page_table_lock);
-out:
-       pte = (pte_t *)pmd_alloc(mm, pud, addr);
-       mutex_unlock(&mapping->i_mmap_mutex);
-       return pte;
-}
-
-/*
- * unmap huge page backed by shared pte.
- *
- * Hugetlb pte page is ref counted at the time of mapping.  If pte is shared
- * indicated by page_count > 1, unmap is achieved by clearing pud and
- * decrementing the ref count. If count == 1, the pte page is not shared.
- *
- * called with vma->vm_mm->page_table_lock held.
- *
- * returns: 1 successfully unmapped a shared pte page
- *         0 the underlying pte page is not shared, or it is the last user
- */
-int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
-{
-       pgd_t *pgd = pgd_offset(mm, *addr);
-       pud_t *pud = pud_offset(pgd, *addr);
-
-       BUG_ON(page_count(virt_to_page(ptep)) == 0);
-       if (page_count(virt_to_page(ptep)) == 1)
-               return 0;
-
-       pud_clear(pud);
-       put_page(virt_to_page(ptep));
-       *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
-       return 1;
-}
-
 pte_t *huge_pte_alloc(struct mm_struct *mm,
                        unsigned long addr, unsigned long sz)
 {