mm: hugetlb: Copy general hugetlb code from x86 to mm.

[linux-2.6-block.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b0bfb292350e6ff12008449f76c8c4d0e456c412..63217261fd14a3949c10ab74157a20724bad7056 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2931,15 +2931,6 @@ out_mutex:
        return ret;
 }
 
-/* Can be overriden by architectures */
-__attribute__((weak)) struct page *
-follow_huge_pud(struct mm_struct *mm, unsigned long address,
-              pud_t *pud, int write)
-{
-       BUG();
-       return NULL;
-}
-
 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
                         struct page **pages, struct vm_area_struct **vmas,
                         unsigned long *position, unsigned long *nr_pages,
@@ -3289,8 +3280,96 @@ int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
        *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
        return 1;
 }
+#define want_pmd_share()       (1)
+#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
+pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
+{
+       return NULL;
+}
+#define want_pmd_share()       (0)
 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
 
+#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+                       unsigned long addr, unsigned long sz)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+       pte_t *pte = NULL;
+
+       pgd = pgd_offset(mm, addr);
+       pud = pud_alloc(mm, pgd, addr);
+       if (pud) {
+               if (sz == PUD_SIZE) {
+                       pte = (pte_t *)pud;
+               } else {
+                       BUG_ON(sz != PMD_SIZE);
+                       if (want_pmd_share() && pud_none(*pud))
+                               pte = huge_pmd_share(mm, addr, pud);
+                       else
+                               pte = (pte_t *)pmd_alloc(mm, pud, addr);
+               }
+       }
+       BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
+
+       return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+       pmd_t *pmd = NULL;
+
+       pgd = pgd_offset(mm, addr);
+       if (pgd_present(*pgd)) {
+               pud = pud_offset(pgd, addr);
+               if (pud_present(*pud)) {
+                       if (pud_huge(*pud))
+                               return (pte_t *)pud;
+                       pmd = pmd_offset(pud, addr);
+               }
+       }
+       return (pte_t *) pmd;
+}
+
+struct page *
+follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+               pmd_t *pmd, int write)
+{
+       struct page *page;
+
+       page = pte_page(*(pte_t *)pmd);
+       if (page)
+               page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
+       return page;
+}
+
+struct page *
+follow_huge_pud(struct mm_struct *mm, unsigned long address,
+               pud_t *pud, int write)
+{
+       struct page *page;
+
+       page = pte_page(*(pte_t *)pud);
+       if (page)
+               page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
+       return page;
+}
+
+#else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
+
+/* Can be overriden by architectures */
+__attribute__((weak)) struct page *
+follow_huge_pud(struct mm_struct *mm, unsigned long address,
+              pud_t *pud, int write)
+{
+       BUG();
+       return NULL;
+}
+
+#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
+
 #ifdef CONFIG_MEMORY_FAILURE
 
 /* Should be called in hugetlb_lock */