[PATCH] freepgt: hugetlb area is clean

Once we're strict about clearing away page tables, hugetlb_prefault can assume
there are no page tables left within its range.  Since the other arches
continue if !pte_none here, let i386 do the same.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 2 insertions, 46 deletions

diff --git a/arch/i386/mm/hugetlbpage.c b/arch/i386/mm/hugetlbpage.c
index a8c45143088b..171fc925e1e4 100644
--- a/arch/i386/mm/hugetlbpage.c
+++ b/arch/i386/mm/hugetlbpage.c
@@ -249,15 +249,8 @@ int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
                         goto out;
                 }
 
-                if (!pte_none(*pte)) {
-                        pmd_t *pmd = (pmd_t *) pte;
-
-                        page = pmd_page(*pmd);
-                        pmd_clear(pmd);
-                        mm->nr_ptes--;
-                        dec_page_state(nr_page_table_pages);
-                        page_cache_release(page);
-                }
+                if (!pte_none(*pte))
+                        continue;
 
                 idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
                         + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
diff --git a/arch/ppc64/mm/hugetlbpage.c b/arch/ppc64/mm/hugetlbpage.c
index 8665bb57e42b..390296efe3e0 100644
--- a/arch/ppc64/mm/hugetlbpage.c
+++ b/arch/ppc64/mm/hugetlbpage.c
@@ -203,8 +203,6 @@ static int prepare_low_seg_for_htlb(struct mm_struct *mm, unsigned long seg)
         unsigned long start = seg << SID_SHIFT;
         unsigned long end = (seg+1) << SID_SHIFT;
         struct vm_area_struct *vma;
-        unsigned long addr;
-        struct mmu_gather *tlb;
 
         BUG_ON(seg >= 16);
 
@@ -213,41 +211,6 @@ static int prepare_low_seg_for_htlb(struct mm_struct *mm, unsigned long seg)
         if (vma && (vma->vm_start < end))
                 return -EBUSY;
 
-        /* Clean up any leftover PTE pages in the region */
-        spin_lock(&mm->page_table_lock);
-        tlb = tlb_gather_mmu(mm, 0);
-        for (addr = start; addr < end; addr += PMD_SIZE) {
-                pgd_t *pgd = pgd_offset(mm, addr);
-                pmd_t *pmd;
-                struct page *page;
-                pte_t *pte;
-                int i;
-
-                if (pgd_none(*pgd))
-                        continue;
-                pmd = pmd_offset(pgd, addr);
-                if (!pmd || pmd_none(*pmd))
-                        continue;
-                if (pmd_bad(*pmd)) {
-                        pmd_ERROR(*pmd);
-                        pmd_clear(pmd);
-                        continue;
-                }
-                pte = (pte_t *)pmd_page_kernel(*pmd);
-                /* No VMAs, so there should be no PTEs, check just in case. */
-                for (i = 0; i < PTRS_PER_PTE; i++) {
-                        BUG_ON(!pte_none(*pte));
-                        pte++;
-                }
-                page = pmd_page(*pmd);
-                pmd_clear(pmd);
-                mm->nr_ptes--;
-                dec_page_state(nr_page_table_pages);
-                pte_free_tlb(tlb, page);
-        }
-        tlb_finish_mmu(tlb, start, end);
-        spin_unlock(&mm->page_table_lock);
-
         return 0;
 }