[PATCH] x86: i8253/i8259A lock cleanup

[pandora-kernel.git] / mm / rmap.c

diff --git a/mm/rmap.c b/mm/rmap.c
index a6203b4..08ac5c7 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -247,8 +247,8 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
  *
  * On success returns with mapped pte and locked mm->page_table_lock.
  */
-static pte_t *page_check_address(struct page *page, struct mm_struct *mm,
-                                       unsigned long address)
+pte_t *page_check_address(struct page *page, struct mm_struct *mm,
+                         unsigned long address)
 {
        pgd_t *pgd;
        pud_t *pud;
@@ -539,27 +539,6 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
                goto out_unmap;
        }
 
-       /*
-        * Don't pull an anonymous page out from under get_user_pages.
-        * GUP carefully breaks COW and raises page count (while holding
-        * page_table_lock, as we have here) to make sure that the page
-        * cannot be freed.  If we unmap that page here, a user write
-        * access to the virtual address will bring back the page, but
-        * its raised count will (ironically) be taken to mean it's not
-        * an exclusive swap page, do_wp_page will replace it by a copy
-        * page, and the user never get to see the data GUP was holding
-        * the original page for.
-        *
-        * This test is also useful for when swapoff (unuse_process) has
-        * to drop page lock: its reference to the page stops existing
-        * ptes from being unmapped, so swapoff can make progress.
-        */
-       if (PageSwapCache(page) &&
-           page_count(page) != page_mapcount(page) + 2) {
-               ret = SWAP_FAIL;
-               goto out_unmap;
-       }
-
        /* Nuke the page table entry. */
        flush_cache_page(vma, address, page_to_pfn(page));
        pteval = ptep_clear_flush(vma, address, pte);
@@ -626,7 +605,7 @@ static void try_to_unmap_cluster(unsigned long cursor,
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
-       pte_t *pte;
+       pte_t *pte, *original_pte;
        pte_t pteval;
        struct page *page;
        unsigned long address;
@@ -658,7 +637,7 @@ static void try_to_unmap_cluster(unsigned long cursor,
        if (!pmd_present(*pmd))
                goto out_unlock;
 
-       for (pte = pte_offset_map(pmd, address);
+       for (original_pte = pte = pte_offset_map(pmd, address);
                        address < end; pte++, address += PAGE_SIZE) {
 
                if (!pte_present(*pte))
@@ -694,7 +673,7 @@ static void try_to_unmap_cluster(unsigned long cursor,
                (*mapcount)--;
        }
 
-       pte_unmap(pte);
+       pte_unmap(original_pte);
 out_unlock:
        spin_unlock(&mm->page_table_lock);
 }