[PATCH] introduce and use kzalloc

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

diff --git a/mm/rmap.c b/mm/rmap.c
index 9827409..450f524 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -34,9 +34,8 @@
  *       anon_vma->lock
  *         mm->page_table_lock
  *           zone->lru_lock (in mark_page_accessed)
- *           swap_list_lock (in swap_free etc's swap_info_get)
+ *           swap_lock (in swap_duplicate, swap_info_get)
  *             mmlist_lock (in mmput, drain_mmlist and others)
- *             swap_device_lock (in swap_duplicate, swap_info_get)
  *             mapping->private_lock (in __set_page_dirty_buffers)
  *             inode_lock (in set_page_dirty's __mark_inode_dirty)
  *               sb_lock (within inode_lock in fs/fs-writeback.c)
@@ -247,8 +246,8 @@ 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;
@@ -290,8 +289,6 @@ static int page_referenced_one(struct page *page,
        pte_t *pte;
        int referenced = 0;
 
-       if (!get_mm_counter(mm, rss))
-               goto out;
        address = vma_address(page, vma);
        if (address == -EFAULT)
                goto out;
@@ -442,22 +439,19 @@ int page_referenced(struct page *page, int is_locked, int ignore_token)
 void page_add_anon_rmap(struct page *page,
        struct vm_area_struct *vma, unsigned long address)
 {
-       struct anon_vma *anon_vma = vma->anon_vma;
-       pgoff_t index;
-
        BUG_ON(PageReserved(page));
-       BUG_ON(!anon_vma);
 
        inc_mm_counter(vma->vm_mm, anon_rss);
 
-       anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
-       index = (address - vma->vm_start) >> PAGE_SHIFT;
-       index += vma->vm_pgoff;
-       index >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
-
        if (atomic_inc_and_test(&page->_mapcount)) {
-               page->index = index;
+               struct anon_vma *anon_vma = vma->anon_vma;
+
+               BUG_ON(!anon_vma);
+               anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
                page->mapping = (struct address_space *) anon_vma;
+
+               page->index = linear_page_index(vma, address);
+
                inc_page_state(nr_mapped);
        }
        /* else checking page index and mapping is racy */
@@ -518,8 +512,6 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
        pte_t pteval;
        int ret = SWAP_AGAIN;
 
-       if (!get_mm_counter(mm, rss))
-               goto out;
        address = vma_address(page, vma);
        if (address == -EFAULT)
                goto out;
@@ -532,6 +524,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
         * If the page is mlock()d, we cannot swap it out.
         * If it's recently referenced (perhaps page_referenced
         * skipped over this mm) then we should reactivate it.
+        *
+        * Pages belonging to VM_RESERVED regions should not happen here.
         */
        if ((vma->vm_flags & (VM_LOCKED|VM_RESERVED)) ||
                        ptep_clear_flush_young(vma, address, pte)) {
@@ -539,27 +533,6 @@ 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);
@@ -788,8 +761,7 @@ static int try_to_unmap_file(struct page *page)
                        if (vma->vm_flags & (VM_LOCKED|VM_RESERVED))
                                continue;
                        cursor = (unsigned long) vma->vm_private_data;
-                       while (get_mm_counter(vma->vm_mm, rss) &&
-                               cursor < max_nl_cursor &&
+                       while ( cursor < max_nl_cursor &&
                                cursor < vma->vm_end - vma->vm_start) {
                                try_to_unmap_cluster(cursor, &mapcount, vma);
                                cursor += CLUSTER_SIZE;