V4L/DVB (8191): gspca: Make CONFIG_VIDEO_ADV_DEBUG actually work.

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

diff --git a/mm/swapfile.c b/mm/swapfile.c
index fddc4cc..bd1bb59 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -507,11 +507,23 @@ unsigned int count_swap_pages(int type, int free)
  * just let do_wp_page work it out if a write is requested later - to
  * force COW, vm_page_prot omits write permission from any private vma.
  */
-static int unuse_pte(struct vm_area_struct *vma, pte_t *pte,
+static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
                unsigned long addr, swp_entry_t entry, struct page *page)
 {
-       if (mem_cgroup_charge(page, vma->vm_mm))
-               return -ENOMEM;
+       spinlock_t *ptl;
+       pte_t *pte;
+       int ret = 1;
+
+       if (mem_cgroup_charge(page, vma->vm_mm, GFP_KERNEL))
+               ret = -ENOMEM;
+
+       pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
+       if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) {
+               if (ret > 0)
+                       mem_cgroup_uncharge_page(page);
+               ret = 0;
+               goto out;
+       }
 
        inc_mm_counter(vma->vm_mm, anon_rss);
        get_page(page);
@@ -524,7 +536,9 @@ static int unuse_pte(struct vm_area_struct *vma, pte_t *pte,
         * immediately swapped out again after swapon.
         */
        activate_page(page);
-       return 1;
+out:
+       pte_unmap_unlock(pte, ptl);
+       return ret;
 }
 
 static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
@@ -533,21 +547,33 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 {
        pte_t swp_pte = swp_entry_to_pte(entry);
        pte_t *pte;
-       spinlock_t *ptl;
        int ret = 0;
 
-       pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
+       /*
+        * We don't actually need pte lock while scanning for swp_pte: since
+        * we hold page lock and mmap_sem, swp_pte cannot be inserted into the
+        * page table while we're scanning; though it could get zapped, and on
+        * some architectures (e.g. x86_32 with PAE) we might catch a glimpse
+        * of unmatched parts which look like swp_pte, so unuse_pte must
+        * recheck under pte lock.  Scanning without pte lock lets it be
+        * preemptible whenever CONFIG_PREEMPT but not CONFIG_HIGHPTE.
+        */
+       pte = pte_offset_map(pmd, addr);
        do {
                /*
                 * swapoff spends a _lot_ of time in this loop!
                 * Test inline before going to call unuse_pte.
                 */
                if (unlikely(pte_same(*pte, swp_pte))) {
-                       ret = unuse_pte(vma, pte++, addr, entry, page);
-                       break;
+                       pte_unmap(pte);
+                       ret = unuse_pte(vma, pmd, addr, entry, page);
+                       if (ret)
+                               goto out;
+                       pte = pte_offset_map(pmd, addr);
                }
        } while (pte++, addr += PAGE_SIZE, addr != end);
-       pte_unmap_unlock(pte - 1, ptl);
+       pte_unmap(pte - 1);
+out:
        return ret;
 }
 
@@ -1368,7 +1394,7 @@ static int swap_show(struct seq_file *swap, void *v)
        }
 
        file = ptr->swap_file;
-       len = seq_path(swap, file->f_path.mnt, file->f_path.dentry, " \t\n\\");
+       len = seq_path(swap, &file->f_path, " \t\n\\");
        seq_printf(swap, "%*s%s\t%u\t%u\t%d\n",
                       len < 40 ? 40 - len : 1, " ",
                       S_ISBLK(file->f_path.dentry->d_inode->i_mode) ?
@@ -1400,11 +1426,7 @@ static const struct file_operations proc_swaps_operations = {
 
 static int __init procswaps_init(void)
 {
-       struct proc_dir_entry *entry;
-
-       entry = create_proc_entry("swaps", 0, NULL);
-       if (entry)
-               entry->proc_fops = &proc_swaps_operations;
+       proc_create("swaps", 0, NULL, &proc_swaps_operations);
        return 0;
 }
 __initcall(procswaps_init);
@@ -1556,6 +1578,14 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
                error = -EINVAL;
                goto bad_swap;
        case 2:
+               /* swap partition endianess hack... */
+               if (swab32(swap_header->info.version) == 1) {
+                       swab32s(&swap_header->info.version);
+                       swab32s(&swap_header->info.last_page);
+                       swab32s(&swap_header->info.nr_badpages);
+                       for (i = 0; i < swap_header->info.nr_badpages; i++)
+                               swab32s(&swap_header->info.badpages[i]);
+               }
                /* Check the swap header's sub-version and the size of
                    the swap file and bad block lists */
                if (swap_header->info.version != 1) {