V4L/DVB (9418): DVB_ATTACH for STB0899, STB6100, TDA8261

[safe/jmp/linux-2.6] / mm / swapfile.c

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 2f33edb..54a9f87 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -33,8 +33,8 @@
 #include <asm/tlbflush.h>
 #include <linux/swapops.h>
 
-DEFINE_SPINLOCK(swap_lock);
-unsigned int nr_swapfiles;
+static DEFINE_SPINLOCK(swap_lock);
+static unsigned int nr_swapfiles;
 long total_swap_pages;
 static int swap_overflow;
 static int least_priority;
@@ -44,7 +44,7 @@ static const char Unused_file[] = "Unused swap file entry ";
 static const char Bad_offset[] = "Bad swap offset entry ";
 static const char Unused_offset[] = "Unused swap offset entry ";
 
-struct swap_list_t swap_list = {-1, -1};
+static struct swap_list_t swap_list = {-1, -1};
 
 static struct swap_info_struct swap_info[MAX_SWAPFILES];
 
@@ -344,7 +344,7 @@ int can_share_swap_page(struct page *page)
  * Work out if there are any other processes sharing this
  * swap cache page. Free it if you can. Return success.
  */
-int remove_exclusive_swap_page(struct page *page)
+static int remove_exclusive_swap_page_count(struct page *page, int count)
 {
        int retval;
        struct swap_info_struct * p;
@@ -357,7 +357,7 @@ int remove_exclusive_swap_page(struct page *page)
                return 0;
        if (PageWriteback(page))
                return 0;
-       if (page_count(page) != 2) /* 2: us + cache */
+       if (page_count(page) != count) /* us + cache + ptes */
                return 0;
 
        entry.val = page_private(page);
@@ -369,13 +369,13 @@ int remove_exclusive_swap_page(struct page *page)
        retval = 0;
        if (p->swap_map[swp_offset(entry)] == 1) {
                /* Recheck the page count with the swapcache lock held.. */
-               write_lock_irq(&swapper_space.tree_lock);
-               if ((page_count(page) == 2) && !PageWriteback(page)) {
+               spin_lock_irq(&swapper_space.tree_lock);
+               if ((page_count(page) == count) && !PageWriteback(page)) {
                        __delete_from_swap_cache(page);
                        SetPageDirty(page);
                        retval = 1;
                }
-               write_unlock_irq(&swapper_space.tree_lock);
+               spin_unlock_irq(&swapper_space.tree_lock);
        }
        spin_unlock(&swap_lock);
 
@@ -388,6 +388,25 @@ int remove_exclusive_swap_page(struct page *page)
 }
 
 /*
+ * Most of the time the page should have two references: one for the
+ * process and one for the swap cache.
+ */
+int remove_exclusive_swap_page(struct page *page)
+{
+       return remove_exclusive_swap_page_count(page, 2);
+}
+
+/*
+ * The pageout code holds an extra reference to the page.  That raises
+ * the reference count to test for to 2 for a page that is only in the
+ * swap cache plus 1 for each process that maps the page.
+ */
+int remove_exclusive_swap_page_ref(struct page *page)
+{
+       return remove_exclusive_swap_page_count(page, 2 + page_mapcount(page));
+}
+
+/*
  * Free the swap entry like above, but also try to
  * free the page cache entry if it is the last user.
  */
@@ -403,7 +422,7 @@ void free_swap_and_cache(swp_entry_t entry)
        if (p) {
                if (swap_entry_free(p, swp_offset(entry)) == 1) {
                        page = find_get_page(&swapper_space, entry.val);
-                       if (page && unlikely(TestSetPageLocked(page))) {
+                       if (page && !trylock_page(page)) {
                                page_cache_release(page);
                                page = NULL;
                        }
@@ -656,8 +675,8 @@ static int unuse_mm(struct mm_struct *mm,
 
        if (!down_read_trylock(&mm->mmap_sem)) {
                /*
-                * Activate page so shrink_cache is unlikely to unmap its
-                * ptes while lock is dropped, so swapoff can make progress.
+                * Activate page so shrink_inactive_list is unlikely to unmap
+                * its ptes while lock is dropped, so swapoff can make progress.
                 */
                activate_page(page);
                unlock_page(page);
@@ -1443,6 +1462,15 @@ static int __init procswaps_init(void)
 __initcall(procswaps_init);
 #endif /* CONFIG_PROC_FS */
 
+#ifdef MAX_SWAPFILES_CHECK
+static int __init max_swapfiles_check(void)
+{
+       MAX_SWAPFILES_CHECK();
+       return 0;
+}
+late_initcall(max_swapfiles_check);
+#endif
+
 /*
  * Written 01/25/92 by Simmule Turner, heavily changed by Linus.
  *