Revert to Fedora kernel-2.6.17-1.2187_FC5 patched with vs2.0.2.1; there are too many...

[linux-2.6.git] / mm / swapfile.c

diff --git a/mm/swapfile.c b/mm/swapfile.c
index c25ffae..0cefbba 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -5,6 +5,7 @@
  *  Swap reorganised 29.12.95, Stephen Tweedie
  */
 
+#include <linux/config.h>
 #include <linux/mm.h>
 #include <linux/hugetlb.h>
 #include <linux/mman.h>
@@ -396,9 +397,6 @@ void free_swap_and_cache(swp_entry_t entry)
        struct swap_info_struct * p;
        struct page *page = NULL;
 
-       if (is_migration_entry(entry))
-               return;
-
        p = swap_info_get(entry);
        if (p) {
                if (swap_entry_free(p, swp_offset(entry)) == 1) {
@@ -620,6 +618,15 @@ static int unuse_mm(struct mm_struct *mm,
        return 0;
 }
 
+#ifdef CONFIG_MIGRATION
+int remove_vma_swap(struct vm_area_struct *vma, struct page *page)
+{
+       swp_entry_t entry = { .val = page_private(page) };
+
+       return unuse_vma(vma, entry, page);
+}
+#endif
+
 /*
  * Scan swap_map from current position to next entry still in use.
  * Recycle to start on reaching the end, returning 0 when empty.
@@ -712,6 +719,7 @@ static int try_to_unuse(unsigned int type)
                 */
                swap_map = &si->swap_map[i];
                entry = swp_entry(type, i);
+again:
                page = read_swap_cache_async(entry, NULL, 0);
                if (!page) {
                        /*
@@ -746,6 +754,12 @@ static int try_to_unuse(unsigned int type)
                wait_on_page_locked(page);
                wait_on_page_writeback(page);
                lock_page(page);
+               if (!PageSwapCache(page)) {
+                       /* Page migration has occured */
+                       unlock_page(page);
+                       page_cache_release(page);
+                       goto again;
+               }
                wait_on_page_writeback(page);
 
                /*
@@ -774,8 +788,10 @@ static int try_to_unuse(unsigned int type)
                        while (*swap_map > 1 && !retval &&
                                        (p = p->next) != &start_mm->mmlist) {
                                mm = list_entry(p, struct mm_struct, mmlist);
-                               if (!atomic_inc_not_zero(&mm->mm_users))
+                               if (atomic_inc_return(&mm->mm_users) == 1) {
+                                       atomic_dec(&mm->mm_users);
                                        continue;
+                               }
                                spin_unlock(&mmlist_lock);
                                mmput(prev_mm);
                                prev_mm = mm;
@@ -1394,7 +1410,19 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
                if (!(p->flags & SWP_USED))
                        break;
        error = -EPERM;
-       if (type >= MAX_SWAPFILES) {
+       /*
+        * Test if adding another swap device is possible. There are
+        * two limiting factors: 1) the number of bits for the swap
+        * type swp_entry_t definition and 2) the number of bits for
+        * the swap type in the swap ptes as defined by the different
+        * architectures. To honor both limitations a swap entry
+        * with swap offset 0 and swap type ~0UL is created, encoded
+        * to a swap pte, decoded to a swp_entry_t again and finally
+        * the swap type part is extracted. This will mask all bits
+        * from the initial ~0UL that can't be encoded in either the
+        * swp_entry_t or the architecture definition of a swap pte.
+        */
+       if (type > swp_type(pte_to_swp_entry(swp_entry_to_pte(swp_entry(~0UL,0))))) {
                spin_unlock(&swap_lock);
                goto out;
        }
@@ -1479,7 +1507,8 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
                error = -EINVAL;
                goto bad_swap;
        }
-       page = read_mapping_page(mapping, 0, swap_file);
+       page = read_cache_page(mapping, 0,
+                       (filler_t *)mapping->a_ops->readpage, swap_file);
        if (IS_ERR(page)) {
                error = PTR_ERR(page);
                goto bad_swap;
@@ -1685,9 +1714,6 @@ int swap_duplicate(swp_entry_t entry)
        unsigned long offset, type;
        int result = 0;
 
-       if (is_migration_entry(entry))
-               return 1;
-
        type = swp_type(entry);
        if (type >= nr_swapfiles)
                goto bad_file;