Merge branch 'v2.6.36-rc8' into for-2.6.37/barrier

Conflicts:
	block/blk-core.c
	drivers/block/loop.c
	mm/swapfile.c

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 43 insertions, 77 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index e132e1708ac..9fc7bac7db0 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -47,8 +47,6 @@ long nr_swap_pages;
 long total_swap_pages;
 static int least_priority;
 
-static bool swap_for_hibernation;
-
 static const char Bad_file[] = "Bad swap file entry ";
 static const char Unused_file[] = "Unused swap file entry ";
 static const char Bad_offset[] = "Bad swap offset entry ";
@@ -317,10 +315,8 @@ checks:
         if (offset > si->highest_bit)
                 scan_base = offset = si->lowest_bit;
 
-        /* reuse swap entry of cache-only swap if not hibernation. */
-        if (vm_swap_full()
-                && usage == SWAP_HAS_CACHE
-                && si->swap_map[offset] == SWAP_HAS_CACHE) {
+        /* reuse swap entry of cache-only swap if not busy. */
+        if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
                 int swap_was_freed;
                 spin_unlock(&swap_lock);
                 swap_was_freed = __try_to_reclaim_swap(si, offset);
@@ -450,8 +446,6 @@ swp_entry_t get_swap_page(void)
         spin_lock(&swap_lock);
         if (nr_swap_pages <= 0)
                 goto noswap;
-        if (swap_for_hibernation)
-                goto noswap;
         nr_swap_pages--;
 
         for (type = swap_list.next; type >= 0 && wrapped < 2; type = next) {
@@ -484,6 +478,28 @@ noswap:
         return (swp_entry_t) {0};
 }
 
+/* The only caller of this function is now susupend routine */
+swp_entry_t get_swap_page_of_type(int type)
+{
+        struct swap_info_struct *si;
+        pgoff_t offset;
+
+        spin_lock(&swap_lock);
+        si = swap_info[type];
+        if (si && (si->flags & SWP_WRITEOK)) {
+                nr_swap_pages--;
+                /* This is called for allocating swap entry, not cache */
+                offset = scan_swap_map(si, 1);
+                if (offset) {
+                        spin_unlock(&swap_lock);
+                        return swp_entry(type, offset);
+                }
+                nr_swap_pages++;
+        }
+        spin_unlock(&swap_lock);
+        return (swp_entry_t) {0};
+}
+
 static struct swap_info_struct *swap_info_get(swp_entry_t entry)
 {
         struct swap_info_struct *p;
@@ -667,6 +683,24 @@ int try_to_free_swap(struct page *page)
         if (page_swapcount(page))
                 return 0;
 
+        /*
+         * Once hibernation has begun to create its image of memory,
+         * there's a danger that one of the calls to try_to_free_swap()
+         * - most probably a call from __try_to_reclaim_swap() while
+         * hibernation is allocating its own swap pages for the image,
+         * but conceivably even a call from memory reclaim - will free
+         * the swap from a page which has already been recorded in the
+         * image as a clean swapcache page, and then reuse its swap for
+         * another page of the image.  On waking from hibernation, the
+         * original page might be freed under memory pressure, then
+         * later read back in from swap, now with the wrong data.
+         *
+         * Hibernation clears bits from gfp_allowed_mask to prevent
+         * memory reclaim from writing to disk, so check that here.
+         */
+        if (!(gfp_allowed_mask & __GFP_IO))
+                return 0;
+
         delete_from_swap_cache(page);
         SetPageDirty(page);
         return 1;
@@ -743,74 +777,6 @@ int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep)
 #endif
 
 #ifdef CONFIG_HIBERNATION
-
-static pgoff_t hibernation_offset[MAX_SWAPFILES];
-/*
- * Once hibernation starts to use swap, we freeze swap_map[]. Otherwise,
- * saved swap_map[] image to the disk will be an incomplete because it's
- * changing without synchronization with hibernation snap shot.
- * At resume, we just make swap_for_hibernation=false. We can forget
- * used maps easily.
- */
-void hibernation_freeze_swap(void)
-{
-        int i;
-
-        spin_lock(&swap_lock);
-
-        printk(KERN_INFO "PM: Freeze Swap\n");
-        swap_for_hibernation = true;
-        for (i = 0; i < MAX_SWAPFILES; i++)
-                hibernation_offset[i] = 1;
-        spin_unlock(&swap_lock);
-}
-
-void hibernation_thaw_swap(void)
-{
-        spin_lock(&swap_lock);
-        if (swap_for_hibernation) {
-                printk(KERN_INFO "PM: Thaw Swap\n");
-                swap_for_hibernation = false;
-        }
-        spin_unlock(&swap_lock);
-}
-
-/*
- * Because updateing swap_map[] can make not-saved-status-change,
- * we use our own easy allocator.
- * Please see kernel/power/swap.c, Used swaps are recorded into
- * RB-tree.
- */
-swp_entry_t get_swap_for_hibernation(int type)
-{
-        pgoff_t off;
-        swp_entry_t val = {0};
-        struct swap_info_struct *si;
-
-        spin_lock(&swap_lock);
-
-        si = swap_info[type];
-        if (!si || !(si->flags & SWP_WRITEOK))
-                goto done;
-
-        for (off = hibernation_offset[type]; off < si->max; ++off) {
-                if (!si->swap_map[off])
-                        break;
-        }
-        if (off < si->max) {
-                val = swp_entry(type, off);
-                hibernation_offset[type] = off + 1;
-        }
-done:
-        spin_unlock(&swap_lock);
-        return val;
-}
-
-void swap_free_for_hibernation(swp_entry_t ent)
-{
-        /* Nothing to do */
-}
-
 /*
  * Find the swap type that corresponds to given device (if any).
  *
@@ -2081,7 +2047,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
                         p->flags |= SWP_SOLIDSTATE;
                         p->cluster_next = 1 + (random32() % p->highest_bit);
                 }
-                if (discard_swap(p) == 0)
+                if (discard_swap(p) == 0 && (swap_flags & SWAP_FLAG_DISCARD))
                         p->flags |= SWP_DISCARDABLE;
         }