Merge branch 'akpm' (patches from Andrew)

Merge updates from Andrew Morton:

 - a few misc bits

 - ocfs2 updates

 - almost all of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (131 commits)
  memory hotplug: fix comments when adding section
  mm: make alloc_node_mem_map a void call if we don't have CONFIG_FLAT_NODE_MEM_MAP
  mm: simplify nodemask printing
  mm,oom_reaper: remove pointless kthread_run() error check
  mm/page_ext.c: check if page_ext is not prepared
  writeback: remove unused function parameter
  mm: do not rely on preempt_count in print_vma_addr
  mm, sparse: do not swamp log with huge vmemmap allocation failures
  mm/hmm: remove redundant variable align_end
  mm/list_lru.c: mark expected switch fall-through
  mm/shmem.c: mark expected switch fall-through
  mm/page_alloc.c: broken deferred calculation
  mm: don't warn about allocations which stall for too long
  fs: fuse: account fuse_inode slab memory as reclaimable
  mm, page_alloc: fix potential false positive in __zone_watermark_ok
  mm: mlock: remove lru_add_drain_all()
  mm, sysctl: make NUMA stats configurable
  shmem: convert shmem_init_inodecache() to void
  Unify migrate_pages and move_pages access checks
  mm, pagevec: rename pagevec drained field
  ...

1 files changed, 9 insertions, 2 deletions

diff --git a/mm/swap_slots.c b/mm/swap_slots.c
index d81cfc5a43d5..bebc19292018 100644
--- a/mm/swap_slots.c
+++ b/mm/swap_slots.c
@@ -149,6 +149,13 @@ static int alloc_swap_slot_cache(unsigned int cpu)
 	cache->nr = 0;
 	cache->cur = 0;
 	cache->n_ret = 0;
+	/*
+	 * We initialized alloc_lock and free_lock earlier.  We use
+	 * !cache->slots or !cache->slots_ret to know if it is safe to acquire
+	 * the corresponding lock and use the cache.  Memory barrier below
+	 * ensures the assumption.
+	 */
+	mb();
 	cache->slots = slots;
 	slots = NULL;
 	cache->slots_ret = slots_ret;
@@ -275,7 +282,7 @@ int free_swap_slot(swp_entry_t entry)
 	struct swap_slots_cache *cache;
 
 	cache = raw_cpu_ptr(&swp_slots);
-	if (use_swap_slot_cache && cache->slots_ret) {
+	if (likely(use_swap_slot_cache && cache->slots_ret)) {
 		spin_lock_irq(&cache->free_lock);
 		/* Swap slots cache may be deactivated before acquiring lock */
 		if (!use_swap_slot_cache || !cache->slots_ret) {
@@ -326,7 +333,7 @@ swp_entry_t get_swap_page(struct page *page)
 	 */
 	cache = raw_cpu_ptr(&swp_slots);
 
-	if (check_cache_active()) {
+	if (likely(check_cache_active() && cache->slots)) {
 		mutex_lock(&cache->alloc_lock);
 		if (cache->slots) {
 repeat: