Merge branch 'akpm' (fixes from Andrew Morton)

Merge misc fixes from Andrew Morton.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (22 commits)
  pidns: fix free_pid() to handle the first fork failure
  ipc,msg: prevent race with rmid in msgsnd,msgrcv
  ipc/sem.c: update sem_otime for all operations
  mm/hwpoison: fix the lack of one reference count against poisoned page
  mm/hwpoison: fix false report on 2nd attempt at page recovery
  mm/hwpoison: fix test for a transparent huge page
  mm/hwpoison: fix traversal of hugetlbfs pages to avoid printk flood
  block: change config option name for cmdline partition parsing
  mm/mlock.c: prevent walking off the end of a pagetable in no-pmd configuration
  mm: avoid reinserting isolated balloon pages into LRU lists
  arch/parisc/mm/fault.c: fix uninitialized variable usage
  include/asm-generic/vtime.h: avoid zero-length file
  nilfs2: fix issue with race condition of competition between segments for dirty blocks
  Documentation/kernel-parameters.txt: replace kernelcore with Movable
  mm/bounce.c: fix a regression where MS_SNAP_STABLE (stable pages snapshotting) was ignored
  kernel/kmod.c: check for NULL in call_usermodehelper_exec()
  ipc/sem.c: synchronize the proc interface
  ipc/sem.c: optimize sem_lock()
  ipc/sem.c: fix race in sem_lock()
  mm/compaction.c: periodically schedule when freeing pages
  ...

1 files changed, 25 insertions, 0 deletions

diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index f7f1d7169b11..089743ade734 100644
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -159,6 +159,26 @@ static inline bool balloon_page_movable(struct page *page)
 }
 
 /*
+ * isolated_balloon_page - identify an isolated balloon page on private
+ *			   compaction/migration page lists.
+ *
+ * After a compaction thread isolates a balloon page for migration, it raises
+ * the page refcount to prevent concurrent compaction threads from re-isolating
+ * the same page. For that reason putback_movable_pages(), or other routines
+ * that need to identify isolated balloon pages on private pagelists, cannot
+ * rely on balloon_page_movable() to accomplish the task.
+ */
+static inline bool isolated_balloon_page(struct page *page)
+{
+	/* Already isolated balloon pages, by default, have a raised refcount */
+	if (page_flags_cleared(page) && !page_mapped(page) &&
+	    page_count(page) >= 2)
+		return __is_movable_balloon_page(page);
+
+	return false;
+}
+
+/*
  * balloon_page_insert - insert a page into the balloon's page list and make
  *		         the page->mapping assignment accordingly.
  * @page    : page to be assigned as a 'balloon page'
@@ -243,6 +263,11 @@ static inline bool balloon_page_movable(struct page *page)
 	return false;
 }
 
+static inline bool isolated_balloon_page(struct page *page)
+{
+	return false;
+}
+
 static inline bool balloon_page_isolate(struct page *page)
 {
 	return false;