Merge branch 'akpm' (incoming fixes from Andrew)

Merge misc fixes from Andrew Morton:
 "The audit fixes have been floating around for a while - Al and Eric
  aren't responding to either myself or Kees so I asked Kees to
  re-review them and here they are."

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (22 commits)
  lib/rbtree.c: avoid the use of non-static __always_inline
  MAINTAINERS: Omar had moved
  mm: compaction: partially revert capture of suitable high-order page
  linux/audit.h: move ptrace.h include to kernel header
  kernel/audit.c: avoid negative sleep durations
  audit: catch possible NULL audit buffers
  audit: create explicit AUDIT_SECCOMP event type
  MAINTAINERS: fix a status pattern
  MAINTAINERS: fix arch/arm/plat-omap/include/plat/omap_hwmod.h
  mm: thp: acquire the anon_vma rwsem for write during split
  mm: mmap: annotate vm_lock_anon_vma locking properly for lockdep
  lockdep, rwsem: provide down_write_nest_lock()
  arch/mn10300/Kconfig: select CONFIG_GENERIC_ATOMIC64
  mm: bootmem: fix free_all_bootmem_core() with odd bitmap alignment
  mm: use aligned zone start for pfn_to_bitidx calculation
  fs/exec.c: work around icc miscompilation
  mm: compaction: fix echo 1 > compact_memory return error issue
  mm: memblock: fix wrong memmove size in memblock_merge_regions()
  drivers/video/ssd1307fb.c: fix bit order bug in the byte translation function
  mm: migrate: check page_count of THP before migrating
  ...

1 files changed, 13 insertions, 2 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 9e894edc7811..6001ee6347a9 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1819,9 +1819,19 @@ int split_huge_page(struct page *page)
 
 	BUG_ON(is_huge_zero_pfn(page_to_pfn(page)));
 	BUG_ON(!PageAnon(page));
-	anon_vma = page_lock_anon_vma_read(page);
+
+	/*
+	 * The caller does not necessarily hold an mmap_sem that would prevent
+	 * the anon_vma disappearing so we first we take a reference to it
+	 * and then lock the anon_vma for write. This is similar to
+	 * page_lock_anon_vma_read except the write lock is taken to serialise
+	 * against parallel split or collapse operations.
+	 */
+	anon_vma = page_get_anon_vma(page);
 	if (!anon_vma)
 		goto out;
+	anon_vma_lock_write(anon_vma);
+
 	ret = 0;
 	if (!PageCompound(page))
 		goto out_unlock;
@@ -1832,7 +1842,8 @@ int split_huge_page(struct page *page)
 
 	BUG_ON(PageCompound(page));
 out_unlock:
-	page_unlock_anon_vma_read(anon_vma);
+	anon_vma_unlock(anon_vma);
+	put_anon_vma(anon_vma);
 out:
 	return ret;
 }