Merge branch 'akpm' (Fixes from Andrew)

Merge misc fixes from Andrew Morton.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (12 patches)
  revert "mm: fix-up zone present pages"
  tmpfs: change final i_blocks BUG to WARNING
  tmpfs: fix shmem_getpage_gfp() VM_BUG_ON
  mm: highmem: don't treat PKMAP_ADDR(LAST_PKMAP) as a highmem address
  mm: revert "mm: vmscan: scale number of pages reclaimed by reclaim/compaction based on failures"
  rapidio: fix kernel-doc warnings
  swapfile: fix name leak in swapoff
  memcg: fix hotplugged memory zone oops
  mips, arc: fix build failure
  memcg: oom: fix totalpages calculation for memory.swappiness==0
  mm: fix build warning for uninitialized value
  mm: add anon_vma_lock to validate_mm()

1 files changed, 15 insertions, 3 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 67afba5117f2..89341b658bd0 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -643,7 +643,7 @@ static void shmem_evict_inode(struct inode *inode)
 		kfree(info->symlink);
 
 	simple_xattrs_free(&info->xattrs);
-	BUG_ON(inode->i_blocks);
+	WARN_ON(inode->i_blocks);
 	shmem_free_inode(inode->i_sb);
 	clear_inode(inode);
 }
@@ -1145,8 +1145,20 @@ repeat:
 		if (!error) {
 			error = shmem_add_to_page_cache(page, mapping, index,
 						gfp, swp_to_radix_entry(swap));
-			/* We already confirmed swap, and make no allocation */
-			VM_BUG_ON(error);
+			/*
+			 * We already confirmed swap under page lock, and make
+			 * no memory allocation here, so usually no possibility
+			 * of error; but free_swap_and_cache() only trylocks a
+			 * page, so it is just possible that the entry has been
+			 * truncated or holepunched since swap was confirmed.
+			 * shmem_undo_range() will have done some of the
+			 * unaccounting, now delete_from_swap_cache() will do
+			 * the rest (including mem_cgroup_uncharge_swapcache).
+			 * Reset swap.val? No, leave it so "failed" goes back to
+			 * "repeat": reading a hole and writing should succeed.
+			 */
+			if (error)
+				delete_from_swap_cache(page);
 		}
 		if (error)
 			goto failed;