x86_64: expand kernel stack to 16K

[pandora-kernel.git] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index 5020b28..088358c 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -257,9 +257,11 @@ static int filemap_check_errors(struct address_space *mapping)
 {
        int ret = 0;
        /* Check for outstanding write errors */
-       if (test_and_clear_bit(AS_ENOSPC, &mapping->flags))
+       if (test_bit(AS_ENOSPC, &mapping->flags) &&
+           test_and_clear_bit(AS_ENOSPC, &mapping->flags))
                ret = -ENOSPC;
-       if (test_and_clear_bit(AS_EIO, &mapping->flags))
+       if (test_bit(AS_EIO, &mapping->flags) &&
+           test_and_clear_bit(AS_EIO, &mapping->flags))
                ret = -EIO;
        return ret;
 }
@@ -906,8 +908,8 @@ EXPORT_SYMBOL(page_cache_prev_hole);
  * Looks up the page cache slot at @mapping & @offset.  If there is a
  * page cache page, it is returned with an increased refcount.
  *
- * If the slot holds a shadow entry of a previously evicted page, it
- * is returned.
+ * If the slot holds a shadow entry of a previously evicted page, or a
+ * swap entry from shmem/tmpfs, it is returned.
  *
  * Otherwise, %NULL is returned.
  */
@@ -928,9 +930,9 @@ repeat:
                        if (radix_tree_deref_retry(page))
                                goto repeat;
                        /*
-                        * Otherwise, shmem/tmpfs must be storing a swap entry
-                        * here as an exceptional entry: so return it without
-                        * attempting to raise page count.
+                        * A shadow entry of a recently evicted page,
+                        * or a swap entry from shmem/tmpfs.  Return
+                        * it without attempting to raise page count.
                         */
                        goto out;
                }
@@ -983,8 +985,8 @@ EXPORT_SYMBOL(find_get_page);
  * page cache page, it is returned locked and with an increased
  * refcount.
  *
- * If the slot holds a shadow entry of a previously evicted page, it
- * is returned.
+ * If the slot holds a shadow entry of a previously evicted page, or a
+ * swap entry from shmem/tmpfs, it is returned.
  *
  * Otherwise, %NULL is returned.
  *
@@ -1099,8 +1101,8 @@ EXPORT_SYMBOL(find_or_create_page);
  * with ascending indexes.  There may be holes in the indices due to
  * not-present pages.
  *
- * Any shadow entries of evicted pages are included in the returned
- * array.
+ * Any shadow entries of evicted pages, or swap entries from
+ * shmem/tmpfs, are included in the returned array.
  *
  * find_get_entries() returns the number of pages and shadow entries
  * which were found.
@@ -1128,9 +1130,9 @@ repeat:
                        if (radix_tree_deref_retry(page))
                                goto restart;
                        /*
-                        * Otherwise, we must be storing a swap entry
-                        * here as an exceptional entry: so return it
-                        * without attempting to raise page count.
+                        * A shadow entry of a recently evicted page,
+                        * or a swap entry from shmem/tmpfs.  Return
+                        * it without attempting to raise page count.
                         */
                        goto export;
                }
@@ -1198,9 +1200,9 @@ repeat:
                                goto restart;
                        }
                        /*
-                        * Otherwise, shmem/tmpfs must be storing a swap entry
-                        * here as an exceptional entry: so skip over it -
-                        * we only reach this from invalidate_mapping_pages().
+                        * A shadow entry of a recently evicted page,
+                        * or a swap entry from shmem/tmpfs.  Skip
+                        * over it.
                         */
                        continue;
                }
@@ -1265,9 +1267,9 @@ repeat:
                                goto restart;
                        }
                        /*
-                        * Otherwise, shmem/tmpfs must be storing a swap entry
-                        * here as an exceptional entry: so stop looking for
-                        * contiguous pages.
+                        * A shadow entry of a recently evicted page,
+                        * or a swap entry from shmem/tmpfs.  Stop
+                        * looking for contiguous pages.
                         */
                        break;
                }
@@ -1341,10 +1343,17 @@ repeat:
                                goto restart;
                        }
                        /*
-                        * This function is never used on a shmem/tmpfs
-                        * mapping, so a swap entry won't be found here.
+                        * A shadow entry of a recently evicted page.
+                        *
+                        * Those entries should never be tagged, but
+                        * this tree walk is lockless and the tags are
+                        * looked up in bulk, one radix tree node at a
+                        * time, so there is a sizable window for page
+                        * reclaim to evict a page we saw tagged.
+                        *
+                        * Skip over it.
                         */
-                       BUG();
+                       continue;
                }
 
                if (!page_cache_get_speculative(page))