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authorKonstantin Khlebnikov <khlebnikov@openvz.org>2012-06-05 21:36:33 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-06-05 10:46:40 -0700
commitfffaee365fded09f9ebf2db19066065fa54323c3 (patch)
treef6a6d331fa62c9814f9875a845afad1e7994cbde
parentf9ba7179ce91fb77b2adf6eaab3676ab3a1f5a15 (diff)
radix-tree: fix contiguous iterator
This patch fixes bug in macro radix_tree_for_each_contig(). If radix_tree_next_slot() sees NULL in next slot it returns NULL, but following radix_tree_next_chunk() switches iterating into next chunk. As result iterating becomes non-contiguous and breaks vfs "splice" and all its users. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Reported-and-bisected-by: Hans de Bruin <jmdebruin@xmsnet.nl> Reported-and-bisected-by: Ondrej Zary <linux@rainbow-software.org> Reported-bisected-and-tested-by: Toralf Förster <toralf.foerster@gmx.de> Link: https://lkml.org/lkml/2012/6/5/64 Cc: stable <stable@vger.kernel.org> # 3.4.x Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/radix-tree.h5
-rw-r--r--lib/radix-tree.c3
2 files changed, 7 insertions, 1 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 0d04cd69ab9..ffc444c38b0 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -368,8 +368,11 @@ radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags)
iter->index++;
if (likely(*slot))
return slot;
- if (flags & RADIX_TREE_ITER_CONTIG)
+ if (flags & RADIX_TREE_ITER_CONTIG) {
+ /* forbid switching to the next chunk */
+ iter->next_index = 0;
break;
+ }
}
}
return NULL;
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index d7c878cc006..e7964296fd5 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -686,6 +686,9 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
* during iterating; it can be zero only at the beginning.
* And we cannot overflow iter->next_index in a single step,
* because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG.
+ *
+ * This condition also used by radix_tree_next_slot() to stop
+ * contiguous iterating, and forbid swithing to the next chunk.
*/
index = iter->next_index;
if (!index && iter->index)