commit: fffaee365fded09f9ebf2db19066065fa54323c3 From: Konstantin Khlebnikov <[email protected]> Date: Tue, 5 Jun 2012 21:36:33 +0400 Subject: radix-tree: fix contiguous iterator MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
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 <[email protected]> Reported-and-bisected-by: Hans de Bruin <[email protected]> Reported-and-bisected-by: Ondrej Zary <[email protected]> Reported-bisected-and-tested-by: Toralf Förster <[email protected]> Link: https://lkml.org/lkml/2012/6/5/64 Cc: stable <[email protected]> # 3.4.x Signed-off-by: Linus Torvalds <[email protected]> --- include/linux/radix-tree.h | 5 ++++- lib/radix-tree.c | 3 +++ 2 files changed, 7 insertions(+), 1 deletions(-) diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 0d04cd6..ffc444c 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 d7c878c..e796429 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) -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
