diff options
| author | Konstantin Khlebnikov <khlebnikov@openvz.org> | 2012-06-05 21:36:33 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-06-10 00:36:17 +0900 |
| commit | b642cb6a143da812f188307c2661c0357776a9d0 (patch) | |
| tree | 2c88df819dc12d6a92bf72cce91eaad3ba62ec88 | |
| parent | f940c5366eaaea9630ba643a036c2df321f66db3 (diff) | |
| download | lwn-b642cb6a143da812f188307c2661c0357776a9d0.tar.gz lwn-b642cb6a143da812f188307c2661c0357776a9d0.zip | |
radix-tree: fix contiguous iterator
commit fffaee365fded09f9ebf2db19066065fa54323c3 upstream.
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
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/radix-tree.h | 5 | ||||
| -rw-r--r-- | 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 0d04cd69ab9b..ffc444c38b0a 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 86516f5588e3..3ac50dc55638 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -673,6 +673,9 @@ 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) |