radix-tree,shmem: introduce radix_tree_iter_next()
shmem likes to occasionally drop the lock, schedule, then reacqire the
lock and continue with the iteration from the last place it left off.
This is currently done with a pretty ugly goto. Introduce
radix_tree_iter_next() and use it throughout shmem.c.
[koct9i@gmail.com: fix bug in radix_tree_iter_next() for tagged iteration]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index b211f14..51a97ac 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -403,6 +403,22 @@
}
/**
+ * radix_tree_iter_next - resume iterating when the chunk may be invalid
+ * @iter: iterator state
+ *
+ * If the iterator needs to release then reacquire a lock, the chunk may
+ * have been invalidated by an insertion or deletion. Call this function
+ * to continue the iteration from the next index.
+ */
+static inline __must_check
+void **radix_tree_iter_next(struct radix_tree_iter *iter)
+{
+ iter->next_index = iter->index + 1;
+ iter->tags = 0;
+ return NULL;
+}
+
+/**
* radix_tree_chunk_size - get current chunk size
*
* @iter: pointer to radix tree iterator