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authorCody P Schafer <cody@linux.vnet.ibm.com>2013-09-11 14:25:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:59:20 -0700
commit2b529089257705499207ce7da9d0e3ae26a844ba (patch)
treefffde388176946c7de6eaddd4e7bdd2b7ea27ffd
parent9dee5c51516d2c3fff22633c1272c5652e68075a (diff)
downloadop-kernel-dev-2b529089257705499207ce7da9d0e3ae26a844ba.zip
op-kernel-dev-2b529089257705499207ce7da9d0e3ae26a844ba.tar.gz
rbtree: add rbtree_postorder_for_each_entry_safe() helper
Because deletion (of the entire tree) is a relatively common use of the rbtree_postorder iteration, and because doing it safely means fiddling with temporary storage, provide a helper to simplify postorder rbtree iteration. Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Reviewed-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/rbtree.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index c467151..aa870a4 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -85,4 +85,22 @@ static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
*rb_link = node;
}
+/**
+ * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
+ * given type safe against removal of rb_node entry
+ *
+ * @pos: the 'type *' to use as a loop cursor.
+ * @n: another 'type *' to use as temporary storage
+ * @root: 'rb_root *' of the rbtree.
+ * @field: the name of the rb_node field within 'type'.
+ */
+#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
+ for (pos = rb_entry(rb_first_postorder(root), typeof(*pos), field),\
+ n = rb_entry(rb_next_postorder(&pos->field), \
+ typeof(*pos), field); \
+ &pos->field; \
+ pos = n, \
+ n = rb_entry(rb_next_postorder(&pos->field), \
+ typeof(*pos), field))
+
#endif /* _LINUX_RBTREE_H */
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