path: root/lib
diff options
authorMichel Lespinasse <walken@google.com>2013-01-11 14:32:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-01-11 14:54:56 -0800
commit3cb7a56344ca45ee56d71c5f8fe9f922306bff1f (patch)
treeda6fd5aa462e9e7c117063740c15fd95241c72d3 /lib
parentMAINTAINERS: Omar had moved (diff)
lib/rbtree.c: avoid the use of non-static __always_inline
lib/rbtree.c declared __rb_erase_color() as __always_inline void, and then exported it with EXPORT_SYMBOL. This was because __rb_erase_color() must be exported for augmented rbtree users, but it must also be inlined into rb_erase() so that the dummy callback can get optimized out of that call site. (Actually with a modern compiler, none of the dummy callback functions should even be generated as separate text functions). The above usage is legal C, but it was unusual enough for some compilers to warn about it. This change makes things more explicit, with a static __always_inline ____rb_erase_color function for use in rb_erase(), and a separate non-inline __rb_erase_color function for use in rb_erase_augmented call sites. Signed-off-by: Michel Lespinasse <walken@google.com> Reported-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
1 files changed, 17 insertions, 3 deletions
diff --git a/lib/rbtree.c b/lib/rbtree.c
index 4f56a11d67fa..c0e31fe2fabf 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -194,8 +194,12 @@ __rb_insert(struct rb_node *node, struct rb_root *root,
-__always_inline void
-__rb_erase_color(struct rb_node *parent, struct rb_root *root,
+ * Inline version for rb_erase() use - we want to be able to inline
+ * and eliminate the dummy_rotate callback there
+ */
+static __always_inline void
+____rb_erase_color(struct rb_node *parent, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
struct rb_node *node = NULL, *sibling, *tmp1, *tmp2;
@@ -355,6 +359,13 @@ __rb_erase_color(struct rb_node *parent, struct rb_root *root,
+/* Non-inline version for rb_erase_augmented() use */
+void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
+ void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
+ ____rb_erase_color(parent, root, augment_rotate);
@@ -380,7 +391,10 @@ EXPORT_SYMBOL(rb_insert_color);
void rb_erase(struct rb_node *node, struct rb_root *root)
- rb_erase_augmented(node, root, &dummy_callbacks);
+ struct rb_node *rebalance;
+ rebalance = __rb_erase_augmented(node, root, &dummy_callbacks);
+ if (rebalance)
+ ____rb_erase_color(rebalance, root, dummy_rotate);