From 3cb7a56344ca45ee56d71c5f8fe9f922306bff1f Mon Sep 17 00:00:00 2001 From: Michel Lespinasse Date: Fri, 11 Jan 2013 14:32:20 -0800 Subject: [PATCH] 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 Reported-by: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/rbtree_augmented.h | 14 +++++++++++--- lib/rbtree.c | 20 +++++++++++++++++--- 2 files changed, 28 insertions(+), 6 deletions(-) diff --git a/include/linux/rbtree_augmented.h b/include/linux/rbtree_augmented.h index 2ac60c9cf644..fea49b5da12a 100644 --- a/include/linux/rbtree_augmented.h +++ b/include/linux/rbtree_augmented.h @@ -123,9 +123,9 @@ __rb_change_child(struct rb_node *old, struct rb_node *new, extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root, void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); -static __always_inline void -rb_erase_augmented(struct rb_node *node, struct rb_root *root, - const struct rb_augment_callbacks *augment) +static __always_inline struct rb_node * +__rb_erase_augmented(struct rb_node *node, struct rb_root *root, + const struct rb_augment_callbacks *augment) { struct rb_node *child = node->rb_right, *tmp = node->rb_left; struct rb_node *parent, *rebalance; @@ -217,6 +217,14 @@ rb_erase_augmented(struct rb_node *node, struct rb_root *root, } augment->propagate(tmp, NULL); + return rebalance; +} + +static __always_inline void +rb_erase_augmented(struct rb_node *node, struct rb_root *root, + const struct rb_augment_callbacks *augment) +{ + struct rb_node *rebalance = __rb_erase_augmented(node, root, augment); if (rebalance) __rb_erase_color(rebalance, root, augment->rotate); } 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); +} EXPORT_SYMBOL(__rb_erase_color); /* @@ -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); } EXPORT_SYMBOL(rb_erase);