From 2d24dd5798d0474d9bf705bfca8725e7d20f9d54 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 29 Apr 2020 17:03:22 +0200 Subject: [PATCH] rbtree: Add generic add and find helpers I've always been bothered by the endless (fragile) boilerplate for rbtree, and I recently wrote some rbtree helpers for objtool and figured I should lift them into the kernel and use them more widely. Provide: partial-order; less() based: - rb_add(): add a new entry to the rbtree - rb_add_cached(): like rb_add(), but for a rb_root_cached total-order; cmp() based: - rb_find(): find an entry in an rbtree - rb_find_add(): find an entry, and add if not found - rb_find_first(): find the first (leftmost) matching entry - rb_next_match(): continue from rb_find_first() - rb_for_each(): iterate a sub-tree using the previous two Inlining and constant propagation should see the compiler inline the whole thing, including the various compare functions. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Michel Lespinasse Acked-by: Davidlohr Bueso --- include/linux/rbtree.h | 190 ++++++++++++++++++++++++++++++++++++++++++ tools/include/linux/rbtree.h | 192 ++++++++++++++++++++++++++++++++++++++++++- tools/objtool/elf.c | 73 +++------------- 3 files changed, 392 insertions(+), 63 deletions(-) diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h index d7db179..e0b300d 100644 --- a/include/linux/rbtree.h +++ b/include/linux/rbtree.h @@ -158,4 +158,194 @@ static inline void rb_replace_node_cached(struct rb_node *victim, rb_replace_node(victim, new, &root->rb_root); } +/* + * The below helper functions use 2 operators with 3 different + * calling conventions. The operators are related like: + * + * comp(a->key,b) < 0 := less(a,b) + * comp(a->key,b) > 0 := less(b,a) + * comp(a->key,b) == 0 := !less(a,b) && !less(b,a) + * + * If these operators define a partial order on the elements we make no + * guarantee on which of the elements matching the key is found. See + * rb_find(). + * + * The reason for this is to allow the find() interface without requiring an + * on-stack dummy object, which might not be feasible due to object size. + */ + +/** + * rb_add_cached() - insert @node into the leftmost cached tree @tree + * @node: node to insert + * @tree: leftmost cached tree to insert @node into + * @less: operator defining the (partial) node order + */ +static __always_inline void +rb_add_cached(struct rb_node *node, struct rb_root_cached *tree, + bool (*less)(struct rb_node *, const struct rb_node *)) +{ + struct rb_node **link = &tree->rb_root.rb_node; + struct rb_node *parent = NULL; + bool leftmost = true; + + while (*link) { + parent = *link; + if (less(node, parent)) { + link = &parent->rb_left; + } else { + link = &parent->rb_right; + leftmost = false; + } + } + + rb_link_node(node, parent, link); + rb_insert_color_cached(node, tree, leftmost); +} + +/** + * rb_add() - insert @node into @tree + * @node: node to insert + * @tree: tree to insert @node into + * @less: operator defining the (partial) node order + */ +static __always_inline void +rb_add(struct rb_node *node, struct rb_root *tree, + bool (*less)(struct rb_node *, const struct rb_node *)) +{ + struct rb_node **link = &tree->rb_node; + struct rb_node *parent = NULL; + + while (*link) { + parent = *link; + if (less(node, parent)) + link = &parent->rb_left; + else + link = &parent->rb_right; + } + + rb_link_node(node, parent, link); + rb_insert_color(node, tree); +} + +/** + * rb_find_add() - find equivalent @node in @tree, or add @node + * @node: node to look-for / insert + * @tree: tree to search / modify + * @cmp: operator defining the node order + * + * Returns the rb_node matching @node, or NULL when no match is found and @node + * is inserted. + */ +static __always_inline struct rb_node * +rb_find_add(struct rb_node *node, struct rb_root *tree, + int (*cmp)(struct rb_node *, const struct rb_node *)) +{ + struct rb_node **link = &tree->rb_node; + struct rb_node *parent = NULL; + int c; + + while (*link) { + parent = *link; + c = cmp(node, parent); + + if (c < 0) + link = &parent->rb_left; + else if (c > 0) + link = &parent->rb_right; + else + return parent; + } + + rb_link_node(node, parent, link); + rb_insert_color(node, tree); + return NULL; +} + +/** + * rb_find() - find @key in tree @tree + * @key: key to match + * @tree: tree to search + * @cmp: operator defining the node order + * + * Returns the rb_node matching @key or NULL. + */ +static __always_inline struct rb_node * +rb_find(const void *key, const struct rb_root *tree, + int (*cmp)(const void *key, const struct rb_node *)) +{ + struct rb_node *node = tree->rb_node; + + while (node) { + int c = cmp(key, node); + + if (c < 0) + node = node->rb_left; + else if (c > 0) + node = node->rb_right; + else + return node; + } + + return NULL; +} + +/** + * rb_find_first() - find the first @key in @tree + * @key: key to match + * @tree: tree to search + * @cmp: operator defining node order + * + * Returns the leftmost node matching @key, or NULL. + */ +static __always_inline struct rb_node * +rb_find_first(const void *key, const struct rb_root *tree, + int (*cmp)(const void *key, const struct rb_node *)) +{ + struct rb_node *node = tree->rb_node; + struct rb_node *match = NULL; + + while (node) { + int c = cmp(key, node); + + if (c <= 0) { + if (!c) + match = node; + node = node->rb_left; + } else if (c > 0) { + node = node->rb_right; + } + } + + return match; +} + +/** + * rb_next_match() - find the next @key in @tree + * @key: key to match + * @tree: tree to search + * @cmp: operator defining node order + * + * Returns the next node matching @key, or NULL. + */ +static __always_inline struct rb_node * +rb_next_match(const void *key, struct rb_node *node, + int (*cmp)(const void *key, const struct rb_node *)) +{ + node = rb_next(node); + if (node && cmp(key, node)) + node = NULL; + return node; +} + +/** + * rb_for_each() - iterates a subtree matching @key + * @node: iterator + * @key: key to match + * @tree: tree to search + * @cmp: operator defining node order + */ +#define rb_for_each(node, key, tree, cmp) \ + for ((node) = rb_find_first((key), (tree), (cmp)); \ + (node); (node) = rb_next_match((key), (node), (cmp))) + #endif /* _LINUX_RBTREE_H */ diff --git a/tools/include/linux/rbtree.h b/tools/include/linux/rbtree.h index 30dd21f..2680f2e 100644 --- a/tools/include/linux/rbtree.h +++ b/tools/include/linux/rbtree.h @@ -152,4 +152,194 @@ static inline void rb_replace_node_cached(struct rb_node *victim, rb_replace_node(victim, new, &root->rb_root); } -#endif /* __TOOLS_LINUX_PERF_RBTREE_H */ +/* + * The below helper functions use 2 operators with 3 different + * calling conventions. The operators are related like: + * + * comp(a->key,b) < 0 := less(a,b) + * comp(a->key,b) > 0 := less(b,a) + * comp(a->key,b) == 0 := !less(a,b) && !less(b,a) + * + * If these operators define a partial order on the elements we make no + * guarantee on which of the elements matching the key is found. See + * rb_find(). + * + * The reason for this is to allow the find() interface without requiring an + * on-stack dummy object, which might not be feasible due to object size. + */ + +/** + * rb_add_cached() - insert @node into the leftmost cached tree @tree + * @node: node to insert + * @tree: leftmost cached tree to insert @node into + * @less: operator defining the (partial) node order + */ +static __always_inline void +rb_add_cached(struct rb_node *node, struct rb_root_cached *tree, + bool (*less)(struct rb_node *, const struct rb_node *)) +{ + struct rb_node **link = &tree->rb_root.rb_node; + struct rb_node *parent = NULL; + bool leftmost = true; + + while (*link) { + parent = *link; + if (less(node, parent)) { + link = &parent->rb_left; + } else { + link = &parent->rb_right; + leftmost = false; + } + } + + rb_link_node(node, parent, link); + rb_insert_color_cached(node, tree, leftmost); +} + +/** + * rb_add() - insert @node into @tree + * @node: node to insert + * @tree: tree to insert @node into + * @less: operator defining the (partial) node order + */ +static __always_inline void +rb_add(struct rb_node *node, struct rb_root *tree, + bool (*less)(struct rb_node *, const struct rb_node *)) +{ + struct rb_node **link = &tree->rb_node; + struct rb_node *parent = NULL; + + while (*link) { + parent = *link; + if (less(node, parent)) + link = &parent->rb_left; + else + link = &parent->rb_right; + } + + rb_link_node(node, parent, link); + rb_insert_color(node, tree); +} + +/** + * rb_find_add() - find equivalent @node in @tree, or add @node + * @node: node to look-for / insert + * @tree: tree to search / modify + * @cmp: operator defining the node order + * + * Returns the rb_node matching @node, or NULL when no match is found and @node + * is inserted. + */ +static __always_inline struct rb_node * +rb_find_add(struct rb_node *node, struct rb_root *tree, + int (*cmp)(struct rb_node *, const struct rb_node *)) +{ + struct rb_node **link = &tree->rb_node; + struct rb_node *parent = NULL; + int c; + + while (*link) { + parent = *link; + c = cmp(node, parent); + + if (c < 0) + link = &parent->rb_left; + else if (c > 0) + link = &parent->rb_right; + else + return parent; + } + + rb_link_node(node, parent, link); + rb_insert_color(node, tree); + return NULL; +} + +/** + * rb_find() - find @key in tree @tree + * @key: key to match + * @tree: tree to search + * @cmp: operator defining the node order + * + * Returns the rb_node matching @key or NULL. + */ +static __always_inline struct rb_node * +rb_find(const void *key, const struct rb_root *tree, + int (*cmp)(const void *key, const struct rb_node *)) +{ + struct rb_node *node = tree->rb_node; + + while (node) { + int c = cmp(key, node); + + if (c < 0) + node = node->rb_left; + else if (c > 0) + node = node->rb_right; + else + return node; + } + + return NULL; +} + +/** + * rb_find_first() - find the first @key in @tree + * @key: key to match + * @tree: tree to search + * @cmp: operator defining node order + * + * Returns the leftmost node matching @key, or NULL. + */ +static __always_inline struct rb_node * +rb_find_first(const void *key, const struct rb_root *tree, + int (*cmp)(const void *key, const struct rb_node *)) +{ + struct rb_node *node = tree->rb_node; + struct rb_node *match = NULL; + + while (node) { + int c = cmp(key, node); + + if (c <= 0) { + if (!c) + match = node; + node = node->rb_left; + } else if (c > 0) { + node = node->rb_right; + } + } + + return match; +} + +/** + * rb_next_match() - find the next @key in @tree + * @key: key to match + * @tree: tree to search + * @cmp: operator defining node order + * + * Returns the next node matching @key, or NULL. + */ +static __always_inline struct rb_node * +rb_next_match(const void *key, struct rb_node *node, + int (*cmp)(const void *key, const struct rb_node *)) +{ + node = rb_next(node); + if (node && cmp(key, node)) + node = NULL; + return node; +} + +/** + * rb_for_each() - iterates a subtree matching @key + * @node: iterator + * @key: key to match + * @tree: tree to search + * @cmp: operator defining node order + */ +#define rb_for_each(node, key, tree, cmp) \ + for ((node) = rb_find_first((key), (tree), (cmp)); \ + (node); (node) = rb_next_match((key), (node), (cmp))) + +#endif /* __TOOLS_LINUX_PERF_RBTREE_H */ diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index d8421e1..e85988c 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -43,75 +43,24 @@ static void elf_hash_init(struct hlist_head *table) #define elf_hash_for_each_possible(name, obj, member, key) \ hlist_for_each_entry(obj, &name[hash_min(key, elf_hash_bits())], member) -static void rb_add(struct rb_root *tree, struct rb_node *node, - int (*cmp)(struct rb_node *, const struct rb_node *)) -{ - struct rb_node **link = &tree->rb_node; - struct rb_node *parent = NULL; - - while (*link) { - parent = *link; - if (cmp(node, parent) < 0) - link = &parent->rb_left; - else - link = &parent->rb_right; - } - - rb_link_node(node, parent, link); - rb_insert_color(node, tree); -} - -static struct rb_node *rb_find_first(const struct rb_root *tree, const void *key, - int (*cmp)(const void *key, const struct rb_node *)) -{ - struct rb_node *node = tree->rb_node; - struct rb_node *match = NULL; - - while (node) { - int c = cmp(key, node); - if (c <= 0) { - if (!c) - match = node; - node = node->rb_left; - } else if (c > 0) { - node = node->rb_right; - } - } - - return match; -} - -static struct rb_node *rb_next_match(struct rb_node *node, const void *key, - int (*cmp)(const void *key, const struct rb_node *)) -{ - node = rb_next(node); - if (node && cmp(key, node)) - node = NULL; - return node; -} - -#define rb_for_each(tree, node, key, cmp) \ - for ((node) = rb_find_first((tree), (key), (cmp)); \ - (node); (node) = rb_next_match((node), (key), (cmp))) - -static int symbol_to_offset(struct rb_node *a, const struct rb_node *b) +static bool symbol_to_offset(struct rb_node *a, const struct rb_node *b) { struct symbol *sa = rb_entry(a, struct symbol, node); struct symbol *sb = rb_entry(b, struct symbol, node); if (sa->offset < sb->offset) - return -1; + return true; if (sa->offset > sb->offset) - return 1; + return false; if (sa->len < sb->len) - return -1; + return true; if (sa->len > sb->len) - return 1; + return false; sa->alias = sb; - return 0; + return false; } static int symbol_by_offset(const void *key, const struct rb_node *node) @@ -165,7 +114,7 @@ struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset) { struct rb_node *node; - rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) { + rb_for_each(node, &offset, &sec->symbol_tree, symbol_by_offset) { struct symbol *s = rb_entry(node, struct symbol, node); if (s->offset == offset && s->type != STT_SECTION) @@ -179,7 +128,7 @@ struct symbol *find_func_by_offset(struct section *sec, unsigned long offset) { struct rb_node *node; - rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) { + rb_for_each(node, &offset, &sec->symbol_tree, symbol_by_offset) { struct symbol *s = rb_entry(node, struct symbol, node); if (s->offset == offset && s->type == STT_FUNC) @@ -193,7 +142,7 @@ struct symbol *find_symbol_containing(const struct section *sec, unsigned long o { struct rb_node *node; - rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) { + rb_for_each(node, &offset, &sec->symbol_tree, symbol_by_offset) { struct symbol *s = rb_entry(node, struct symbol, node); if (s->type != STT_SECTION) @@ -207,7 +156,7 @@ struct symbol *find_func_containing(struct section *sec, unsigned long offset) { struct rb_node *node; - rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) { + rb_for_each(node, &offset, &sec->symbol_tree, symbol_by_offset) { struct symbol *s = rb_entry(node, struct symbol, node); if (s->type == STT_FUNC) @@ -442,7 +391,7 @@ static int read_symbols(struct elf *elf) sym->offset = sym->sym.st_value; sym->len = sym->sym.st_size; - rb_add(&sym->sec->symbol_tree, &sym->node, symbol_to_offset); + rb_add(&sym->node, &sym->sec->symbol_tree, symbol_to_offset); pnode = rb_prev(&sym->node); if (pnode) entry = &rb_entry(pnode, struct symbol, node)->list; -- 2.7.4