From 0a5c047507aaaf00519921336d19c0f8f5f9f363 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 31 Mar 2011 01:51:35 -0700 Subject: [PATCH] fib: add __rcu annotations Add __rcu annotations and lockdep checks. Add const qualifiers node_parent() and node_parent_rcu() can use rcu_dereference_index_check() Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/fib_trie.c | 103 +++++++++++++++++++++++++------------------- 1 file changed, 58 insertions(+), 45 deletions(-) diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index b92c86f6e9b3..b9d1f33e5e04 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -126,7 +126,7 @@ struct tnode { struct work_struct work; struct tnode *tnode_free; }; - struct rt_trie_node *child[0]; + struct rt_trie_node __rcu *child[0]; }; #ifdef CONFIG_IP_FIB_TRIE_STATS @@ -151,7 +151,7 @@ struct trie_stat { }; struct trie { - struct rt_trie_node *trie; + struct rt_trie_node __rcu *trie; #ifdef CONFIG_IP_FIB_TRIE_STATS struct trie_use_stats stats; #endif @@ -177,16 +177,29 @@ static const int sync_pages = 128; static struct kmem_cache *fn_alias_kmem __read_mostly; static struct kmem_cache *trie_leaf_kmem __read_mostly; -static inline struct tnode *node_parent(struct rt_trie_node *node) +/* + * caller must hold RTNL + */ +static inline struct tnode *node_parent(const struct rt_trie_node *node) { - return (struct tnode *)(node->parent & ~NODE_TYPE_MASK); + unsigned long parent; + + parent = rcu_dereference_index_check(node->parent, lockdep_rtnl_is_held()); + + return (struct tnode *)(parent & ~NODE_TYPE_MASK); } -static inline struct tnode *node_parent_rcu(struct rt_trie_node *node) +/* + * caller must hold RCU read lock or RTNL + */ +static inline struct tnode *node_parent_rcu(const struct rt_trie_node *node) { - struct tnode *ret = node_parent(node); + unsigned long parent; + + parent = rcu_dereference_index_check(node->parent, rcu_read_lock_held() || + lockdep_rtnl_is_held()); - return rcu_dereference_rtnl(ret); + return (struct tnode *)(parent & ~NODE_TYPE_MASK); } /* Same as rcu_assign_pointer @@ -198,18 +211,24 @@ static inline void node_set_parent(struct rt_trie_node *node, struct tnode *ptr) node->parent = (unsigned long)ptr | NODE_TYPE(node); } -static inline struct rt_trie_node *tnode_get_child(struct tnode *tn, unsigned int i) +/* + * caller must hold RTNL + */ +static inline struct rt_trie_node *tnode_get_child(const struct tnode *tn, unsigned int i) { BUG_ON(i >= 1U << tn->bits); - return tn->child[i]; + return rtnl_dereference(tn->child[i]); } -static inline struct rt_trie_node *tnode_get_child_rcu(struct tnode *tn, unsigned int i) +/* + * caller must hold RCU read lock or RTNL + */ +static inline struct rt_trie_node *tnode_get_child_rcu(const struct tnode *tn, unsigned int i) { - struct rt_trie_node *ret = tnode_get_child(tn, i); + BUG_ON(i >= 1U << tn->bits); - return rcu_dereference_rtnl(ret); + return rcu_dereference_rtnl(tn->child[i]); } static inline int tnode_child_length(const struct tnode *tn) @@ -487,7 +506,7 @@ static inline void put_child(struct trie *t, struct tnode *tn, int i, static void tnode_put_child_reorg(struct tnode *tn, int i, struct rt_trie_node *n, int wasfull) { - struct rt_trie_node *chi = tn->child[i]; + struct rt_trie_node *chi = rtnl_dereference(tn->child[i]); int isfull; BUG_ON(i >= 1<bits); @@ -665,7 +684,7 @@ one_child: for (i = 0; i < tnode_child_length(tn); i++) { struct rt_trie_node *n; - n = tn->child[i]; + n = rtnl_dereference(tn->child[i]); if (!n) continue; @@ -679,6 +698,20 @@ one_child: return (struct rt_trie_node *) tn; } + +static void tnode_clean_free(struct tnode *tn) +{ + int i; + struct tnode *tofree; + + for (i = 0; i < tnode_child_length(tn); i++) { + tofree = (struct tnode *)rtnl_dereference(tn->child[i]); + if (tofree) + tnode_free(tofree); + } + tnode_free(tn); +} + static struct tnode *inflate(struct trie *t, struct tnode *tn) { struct tnode *oldtnode = tn; @@ -755,8 +788,8 @@ static struct tnode *inflate(struct trie *t, struct tnode *tn) inode = (struct tnode *) node; if (inode->bits == 1) { - put_child(t, tn, 2*i, inode->child[0]); - put_child(t, tn, 2*i+1, inode->child[1]); + put_child(t, tn, 2*i, rtnl_dereference(inode->child[0])); + put_child(t, tn, 2*i+1, rtnl_dereference(inode->child[1])); tnode_free_safe(inode); continue; @@ -797,8 +830,8 @@ static struct tnode *inflate(struct trie *t, struct tnode *tn) size = tnode_child_length(left); for (j = 0; j < size; j++) { - put_child(t, left, j, inode->child[j]); - put_child(t, right, j, inode->child[j + size]); + put_child(t, left, j, rtnl_dereference(inode->child[j])); + put_child(t, right, j, rtnl_dereference(inode->child[j + size])); } put_child(t, tn, 2*i, resize(t, left)); put_child(t, tn, 2*i+1, resize(t, right)); @@ -808,18 +841,8 @@ static struct tnode *inflate(struct trie *t, struct tnode *tn) tnode_free_safe(oldtnode); return tn; nomem: - { - int size = tnode_child_length(tn); - int j; - - for (j = 0; j < size; j++) - if (tn->child[j]) - tnode_free((struct tnode *)tn->child[j]); - - tnode_free(tn); - - return ERR_PTR(-ENOMEM); - } + tnode_clean_free(tn); + return ERR_PTR(-ENOMEM); } static struct tnode *halve(struct trie *t, struct tnode *tn) @@ -890,18 +913,8 @@ static struct tnode *halve(struct trie *t, struct tnode *tn) tnode_free_safe(oldtnode); return tn; nomem: - { - int size = tnode_child_length(tn); - int j; - - for (j = 0; j < size; j++) - if (tn->child[j]) - tnode_free((struct tnode *)tn->child[j]); - - tnode_free(tn); - - return ERR_PTR(-ENOMEM); - } + tnode_clean_free(tn); + return ERR_PTR(-ENOMEM); } /* readside must use rcu_read_lock currently dump routines @@ -1033,7 +1046,7 @@ static struct list_head *fib_insert_node(struct trie *t, u32 key, int plen) t_key cindex; pos = 0; - n = t->trie; + n = rtnl_dereference(t->trie); /* If we point to NULL, stop. Either the tree is empty and we should * just put a new leaf in if, or we have reached an empty child slot, @@ -1756,7 +1769,7 @@ static struct leaf *leaf_walk_rcu(struct tnode *p, struct rt_trie_node *c) continue; if (IS_LEAF(c)) { - prefetch(p->child[idx]); + prefetch(rcu_dereference_rtnl(p->child[idx])); return (struct leaf *) c; } @@ -2272,7 +2285,7 @@ static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos) /* walk rest of this hash chain */ h = tb->tb_id & (FIB_TABLE_HASHSZ - 1); - while ( (tb_node = rcu_dereference(tb->tb_hlist.next)) ) { + while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) { tb = hlist_entry(tb_node, struct fib_table, tb_hlist); n = fib_trie_get_first(iter, (struct trie *) tb->tb_data); if (n) -- 2.20.1