From 88ab1932eac721c6e7336708558fa5ed02c85c80 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 16 Nov 2008 19:39:21 -0800 Subject: udp: Use hlist_nulls in UDP RCU code This is a straightforward patch, using hlist_nulls infrastructure. RCUification already done on UDP two weeks ago. Using hlist_nulls permits us to avoid some memory barriers, both at lookup time and delete time. Patch is large because it adds new macros to include/net/sock.h. These macros will be used by TCP & DCCP in next patch. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/rculist.h | 17 --------------- include/net/sock.h | 57 +++++++++++++++++++++++++++++++++++++++---------- include/net/udp.h | 2 +- 3 files changed, 47 insertions(+), 29 deletions(-) (limited to 'include') diff --git a/include/linux/rculist.h b/include/linux/rculist.h index 3ba2998b22b..e649bd3f2c9 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -383,22 +383,5 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ pos = rcu_dereference(pos->next)) -/** - * hlist_for_each_entry_rcu_safenext - iterate over rcu list of given type - * @tpos: the type * to use as a loop cursor. - * @pos: the &struct hlist_node to use as a loop cursor. - * @head: the head for your list. - * @member: the name of the hlist_node within the struct. - * @next: the &struct hlist_node to use as a next cursor - * - * Special version of hlist_for_each_entry_rcu that make sure - * each next pointer is fetched before each iteration. - */ -#define hlist_for_each_entry_rcu_safenext(tpos, pos, head, member, next) \ - for (pos = rcu_dereference((head)->first); \ - pos && ({ next = pos->next; smp_rmb(); prefetch(next); 1; }) && \ - ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ - pos = rcu_dereference(next)) - #endif /* __KERNEL__ */ #endif diff --git a/include/net/sock.h b/include/net/sock.h index 8b2b82131b6..0a638948868 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -42,6 +42,7 @@ #include #include +#include #include #include #include @@ -52,6 +53,7 @@ #include #include +#include #include #include @@ -106,6 +108,7 @@ struct net; * @skc_reuse: %SO_REUSEADDR setting * @skc_bound_dev_if: bound device index if != 0 * @skc_node: main hash linkage for various protocol lookup tables + * @skc_nulls_node: main hash linkage for UDP/UDP-Lite protocol * @skc_bind_node: bind hash linkage for various protocol lookup tables * @skc_refcnt: reference count * @skc_hash: hash value used with various protocol lookup tables @@ -120,7 +123,10 @@ struct sock_common { volatile unsigned char skc_state; unsigned char skc_reuse; int skc_bound_dev_if; - struct hlist_node skc_node; + union { + struct hlist_node skc_node; + struct hlist_nulls_node skc_nulls_node; + }; struct hlist_node skc_bind_node; atomic_t skc_refcnt; unsigned int skc_hash; @@ -206,6 +212,7 @@ struct sock { #define sk_reuse __sk_common.skc_reuse #define sk_bound_dev_if __sk_common.skc_bound_dev_if #define sk_node __sk_common.skc_node +#define sk_nulls_node __sk_common.skc_nulls_node #define sk_bind_node __sk_common.skc_bind_node #define sk_refcnt __sk_common.skc_refcnt #define sk_hash __sk_common.skc_hash @@ -300,12 +307,30 @@ static inline struct sock *sk_head(const struct hlist_head *head) return hlist_empty(head) ? NULL : __sk_head(head); } +static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head) +{ + return hlist_nulls_entry(head->first, struct sock, sk_nulls_node); +} + +static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head) +{ + return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head); +} + static inline struct sock *sk_next(const struct sock *sk) { return sk->sk_node.next ? hlist_entry(sk->sk_node.next, struct sock, sk_node) : NULL; } +static inline struct sock *sk_nulls_next(const struct sock *sk) +{ + return (!is_a_nulls(sk->sk_nulls_node.next)) ? + hlist_nulls_entry(sk->sk_nulls_node.next, + struct sock, sk_nulls_node) : + NULL; +} + static inline int sk_unhashed(const struct sock *sk) { return hlist_unhashed(&sk->sk_node); @@ -321,6 +346,11 @@ static __inline__ void sk_node_init(struct hlist_node *node) node->pprev = NULL; } +static __inline__ void sk_nulls_node_init(struct hlist_nulls_node *node) +{ + node->pprev = NULL; +} + static __inline__ void __sk_del_node(struct sock *sk) { __hlist_del(&sk->sk_node); @@ -367,18 +397,18 @@ static __inline__ int sk_del_node_init(struct sock *sk) return rc; } -static __inline__ int __sk_del_node_init_rcu(struct sock *sk) +static __inline__ int __sk_nulls_del_node_init_rcu(struct sock *sk) { if (sk_hashed(sk)) { - hlist_del_init_rcu(&sk->sk_node); + hlist_nulls_del_init_rcu(&sk->sk_nulls_node); return 1; } return 0; } -static __inline__ int sk_del_node_init_rcu(struct sock *sk) +static __inline__ int sk_nulls_del_node_init_rcu(struct sock *sk) { - int rc = __sk_del_node_init_rcu(sk); + int rc = __sk_nulls_del_node_init_rcu(sk); if (rc) { /* paranoid for a while -acme */ @@ -399,15 +429,15 @@ static __inline__ void sk_add_node(struct sock *sk, struct hlist_head *list) __sk_add_node(sk, list); } -static __inline__ void __sk_add_node_rcu(struct sock *sk, struct hlist_head *list) +static __inline__ void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list) { - hlist_add_head_rcu(&sk->sk_node, list); + hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list); } -static __inline__ void sk_add_node_rcu(struct sock *sk, struct hlist_head *list) +static __inline__ void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list) { sock_hold(sk); - __sk_add_node_rcu(sk, list); + __sk_nulls_add_node_rcu(sk, list); } static __inline__ void __sk_del_bind_node(struct sock *sk) @@ -423,11 +453,16 @@ static __inline__ void sk_add_bind_node(struct sock *sk, #define sk_for_each(__sk, node, list) \ hlist_for_each_entry(__sk, node, list, sk_node) -#define sk_for_each_rcu_safenext(__sk, node, list, next) \ - hlist_for_each_entry_rcu_safenext(__sk, node, list, sk_node, next) +#define sk_nulls_for_each(__sk, node, list) \ + hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node) +#define sk_nulls_for_each_rcu(__sk, node, list) \ + hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node) #define sk_for_each_from(__sk, node) \ if (__sk && ({ node = &(__sk)->sk_node; 1; })) \ hlist_for_each_entry_from(__sk, node, sk_node) +#define sk_nulls_for_each_from(__sk, node) \ + if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \ + hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node) #define sk_for_each_continue(__sk, node) \ if (__sk && ({ node = &(__sk)->sk_node; 1; })) \ hlist_for_each_entry_continue(__sk, node, sk_node) diff --git a/include/net/udp.h b/include/net/udp.h index df2bfe54537..90e6ce56be6 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -51,7 +51,7 @@ struct udp_skb_cb { #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb)) struct udp_hslot { - struct hlist_head head; + struct hlist_nulls_head head; spinlock_t lock; } __attribute__((aligned(2 * sizeof(long)))); struct udp_table { -- cgit v1.2.3-70-g09d2