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-rw-r--r--include/linux/rculist.h17
-rw-r--r--include/net/sock.h4
-rw-r--r--net/ipv4/udp.c4
-rw-r--r--net/ipv6/udp.c4
4 files changed, 23 insertions, 6 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index e649bd3..3ba2998 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -383,5 +383,22 @@ 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 0bea25d..a4f6d3f 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -419,8 +419,8 @@ 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(__sk, node, list) \
- hlist_for_each_entry_rcu(__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_for_each_from(__sk, node) \
if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
hlist_for_each_entry_from(__sk, node, sk_node)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ced8203..c3ecec8 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -256,7 +256,7 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
int dif, struct udp_table *udptable)
{
struct sock *sk, *result;
- struct hlist_node *node;
+ struct hlist_node *node, *next;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
@@ -266,7 +266,7 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
begin:
result = NULL;
badness = -1;
- sk_for_each_rcu(sk, node, &hslot->head) {
+ sk_for_each_rcu_safenext(sk, node, &hslot->head, next) {
/*
* lockless reader, and SLAB_DESTROY_BY_RCU items:
* We must check this item was not moved to another chain
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1d9790e..32d914d 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -98,7 +98,7 @@ static struct sock *__udp6_lib_lookup(struct net *net,
int dif, struct udp_table *udptable)
{
struct sock *sk, *result;
- struct hlist_node *node;
+ struct hlist_node *node, *next;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
@@ -108,7 +108,7 @@ static struct sock *__udp6_lib_lookup(struct net *net,
begin:
result = NULL;
badness = -1;
- sk_for_each_rcu(sk, node, &hslot->head) {
+ sk_for_each_rcu_safenext(sk, node, &hslot->head, next) {
/*
* lockless reader, and SLAB_DESTROY_BY_RCU items:
* We must check this item was not moved to another chain
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