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Message-ID: <1275916328.2545.64.camel@edumazet-laptop>
Date: Mon, 07 Jun 2010 15:12:08 +0200
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>
Subject: [PATCH net-next-2.6] ip: Router Alert RCU conversion
Straightforward conversion to RCU.
One rwlock becomes a spinlock, and is static.
Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
---
include/net/ip.h | 2 +-
net/ipv4/ip_input.c | 11 +++--------
net/ipv4/ip_sockglue.c | 23 ++++++++++++++---------
3 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/include/net/ip.h b/include/net/ip.h
index 452f229..9982c97 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -62,10 +62,10 @@ struct ip_ra_chain {
struct ip_ra_chain *next;
struct sock *sk;
void (*destructor)(struct sock *);
+ struct rcu_head rcu;
};
extern struct ip_ra_chain *ip_ra_chain;
-extern rwlock_t ip_ra_lock;
/* IP flags. */
#define IP_CE 0x8000 /* Flag: "Congestion" */
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index d52c9da..08a3b12 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -146,7 +146,7 @@
#include <linux/netlink.h>
/*
- * Process Router Attention IP option
+ * Process Router Attention IP option (RFC 2113)
*/
int ip_call_ra_chain(struct sk_buff *skb)
{
@@ -155,8 +155,7 @@ int ip_call_ra_chain(struct sk_buff *skb)
struct sock *last = NULL;
struct net_device *dev = skb->dev;
- read_lock(&ip_ra_lock);
- for (ra = ip_ra_chain; ra; ra = ra->next) {
+ for (ra = rcu_dereference(ip_ra_chain); ra; ra = rcu_dereference(ra->next)) {
struct sock *sk = ra->sk;
/* If socket is bound to an interface, only report
@@ -167,10 +166,8 @@ int ip_call_ra_chain(struct sk_buff *skb)
sk->sk_bound_dev_if == dev->ifindex) &&
net_eq(sock_net(sk), dev_net(dev))) {
if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
- if (ip_defrag(skb, IP_DEFRAG_CALL_RA_CHAIN)) {
- read_unlock(&ip_ra_lock);
+ if (ip_defrag(skb, IP_DEFRAG_CALL_RA_CHAIN))
return 1;
- }
}
if (last) {
struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
@@ -183,10 +180,8 @@ int ip_call_ra_chain(struct sk_buff *skb)
if (last) {
raw_rcv(last, skb);
- read_unlock(&ip_ra_lock);
return 1;
}
- read_unlock(&ip_ra_lock);
return 0;
}
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index ce23178..08b9519 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -239,7 +239,12 @@ int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc)
sent to multicast group to reach destination designated router.
*/
struct ip_ra_chain *ip_ra_chain;
-DEFINE_RWLOCK(ip_ra_lock);
+static DEFINE_SPINLOCK(ip_ra_lock);
+
+static void ip_ra_free_rcu(struct rcu_head *head)
+{
+ kfree(container_of(head, struct ip_ra_chain, rcu));
+}
int ip_ra_control(struct sock *sk, unsigned char on,
void (*destructor)(struct sock *))
@@ -251,35 +256,35 @@ int ip_ra_control(struct sock *sk, unsigned char on,
new_ra = on ? kmalloc(sizeof(*new_ra), GFP_KERNEL) : NULL;
- write_lock_bh(&ip_ra_lock);
+ spin_lock_bh(&ip_ra_lock);
for (rap = &ip_ra_chain; (ra = *rap) != NULL; rap = &ra->next) {
if (ra->sk == sk) {
if (on) {
- write_unlock_bh(&ip_ra_lock);
+ spin_unlock_bh(&ip_ra_lock);
kfree(new_ra);
return -EADDRINUSE;
}
- *rap = ra->next;
- write_unlock_bh(&ip_ra_lock);
+ rcu_assign_pointer(*rap, ra->next);
+ spin_unlock_bh(&ip_ra_lock);
if (ra->destructor)
ra->destructor(sk);
sock_put(sk);
- kfree(ra);
+ call_rcu(&ra->rcu, ip_ra_free_rcu);
return 0;
}
}
if (new_ra == NULL) {
- write_unlock_bh(&ip_ra_lock);
+ spin_unlock_bh(&ip_ra_lock);
return -ENOBUFS;
}
new_ra->sk = sk;
new_ra->destructor = destructor;
new_ra->next = ra;
- *rap = new_ra;
+ rcu_assign_pointer(*rap, new_ra);
sock_hold(sk);
- write_unlock_bh(&ip_ra_lock);
+ spin_unlock_bh(&ip_ra_lock);
return 0;
}
--
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