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Date: Thu, 2 Feb 2012 11:13:36 +0100
From: Steffen Klassert <steffen.klassert@...unet.com>
To: David Miller <davem@...emloft.net>
Cc: timo.teras@....fi, netdev@...r.kernel.org
Subject: [PATCH 3/4] inetpeer: protect the inetpeerpeer metrics with rcu
In order to be able to exchange the inetpeer metrics,
we add rcu protection to the struct inetpeer_metrics.
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
include/net/dst.h | 21 +++++++++++++++++----
include/net/inetpeer.h | 8 ++++++--
net/ipv4/inetpeer.c | 26 ++++++++++++++++++++++++++
net/ipv4/route.c | 6 +++++-
net/ipv6/route.c | 6 +++++-
5 files changed, 59 insertions(+), 8 deletions(-)
diff --git a/include/net/dst.h b/include/net/dst.h
index be1ffc8..f1141d8 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -159,21 +159,31 @@ static inline void dst_init_metrics(struct dst_entry *dst,
static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
{
- u32 *dst_metrics = dst_metrics_write_ptr(dest);
+ u32 *dst_metrics;
+
+ rcu_read_lock();
+ dst_metrics = dst_metrics_write_ptr(dest);
if (dst_metrics) {
u32 *src_metrics = dst_metrics_ptr(src);
memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
}
+ rcu_read_unlock();
}
static inline u32
dst_metric_raw(const struct dst_entry *dst, const int metric)
{
- u32 *p = dst_metrics_ptr(dst);
+ u32 *p;
+ u32 val;
+
+ rcu_read_lock();
+ p = dst_metrics_ptr(dst);
+ val = p[metric-1];
+ rcu_read_unlock();
- return p[metric-1];
+ return val;
}
static inline u32
@@ -198,10 +208,13 @@ dst_metric_advmss(const struct dst_entry *dst)
static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
{
- u32 *p = dst_metrics_write_ptr(dst);
+ u32 *p;
+ rcu_read_lock();
+ p = dst_metrics_write_ptr(dst);
if (p)
p[metric-1] = val;
+ rcu_read_unlock();
}
static inline u32
diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h
index 6bb8060..d97211a 100644
--- a/include/net/inetpeer.h
+++ b/include/net/inetpeer.h
@@ -28,6 +28,7 @@ struct inetpeer_addr {
};
struct inetpeer_metrics {
+ struct rcu_head rcu;
u32 m[RTAX_MAX];
};
@@ -37,7 +38,7 @@ struct inet_peer {
struct inetpeer_addr daddr;
__u32 avl_height;
- struct inetpeer_metrics *metrics;
+ struct inetpeer_metrics __rcu *metrics;
u32 rate_tokens; /* rate limiting for ICMP */
int redirect_genid;
unsigned long rate_last;
@@ -75,9 +76,11 @@ static inline bool inet_metrics_new(const struct inet_peer *p)
return p->metrics->m[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
}
+/* called in rcu_read_lock() section */
static inline u32 *inetpeer_metrics(const struct inet_peer *p)
{
- return p->metrics->m;
+ struct inetpeer_metrics *metrics = rcu_dereference(p->metrics);
+ return metrics->m;
}
/* can be called with or without local BH being disabled */
@@ -130,4 +133,5 @@ static inline int inet_getid(struct inet_peer *p, int more)
return new;
}
+extern bool inetpeer_reset_metrics(struct inet_peer *p);
#endif /* _NET_INETPEER_H */
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 92071a4..2bf23a9 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -519,3 +519,29 @@ bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout)
return rc;
}
EXPORT_SYMBOL(inet_peer_xrlim_allow);
+
+bool inetpeer_reset_metrics(struct inet_peer *p)
+{
+ struct inetpeer_metrics *old, *prev, *new;
+
+ if (inet_metrics_new(p))
+ return true;
+
+ new = kmalloc(sizeof(struct inetpeer_metrics), GFP_ATOMIC);
+ if (!new)
+ return false;
+
+ new->m[RTAX_LOCK-1] = INETPEER_METRICS_NEW;
+
+ old = p->metrics;
+
+ prev = cmpxchg(&p->metrics, old, new);
+ if (prev != old) {
+ kfree(new);
+ return false;
+ }
+
+ kfree_rcu(old, rcu);
+ return true;
+}
+EXPORT_SYMBOL(inetpeer_reset_metrics);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index dc22d6f..1a88484 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2971,6 +2971,7 @@ static int rt_fill_info(struct net *net,
unsigned long expires = 0;
const struct inet_peer *peer = rt->peer;
u32 id = 0, ts = 0, tsage = 0, error;
+ int ret;
nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
if (nlh == NULL)
@@ -3010,7 +3011,10 @@ static int rt_fill_info(struct net *net,
if (rt->rt_dst != rt->rt_gateway)
NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway);
- if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
+ rcu_read_lock();
+ ret = rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst));
+ rcu_read_unlock();
+ if (ret < 0)
goto nla_put_failure;
if (rt->rt_mark)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index d8b01c0..5a1c256 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2378,6 +2378,7 @@ static int rt6_fill_node(struct net *net,
u32 table;
struct neighbour *n;
u32 ts, tsage;
+ int ret;
if (prefix) { /* user wants prefix routes only */
if (!(rt->rt6i_flags & RTF_PREFIX_RT)) {
@@ -2463,7 +2464,10 @@ static int rt6_fill_node(struct net *net,
NLA_PUT(skb, RTA_PREFSRC, 16, &saddr_buf);
}
- if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
+ rcu_read_lock();
+ ret = rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst));
+ rcu_read_unlock();
+ if (ret < 0)
goto nla_put_failure;
rcu_read_lock();
--
1.7.0.4
--
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