net/smc: take RCU read lock for routing cache lookup

smc_netinfo_by_tcpsk() looks up the routing cache. Such a lookup requires
protection by an RCU read lock.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 8c6d24b2995dd5ced548275acce04d3a6d70f043..2e8d2dabac0ca38d22c9bc4e74a91f700be379ce 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -282,6 +282,7 @@ int smc_netinfo_by_tcpsk(struct socket *clcsock,
                         __be32 *subnet, u8 *prefix_len)
 {
        struct dst_entry *dst = sk_dst_get(clcsock->sk);
+       struct in_device *in_dev;
        struct sockaddr_in addr;
        int rc = -ENOENT;
        int len;
@@ -298,14 +299,17 @@ int smc_netinfo_by_tcpsk(struct socket *clcsock,
        /* get address to which the internal TCP socket is bound */
        kernel_getsockname(clcsock, (struct sockaddr *)&addr, &len);
        /* analyze IPv4 specific data of net_device belonging to TCP socket */
-       for_ifa(dst->dev->ip_ptr) {
-               if (ifa->ifa_address != addr.sin_addr.s_addr)
+       rcu_read_lock();
+       in_dev = __in_dev_get_rcu(dst->dev);
+       for_ifa(in_dev) {
+               if (!inet_ifa_match(addr.sin_addr.s_addr, ifa))
                        continue;
                *prefix_len = inet_mask_len(ifa->ifa_mask);
                *subnet = ifa->ifa_address & ifa->ifa_mask;
                rc = 0;
                break;
-       } endfor_ifa(dst->dev->ip_ptr);
+       } endfor_ifa(in_dev);
+       rcu_read_unlock();
 
 out_rel:
        dst_release(dst);