ipv4: Remove redundant RCU locking in ip_check_mc().

All callers are under rcu_read_lock() protection already.

Rename to ip_check_mc_rcu() to make it even more clear.

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 6 insertions, 7 deletions

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 44ba9068b72f..12b65ccca8e9 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -2333,13 +2333,13 @@ void ip_mc_drop_socket(struct sock *sk)
         rtnl_unlock();
 }
 
-int ip_check_mc(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u16 proto)
+/* called with rcu_read_lock() */
+int ip_check_mc_rcu(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u16 proto)
 {
         struct ip_mc_list *im;
         struct ip_sf_list *psf;
         int rv = 0;
 
-        rcu_read_lock();
         for_each_pmc_rcu(in_dev, im) {
                 if (im->multiaddr == mc_addr)
                         break;
@@ -2361,7 +2361,6 @@ int ip_check_mc(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u16 p
                 } else
                         rv = 1; /* unspecified source; tentatively allow */
         }
-        rcu_read_unlock();
         return rv;
 }
 
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index ac32d8f3d68f..f6730d94e307 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2309,8 +2309,8 @@ skip_cache:
                 struct in_device *in_dev = __in_dev_get_rcu(dev);
 
                 if (in_dev) {
-                        int our = ip_check_mc(in_dev, daddr, saddr,
-                                              ip_hdr(skb)->protocol);
+                        int our = ip_check_mc_rcu(in_dev, daddr, saddr,
+                                                  ip_hdr(skb)->protocol);
                         if (our
 #ifdef CONFIG_IP_MROUTE
                                 ||
@@ -2368,8 +2368,8 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
                 fi = NULL;
         } else if (type == RTN_MULTICAST) {
                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
-                if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
-                                 oldflp->proto))
+                if (!ip_check_mc_rcu(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
+                                     oldflp->proto))
                         flags &= ~RTCF_LOCAL;
                 /* If multicast route do not exist use
                  * default one, but do not gateway in this case.