net/ipv6: Remove unnecessary checks on fib6_idev

Prior to 4832c30d ("net: ipv6: put host and anycast routes on device
with address") host routes and anycast routes were installed with the
device set to loopback (or VRF device once that feature was added). In the
older code dst.dev was set to loopback (needed for packet tx) and rt6i_idev
was used to denote the actual interface.

Commit 4832c30d changed the code to have dst.dev pointing to the real
device with the switch to lo or vrf device done on dst clones. As a
consequence of this change a couple of device checks during route lookups
are no longer needed. Remove them.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -455,7 +455,6 @@ static inline struct fib6_info *rt6_device_match(struct net *net,
 						    int oif,
 						    int flags)
 {
-	struct fib6_info *local = NULL;
 	struct fib6_info *sprt;
 
 	if (!oif && ipv6_addr_any(saddr) &&
@@ -471,17 +470,6 @@ static inline struct fib6_info *rt6_device_match(struct net *net,
 		if (oif) {
 			if (dev->ifindex == oif)
 				return sprt;
-			if (dev->flags & IFF_LOOPBACK) {
-				if (!sprt->fib6_idev ||
-				    sprt->fib6_idev->dev->ifindex != oif) {
-					if (flags & RT6_LOOKUP_F_IFACE)
-						continue;
-					if (local &&
-					    local->fib6_idev->dev->ifindex == oif)
-						continue;
-				}
-				local = sprt;
-			}
 		} else {
 			if (ipv6_chk_addr(net, saddr, dev,
 					  flags & RT6_LOOKUP_F_IFACE))
@@ -489,13 +477,8 @@ static inline struct fib6_info *rt6_device_match(struct net *net,
 		}
 	}
 
-	if (oif) {
-		if (local)
-			return local;
-
-		if (flags & RT6_LOOKUP_F_IFACE)
-			return net->ipv6.fib6_null_entry;
-	}
+	if (oif && flags & RT6_LOOKUP_F_IFACE)
+		return net->ipv6.fib6_null_entry;
 
 	return rt->fib6_nh.nh_flags & RTNH_F_DEAD ? net->ipv6.fib6_null_entry : rt;
 }
@@ -586,9 +569,6 @@ static inline int rt6_check_dev(struct fib6_info *rt, int oif)
 
 	if (!oif || dev->ifindex == oif)
 		return 2;
-	if ((dev->flags & IFF_LOOPBACK) &&
-	    rt->fib6_idev && rt->fib6_idev->dev->ifindex == oif)
-		return 1;
 	return 0;
 }