net: ipmr: make ip_mroute_getsockopt more understandable

Use a switch to determine if optname is correct and set val accordingly.
This produces a much more straight-forward and readable code.
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ipmr.c

@@ -1443,29 +1443,29 @@ int ip_mroute_getsockopt(struct sock *sk, int optname, char __user *optval, int
 	if (!mrt)
 		return -ENOENT;
 
-	if (optname != MRT_VERSION &&
-	   optname != MRT_PIM &&
-	   optname != MRT_ASSERT)
+	switch (optname) {
+	case MRT_VERSION:
+		val = 0x0305;
+		break;
+	case MRT_PIM:
+		if (!pimsm_enabled())
+			return -ENOPROTOOPT;
+		val = mrt->mroute_do_pim;
+		break;
+	case MRT_ASSERT:
+		val = mrt->mroute_do_assert;
+		break;
+	default:
 		return -ENOPROTOOPT;
+	}
 
 	if (get_user(olr, optlen))
 		return -EFAULT;
-
 	olr = min_t(unsigned int, olr, sizeof(int));
 	if (olr < 0)
 		return -EINVAL;
-
 	if (put_user(olr, optlen))
 		return -EFAULT;
-	if (optname == MRT_VERSION) {
-		val = 0x0305;
-	} else if (optname == MRT_PIM) {
-		if (!pimsm_enabled())
-			return -ENOPROTOOPT;
-		val = mrt->mroute_do_pim;
-	} else {
-		val = mrt->mroute_do_assert;
-	}
 	if (copy_to_user(optval, &val, olr))
 		return -EFAULT;
 	return 0;