tipc: delete tipc_mtu_bad from tipc_udp_enable

Since commit a4dfa72d0acd ("tipc: set default MTU for UDP media"), it's
been no longer using dev->mtu for b->mtu, and the issue described in
commit 3de81b758853 ("tipc: check minimum bearer MTU") doesn't exist
in UDP bearer any more.

Besides, dev->mtu can still be changed to a too small mtu after the UDP
bearer is created even with tipc_mtu_bad() check in tipc_udp_enable().
Note that NETDEV_CHANGEMTU event processing in tipc_l2_device_event()
doesn't really work for UDP bearer.

So this patch deletes the unnecessary tipc_mtu_bad from tipc_udp_enable.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Link: https://lore.kernel.org/r/282f1f5cc40e6cad385aa1c60569e6c5b70e2fb3.1685371933.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index 5388140..114140c 100644 (file)
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -431,7 +431,7 @@ int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b,
        dev = dev_get_by_name(net, dev_name);
        if (!dev)
                return -ENODEV;
-       if (tipc_mtu_bad(dev, 0)) {
+       if (tipc_mtu_bad(dev)) {
                dev_put(dev);
                return -EINVAL;
        }
@@ -708,7 +708,7 @@ static int tipc_l2_device_event(struct notifier_block *nb, unsigned long evt,
                test_and_set_bit_lock(0, &b->up);
                break;
        case NETDEV_CHANGEMTU:
-               if (tipc_mtu_bad(dev, 0)) {
+               if (tipc_mtu_bad(dev)) {
                        bearer_disable(net, b);
                        break;
                }

diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index bd0cc5c..1ee6064 100644 (file)
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -257,9 +257,9 @@ static inline void tipc_loopback_trace(struct net *net,
 }
 
 /* check if device MTU is too low for tipc headers */
-static inline bool tipc_mtu_bad(struct net_device *dev, unsigned int reserve)
+static inline bool tipc_mtu_bad(struct net_device *dev)
 {
-       if (dev->mtu >= TIPC_MIN_BEARER_MTU + reserve)
+       if (dev->mtu >= TIPC_MIN_BEARER_MTU)
                return false;
        netdev_warn(dev, "MTU too low for tipc bearer\n");
        return true;

diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 0a85244..9262325 100644 (file)
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -739,10 +739,6 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
                udp_conf.use_udp_checksums = false;
                ub->ifindex = dev->ifindex;
                b->encap_hlen = sizeof(struct iphdr) + sizeof(struct udphdr);
-               if (tipc_mtu_bad(dev, b->encap_hlen)) {
-                       err = -EINVAL;
-                       goto err;
-               }
                b->mtu = b->media->mtu;
 #if IS_ENABLED(CONFIG_IPV6)
        } else if (local.proto == htons(ETH_P_IPV6)) {