hsr: add restart routine into hsr_get_node_list()

[ Upstream commit ca19c70f5225771c05bcdcb832b4eb84d7271c5e ]

The hsr_get_node_list() is to send node addresses to the userspace.
If there are so many nodes, it could fail because of buffer size.
In order to avoid this failure, the restart routine is added.

Fixes: f421436a591d ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
index f7f96b2050a5f791a88d7afe73f322dd6d150490..3f2fe3d50328e6c8175fe99bb1086d3da95ea4f4 100644 (file)
--- a/net/hsr/hsr_netlink.c
+++ b/net/hsr/hsr_netlink.c
@@ -366,16 +366,14 @@ fail:
  */
 static int hsr_get_node_list(struct sk_buff *skb_in, struct genl_info *info)
 {
-       /* For receiving */
-       struct nlattr *na;
+       unsigned char addr[ETH_ALEN];
        struct net_device *hsr_dev;
-
-       /* For sending */
        struct sk_buff *skb_out;
-       void *msg_head;
        struct hsr_priv *hsr;
-       void *pos;
-       unsigned char addr[ETH_ALEN];
+       bool restart = false;
+       struct nlattr *na;
+       void *pos = NULL;
+       void *msg_head;
        int res;
 
        if (!info)
@@ -393,8 +391,9 @@ static int hsr_get_node_list(struct sk_buff *skb_in, struct genl_info *info)
        if (!is_hsr_master(hsr_dev))
                goto rcu_unlock;
 
+restart:
        /* Send reply */
-       skb_out = genlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
+       skb_out = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_ATOMIC);
        if (!skb_out) {
                res = -ENOMEM;
                goto fail;
@@ -408,17 +407,28 @@ static int hsr_get_node_list(struct sk_buff *skb_in, struct genl_info *info)
                goto nla_put_failure;
        }
 
-       res = nla_put_u32(skb_out, HSR_A_IFINDEX, hsr_dev->ifindex);
-       if (res < 0)
-               goto nla_put_failure;
+       if (!restart) {
+               res = nla_put_u32(skb_out, HSR_A_IFINDEX, hsr_dev->ifindex);
+               if (res < 0)
+                       goto nla_put_failure;
+       }
 
        hsr = netdev_priv(hsr_dev);
 
-       pos = hsr_get_next_node(hsr, NULL, addr);
+       if (!pos)
+               pos = hsr_get_next_node(hsr, NULL, addr);
        while (pos) {
                res = nla_put(skb_out, HSR_A_NODE_ADDR, ETH_ALEN, addr);
-               if (res < 0)
+               if (res < 0) {
+                       if (res == -EMSGSIZE) {
+                               genlmsg_end(skb_out, msg_head);
+                               genlmsg_unicast(genl_info_net(info), skb_out,
+                                               info->snd_portid);
+                               restart = true;
+                               goto restart;
+                       }
                        goto nla_put_failure;
+               }
                pos = hsr_get_next_node(hsr, pos, addr);
        }
        rcu_read_unlock();
@@ -435,7 +445,7 @@ invalid:
        return 0;
 
 nla_put_failure:
-       kfree_skb(skb_out);
+       nlmsg_free(skb_out);
        /* Fall through */
 
 fail: