Merge branch 'rtnetlink_vf_ports'

David Gibson says:

====================
Fix problems with with IFLA_VF_PORTS (v2)

I've had a customer encounter a problem with getifaddrs(3) freezing up
on a system with a Cisco enic device.

I've discovered that the problem is caused by an enic device with a
large number of SR-IOV virtual functions overflowing the normal sized
packet buffer for netlink, leading to interfaces not being reported
from an RTM_GETLINK request.

The first patch here just makes the problem easier to locate if it
occurs again in a different way, by adding a WARN_ON() when we run out
of room in a netlink packet in this manner.

The second patch actually fixes the problem, by only reporting
IFLA_VF_PORTS information when the RTEXT_FILTER_VF flag is specified.

v2: Corrected some CodingStyle problems
====================

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

1 files changed, 22 insertions, 11 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 64ad17d077ed..9837bebf93ce 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -774,7 +774,8 @@ static inline int rtnl_vfinfo_size(const struct net_device *dev,
 		return 0;
 }
 
-static size_t rtnl_port_size(const struct net_device *dev)
+static size_t rtnl_port_size(const struct net_device *dev,
+			     u32 ext_filter_mask)
 {
 	size_t port_size = nla_total_size(4)		/* PORT_VF */
 		+ nla_total_size(PORT_PROFILE_MAX)	/* PORT_PROFILE */
@@ -790,7 +791,8 @@ static size_t rtnl_port_size(const struct net_device *dev)
 	size_t port_self_size = nla_total_size(sizeof(struct nlattr))
 		+ port_size;
 
-	if (!dev->netdev_ops->ndo_get_vf_port || !dev->dev.parent)
+	if (!dev->netdev_ops->ndo_get_vf_port || !dev->dev.parent ||
+	    !(ext_filter_mask & RTEXT_FILTER_VF))
 		return 0;
 	if (dev_num_vf(dev->dev.parent))
 		return port_self_size + vf_ports_size +
@@ -826,7 +828,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + nla_total_size(ext_filter_mask
 			        & RTEXT_FILTER_VF ? 4 : 0) /* IFLA_NUM_VF */
 	       + rtnl_vfinfo_size(dev, ext_filter_mask) /* IFLA_VFINFO_LIST */
-	       + rtnl_port_size(dev) /* IFLA_VF_PORTS + IFLA_PORT_SELF */
+	       + rtnl_port_size(dev, ext_filter_mask) /* IFLA_VF_PORTS + IFLA_PORT_SELF */
 	       + rtnl_link_get_size(dev) /* IFLA_LINKINFO */
 	       + rtnl_link_get_af_size(dev) /* IFLA_AF_SPEC */
 	       + nla_total_size(MAX_PHYS_PORT_ID_LEN); /* IFLA_PHYS_PORT_ID */
@@ -888,11 +890,13 @@ static int rtnl_port_self_fill(struct sk_buff *skb, struct net_device *dev)
 	return 0;
 }
 
-static int rtnl_port_fill(struct sk_buff *skb, struct net_device *dev)
+static int rtnl_port_fill(struct sk_buff *skb, struct net_device *dev,
+			  u32 ext_filter_mask)
 {
 	int err;
 
-	if (!dev->netdev_ops->ndo_get_vf_port || !dev->dev.parent)
+	if (!dev->netdev_ops->ndo_get_vf_port || !dev->dev.parent ||
+	    !(ext_filter_mask & RTEXT_FILTER_VF))
 		return 0;
 
 	err = rtnl_port_self_fill(skb, dev);
@@ -1079,7 +1083,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 		nla_nest_end(skb, vfinfo);
 	}
 
-	if (rtnl_port_fill(skb, dev))
+	if (rtnl_port_fill(skb, dev, ext_filter_mask))
 		goto nla_put_failure;
 
 	if (dev->rtnl_link_ops || rtnl_have_link_slave_info(dev)) {
@@ -1198,6 +1202,7 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 	struct hlist_head *head;
 	struct nlattr *tb[IFLA_MAX+1];
 	u32 ext_filter_mask = 0;
+	int err;
 
 	s_h = cb->args[0];
 	s_idx = cb->args[1];
@@ -1218,11 +1223,17 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 		hlist_for_each_entry_rcu(dev, head, index_hlist) {
 			if (idx < s_idx)
 				goto cont;
-			if (rtnl_fill_ifinfo(skb, dev, RTM_NEWLINK,
-					     NETLINK_CB(cb->skb).portid,
-					     cb->nlh->nlmsg_seq, 0,
-					     NLM_F_MULTI,
-					     ext_filter_mask) <= 0)
+			err = rtnl_fill_ifinfo(skb, dev, RTM_NEWLINK,
+					       NETLINK_CB(cb->skb).portid,
+					       cb->nlh->nlmsg_seq, 0,
+					       NLM_F_MULTI,
+					       ext_filter_mask);
+			/* If we ran out of room on the first message,
+			 * we're in trouble
+			 */
+			WARN_ON((err == -EMSGSIZE) && (skb->len == 0));
+
+			if (err <= 0)
 				goto out;
 
 			nl_dump_check_consistent(cb, nlmsg_hdr(skb));