netlink: Rightsize IFLA_AF_SPEC size calculation

if_nlmsg_size() overestimates the minimum allocation size of netlink
dump request (when called from rtnl_calcit()) or the size of the
message (when called from rtnl_getlink()). This is because
ext_filter_mask is not supported by rtnl_link_get_af_size() and
rtnl_link_get_size().

The over-estimation is significant when at least one netdev has many
VLANs configured (8 bytes for each configured VLAN).

This patch-set "rightsizes" the protocol specific attribute size
calculation by propagating ext_filter_mask to rtnl_link_get_af_size()
and adding this a argument to get_link_af_size op in rtnl_af_ops.

Bridge module already used filtering aware sizing for notifications.
br_get_link_af_size_filtered() is consistent with the modified
get_link_af_size op so it replaces br_get_link_af_size() in br_af_ops.
br_get_link_af_size() becomes unused and thus removed.

Signed-off-by: Ronen Arad <ronen.arad@intel.com>
Acked-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 735008472844..cebd9d31e65a 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1644,7 +1644,8 @@ errout:
                 rtnl_set_sk_err(net, RTNLGRP_IPV4_IFADDR, err);
 }
 
-static size_t inet_get_link_af_size(const struct net_device *dev)
+static size_t inet_get_link_af_size(const struct net_device *dev,
+                                    u32 ext_filter_mask)
 {
         struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);
 
@@ -2398,4 +2399,3 @@ void __init devinet_init(void)
         rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf,
                       inet_netconf_dump_devconf, NULL);
 }
-