[NETLINK]: Do precise netlink message allocations where possible
Account for the netlink message header size directly in nlmsg_new()
instead of relying on the caller calculate it correctly.
Replaces error handling of message construction functions when
constructing notifications with bug traps since a failure implies
a bug in calculating the size of the skb.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 8f66119..15d6efb 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -15,6 +15,18 @@
#include <net/netlink.h>
#include "br_private.h"
+static inline size_t br_nlmsg_size(void)
+{
+ return NLMSG_ALIGN(sizeof(struct ifinfomsg))
+ + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
+ + nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
+ + nla_total_size(4) /* IFLA_MASTER */
+ + nla_total_size(4) /* IFLA_MTU */
+ + nla_total_size(4) /* IFLA_LINK */
+ + nla_total_size(1) /* IFLA_OPERSTATE */
+ + nla_total_size(1); /* IFLA_PROTINFO */
+}
+
/*
* Create one netlink message for one interface
* Contains port and master info as well as carrier and bridge state.
@@ -77,19 +89,16 @@
void br_ifinfo_notify(int event, struct net_bridge_port *port)
{
struct sk_buff *skb;
- int payload = sizeof(struct ifinfomsg) + 128;
int err = -ENOBUFS;
pr_debug("bridge notify event=%d\n", event);
- skb = nlmsg_new(nlmsg_total_size(payload), GFP_ATOMIC);
+ skb = nlmsg_new(br_nlmsg_size(), GFP_ATOMIC);
if (skb == NULL)
goto errout;
err = br_fill_ifinfo(skb, port, 0, 0, event, 0);
- if (err < 0) {
- kfree_skb(skb);
- goto errout;
- }
+ /* failure implies BUG in br_nlmsg_size() */
+ BUG_ON(err < 0);
err = rtnl_notify(skb, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
errout:
