[PATCH net-next] ipv4: avoid a test in ip_rt_put()
flat view
STALE5093d
From: Eric Dumazet <hidden>
Date: 2012-10-29 08:33:27
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
From: Eric Dumazet <redacted> We can save a test in ip_rt_put(), considering dst_release() accepts a NULL parameter, and dst is first element in rtable. Add a BUILD_BUG_ON() to catch any change that could break this assertion. Signed-off-by: Eric Dumazet <redacted> Cc: Cong Wang <redacted> --- include/net/route.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/include/net/route.h b/include/net/route.h
index bc40b63..2ea40c1 100644
--- a/include/net/route.h
+++ b/include/net/route.h@@ -198,10 +198,13 @@ struct in_ifaddr; extern void fib_add_ifaddr(struct in_ifaddr *); extern void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); -static inline void ip_rt_put(struct rtable * rt) +static inline void ip_rt_put(struct rtable *rt) { - if (rt) - dst_release(&rt->dst); + /* dst_release() accepts a NULL parameter. + * We rely on dst being first structure in struct rtable + */ + BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); + dst_release(&rt->dst); } #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)