* [PATCH net-next] ipv4: avoid a test in ip_rt_put()
@ 2012-10-29 8:33 Eric Dumazet
2012-10-29 9:09 ` Cong Wang
0 siblings, 1 reply; 3+ messages in thread
From: Eric Dumazet @ 2012-10-29 8:33 UTC (permalink / raw)
To: David Miller; +Cc: netdev, Cong Wang
From: Eric Dumazet <edumazet@google.com>
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 <edumazet@google.com>
Cc: Cong Wang <amwang@redhat.com>
---
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)
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH net-next] ipv4: avoid a test in ip_rt_put()
2012-10-29 8:33 [PATCH net-next] ipv4: avoid a test in ip_rt_put() Eric Dumazet
@ 2012-10-29 9:09 ` Cong Wang
2012-11-03 19:00 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Cong Wang @ 2012-10-29 9:09 UTC (permalink / raw)
To: Eric Dumazet; +Cc: David Miller, netdev
On Mon, 2012-10-29 at 09:33 +0100, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> 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 <edumazet@google.com>
> Cc: Cong Wang <amwang@redhat.com>
Acked-by: Cong Wang <amwang@redhat.com>
Thanks!
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] ipv4: avoid a test in ip_rt_put()
2012-10-29 9:09 ` Cong Wang
@ 2012-11-03 19:00 ` David Miller
0 siblings, 0 replies; 3+ messages in thread
From: David Miller @ 2012-11-03 19:00 UTC (permalink / raw)
To: amwang; +Cc: eric.dumazet, netdev
From: Cong Wang <amwang@redhat.com>
Date: Mon, 29 Oct 2012 17:09:06 +0800
> On Mon, 2012-10-29 at 09:33 +0100, Eric Dumazet wrote:
>> From: Eric Dumazet <edumazet@google.com>
>>
>> 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 <edumazet@google.com>
>> Cc: Cong Wang <amwang@redhat.com>
>
> Acked-by: Cong Wang <amwang@redhat.com>
Applied.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-10-29 9:09 ` Cong Wang
2012-11-03 19:00 ` David Miller
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