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| author |   Eric Dumazet <eric.dumazet@gmail.com> | 2010-05-11 23:19:48 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2010-05-17 17:18:50 -0700 |
| commit | 7fee226ad2397b635e2fd565a59ca3ae08a164cd (patch) | |
| tree | 0bcd26150ad74ec1a237109de87a3d214a07fc22 /net/core | |
| parent | rps: avoid one atomic in enqueue_to_backlog (diff) | |
| download | linux-dev-7fee226ad2397b635e2fd565a59ca3ae08a164cd.tar.xz linux-dev-7fee226ad2397b635e2fd565a59ca3ae08a164cd.zip | |
net: add a noref bit on skb dst
Use low order bit of skb->_skb_dst to tell dst is not refcounted.
Change _skb_dst to _skb_refdst to make sure all uses are catched.
skb_dst() returns the dst, regardless of noref bit set or not, but
with a lockdep check to make sure a noref dst is not given if current
user is not rcu protected.
New skb_dst_set_noref() helper to set an notrefcounted dst on a skb.
(with lockdep check)
skb_dst_drop() drops a reference only if skb dst was refcounted.
skb_dst_force() helper is used to force a refcount on dst, when skb
is queued and not anymore RCU protected.
Use skb_dst_force() in __sk_add_backlog(), __dev_xmit_skb() if
!IFF_XMIT_DST_RELEASE or skb enqueued on qdisc queue, in
sock_queue_rcv_skb(), in __nf_queue().
Use skb_dst_force() in dev_requeue_skb().
Note: dst_use_noref() still dirties dst, we might transform it
later to do one dirtying per jiffies.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev.c | 3 | ||||
| -rw-r--r-- | net/core/skbuff.c | 2 | ||||
| -rw-r--r-- | net/core/sock.c | 6 |
3 files changed, 10 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index cdcb9cbedf41..6c820650b80f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2052,6 +2052,8 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, * waiting to be sent out; and the qdisc is not running - * xmit the skb directly. */ + if (!(dev->priv_flags & IFF_XMIT_DST_RELEASE)) + skb_dst_force(skb); __qdisc_update_bstats(q, skb->len); if (sch_direct_xmit(skb, q, dev, txq, root_lock)) __qdisc_run(q); @@ -2060,6 +2062,7 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, rc = NET_XMIT_SUCCESS; } else { + skb_dst_force(skb); rc = qdisc_enqueue_root(skb, q); qdisc_run(q); } diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a9b0e1f77806..c543dd252433 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -520,7 +520,7 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) new->transport_header = old->transport_header; new->network_header = old->network_header; new->mac_header = old->mac_header; - skb_dst_set(new, dst_clone(skb_dst(old))); + skb_dst_copy(new, old); new->rxhash = old->rxhash; #ifdef CONFIG_XFRM new->sp = secpath_get(old->sp); diff --git a/net/core/sock.c b/net/core/sock.c index 63530a03b8c2..bf88a167c8f2 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -307,6 +307,11 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) */ skb_len = skb->len; + /* we escape from rcu protected region, make sure we dont leak + * a norefcounted dst + */ + skb_dst_force(skb); + spin_lock_irqsave(&list->lock, flags); skb->dropcount = atomic_read(&sk->sk_drops); __skb_queue_tail(list, skb); @@ -1536,6 +1541,7 @@ static void __release_sock(struct sock *sk) do { struct sk_buff *next = skb->next; + WARN_ON_ONCE(skb_dst_is_noref(skb)); skb->next = NULL; sk_backlog_rcv(sk, skb); |