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authorEric Dumazet <eric.dumazet@gmail.com>2010-05-11 23:19:48 +0000
committerDavid S. Miller <davem@davemloft.net>2010-05-17 17:18:50 -0700
commit7fee226ad2397b635e2fd565a59ca3ae08a164cd (patch)
tree0bcd26150ad74ec1a237109de87a3d214a07fc22 /net/sched
parentebda37c27d0c768947e9b058332d7ea798210cf8 (diff)
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/sched')
-rw-r--r--net/sched/sch_generic.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index a969b111bd7..a63029ef3ed 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -26,6 +26,7 @@
#include <linux/list.h>
#include <linux/slab.h>
#include <net/pkt_sched.h>
+#include <net/dst.h>
/* Main transmission queue. */
@@ -40,6 +41,7 @@
static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
{
+ skb_dst_force(skb);
q->gso_skb = skb;
q->qstats.requeues++;
q->q.qlen++; /* it's still part of the queue */
@@ -179,7 +181,7 @@ static inline int qdisc_restart(struct Qdisc *q)
skb = dequeue_skb(q);
if (unlikely(!skb))
return 0;
-
+ WARN_ON_ONCE(skb_dst_is_noref(skb));
root_lock = qdisc_lock(q);
dev = qdisc_dev(q);
txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));