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authorJiri Kosina <jkosina@suse.cz>2016-08-17 00:53:46 +0300
committerDavid S. Miller <davem@davemloft.net>2016-08-19 07:19:08 +0300
commitea3274695353127d12155d45be1f2d62ab19c897 (patch)
tree3c2021737a3e03e57190ccfc5c9c33a0fc4f2e07 /net/sched/sch_api.c
parent69012ae425d76ecacc573ecdbd2c360bd8c2b842 (diff)
downloadlinux-ea3274695353127d12155d45be1f2d62ab19c897.tar.xz
net: sched: avoid duplicates in qdisc dump
tc_dump_qdisc() performs dumping of the per-device qdiscs in two phases; first, the "standard" dev->qdisc is being dumped. Second, if there is/are ingress queue(s), they are being dumped as well. After conversion of netdevice's qdisc linked-list into hashtable, these two sets are not in two disjunctive sets/lists any more, but are both "reachable" directly from netdevice's hashtable. As a consequence, the "full-depth" dump of the ingress qdiscs results in immediately hitting the netdevice hashtable again, and duplicating the dump that has already been performed for dev->qdisc. What in fact needs to be dumped in case of ingress queue is "just" the top-level ingress qdisc, as everything else has been dumped already. Fix this by extending tc_dump_qdisc_root() in a way that it can be instructed whether it should (while performing the "full" per-netdev qdisc dump) perform the whole recursion, or just dump "additional" top-level (ingress) qdiscs without performing any kind of recursion. This fixes duplicate dumps such as qdisc mq 0: root qdisc pfifo_fast 0: parent :4 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :3 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :1 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc clsact ffff: parent ffff:fff1 qdisc pfifo_fast 0: parent :4 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :3 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :1 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 Fixes: 59cc1f61f ("net: sched: convert qdisc linked list to hashtable") Reported-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_api.c')
-rw-r--r--net/sched/sch_api.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index ff515d01951e..d677b3484d81 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1435,7 +1435,7 @@ err_out:
static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
struct netlink_callback *cb,
- int *q_idx_p, int s_q_idx)
+ int *q_idx_p, int s_q_idx, bool recur)
{
int ret = 0, q_idx = *q_idx_p;
struct Qdisc *q;
@@ -1455,7 +1455,13 @@ static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
q_idx++;
}
- if (!qdisc_dev(root))
+ /* If dumping singletons, there is no qdisc_dev(root) and the singleton
+ * itself has already been dumped.
+ *
+ * If we've already dumped the top-level (ingress) qdisc above and the global
+ * qdisc hashtable, we don't want to hit it again
+ */
+ if (!qdisc_dev(root) || !recur)
goto out;
hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
@@ -1499,13 +1505,13 @@ static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
s_q_idx = 0;
q_idx = 0;
- if (tc_dump_qdisc_root(dev->qdisc, skb, cb, &q_idx, s_q_idx) < 0)
+ if (tc_dump_qdisc_root(dev->qdisc, skb, cb, &q_idx, s_q_idx, true) < 0)
goto done;
dev_queue = dev_ingress_queue(dev);
if (dev_queue &&
tc_dump_qdisc_root(dev_queue->qdisc_sleeping, skb, cb,
- &q_idx, s_q_idx) < 0)
+ &q_idx, s_q_idx, false) < 0)
goto done;
cont: