kernel/linux.git/include/net/sch_generic.h, branch v4.12.9

net_sched: move the empty tp check from ->destroy() to ->delete()

2017-04-21T17:58:15+00:00

We could have a race condition where in ->classify() path we dereference tp->root and meanwhile a parallel ->destroy() makes it a NULL. Daniel cured this bug in commit d936377414fa ("net, sched: respect rcu grace period on cls destruction"). This happens when ->destroy() is called for deleting a filter to check if we are the last one in tp, this tp is still linked and visible at that time. The root cause of this problem is the semantic of ->destroy(), it does two things (for non-force case): 1) check if tp is empty 2) if tp is empty we could really destroy it and its caller, if cares, needs to check its return value to see if it is really destroyed. Therefore we can't unlink tp unless we know it is empty. As suggested by Daniel, we could actually move the test logic to ->delete() so that we can safely unlink tp after ->delete() tells us the last one is just deleted and before ->destroy(). Fixes: 1e052be69d04 ("net_sched: destroy proto tp when all filters are gone") Cc: Roi Dayan Cc: Daniel Borkmann Cc: John Fastabend Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Acked-by: Daniel Borkmann Signed-off-by: David S. Miller

net: sched: make default fifo qdiscs appear in the dump

2017-03-13T05:53:02+00:00

The original reason [1] for having hidden qdiscs (potential scalability issues in qdisc_match_from_root() with single linked list in case of large amount of qdiscs) has been invalidated by 59cc1f61f0 ("net: sched: convert qdisc linked list to hashtable"). This allows us for bringing more clarity and determinism into the dump by making default pfifo qdiscs visible. We're not turning this on by default though, at it was deemed [2] too intrusive / unnecessary change of default behavior towards userspace. Instead, TCA_DUMP_INVISIBLE netlink attribute is introduced, which allows applications to request complete qdisc hierarchy dump, including the ones that have always been implicit/invisible. Singleton noop_qdisc stays invisible, as teaching the whole infrastructure about singletons would require quite some surgery with very little gain (seeing no qdisc or seeing noop qdisc in the dump is probably setting the same user expectation). [1] http://lkml.kernel.org/r/1460732328.10638.74.camel@edumazet-glaptop3.roam.corp.google.com [2] http://lkml.kernel.org/r/20161021.105935.1907696543877061916.davem@davemloft.net Signed-off-by: Jiri Kosina Signed-off-by: David S. Miller

sched: move tcf_proto_destroy and tcf_destroy_chain helpers into cls_api

2017-02-10T16:38:08+00:00

Creation is done in this file, move destruction to be at the same place. Signed-off-by: Jiri Pirko Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

sched: rename tcf_destroy to tcf_destroy_proto

2017-02-10T16:38:08+00:00

This function destroys TC filter protocol, not TC filter. So name it accordingly. Signed-off-by: Jiri Pirko Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net-tc: convert tc_from to tc_from_ingress and tc_redirected

2017-01-09T01:58:52+00:00

The tc_from field fulfills two roles. It encodes whether a packet was redirected by an act_mirred device and, if so, whether act_mirred was called on ingress or egress. Split it into separate fields. The information is needed by the special IFB loop, where packets are taken out of the normal path by act_mirred, forwarded to IFB, then reinjected at their original location (ingress or egress) by IFB. The IFB device cannot use skb->tc_at_ingress, because that may have been overwritten as the packet travels from act_mirred to ifb_xmit, when it passes through tc_classify on the IFB egress path. Cache this value in skb->tc_from_ingress. That field is valid only if a packet arriving at ifb_xmit came from act_mirred. Other packets can be crafted to reach ifb_xmit. These must be dropped. Set tc_redirected on redirection and drop all packets that do not have this bit set. Both fields are set only on cloned skbs in tc actions, so original packet sources do not have to clear the bit when reusing packets (notably, pktgen and octeon). Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller

net-tc: convert tc_at to tc_at_ingress

2017-01-09T01:58:52+00:00

Field tc_at is used only within tc actions to distinguish ingress from egress processing. A single bit is sufficient for this purpose. Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller

net-tc: convert tc_verd to integer bitfields

2017-01-09T01:58:52+00:00

Extract the remaining two fields from tc_verd and remove the __u16 completely. TC_AT and TC_FROM are converted to equivalent two-bit integer fields tc_at and tc_from. Where possible, use existing helper skb_at_tc_ingress when reading tc_at. Introduce helper skb_reset_tc to clear fields. Not documenting tc_from and tc_at, because they will be replaced with single bit fields in follow-on patches. Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller

net-tc: extract skip classify bit from tc_verd

2017-01-09T01:58:52+00:00

Packets sent by the IFB device skip subsequent tc classification. A single bit governs this state. Move it out of tc_verd in anticipation of removing that __u16 completely. The new bitfield tc_skip_classify temporarily uses one bit of a hole, until tc_verd is removed completely in a follow-up patch. Remove the bit hole comment. It could be 2, 3, 4 or 5 bits long. With that many options, little value in documenting it. Introduce a helper function to deduplicate the logic in the two sites that check this bit. The field tc_skip_classify is set only in IFB on skbs cloned in act_mirred, so original packet sources do not have to clear the bit when reusing packets (notably, pktgen and octeon). Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller

net_sched: gen_estimator: complete rewrite of rate estimators

2016-12-05T20:21:59+00:00

1) Old code was hard to maintain, due to complex lock chains. (We probably will be able to remove some kfree_rcu() in callers) 2) Using a single timer to update all estimators does not scale. 3) Code was buggy on 32bit kernel (WRITE_ONCE() on 64bit quantity is not supposed to work well) In this rewrite : - I removed the RB tree that had to be scanned in gen_estimator_active(). qdisc dumps should be much faster. - Each estimator has its own timer. - Estimations are maintained in net_rate_estimator structure, instead of dirtying the qdisc. Minor, but part of the simplification. - Reading the estimator uses RCU and a seqcount to provide proper support for 32bit kernels. - We reduce memory need when estimators are not used, since we store a pointer, instead of the bytes/packets counters. - xt_rateest_mt() no longer has to grab a spinlock. (In the future, xt_rateest_tg() could be switched to per cpu counters) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

sched: add and use qdisc_skb_head helpers

2016-09-19T05:47:18+00:00

This change replaces sk_buff_head struct in Qdiscs with new qdisc_skb_head. Its similar to the skb_buff_head api, but does not use skb->prev pointers. Qdiscs will commonly enqueue at the tail of a list and dequeue at head. While skb_buff_head works fine for this, enqueue/dequeue needs to also adjust the prev pointer of next element. The ->prev pointer is not required for qdiscs so we can just leave it undefined and avoid one cacheline write access for en/dequeue. Suggested-by: Eric Dumazet Signed-off-by: Florian Westphal Signed-off-by: David S. Miller