kernel/linux.git/include/net/sch_generic.h, branch v4.19.67

net: sched: put back q.qlen into a single location

2019-03-10T06:17:16+00:00

[ Upstream commit 46b1c18f9deb326a7e18348e668e4c7ab7c7458b ] In the series fc8b81a5981f ("Merge branch 'lockless-qdisc-series'") John made the assumption that the data path had no need to read the qdisc qlen (number of packets in the qdisc). It is true when pfifo_fast is used as the root qdisc, or as direct MQ/MQPRIO children. But pfifo_fast can be used as leaf in class full qdiscs, and existing logic needs to access the child qlen in an efficient way. HTB breaks badly, since it uses cl->leaf.q->q.qlen in : htb_activate() -> WARN_ON() htb_dequeue_tree() to decide if a class can be htb_deactivated when it has no more packets. HFSC, DRR, CBQ, QFQ have similar issues, and some calls to qdisc_tree_reduce_backlog() also read q.qlen directly. Using qdisc_qlen_sum() (which iterates over all possible cpus) in the data path is a non starter. It seems we have to put back qlen in a central location, at least for stable kernels. For all qdisc but pfifo_fast, qlen is guarded by the qdisc lock, so the existing q.qlen{++|--} are correct. For 'lockless' qdisc (pfifo_fast so far), we need to use atomic_{inc|dec}() because the spinlock might be not held (for example from pfifo_fast_enqueue() and pfifo_fast_dequeue()) This patch adds atomic_qlen (in the same location than qlen) and renames the following helpers, since we want to express they can be used without qdisc lock, and that qlen is no longer percpu. - qdisc_qstats_cpu_qlen_dec -> qdisc_qstats_atomic_qlen_dec() - qdisc_qstats_cpu_qlen_inc -> qdisc_qstats_atomic_qlen_inc() Later (net-next) we might revert this patch by tracking all these qlen uses and replace them by a more efficient method (not having to access a precise qlen, but an empty/non_empty status that might be less expensive to maintain/track). Another possibility is to have a legacy pfifo_fast version that would be used when used a a child qdisc, since the parent qdisc needs a spinlock anyway. But then, future lockless qdiscs would also have the same problem. Fixes: 7e66016f2c65 ("net: sched: helpers to sum qlen and qlen for per cpu logic") Signed-off-by: Eric Dumazet Cc: John Fastabend Cc: Jamal Hadi Salim Cc: Cong Wang Cc: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/tc: introduce TC_ACT_REINSERT.

2018-07-30T16:31:14+00:00

This is similar TC_ACT_REDIRECT, but with a slightly different semantic: - on ingress the mirred skbs are passed to the target device network stack without any additional check not scrubbing. - the rcu-protected stats provided via the tcf_result struct are updated on error conditions. This new tcfa_action value is not exposed to the user-space and can be used only internally by clsact. v1 -> v2: do not touch TC_ACT_REDIRECT code path, introduce a new action type instead v2 -> v3: - rename the new action value TC_ACT_REINJECT, update the helper accordingly - take care of uncloned reinjected packets in XDP generic hook v3 -> v4: - renamed again the new action value (JiriP) v4 -> v5: - fix build error with !NET_CLS_ACT (kbuild bot) Signed-off-by: Paolo Abeni Acked-by: Jiri Pirko Signed-off-by: David S. Miller

tc/act: remove unneeded RCU lock in action callback

2018-07-30T16:31:13+00:00

Each lockless action currently does its own RCU locking in ->act(). This allows using plain RCU accessor, even if the context is really RCU BH. This change drops the per action RCU lock, replace the accessors with the _bh variant, cleans up a bit the surrounding code and documents the RCU status in the relevant header. No functional nor performance change is intended. The goal of this patch is clarifying that the RCU critical section used by the tc actions extends up to the classifier's caller. v1 -> v2: - preserve rcu lock in act_bpf: it's needed by eBPF helpers, as pointed out by Daniel v3 -> v4: - fixed some typos in the commit message (JiriP) Signed-off-by: Paolo Abeni Acked-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: don't dump chains only held by actions

2018-07-27T16:38:46+00:00

In case a chain is empty and not explicitly created by a user, such chain should not exist. The only exception is if there is an action "goto chain" pointing to it. In that case, don't show the chain in the dump. Track the chain references held by actions and use them to find out if a chain should or should not be shown in chain dump. Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: introduce chain templates

2018-07-24T03:44:12+00:00

Allow user to set a template for newly created chains. Template lock down the chain for particular classifier type/options combinations. The classifier needs to support templates, otherwise kernel would reply with error. Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: introduce chain object to uapi

2018-07-24T03:44:12+00:00

Allow user to create, destroy, get and dump chain objects. Do that by extending rtnl commands by the chain-specific ones. User will now be able to explicitly create or destroy chains (so far this was done only automatically according the filter/act needs and refcounting). Also, the user will receive notification about any chain creation or destuction. Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: Avoid implicit chain 0 creation

2018-07-24T03:44:12+00:00

Currently, chain 0 is implicitly created during block creation. However that does not align with chain object exposure, creation and destruction api introduced later on. So make the chain 0 behave the same way as any other chain and only create it when it is needed. Since chain 0 is somehow special as the qdiscs need to hold pointer to the first chain tp, this requires to move the chain head change callback infra to the block structure. Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: cls_flower: implement offload tcf_proto_op

2018-06-26T14:21:32+00:00

Add the reoffload tcf_proto_op in flower to generate an offload message for each filter in the given tcf_proto. Call the specified callback with this new offload message. The function only returns an error if the callback rejects adding a 'hardware only' rule. A filter contains a flag to indicate if it is in hardware or not. To ensure the reoffload function properly maintains this flag, keep a reference counter for the number of instances of the filter that are in hardware. Only update the flag when this counter changes from or to 0. Add a generic helper function to implement this behaviour. Signed-off-by: John Hurley Signed-off-by: Jakub Kicinski Acked-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: add tcf_proto_op to offload a rule

2018-06-26T14:21:32+00:00

Create a new tcf_proto_op called 'reoffload' that generates a new offload message for each node in a tcf_proto. Pointers to the tcf_proto and whether the offload request is to add or delete the node are included. Also included is a callback function to send the offload message to and the option of priv data to go with the cb. Signed-off-by: John Hurley Signed-off-by: Jakub Kicinski Acked-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: add qstats.qlen to qlen

2018-05-29T13:49:15+00:00

AFAICT struct gnet_stats_queue.qlen is not used in Qdiscs. It may, however, be useful for offloads to report HW queue length there. Add that value to the result of qdisc_qlen_sum(). Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller