tracing/net_sched: Fix tracepoints that save qdisc_dev() as a string

I'm updating __assign_str() and will be removing the second parameter. To
make sure that it does not break anything, I make sure that it matches the
__string() field, as that is where the string is actually going to be
saved in. To make sure there's nothing that breaks, I added a WARN_ON() to
make sure that what was used in __string() is the same that is used in
__assign_str().

In doing this change, an error was triggered as __assign_str() now expects
the string passed in to be a char * value. I instead had the following
warning:

include/trace/events/qdisc.h: In function ‘trace_event_raw_event_qdisc_reset’:
include/trace/events/qdisc.h:91:35: error: passing argument 1 of 'strcmp' from incompatible pointer type [-Werror=incompatible-pointer-types]
91 | __assign_str(dev, qdisc_dev(q));

That's because the qdisc_enqueue() and qdisc_reset() pass in qdisc_dev(q)
to __assign_str() and to __string(). But that function returns a pointer
to struct net_device and not a string.

It appears that these events are just saving the pointer as a string and
then reading it as a string as well.

Use qdisc_dev(q)->name to save the device instead.

Fixes: a34dac0b90552 ("net_sched: add tracepoints for qdisc_reset() and qdisc_destroy()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Print hashed skb addresses for all net and qdisc events

The following commits added support for printing the real address-
65875073eddd ("net: use %px to print skb address in trace_netif_receive_skb")
70713dddf3d2 ("net_sched: introduce tracepoint trace_qdisc_enqueue()")
851f36e40962 ("net_sched: use %px to print skb address in trace_qdisc_dequeue()")

However, tracing the packet traversal shows a mix of hashes and real
addresses. Pasting a sample trace for reference-

ping-14249 [002] ..... 3424.046612: netif_rx_entry: dev=lo napi_id=0x3 queue_mapping=0
skbaddr=00000000dcbed83e vlan_tagged=0 vlan_proto=0x0000 vlan_tci=0x0000 protocol=0x0800
ip_summed=0 hash=0x00000000 l4_hash=0 len=84 data_len=0 truesize=768 mac_header_valid=1
mac_header=-14 nr_frags=0 gso_size=0 gso_type=0x0
ping-14249 [002] ..... 3424.046615: netif_rx: dev=lo skbaddr=ffffff888e5d1000 len=84

Switch the trace print formats to %p for all the events to have a
consistent format of printing the hashed addresses in all cases.

Signed-off-by: Sean Tranchetti <quic_stranche@quicinc.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

qdisc: add new field for qdisc_enqueue tracepoint

qdisc_enqueue tracepoint can work with qdisc:qdisc_dequeue
to measure packets latency in qdisc queues.

Add a new field txq for it, then we can retrieve more info.

Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: introduce tracepoint trace_qdisc_enqueue()

Tracepoint trace_qdisc_enqueue() is introduced to trace skb at
the entrance of TC layer on TX side. This is similar to
trace_qdisc_dequeue():

1. For both we only trace successful cases. The failure cases
can be traced via trace_kfree_skb().

2. They are called at entrance or exit of TC layer, not for each
->enqueue() or ->dequeue(). This is intentional, because
we want to make trace_qdisc_enqueue() symmetric to
trace_qdisc_dequeue(), which is easier to use.

The return value of qdisc_enqueue() is not interesting here,
we have Qdisc's drop packets in ->dequeue(), it is impossible to
trace them even if we have the return value, the only way to trace
them is tracing kfree_skb().

We only add information we need to trace ring buffer. If any other
information is needed, it is easy to extend it without breaking ABI,
see commit 3dd344ea84e1 ("net: tracepoint: exposing sk_family in all
tcp:tracepoints").

Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Qitao Xu <qitao.xu@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: use %px to print skb address in trace_qdisc_dequeue()

Print format of skbaddr is changed to %px from %p, because we want
to use skb address as a quick way to identify a packet.

Note, trace ring buffer is only accessible to privileged users,
it is safe to use a real kernel address here.

Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Qitao Xu <qitao.xu@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: add a tracepoint for qdisc creation

With this tracepoint, we could know when qdisc's are created,
especially those default qdisc's.

Sample output:

tc-736 [001] ...1 56.230107: qdisc_create: dev=ens3 kind=pfifo parent=1:0
tc-736 [001] ...1 56.230113: qdisc_create: dev=ens3 kind=hfsc parent=ffff:ffff
tc-738 [001] ...1 56.256816: qdisc_create: dev=ens3 kind=pfifo parent=1:100
tc-739 [001] ...1 56.267584: qdisc_create: dev=ens3 kind=pfifo parent=1:200
tc-740 [001] ...1 56.279649: qdisc_create: dev=ens3 kind=fq_codel parent=1:100
tc-741 [001] ...1 56.289996: qdisc_create: dev=ens3 kind=pfifo_fast parent=1:200
tc-745 [000] .N.1 111.687483: qdisc_create: dev=ens3 kind=ingress parent=ffff:fff1

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: add tracepoints for qdisc_reset() and qdisc_destroy()

Add two tracepoints for qdisc_reset() and qdisc_destroy() to track
qdisc resetting and destroying.

Sample output:

tc-756 [000] ...3 138.355662: qdisc_reset: dev=ens3 kind=pfifo_fast parent=ffff:ffff handle=0:0
tc-756 [000] ...1 138.355720: qdisc_reset: dev=ens3 kind=pfifo_fast parent=ffff:ffff handle=0:0
tc-756 [000] ...1 138.355867: qdisc_reset: dev=ens3 kind=pfifo_fast parent=ffff:ffff handle=0:0
tc-756 [000] ...1 138.355930: qdisc_destroy: dev=ens3 kind=pfifo_fast parent=ffff:ffff handle=0:0
tc-757 [000] ...2 143.073780: qdisc_reset: dev=ens3 kind=fq_codel parent=ffff:ffff handle=8001:0
tc-757 [000] ...1 143.073878: qdisc_reset: dev=ens3 kind=fq_codel parent=ffff:ffff handle=8001:0
tc-757 [000] ...1 143.074114: qdisc_reset: dev=ens3 kind=fq_codel parent=ffff:ffff handle=8001:0
tc-757 [000] ...1 143.074228: qdisc_destroy: dev=ens3 kind=fq_codel parent=ffff:ffff handle=8001:0

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tracing: Fix header include guards in trace event headers

These include guards are broken.

Match the #if !define() and #define lines so that they work correctly.

Link: http://lkml.kernel.org/r/20190720103943.16982-1-yamada.masahiro@socionext.com

Fixes: f54d1867005c3 ("dma-buf: Rename struct fence to dma_fence")
Fixes: 2e26ca7150a4f ("tracing: Fix tracepoint.h DECLARE_TRACE() to allow more than one header")
Fixes: e543002f77f46 ("qdisc: add tracepoint qdisc:qdisc_dequeue for dequeued SKBs")
Fixes: 95f295f9fe081 ("dmaengine: tegra: add tracepoints to driver")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

qdisc: add tracepoint qdisc:qdisc_dequeue for dequeued SKBs

The main purpose of this tracepoint is to monitor bulk dequeue
in the network qdisc layer, as it cannot be deducted from the
existing qdisc stats.

The txq_state can be used for determining the reason for zero packet
dequeues, see enum netdev_queue_state_t.

Notice all packets doesn't necessary activate this tracepoint. As
qdiscs with flag TCQ_F_CAN_BYPASS, can directly invoke
sch_direct_xmit() when qdisc_qlen is zero.

Remember that perf record supports filters like:

perf record -e qdisc:qdisc_dequeue \
--filter 'ifindex == 4 && (packets > 1 || txq_state > 0)'

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>