Commit Graph

315 Commits

Author SHA1 Message Date
Kevin Bracey fb80445c43 net_sched: restore "mpu xxx" handling
commit 56b765b79e ("htb: improved accuracy at high rates") broke
"overhead X", "linklayer atm" and "mpu X" attributes.

"overhead X" and "linklayer atm" have already been fixed. This restores
the "mpu X" handling, as might be used by DOCSIS or Ethernet shaping:

    tc class add ... htb rate X overhead 4 mpu 64

The code being fixed is used by htb, tbf and act_police. Cake has its
own mpu handling. qdisc_calculate_pkt_len still uses the size table
containing values adjusted for mpu by user space.

iproute2 tc has always passed mpu into the kernel via a tc_ratespec
structure, but the kernel never directly acted on it, merely stored it
so that it could be read back by `tc class show`.

Rather, tc would generate length-to-time tables that included the mpu
(and linklayer) in their construction, and the kernel used those tables.

Since v3.7, the tables were no longer used. Along with "mpu", this also
broke "overhead" and "linklayer" which were fixed in 01cb71d2d4
("net_sched: restore "overhead xxx" handling", v3.10) and 8a8e3d84b1
("net_sched: restore "linklayer atm" handling", v3.11).

"overhead" was fixed by simply restoring use of tc_ratespec::overhead -
this had originally been used by the kernel but was initially omitted
from the new non-table-based calculations.

"linklayer" had been handled in the table like "mpu", but the mode was
not originally passed in tc_ratespec. The new implementation was made to
handle it by getting new versions of tc to pass the mode in an extended
tc_ratespec, and for older versions of tc the table contents were analysed
at load time to deduce linklayer.

As "mpu" has always been given to the kernel in tc_ratespec,
accompanying the mpu-based table, we can restore system functionality
with no userspace change by making the kernel act on the tc_ratespec
value.

Fixes: 56b765b79e ("htb: improved accuracy at high rates")
Signed-off-by: Kevin Bracey <kevin@bracey.fi>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Vimalkumar <j.vimal@gmail.com>
Link: https://lore.kernel.org/r/20220112170210.1014351-1-kevin@bracey.fi
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-13 11:06:42 -08:00
Eric Dumazet f12bf6f3f9 net: watchdog: add net device refcount tracker
Add a netdevice_tracker inside struct net_device, to track
the self reference when a device has an active watchdog timer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-07 20:44:58 -08:00
Eric Dumazet 606509f27f net/sched: add net device refcount tracker to struct Qdisc
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-06 16:05:12 -08:00
Eric Dumazet bec251bc8b net: no longer stop all TX queues in dev_watchdog()
There is no reason for stopping all TX queues from dev_watchdog()

Not only this stops feeding the NIC, it also migrates all qdiscs
to be serviced on the cpu calling netif_tx_unlock(), causing
a potential latency artifact.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-17 14:56:16 +00:00
Eric Dumazet dab8fe3207 net: do not inline netif_tx_lock()/netif_tx_unlock()
These are not fast path, there is no point in inlining them.

Also provide netif_freeze_queues()/netif_unfreeze_queues()
so that we can use them from dev_watchdog() in the following patch.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-17 14:56:16 +00:00
Eric Dumazet 5337824f4d net: annotate accesses to queue->trans_start
In following patches, dev_watchdog() will no longer stop all queues.
It will read queue->trans_start locklessly.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-17 14:56:16 +00:00
Eric Dumazet 8160fb43d5 net: use an atomic_long_t for queue->trans_timeout
tx_timeout_show() assumed dev_watchdog() would stop all
the queues, to fetch queue->trans_timeout under protection
of the queue->_xmit_lock.

As we want to no longer disrupt transmits, we use an
atomic_long_t instead.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: david decotigny <david.decotigny@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-17 14:56:16 +00:00
Seth Forshee 85c0c3eb9a net: sch: simplify condtion for selecting mini_Qdisc_pair buffer
The only valid values for a miniq pointer are NULL or a pointer to
miniq1 or miniq2, so testing for miniq_old != &miniq1 is functionally
equivalent to testing that it is NULL or equal to &miniq2.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Seth Forshee <sforshee@digitalocean.com>
Link: https://lore.kernel.org/r/20211026183721.137930-1-seth@forshee.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-27 17:09:26 -07:00
Seth Forshee 267463823a net: sch: eliminate unnecessary RCU waits in mini_qdisc_pair_swap()
Currently rcu_barrier() is used to ensure that no readers of the
inactive mini_Qdisc buffer remain before it is reused. This waits for
any pending RCU callbacks to complete, when all that is actually
required is to wait for one RCU grace period to elapse after the buffer
was made inactive. This means that using rcu_barrier() may result in
unnecessary waits.

To improve this, store the current RCU state when a buffer is made
inactive and use poll_state_synchronize_rcu() to check whether a full
grace period has elapsed before reusing it. If a full grace period has
not elapsed, wait for a grace period to elapse, and in the non-RT case
use synchronize_rcu_expedited() to hasten it.

Since this approach eliminates the RCU callback it is no longer
necessary to synchronize_rcu() in the tp_head==NULL case. However, the
RCU state should still be saved for the previously active buffer.

Before this change I would typically see mini_qdisc_pair_swap() take
tens of milliseconds to complete. After this change it typcially
finishes in less than 1 ms, and often it takes just a few microseconds.

Thanks to Paul for walking me through the options for improving this.

Cc: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Seth Forshee <sforshee@digitalocean.com>
Link: https://lore.kernel.org/r/20211026130700.121189-1-seth@forshee.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-27 17:09:26 -07:00
Ahmed S. Darwish 29cbcd8582 net: sched: Remove Qdisc::running sequence counter
The Qdisc::running sequence counter has two uses:

  1. Reliably reading qdisc's tc statistics while the qdisc is running
     (a seqcount read/retry loop at gnet_stats_add_basic()).

  2. As a flag, indicating whether the qdisc in question is running
     (without any retry loops).

For the first usage, the Qdisc::running sequence counter write section,
qdisc_run_begin() => qdisc_run_end(), covers a much wider area than what
is actually needed: the raw qdisc's bstats update. A u64_stats sync
point was thus introduced (in previous commits) inside the bstats
structure itself. A local u64_stats write section is then started and
stopped for the bstats updates.

Use that u64_stats sync point mechanism for the bstats read/retry loop
at gnet_stats_add_basic().

For the second qdisc->running usage, a __QDISC_STATE_RUNNING bit flag,
accessed with atomic bitops, is sufficient. Using a bit flag instead of
a sequence counter at qdisc_run_begin/end() and qdisc_is_running() leads
to the SMP barriers implicitly added through raw_read_seqcount() and
write_seqcount_begin/end() getting removed. All call sites have been
surveyed though, and no required ordering was identified.

Now that the qdisc->running sequence counter is no longer used, remove
it.

Note, using u64_stats implies no sequence counter protection for 64-bit
architectures. This can lead to the qdisc tc statistics "packets" vs.
"bytes" values getting out of sync on rare occasions. The individual
values will still be valid.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-18 12:54:41 +01:00
Ahmed S. Darwish 50dc9a8572 net: sched: Merge Qdisc::bstats and Qdisc::cpu_bstats data types
The only factor differentiating per-CPU bstats data type (struct
gnet_stats_basic_cpu) from the packed non-per-CPU one (struct
gnet_stats_basic_packed) was a u64_stats sync point inside the former.
The two data types are now equivalent: earlier commits added a u64_stats
sync point to the latter.

Combine both data types into "struct gnet_stats_basic_sync". This
eliminates redundancy and simplifies the bstats read/write APIs.

Use u64_stats_t for bstats "packets" and "bytes" data types. On 64-bit
architectures, u64_stats sync points do not use sequence counter
protection.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-18 12:54:41 +01:00
Ahmed S. Darwish 67c9e6270f net: sched: Protect Qdisc::bstats with u64_stats
The not-per-CPU variant of qdisc tc (traffic control) statistics,
Qdisc::gnet_stats_basic_packed bstats, is protected with Qdisc::running
sequence counter.

This sequence counter is used for reliably protecting bstats reads from
parallel writes. Meanwhile, the seqcount's write section covers a much
wider area than bstats update: qdisc_run_begin() => qdisc_run_end().

That read/write section asymmetry can lead to needless retries of the
read section. To prepare for removing the Qdisc::running sequence
counter altogether, introduce a u64_stats sync point inside bstats
instead.

Modify _bstats_update() to start/end the bstats u64_stats write
section.

For bisectability, and finer commits granularity, the bstats read
section is still protected with a Qdisc::running read/retry loop and
qdisc_run_begin/end() still starts/ends that seqcount write section.
Once all call sites are modified to use _bstats_update(), the
Qdisc::running seqcount will be removed and bstats read/retry loop will
be modified to utilize the internal u64_stats sync point.

Note, using u64_stats implies no sequence counter protection for 64-bit
architectures. This can lead to the statistics "packets" vs. "bytes"
values getting out of sync on rare occasions. The individual values will
still be valid.

[bigeasy: Minor commit message edits, init all gnet_stats_basic_packed.]

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-18 12:54:41 +01:00
Jakub Kicinski f7116fb460 net: sched: move and reuse mq_change_real_num_tx()
The code for handling active queue changes is identical
between mq and mqprio, reuse it.

Suggested-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-19 13:26:01 +01:00
Jakub Kicinski 1e080f1775 net: sched: update default qdisc visibility after Tx queue cnt changes
mq / mqprio make the default child qdiscs visible. They only do
so for the qdiscs which are within real_num_tx_queues when the
device is registered. Depending on order of calls in the driver,
or if user space changes config via ethtool -L the number of
qdiscs visible under tc qdisc show will differ from the number
of queues. This is confusing to users and potentially to system
configuration scripts which try to make sure qdiscs have the
right parameters.

Add a new Qdisc_ops callback and make relevant qdiscs TTRT.

Note that this uncovers the "shortcut" created by
commit 1f27cde313 ("net: sched: use pfifo_fast for non real queues")
The default child qdiscs beyond initial real_num_tx are always
pfifo_fast, no matter what the sysfs setting is. Fixing this
gets a little tricky because we'd need to keep a reference
on whatever the default qdisc was at the time of creation.
In practice this is likely an non-issue the qdiscs likely have
to be configured to non-default settings, so whatever user space
is doing such configuration can replace the pfifos... now that
it will see them.

Reported-by: Matthew Massey <matthewmassey@fb.com>
Reviewed-by: Dave Taht <dave.taht@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-15 15:46:02 +01:00
Yunsheng Lin 06f5553e0f net: sched: fix lockdep_set_class() typo error for sch->seqlock
According to comment in qdisc_alloc(), sch->seqlock's lockdep
class key should be set to qdisc_tx_busylock, due to possible
type error, sch->busylock's lockdep class key is set to
qdisc_tx_busylock, which is duplicated because sch->busylock's
lockdep class key is already set in qdisc_alloc().

So fix it by replacing sch->busylock with sch->seqlock.

Fixes: 96009c7d50 ("sched: replace __QDISC_STATE_RUNNING bit with a spin lock")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-04 09:59:24 +01:00
Yunsheng Lin d3e0f57501 net: sched: remove qdisc->empty for lockless qdisc
As MISSED and DRAINING state are used to indicate a non-empty
qdisc, qdisc->empty is not longer needed, so remove it.

Acked-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> # flexcan
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-23 12:17:35 -07:00
Yunsheng Lin c4fef01ba4 net: sched: implement TCQ_F_CAN_BYPASS for lockless qdisc
Currently pfifo_fast has both TCQ_F_CAN_BYPASS and TCQ_F_NOLOCK
flag set, but queue discipline by-pass does not work for lockless
qdisc because skb is always enqueued to qdisc even when the qdisc
is empty, see __dev_xmit_skb().

This patch calls sch_direct_xmit() to transmit the skb directly
to the driver for empty lockless qdisc, which aviod enqueuing
and dequeuing operation.

As qdisc->empty is not reliable to indicate a empty qdisc because
there is a time window between enqueuing and setting qdisc->empty.
So we use the MISSED state added in commit a90c57f2ce ("net:
sched: fix packet stuck problem for lockless qdisc"), which
indicate there is lock contention, suggesting that it is better
not to do the qdisc bypass in order to avoid packet out of order
problem.

In order to make MISSED state reliable to indicate a empty qdisc,
we need to ensure that testing and clearing of MISSED state is
within the protection of qdisc->seqlock, only setting MISSED state
can be done without the protection of qdisc->seqlock. A MISSED
state testing is added without the protection of qdisc->seqlock to
aviod doing unnecessary spin_trylock() for contention case.

As the enqueuing is not within the protection of qdisc->seqlock,
there is still a potential data race as mentioned by Jakub [1]:

      thread1               thread2             thread3
qdisc_run_begin() # true
                        qdisc_run_begin(q)
                             set(MISSED)
pfifo_fast_dequeue
  clear(MISSED)
  # recheck the queue
qdisc_run_end()
                            enqueue skb1
                                             qdisc empty # true
                                          qdisc_run_begin() # true
                                          sch_direct_xmit() # skb2
                         qdisc_run_begin()
                            set(MISSED)

When above happens, skb1 enqueued by thread2 is transmited after
skb2 is transmited by thread3 because MISSED state setting and
enqueuing is not under the qdisc->seqlock. If qdisc bypass is
disabled, skb1 has better chance to be transmited quicker than
skb2.

This patch does not take care of the above data race, because we
view this as similar as below:
Even at the same time CPU1 and CPU2 write the skb to two socket
which both heading to the same qdisc, there is no guarantee that
which skb will hit the qdisc first, because there is a lot of
factor like interrupt/softirq/cache miss/scheduling afffecting
that.

There are below cases that need special handling:
1. When MISSED state is cleared before another round of dequeuing
   in pfifo_fast_dequeue(), and __qdisc_run() might not be able to
   dequeue all skb in one round and call __netif_schedule(), which
   might result in a non-empty qdisc without MISSED set. In order
   to avoid this, the MISSED state is set for lockless qdisc and
   __netif_schedule() will be called at the end of qdisc_run_end.

2. The MISSED state also need to be set for lockless qdisc instead
   of calling __netif_schedule() directly when requeuing a skb for
   a similar reason.

3. For netdev queue stopped case, the MISSED case need clearing
   while the netdev queue is stopped, otherwise there may be
   unnecessary __netif_schedule() calling. So a new DRAINING state
   is added to indicate this case, which also indicate a non-empty
   qdisc.

4. As there is already netif_xmit_frozen_or_stopped() checking in
   dequeue_skb() and sch_direct_xmit(), which are both within the
   protection of qdisc->seqlock, but the same checking in
   __dev_xmit_skb() is without the protection, which might cause
   empty indication of a lockless qdisc to be not reliable. So
   remove the checking in __dev_xmit_skb(), and the checking in
   the protection of qdisc->seqlock seems enough to avoid the cpu
   consumption problem for netdev queue stopped case.

1. https://lkml.org/lkml/2021/5/29/215

Acked-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> # flexcan
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-23 12:17:35 -07:00
Jakub Kicinski 490dcecabb mlx5: count all link events
mlx5 devices were observed generating MLX5_PORT_CHANGE_SUBTYPE_ACTIVE
events without an intervening MLX5_PORT_CHANGE_SUBTYPE_DOWN. This
breaks link flap detection based on Linux carrier state transition
count as netif_carrier_on() does nothing if carrier is already on.
Make sure we count such events.

netif_carrier_event() increments the counters and fires the linkwatch
events. The latter is not necessary for the use case but seems like
the right thing to do.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
2021-06-03 13:10:17 -07:00
Yunsheng Lin dcad9ee9e0 net: sched: fix tx action reschedule issue with stopped queue
The netdev qeueue might be stopped when byte queue limit has
reached or tx hw ring is full, net_tx_action() may still be
rescheduled if STATE_MISSED is set, which consumes unnecessary
cpu without dequeuing and transmiting any skb because the
netdev queue is stopped, see qdisc_run_end().

This patch fixes it by checking the netdev queue state before
calling qdisc_run() and clearing STATE_MISSED if netdev queue is
stopped during qdisc_run(), the net_tx_action() is rescheduled
again when netdev qeueue is restarted, see netif_tx_wake_queue().

As there is time window between netif_xmit_frozen_or_stopped()
checking and STATE_MISSED clearing, between which STATE_MISSED
may set by net_tx_action() scheduled by netif_tx_wake_queue(),
so set the STATE_MISSED again if netdev queue is restarted.

Fixes: 6b3ba9146f ("net: sched: allow qdiscs to handle locking")
Reported-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-05-14 15:05:46 -07:00
Yunsheng Lin 102b55ee92 net: sched: fix tx action rescheduling issue during deactivation
Currently qdisc_run() checks the STATE_DEACTIVATED of lockless
qdisc before calling __qdisc_run(), which ultimately clear the
STATE_MISSED when all the skb is dequeued. If STATE_DEACTIVATED
is set before clearing STATE_MISSED, there may be rescheduling
of net_tx_action() at the end of qdisc_run_end(), see below:

CPU0(net_tx_atcion)  CPU1(__dev_xmit_skb)  CPU2(dev_deactivate)
          .                   .                     .
          .            set STATE_MISSED             .
          .           __netif_schedule()            .
          .                   .           set STATE_DEACTIVATED
          .                   .                qdisc_reset()
          .                   .                     .
          .<---------------   .              synchronize_net()
clear __QDISC_STATE_SCHED  |  .                     .
          .                |  .                     .
          .                |  .            some_qdisc_is_busy()
          .                |  .               return *false*
          .                |  .                     .
  test STATE_DEACTIVATED   |  .                     .
__qdisc_run() *not* called |  .                     .
          .                |  .                     .
   test STATE_MISS         |  .                     .
 __netif_schedule()--------|  .                     .
          .                   .                     .
          .                   .                     .

__qdisc_run() is not called by net_tx_atcion() in CPU0 because
CPU2 has set STATE_DEACTIVATED flag during dev_deactivate(), and
STATE_MISSED is only cleared in __qdisc_run(), __netif_schedule
is called at the end of qdisc_run_end(), causing tx action
rescheduling problem.

qdisc_run() called by net_tx_action() runs in the softirq context,
which should has the same semantic as the qdisc_run() called by
__dev_xmit_skb() protected by rcu_read_lock_bh(). And there is a
synchronize_net() between STATE_DEACTIVATED flag being set and
qdisc_reset()/some_qdisc_is_busy in dev_deactivate(), we can safely
bail out for the deactived lockless qdisc in net_tx_action(), and
qdisc_reset() will reset all skb not dequeued yet.

So add the rcu_read_lock() explicitly to protect the qdisc_run()
and do the STATE_DEACTIVATED checking in net_tx_action() before
calling qdisc_run_begin(). Another option is to do the checking in
the qdisc_run_end(), but it will add unnecessary overhead for
non-tx_action case, because __dev_queue_xmit() will not see qdisc
with STATE_DEACTIVATED after synchronize_net(), the qdisc with
STATE_DEACTIVATED can only be seen by net_tx_action() because of
__netif_schedule().

The STATE_DEACTIVATED checking in qdisc_run() is to avoid race
between net_tx_action() and qdisc_reset(), see:
commit d518d2ed86 ("net/sched: fix race between deactivation
and dequeue for NOLOCK qdisc"). As the bailout added above for
deactived lockless qdisc in net_tx_action() provides better
protection for the race without calling qdisc_run() at all, so
remove the STATE_DEACTIVATED checking in qdisc_run().

After qdisc_reset(), there is no skb in qdisc to be dequeued, so
clear the STATE_MISSED in dev_reset_queue() too.

Fixes: 6b3ba9146f ("net: sched: allow qdiscs to handle locking")
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
V8: Clearing STATE_MISSED before calling __netif_schedule() has
    avoid the endless rescheduling problem, but there may still
    be a unnecessary rescheduling, so adjust the commit log.
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-05-14 15:05:46 -07:00
Yunsheng Lin a90c57f2ce net: sched: fix packet stuck problem for lockless qdisc
Lockless qdisc has below concurrent problem:
    cpu0                 cpu1
     .                     .
q->enqueue                 .
     .                     .
qdisc_run_begin()          .
     .                     .
dequeue_skb()              .
     .                     .
sch_direct_xmit()          .
     .                     .
     .                q->enqueue
     .             qdisc_run_begin()
     .            return and do nothing
     .                     .
qdisc_run_end()            .

cpu1 enqueue a skb without calling __qdisc_run() because cpu0
has not released the lock yet and spin_trylock() return false
for cpu1 in qdisc_run_begin(), and cpu0 do not see the skb
enqueued by cpu1 when calling dequeue_skb() because cpu1 may
enqueue the skb after cpu0 calling dequeue_skb() and before
cpu0 calling qdisc_run_end().

Lockless qdisc has below another concurrent problem when
tx_action is involved:

cpu0(serving tx_action)     cpu1             cpu2
          .                   .                .
          .              q->enqueue            .
          .            qdisc_run_begin()       .
          .              dequeue_skb()         .
          .                   .            q->enqueue
          .                   .                .
          .             sch_direct_xmit()      .
          .                   .         qdisc_run_begin()
          .                   .       return and do nothing
          .                   .                .
 clear __QDISC_STATE_SCHED    .                .
 qdisc_run_begin()            .                .
 return and do nothing        .                .
          .                   .                .
          .            qdisc_run_end()         .

This patch fixes the above data race by:
1. If the first spin_trylock() return false and STATE_MISSED is
   not set, set STATE_MISSED and retry another spin_trylock() in
   case other CPU may not see STATE_MISSED after it releases the
   lock.
2. reschedule if STATE_MISSED is set after the lock is released
   at the end of qdisc_run_end().

For tx_action case, STATE_MISSED is also set when cpu1 is at the
end if qdisc_run_end(), so tx_action will be rescheduled again
to dequeue the skb enqueued by cpu2.

Clear STATE_MISSED before retrying a dequeuing when dequeuing
returns NULL in order to reduce the overhead of the second
spin_trylock() and __netif_schedule() calling.

Also clear the STATE_MISSED before calling __netif_schedule()
at the end of qdisc_run_end() to avoid doing another round of
dequeuing in the pfifo_fast_dequeue().

The performance impact of this patch, tested using pktgen and
dummy netdev with pfifo_fast qdisc attached:

 threads  without+this_patch   with+this_patch      delta
    1        2.61Mpps            2.60Mpps           -0.3%
    2        3.97Mpps            3.82Mpps           -3.7%
    4        5.62Mpps            5.59Mpps           -0.5%
    8        2.78Mpps            2.77Mpps           -0.3%
   16        2.22Mpps            2.22Mpps           -0.0%

Fixes: 6b3ba9146f ("net: sched: allow qdiscs to handle locking")
Acked-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-05-14 15:05:46 -07:00
Baowen Zheng 2ffe039528 net/sched: act_police: add support for packet-per-second policing
Allow a policer action to enforce a rate-limit based on packets-per-second,
configurable using a packet-per-second rate and burst parameters.

e.g.
tc filter add dev tap1 parent ffff: u32 match \
        u32 0 0 police pkts_rate 3000 pkts_burst 1000

Testing was unable to uncover a performance impact of this change on
existing features.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Louis Peens <louis.peens@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-13 14:18:09 -08:00
Eric Dumazet 846e463a70 net/sched: get rid of qdisc->padded
kmalloc() of sufficiently big portion of memory is cache-aligned
in regular conditions. If some debugging options are used,
there is no reason qdisc structures would need 64-byte alignment
if most other kernel structures are not aligned.

This get rid of QDISC_ALIGN and QDISC_ALIGNTO.

Addition of privdata field will help implementing
the reverse of qdisc_priv() and documents where
the private data is.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Allen Pais <allen.lkml@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-10-09 08:08:08 -07:00
Yunsheng Lin 2fb541c862 net: sch_generic: aviod concurrent reset and enqueue op for lockless qdisc
Currently there is concurrent reset and enqueue operation for the
same lockless qdisc when there is no lock to synchronize the
q->enqueue() in __dev_xmit_skb() with the qdisc reset operation in
qdisc_deactivate() called by dev_deactivate_queue(), which may cause
out-of-bounds access for priv->ring[] in hns3 driver if user has
requested a smaller queue num when __dev_xmit_skb() still enqueue a
skb with a larger queue_mapping after the corresponding qdisc is
reset, and call hns3_nic_net_xmit() with that skb later.

Reused the existing synchronize_net() in dev_deactivate_many() to
make sure skb with larger queue_mapping enqueued to old qdisc(which
is saved in dev_queue->qdisc_sleeping) will always be reset when
dev_reset_queue() is called.

Fixes: 6b3ba9146f ("net: sched: allow qdiscs to handle locking")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-10 12:38:26 -07:00
Valentin Longchamp 1a3db27ad9 net: sched: export __netdev_watchdog_up()
Since the quiesce/activate rework, __netdev_watchdog_up() is directly
called in the ucc_geth driver.

Unfortunately, this function is not available for modules and thus
ucc_geth cannot be built as a module anymore. Fix it by exporting
__netdev_watchdog_up().

Since the commit introducing the regression was backported to stable
branches, this one should ideally be as well.

Fixes: 79dde73cf9 ("net/ethernet/freescale: rework quiesce/activate for ucc_geth")
Signed-off-by: Valentin Longchamp <valentin@longchamp.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-09 13:14:31 -07:00
Cong Wang 759ae57f1b net_sched: get rid of unnecessary dev_qdisc_reset()
Resetting old qdisc on dev_queue->qdisc_sleeping in
dev_qdisc_reset() is redundant, because this qdisc,
even if not same with dev_queue->qdisc, is reset via
qdisc_put() right after calling dev_graft_qdisc() when
hitting refcnt 0.

This is very easy to observe with qdisc_reset() tracepoint
and stack traces.

Reported-by: Václav Zindulka <vaclav.zindulka@tlapnet.cz>
Tested-by: Václav Zindulka <vaclav.zindulka@tlapnet.cz>
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>
2020-05-27 15:05:49 -07:00
Cong Wang 70f5096533 net_sched: avoid resetting active qdisc for multiple times
Except for sch_mq and sch_mqprio, each dev queue points to the
same root qdisc, so when we reset the dev queues with
netdev_for_each_tx_queue() we end up resetting the same instance
of the root qdisc for multiple times.

Avoid this by checking the __QDISC_STATE_DEACTIVATED bit in
each iteration, so for sch_mq/sch_mqprio, we still reset all
of them like before, for the rest, we only reset it once.

Reported-by: Václav Zindulka <vaclav.zindulka@tlapnet.cz>
Tested-by: Václav Zindulka <vaclav.zindulka@tlapnet.cz>
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>
2020-05-27 15:05:49 -07:00
Cong Wang f5a7833e83 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>
2020-05-27 15:05:49 -07:00
Cong Wang a34dac0b90 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>
2020-05-27 15:05:49 -07:00
Cong Wang 4909daba37 net_sched: use qdisc_reset() in qdisc_destroy()
qdisc_destroy() calls ops->reset() and cleans up qdisc->gso_skb
and qdisc->skb_bad_txq, these are nearly same with qdisc_reset(),
so just call it directly, and cosolidate the code for the next
patch.

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>
2020-05-27 15:05:49 -07:00
Cong Wang 1a33e10e4a net: partially revert dynamic lockdep key changes
This patch reverts the folowing commits:

commit 064ff66e2b
"bonding: add missing netdev_update_lockdep_key()"

commit 53d374979e
"net: avoid updating qdisc_xmit_lock_key in netdev_update_lockdep_key()"

commit 1f26c0d3d2
"net: fix kernel-doc warning in <linux/netdevice.h>"

commit ab92d68fc2
"net: core: add generic lockdep keys"

but keeps the addr_list_lock_key because we still lock
addr_list_lock nestedly on stack devices, unlikely xmit_lock
this is safe because we don't take addr_list_lock on any fast
path.

Reported-and-tested-by: syzbot+aaa6fa4949cc5d9b7b25@syzkaller.appspotmail.com
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-04 12:05:56 -07:00
Jesper Dangaard Brouer bf6dba76d2 net: sched: fallback to qdisc noqueue if default qdisc setup fail
Currently if the default qdisc setup/init fails, the device ends up with
qdisc "noop", which causes all TX packets to get dropped.

With the introduction of sysctl net/core/default_qdisc it is possible
to change the default qdisc to be more advanced, which opens for the
possibility that Qdisc_ops->init() can fail.

This patch detect these kind of failures, and choose to fallback to
qdisc "noqueue", which is so simple that its init call will not fail.
This allows the interface to continue functioning.

V2:
As this also captures memory failures, which are transient, the
device is not kept in IFF_NO_QUEUE state.  This allows the net_device
to retry to default qdisc assignment.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-04 11:50:51 -07:00
Paul Blakey 7d17c544cd net: sched: Pass ingress block to tcf_classify_ingress
On ingress and cls_act qdiscs init, save the block on ingress
mini_Qdisc and and pass it on to ingress classification, so it
can be used for the looking up a specified chain index.

Co-developed-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2020-02-19 17:49:48 -08:00
Michael S. Tsirkin 0290bd291c netdev: pass the stuck queue to the timeout handler
This allows incrementing the correct timeout statistic without any mess.
Down the road, devices can learn to reset just the specific queue.

The patch was generated with the following script:

use strict;
use warnings;

our $^I = '.bak';

my @work = (
["arch/m68k/emu/nfeth.c", "nfeth_tx_timeout"],
["arch/um/drivers/net_kern.c", "uml_net_tx_timeout"],
["arch/um/drivers/vector_kern.c", "vector_net_tx_timeout"],
["arch/xtensa/platforms/iss/network.c", "iss_net_tx_timeout"],
["drivers/char/pcmcia/synclink_cs.c", "hdlcdev_tx_timeout"],
["drivers/infiniband/ulp/ipoib/ipoib_main.c", "ipoib_timeout"],
["drivers/infiniband/ulp/ipoib/ipoib_main.c", "ipoib_timeout"],
["drivers/message/fusion/mptlan.c", "mpt_lan_tx_timeout"],
["drivers/misc/sgi-xp/xpnet.c", "xpnet_dev_tx_timeout"],
["drivers/net/appletalk/cops.c", "cops_timeout"],
["drivers/net/arcnet/arcdevice.h", "arcnet_timeout"],
["drivers/net/arcnet/arcnet.c", "arcnet_timeout"],
["drivers/net/arcnet/com20020.c", "arcnet_timeout"],
["drivers/net/ethernet/3com/3c509.c", "el3_tx_timeout"],
["drivers/net/ethernet/3com/3c515.c", "corkscrew_timeout"],
["drivers/net/ethernet/3com/3c574_cs.c", "el3_tx_timeout"],
["drivers/net/ethernet/3com/3c589_cs.c", "el3_tx_timeout"],
["drivers/net/ethernet/3com/3c59x.c", "vortex_tx_timeout"],
["drivers/net/ethernet/3com/3c59x.c", "vortex_tx_timeout"],
["drivers/net/ethernet/3com/typhoon.c", "typhoon_tx_timeout"],
["drivers/net/ethernet/8390/8390.h", "ei_tx_timeout"],
["drivers/net/ethernet/8390/8390.h", "eip_tx_timeout"],
["drivers/net/ethernet/8390/8390.c", "ei_tx_timeout"],
["drivers/net/ethernet/8390/8390p.c", "eip_tx_timeout"],
["drivers/net/ethernet/8390/ax88796.c", "ax_ei_tx_timeout"],
["drivers/net/ethernet/8390/axnet_cs.c", "axnet_tx_timeout"],
["drivers/net/ethernet/8390/etherh.c", "__ei_tx_timeout"],
["drivers/net/ethernet/8390/hydra.c", "__ei_tx_timeout"],
["drivers/net/ethernet/8390/mac8390.c", "__ei_tx_timeout"],
["drivers/net/ethernet/8390/mcf8390.c", "__ei_tx_timeout"],
["drivers/net/ethernet/8390/lib8390.c", "__ei_tx_timeout"],
["drivers/net/ethernet/8390/ne2k-pci.c", "ei_tx_timeout"],
["drivers/net/ethernet/8390/pcnet_cs.c", "ei_tx_timeout"],
["drivers/net/ethernet/8390/smc-ultra.c", "ei_tx_timeout"],
["drivers/net/ethernet/8390/wd.c", "ei_tx_timeout"],
["drivers/net/ethernet/8390/zorro8390.c", "__ei_tx_timeout"],
["drivers/net/ethernet/adaptec/starfire.c", "tx_timeout"],
["drivers/net/ethernet/agere/et131x.c", "et131x_tx_timeout"],
["drivers/net/ethernet/allwinner/sun4i-emac.c", "emac_timeout"],
["drivers/net/ethernet/alteon/acenic.c", "ace_watchdog"],
["drivers/net/ethernet/amazon/ena/ena_netdev.c", "ena_tx_timeout"],
["drivers/net/ethernet/amd/7990.h", "lance_tx_timeout"],
["drivers/net/ethernet/amd/7990.c", "lance_tx_timeout"],
["drivers/net/ethernet/amd/a2065.c", "lance_tx_timeout"],
["drivers/net/ethernet/amd/am79c961a.c", "am79c961_timeout"],
["drivers/net/ethernet/amd/amd8111e.c", "amd8111e_tx_timeout"],
["drivers/net/ethernet/amd/ariadne.c", "ariadne_tx_timeout"],
["drivers/net/ethernet/amd/atarilance.c", "lance_tx_timeout"],
["drivers/net/ethernet/amd/au1000_eth.c", "au1000_tx_timeout"],
["drivers/net/ethernet/amd/declance.c", "lance_tx_timeout"],
["drivers/net/ethernet/amd/lance.c", "lance_tx_timeout"],
["drivers/net/ethernet/amd/mvme147.c", "lance_tx_timeout"],
["drivers/net/ethernet/amd/ni65.c", "ni65_timeout"],
["drivers/net/ethernet/amd/nmclan_cs.c", "mace_tx_timeout"],
["drivers/net/ethernet/amd/pcnet32.c", "pcnet32_tx_timeout"],
["drivers/net/ethernet/amd/sunlance.c", "lance_tx_timeout"],
["drivers/net/ethernet/amd/xgbe/xgbe-drv.c", "xgbe_tx_timeout"],
["drivers/net/ethernet/apm/xgene-v2/main.c", "xge_timeout"],
["drivers/net/ethernet/apm/xgene/xgene_enet_main.c", "xgene_enet_timeout"],
["drivers/net/ethernet/apple/macmace.c", "mace_tx_timeout"],
["drivers/net/ethernet/atheros/ag71xx.c", "ag71xx_tx_timeout"],
["drivers/net/ethernet/atheros/alx/main.c", "alx_tx_timeout"],
["drivers/net/ethernet/atheros/atl1c/atl1c_main.c", "atl1c_tx_timeout"],
["drivers/net/ethernet/atheros/atl1e/atl1e_main.c", "atl1e_tx_timeout"],
["drivers/net/ethernet/atheros/atlx/atl.c", "atlx_tx_timeout"],
["drivers/net/ethernet/atheros/atlx/atl1.c", "atlx_tx_timeout"],
["drivers/net/ethernet/atheros/atlx/atl2.c", "atl2_tx_timeout"],
["drivers/net/ethernet/broadcom/b44.c", "b44_tx_timeout"],
["drivers/net/ethernet/broadcom/bcmsysport.c", "bcm_sysport_tx_timeout"],
["drivers/net/ethernet/broadcom/bnx2.c", "bnx2_tx_timeout"],
["drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h", "bnx2x_tx_timeout"],
["drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c", "bnx2x_tx_timeout"],
["drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c", "bnx2x_tx_timeout"],
["drivers/net/ethernet/broadcom/bnxt/bnxt.c", "bnxt_tx_timeout"],
["drivers/net/ethernet/broadcom/genet/bcmgenet.c", "bcmgenet_timeout"],
["drivers/net/ethernet/broadcom/sb1250-mac.c", "sbmac_tx_timeout"],
["drivers/net/ethernet/broadcom/tg3.c", "tg3_tx_timeout"],
["drivers/net/ethernet/calxeda/xgmac.c", "xgmac_tx_timeout"],
["drivers/net/ethernet/cavium/liquidio/lio_main.c", "liquidio_tx_timeout"],
["drivers/net/ethernet/cavium/liquidio/lio_vf_main.c", "liquidio_tx_timeout"],
["drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c", "lio_vf_rep_tx_timeout"],
["drivers/net/ethernet/cavium/thunder/nicvf_main.c", "nicvf_tx_timeout"],
["drivers/net/ethernet/cirrus/cs89x0.c", "net_timeout"],
["drivers/net/ethernet/cisco/enic/enic_main.c", "enic_tx_timeout"],
["drivers/net/ethernet/cisco/enic/enic_main.c", "enic_tx_timeout"],
["drivers/net/ethernet/cortina/gemini.c", "gmac_tx_timeout"],
["drivers/net/ethernet/davicom/dm9000.c", "dm9000_timeout"],
["drivers/net/ethernet/dec/tulip/de2104x.c", "de_tx_timeout"],
["drivers/net/ethernet/dec/tulip/tulip_core.c", "tulip_tx_timeout"],
["drivers/net/ethernet/dec/tulip/winbond-840.c", "tx_timeout"],
["drivers/net/ethernet/dlink/dl2k.c", "rio_tx_timeout"],
["drivers/net/ethernet/dlink/sundance.c", "tx_timeout"],
["drivers/net/ethernet/emulex/benet/be_main.c", "be_tx_timeout"],
["drivers/net/ethernet/ethoc.c", "ethoc_tx_timeout"],
["drivers/net/ethernet/faraday/ftgmac100.c", "ftgmac100_tx_timeout"],
["drivers/net/ethernet/fealnx.c", "fealnx_tx_timeout"],
["drivers/net/ethernet/freescale/dpaa/dpaa_eth.c", "dpaa_tx_timeout"],
["drivers/net/ethernet/freescale/fec_main.c", "fec_timeout"],
["drivers/net/ethernet/freescale/fec_mpc52xx.c", "mpc52xx_fec_tx_timeout"],
["drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c", "fs_timeout"],
["drivers/net/ethernet/freescale/gianfar.c", "gfar_timeout"],
["drivers/net/ethernet/freescale/ucc_geth.c", "ucc_geth_timeout"],
["drivers/net/ethernet/fujitsu/fmvj18x_cs.c", "fjn_tx_timeout"],
["drivers/net/ethernet/google/gve/gve_main.c", "gve_tx_timeout"],
["drivers/net/ethernet/hisilicon/hip04_eth.c", "hip04_timeout"],
["drivers/net/ethernet/hisilicon/hix5hd2_gmac.c", "hix5hd2_net_timeout"],
["drivers/net/ethernet/hisilicon/hns/hns_enet.c", "hns_nic_net_timeout"],
["drivers/net/ethernet/hisilicon/hns3/hns3_enet.c", "hns3_nic_net_timeout"],
["drivers/net/ethernet/huawei/hinic/hinic_main.c", "hinic_tx_timeout"],
["drivers/net/ethernet/i825xx/82596.c", "i596_tx_timeout"],
["drivers/net/ethernet/i825xx/ether1.c", "ether1_timeout"],
["drivers/net/ethernet/i825xx/lib82596.c", "i596_tx_timeout"],
["drivers/net/ethernet/i825xx/sun3_82586.c", "sun3_82586_timeout"],
["drivers/net/ethernet/ibm/ehea/ehea_main.c", "ehea_tx_watchdog"],
["drivers/net/ethernet/ibm/emac/core.c", "emac_tx_timeout"],
["drivers/net/ethernet/ibm/emac/core.c", "emac_tx_timeout"],
["drivers/net/ethernet/ibm/ibmvnic.c", "ibmvnic_tx_timeout"],
["drivers/net/ethernet/intel/e100.c", "e100_tx_timeout"],
["drivers/net/ethernet/intel/e1000/e1000_main.c", "e1000_tx_timeout"],
["drivers/net/ethernet/intel/e1000e/netdev.c", "e1000_tx_timeout"],
["drivers/net/ethernet/intel/fm10k/fm10k_netdev.c", "fm10k_tx_timeout"],
["drivers/net/ethernet/intel/i40e/i40e_main.c", "i40e_tx_timeout"],
["drivers/net/ethernet/intel/iavf/iavf_main.c", "iavf_tx_timeout"],
["drivers/net/ethernet/intel/ice/ice_main.c", "ice_tx_timeout"],
["drivers/net/ethernet/intel/ice/ice_main.c", "ice_tx_timeout"],
["drivers/net/ethernet/intel/igb/igb_main.c", "igb_tx_timeout"],
["drivers/net/ethernet/intel/igbvf/netdev.c", "igbvf_tx_timeout"],
["drivers/net/ethernet/intel/ixgb/ixgb_main.c", "ixgb_tx_timeout"],
["drivers/net/ethernet/intel/ixgbe/ixgbe_debugfs.c", "adapter->netdev->netdev_ops->ndo_tx_timeout(adapter->netdev);"],
["drivers/net/ethernet/intel/ixgbe/ixgbe_main.c", "ixgbe_tx_timeout"],
["drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c", "ixgbevf_tx_timeout"],
["drivers/net/ethernet/jme.c", "jme_tx_timeout"],
["drivers/net/ethernet/korina.c", "korina_tx_timeout"],
["drivers/net/ethernet/lantiq_etop.c", "ltq_etop_tx_timeout"],
["drivers/net/ethernet/marvell/mv643xx_eth.c", "mv643xx_eth_tx_timeout"],
["drivers/net/ethernet/marvell/pxa168_eth.c", "pxa168_eth_tx_timeout"],
["drivers/net/ethernet/marvell/skge.c", "skge_tx_timeout"],
["drivers/net/ethernet/marvell/sky2.c", "sky2_tx_timeout"],
["drivers/net/ethernet/marvell/sky2.c", "sky2_tx_timeout"],
["drivers/net/ethernet/mediatek/mtk_eth_soc.c", "mtk_tx_timeout"],
["drivers/net/ethernet/mellanox/mlx4/en_netdev.c", "mlx4_en_tx_timeout"],
["drivers/net/ethernet/mellanox/mlx4/en_netdev.c", "mlx4_en_tx_timeout"],
["drivers/net/ethernet/mellanox/mlx5/core/en_main.c", "mlx5e_tx_timeout"],
["drivers/net/ethernet/micrel/ks8842.c", "ks8842_tx_timeout"],
["drivers/net/ethernet/micrel/ksz884x.c", "netdev_tx_timeout"],
["drivers/net/ethernet/microchip/enc28j60.c", "enc28j60_tx_timeout"],
["drivers/net/ethernet/microchip/encx24j600.c", "encx24j600_tx_timeout"],
["drivers/net/ethernet/natsemi/sonic.h", "sonic_tx_timeout"],
["drivers/net/ethernet/natsemi/sonic.c", "sonic_tx_timeout"],
["drivers/net/ethernet/natsemi/jazzsonic.c", "sonic_tx_timeout"],
["drivers/net/ethernet/natsemi/macsonic.c", "sonic_tx_timeout"],
["drivers/net/ethernet/natsemi/natsemi.c", "ns_tx_timeout"],
["drivers/net/ethernet/natsemi/ns83820.c", "ns83820_tx_timeout"],
["drivers/net/ethernet/natsemi/xtsonic.c", "sonic_tx_timeout"],
["drivers/net/ethernet/neterion/s2io.h", "s2io_tx_watchdog"],
["drivers/net/ethernet/neterion/s2io.c", "s2io_tx_watchdog"],
["drivers/net/ethernet/neterion/vxge/vxge-main.c", "vxge_tx_watchdog"],
["drivers/net/ethernet/netronome/nfp/nfp_net_common.c", "nfp_net_tx_timeout"],
["drivers/net/ethernet/nvidia/forcedeth.c", "nv_tx_timeout"],
["drivers/net/ethernet/nvidia/forcedeth.c", "nv_tx_timeout"],
["drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c", "pch_gbe_tx_timeout"],
["drivers/net/ethernet/packetengines/hamachi.c", "hamachi_tx_timeout"],
["drivers/net/ethernet/packetengines/yellowfin.c", "yellowfin_tx_timeout"],
["drivers/net/ethernet/pensando/ionic/ionic_lif.c", "ionic_tx_timeout"],
["drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c", "netxen_tx_timeout"],
["drivers/net/ethernet/qlogic/qla3xxx.c", "ql3xxx_tx_timeout"],
["drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c", "qlcnic_tx_timeout"],
["drivers/net/ethernet/qualcomm/emac/emac.c", "emac_tx_timeout"],
["drivers/net/ethernet/qualcomm/qca_spi.c", "qcaspi_netdev_tx_timeout"],
["drivers/net/ethernet/qualcomm/qca_uart.c", "qcauart_netdev_tx_timeout"],
["drivers/net/ethernet/rdc/r6040.c", "r6040_tx_timeout"],
["drivers/net/ethernet/realtek/8139cp.c", "cp_tx_timeout"],
["drivers/net/ethernet/realtek/8139too.c", "rtl8139_tx_timeout"],
["drivers/net/ethernet/realtek/atp.c", "tx_timeout"],
["drivers/net/ethernet/realtek/r8169_main.c", "rtl8169_tx_timeout"],
["drivers/net/ethernet/renesas/ravb_main.c", "ravb_tx_timeout"],
["drivers/net/ethernet/renesas/sh_eth.c", "sh_eth_tx_timeout"],
["drivers/net/ethernet/renesas/sh_eth.c", "sh_eth_tx_timeout"],
["drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c", "sxgbe_tx_timeout"],
["drivers/net/ethernet/seeq/ether3.c", "ether3_timeout"],
["drivers/net/ethernet/seeq/sgiseeq.c", "timeout"],
["drivers/net/ethernet/sfc/efx.c", "efx_watchdog"],
["drivers/net/ethernet/sfc/falcon/efx.c", "ef4_watchdog"],
["drivers/net/ethernet/sgi/ioc3-eth.c", "ioc3_timeout"],
["drivers/net/ethernet/sgi/meth.c", "meth_tx_timeout"],
["drivers/net/ethernet/silan/sc92031.c", "sc92031_tx_timeout"],
["drivers/net/ethernet/sis/sis190.c", "sis190_tx_timeout"],
["drivers/net/ethernet/sis/sis900.c", "sis900_tx_timeout"],
["drivers/net/ethernet/smsc/epic100.c", "epic_tx_timeout"],
["drivers/net/ethernet/smsc/smc911x.c", "smc911x_timeout"],
["drivers/net/ethernet/smsc/smc9194.c", "smc_timeout"],
["drivers/net/ethernet/smsc/smc91c92_cs.c", "smc_tx_timeout"],
["drivers/net/ethernet/smsc/smc91x.c", "smc_timeout"],
["drivers/net/ethernet/stmicro/stmmac/stmmac_main.c", "stmmac_tx_timeout"],
["drivers/net/ethernet/sun/cassini.c", "cas_tx_timeout"],
["drivers/net/ethernet/sun/ldmvsw.c", "sunvnet_tx_timeout_common"],
["drivers/net/ethernet/sun/niu.c", "niu_tx_timeout"],
["drivers/net/ethernet/sun/sunbmac.c", "bigmac_tx_timeout"],
["drivers/net/ethernet/sun/sungem.c", "gem_tx_timeout"],
["drivers/net/ethernet/sun/sunhme.c", "happy_meal_tx_timeout"],
["drivers/net/ethernet/sun/sunqe.c", "qe_tx_timeout"],
["drivers/net/ethernet/sun/sunvnet.c", "sunvnet_tx_timeout_common"],
["drivers/net/ethernet/sun/sunvnet_common.c", "sunvnet_tx_timeout_common"],
["drivers/net/ethernet/sun/sunvnet_common.h", "sunvnet_tx_timeout_common"],
["drivers/net/ethernet/synopsys/dwc-xlgmac-net.c", "xlgmac_tx_timeout"],
["drivers/net/ethernet/ti/cpmac.c", "cpmac_tx_timeout"],
["drivers/net/ethernet/ti/cpsw.c", "cpsw_ndo_tx_timeout"],
["drivers/net/ethernet/ti/cpsw_priv.c", "cpsw_ndo_tx_timeout"],
["drivers/net/ethernet/ti/cpsw_priv.h", "cpsw_ndo_tx_timeout"],
["drivers/net/ethernet/ti/davinci_emac.c", "emac_dev_tx_timeout"],
["drivers/net/ethernet/ti/netcp_core.c", "netcp_ndo_tx_timeout"],
["drivers/net/ethernet/ti/tlan.c", "tlan_tx_timeout"],
["drivers/net/ethernet/toshiba/ps3_gelic_net.h", "gelic_net_tx_timeout"],
["drivers/net/ethernet/toshiba/ps3_gelic_net.c", "gelic_net_tx_timeout"],
["drivers/net/ethernet/toshiba/ps3_gelic_wireless.c", "gelic_net_tx_timeout"],
["drivers/net/ethernet/toshiba/spider_net.c", "spider_net_tx_timeout"],
["drivers/net/ethernet/toshiba/tc35815.c", "tc35815_tx_timeout"],
["drivers/net/ethernet/via/via-rhine.c", "rhine_tx_timeout"],
["drivers/net/ethernet/wiznet/w5100.c", "w5100_tx_timeout"],
["drivers/net/ethernet/wiznet/w5300.c", "w5300_tx_timeout"],
["drivers/net/ethernet/xilinx/xilinx_emaclite.c", "xemaclite_tx_timeout"],
["drivers/net/ethernet/xircom/xirc2ps_cs.c", "xirc_tx_timeout"],
["drivers/net/fjes/fjes_main.c", "fjes_tx_retry"],
["drivers/net/slip/slip.c", "sl_tx_timeout"],
["include/linux/usb/usbnet.h", "usbnet_tx_timeout"],
["drivers/net/usb/aqc111.c", "usbnet_tx_timeout"],
["drivers/net/usb/asix_devices.c", "usbnet_tx_timeout"],
["drivers/net/usb/asix_devices.c", "usbnet_tx_timeout"],
["drivers/net/usb/asix_devices.c", "usbnet_tx_timeout"],
["drivers/net/usb/ax88172a.c", "usbnet_tx_timeout"],
["drivers/net/usb/ax88179_178a.c", "usbnet_tx_timeout"],
["drivers/net/usb/catc.c", "catc_tx_timeout"],
["drivers/net/usb/cdc_mbim.c", "usbnet_tx_timeout"],
["drivers/net/usb/cdc_ncm.c", "usbnet_tx_timeout"],
["drivers/net/usb/dm9601.c", "usbnet_tx_timeout"],
["drivers/net/usb/hso.c", "hso_net_tx_timeout"],
["drivers/net/usb/int51x1.c", "usbnet_tx_timeout"],
["drivers/net/usb/ipheth.c", "ipheth_tx_timeout"],
["drivers/net/usb/kaweth.c", "kaweth_tx_timeout"],
["drivers/net/usb/lan78xx.c", "lan78xx_tx_timeout"],
["drivers/net/usb/mcs7830.c", "usbnet_tx_timeout"],
["drivers/net/usb/pegasus.c", "pegasus_tx_timeout"],
["drivers/net/usb/qmi_wwan.c", "usbnet_tx_timeout"],
["drivers/net/usb/r8152.c", "rtl8152_tx_timeout"],
["drivers/net/usb/rndis_host.c", "usbnet_tx_timeout"],
["drivers/net/usb/rtl8150.c", "rtl8150_tx_timeout"],
["drivers/net/usb/sierra_net.c", "usbnet_tx_timeout"],
["drivers/net/usb/smsc75xx.c", "usbnet_tx_timeout"],
["drivers/net/usb/smsc95xx.c", "usbnet_tx_timeout"],
["drivers/net/usb/sr9700.c", "usbnet_tx_timeout"],
["drivers/net/usb/sr9800.c", "usbnet_tx_timeout"],
["drivers/net/usb/usbnet.c", "usbnet_tx_timeout"],
["drivers/net/vmxnet3/vmxnet3_drv.c", "vmxnet3_tx_timeout"],
["drivers/net/wan/cosa.c", "cosa_net_timeout"],
["drivers/net/wan/farsync.c", "fst_tx_timeout"],
["drivers/net/wan/fsl_ucc_hdlc.c", "uhdlc_tx_timeout"],
["drivers/net/wan/lmc/lmc_main.c", "lmc_driver_timeout"],
["drivers/net/wan/x25_asy.c", "x25_asy_timeout"],
["drivers/net/wimax/i2400m/netdev.c", "i2400m_tx_timeout"],
["drivers/net/wireless/intel/ipw2x00/ipw2100.c", "ipw2100_tx_timeout"],
["drivers/net/wireless/intersil/hostap/hostap_main.c", "prism2_tx_timeout"],
["drivers/net/wireless/intersil/hostap/hostap_main.c", "prism2_tx_timeout"],
["drivers/net/wireless/intersil/hostap/hostap_main.c", "prism2_tx_timeout"],
["drivers/net/wireless/intersil/orinoco/main.c", "orinoco_tx_timeout"],
["drivers/net/wireless/intersil/orinoco/orinoco_usb.c", "orinoco_tx_timeout"],
["drivers/net/wireless/intersil/orinoco/orinoco.h", "orinoco_tx_timeout"],
["drivers/net/wireless/intersil/prism54/islpci_dev.c", "islpci_eth_tx_timeout"],
["drivers/net/wireless/intersil/prism54/islpci_eth.c", "islpci_eth_tx_timeout"],
["drivers/net/wireless/intersil/prism54/islpci_eth.h", "islpci_eth_tx_timeout"],
["drivers/net/wireless/marvell/mwifiex/main.c", "mwifiex_tx_timeout"],
["drivers/net/wireless/quantenna/qtnfmac/core.c", "qtnf_netdev_tx_timeout"],
["drivers/net/wireless/quantenna/qtnfmac/core.h", "qtnf_netdev_tx_timeout"],
["drivers/net/wireless/rndis_wlan.c", "usbnet_tx_timeout"],
["drivers/net/wireless/wl3501_cs.c", "wl3501_tx_timeout"],
["drivers/net/wireless/zydas/zd1201.c", "zd1201_tx_timeout"],
["drivers/s390/net/qeth_core.h", "qeth_tx_timeout"],
["drivers/s390/net/qeth_core_main.c", "qeth_tx_timeout"],
["drivers/s390/net/qeth_l2_main.c", "qeth_tx_timeout"],
["drivers/s390/net/qeth_l2_main.c", "qeth_tx_timeout"],
["drivers/s390/net/qeth_l3_main.c", "qeth_tx_timeout"],
["drivers/s390/net/qeth_l3_main.c", "qeth_tx_timeout"],
["drivers/staging/ks7010/ks_wlan_net.c", "ks_wlan_tx_timeout"],
["drivers/staging/qlge/qlge_main.c", "qlge_tx_timeout"],
["drivers/staging/rtl8192e/rtl8192e/rtl_core.c", "_rtl92e_tx_timeout"],
["drivers/staging/rtl8192u/r8192U_core.c", "tx_timeout"],
["drivers/staging/unisys/visornic/visornic_main.c", "visornic_xmit_timeout"],
["drivers/staging/wlan-ng/p80211netdev.c", "p80211knetdev_tx_timeout"],
["drivers/tty/n_gsm.c", "gsm_mux_net_tx_timeout"],
["drivers/tty/synclink.c", "hdlcdev_tx_timeout"],
["drivers/tty/synclink_gt.c", "hdlcdev_tx_timeout"],
["drivers/tty/synclinkmp.c", "hdlcdev_tx_timeout"],
["net/atm/lec.c", "lec_tx_timeout"],
["net/bluetooth/bnep/netdev.c", "bnep_net_timeout"]
);

for my $p (@work) {
	my @pair = @$p;
	my $file = $pair[0];
	my $func = $pair[1];
	print STDERR $file , ": ", $func,"\n";
	our @ARGV = ($file);
	while (<ARGV>) {
		if (m/($func\s*\(struct\s+net_device\s+\*[A-Za-z_]?[A-Za-z-0-9_]*)(\))/) {
			print STDERR "found $1+$2 in $file\n";
		}
		if (s/($func\s*\(struct\s+net_device\s+\*[A-Za-z_]?[A-Za-z-0-9_]*)(\))/$1, unsigned int txqueue$2/) {
			print STDERR "$func found in $file\n";
		}
		print;
	}
}

where the list of files and functions is simply from:

git grep ndo_tx_timeout, with manual addition of headers
in the rare cases where the function is from a header,
then manually changing the few places which actually
call ndo_tx_timeout.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Shannon Nelson <snelson@pensando.io>
Reviewed-by: Martin Habets <mhabets@solarflare.com>

changes from v9:
	fixup a forward declaration
changes from v9:
	more leftovers from v3 change
changes from v8:
        fix up a missing direct call to timeout
        rebased on net-next
changes from v7:
	fixup leftovers from v3 change
changes from v6:
	fix typo in rtl driver
changes from v5:
	add missing files (allow any net device argument name)
changes from v4:
	add a missing driver header
changes from v3:
        change queue # to unsigned
Changes from v2:
        added headers
Changes from v1:
        Fix errors found by kbuild:
        generalize the pattern a bit, to pick up
        a couple of instances missed by the previous
        version.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-12 21:38:57 -08:00
Eric Dumazet 90b2be27bb net/sched: annotate lockless accesses to qdisc->empty
KCSAN reported the following race [1]

BUG: KCSAN: data-race in __dev_queue_xmit / net_tx_action

read to 0xffff8880ba403508 of 1 bytes by task 21814 on cpu 1:
 __dev_xmit_skb net/core/dev.c:3389 [inline]
 __dev_queue_xmit+0x9db/0x1b40 net/core/dev.c:3761
 dev_queue_xmit+0x21/0x30 net/core/dev.c:3825
 neigh_hh_output include/net/neighbour.h:500 [inline]
 neigh_output include/net/neighbour.h:509 [inline]
 ip6_finish_output2+0x873/0xec0 net/ipv6/ip6_output.c:116
 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline]
 __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127
 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 ip6_local_out+0x74/0x90 net/ipv6/output_core.c:179
 ip6_send_skb+0x53/0x110 net/ipv6/ip6_output.c:1795
 udp_v6_send_skb.isra.0+0x3ec/0xa70 net/ipv6/udp.c:1173
 udpv6_sendmsg+0x1906/0x1c20 net/ipv6/udp.c:1471
 inet6_sendmsg+0x6d/0x90 net/ipv6/af_inet6.c:576
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311
 __sys_sendmmsg+0x123/0x350 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880ba403508 of 1 bytes by interrupt on cpu 0:
 qdisc_run_begin include/net/sch_generic.h:160 [inline]
 qdisc_run include/net/pkt_sched.h:120 [inline]
 net_tx_action+0x2b1/0x6c0 net/core/dev.c:4551
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082
 do_softirq.part.0+0x6b/0x80 kernel/softirq.c:337
 do_softirq kernel/softirq.c:329 [inline]
 __local_bh_enable_ip+0x76/0x80 kernel/softirq.c:189
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:688 [inline]
 ip6_finish_output2+0x7bb/0xec0 net/ipv6/ip6_output.c:117
 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline]
 __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127
 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 ip6_local_out+0x74/0x90 net/ipv6/output_core.c:179
 ip6_send_skb+0x53/0x110 net/ipv6/ip6_output.c:1795
 udp_v6_send_skb.isra.0+0x3ec/0xa70 net/ipv6/udp.c:1173
 udpv6_sendmsg+0x1906/0x1c20 net/ipv6/udp.c:1471
 inet6_sendmsg+0x6d/0x90 net/ipv6/af_inet6.c:576
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311
 __sys_sendmmsg+0x123/0x350 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21817 Comm: syz-executor.2 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: d518d2ed86 ("net/sched: fix race between deactivation and dequeue for NOLOCK qdisc")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-08 12:21:55 -08:00
David S. Miller d31e95585c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
The only slightly tricky merge conflict was the netdevsim because the
mutex locking fix overlapped a lot of driver reload reorganization.

The rest were (relatively) trivial in nature.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-02 13:54:56 -07:00
Vincent Prince 546b85bb0a net: sch_generic: Use pfifo_fast as fallback scheduler for CAN hardware
There is networking hardware that isn't based on Ethernet for layers 1 and 2.

For example CAN.

CAN is a multi-master serial bus standard for connecting Electronic Control
Units [ECUs] also known as nodes. A frame on the CAN bus carries up to 8 bytes
of payload. Frame corruption is detected by a CRC. However frame loss due to
corruption is possible, but a quite unusual phenomenon.

While fq_codel works great for TCP/IP, it doesn't for CAN. There are a lot of
legacy protocols on top of CAN, which are not build with flow control or high
CAN frame drop rates in mind.

When using fq_codel, as soon as the queue reaches a certain delay based length,
skbs from the head of the queue are silently dropped. Silently meaning that the
user space using a send() or similar syscall doesn't get an error. However
TCP's flow control algorithm will detect dropped packages and adjust the
bandwidth accordingly.

When using fq_codel and sending raw frames over CAN, which is the common use
case, the user space thinks the package has been sent without problems, because
send() returned without an error. pfifo_fast will drop skbs, if the queue
length exceeds the maximum. But with this scheduler the skbs at the tail are
dropped, an error (-ENOBUFS) is propagated to user space. So that the user
space can slow down the package generation.

On distributions, where fq_codel is made default via CONFIG_DEFAULT_NET_SCH
during compile time, or set default during runtime with sysctl
net.core.default_qdisc (see [1]), we get a bad user experience. In my test case
with pfifo_fast, I can transfer thousands of million CAN frames without a frame
drop. On the other hand with fq_codel there is more then one lost CAN frame per
thousand frames.

As pointed out fq_codel is not suited for CAN hardware, so this patch changes
attach_one_default_qdisc() to use pfifo_fast for "ARPHRD_CAN" network devices.

During transition of a netdev from down to up state the default queuing
discipline is attached by attach_default_qdiscs() with the help of
attach_one_default_qdisc(). This patch modifies attach_one_default_qdisc() to
attach the pfifo_fast (pfifo_fast_ops) if the network device type is
"ARPHRD_CAN".

[1] https://github.com/systemd/systemd/issues/9194

Suggested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Vincent Prince <vincent.prince.fr@gmail.com>
Acked-by: Dave Taht <dave.taht@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-25 19:19:51 -07:00
Vincent Prince fa784f2ac0 net: sch_generic: Use pfifo_fast as fallback scheduler for CAN hardware
There is networking hardware that isn't based on Ethernet for layers 1 and 2.

For example CAN.

CAN is a multi-master serial bus standard for connecting Electronic Control
Units [ECUs] also known as nodes. A frame on the CAN bus carries up to 8 bytes
of payload. Frame corruption is detected by a CRC. However frame loss due to
corruption is possible, but a quite unusual phenomenon.

While fq_codel works great for TCP/IP, it doesn't for CAN. There are a lot of
legacy protocols on top of CAN, which are not build with flow control or high
CAN frame drop rates in mind.

When using fq_codel, as soon as the queue reaches a certain delay based length,
skbs from the head of the queue are silently dropped. Silently meaning that the
user space using a send() or similar syscall doesn't get an error. However
TCP's flow control algorithm will detect dropped packages and adjust the
bandwidth accordingly.

When using fq_codel and sending raw frames over CAN, which is the common use
case, the user space thinks the package has been sent without problems, because
send() returned without an error. pfifo_fast will drop skbs, if the queue
length exceeds the maximum. But with this scheduler the skbs at the tail are
dropped, an error (-ENOBUFS) is propagated to user space. So that the user
space can slow down the package generation.

On distributions, where fq_codel is made default via CONFIG_DEFAULT_NET_SCH
during compile time, or set default during runtime with sysctl
net.core.default_qdisc (see [1]), we get a bad user experience. In my test case
with pfifo_fast, I can transfer thousands of million CAN frames without a frame
drop. On the other hand with fq_codel there is more then one lost CAN frame per
thousand frames.

As pointed out fq_codel is not suited for CAN hardware, so this patch changes
attach_one_default_qdisc() to use pfifo_fast for "ARPHRD_CAN" network devices.

During transition of a netdev from down to up state the default queuing
discipline is attached by attach_default_qdiscs() with the help of
attach_one_default_qdisc(). This patch modifies attach_one_default_qdisc() to
attach the pfifo_fast (pfifo_fast_ops) if the network device type is
"ARPHRD_CAN".

[1] https://github.com/systemd/systemd/issues/9194

Signed-off-by: Vincent Prince <vincent.prince.fr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-25 16:14:05 -07:00
Taehee Yoo ab92d68fc2 net: core: add generic lockdep keys
Some interface types could be nested.
(VLAN, BONDING, TEAM, MACSEC, MACVLAN, IPVLAN, VIRT_WIFI, VXLAN, etc..)
These interface types should set lockdep class because, without lockdep
class key, lockdep always warn about unexisting circular locking.

In the current code, these interfaces have their own lockdep class keys and
these manage itself. So that there are so many duplicate code around the
/driver/net and /net/.
This patch adds new generic lockdep keys and some helper functions for it.

This patch does below changes.
a) Add lockdep class keys in struct net_device
   - qdisc_running, xmit, addr_list, qdisc_busylock
   - these keys are used as dynamic lockdep key.
b) When net_device is being allocated, lockdep keys are registered.
   - alloc_netdev_mqs()
c) When net_device is being free'd llockdep keys are unregistered.
   - free_netdev()
d) Add generic lockdep key helper function
   - netdev_register_lockdep_key()
   - netdev_unregister_lockdep_key()
   - netdev_update_lockdep_key()
e) Remove unnecessary generic lockdep macro and functions
f) Remove unnecessary lockdep code of each interfaces.

After this patch, each interface modules don't need to maintain
their lockdep keys.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-24 14:53:48 -07:00
Marc Kleine-Budde 4eab421bc3 net: sched: Avoid using yield() in a busy waiting loop
With threaded interrupts enabled, the interrupt thread runs as SCHED_RR
with priority 50. If a user application with a higher priority preempts
the interrupt thread and tries to shutdown the network interface then it
will loop forever. The kernel will spin in the loop waiting for the
device to become idle and the scheduler will never consider the
interrupt thread because its priority is lower.

Avoid the problem by sleeping for a jiffy giving other tasks,
including the interrupt thread, a chance to run and make progress.

In the original thread it has been suggested to use wait_event() and
properly waiting for the state to occur. DaveM explained that this would
require to add expensive checks in the fast paths of packet processing.

Link: https://lkml.kernel.org/r/1393976987-23555-1-git-send-email-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
[bigeasy: Rewrite commit message, add comment, use
          schedule_timeout_uninterruptible()]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-17 15:33:03 -04:00
Eric Dumazet b60fa1c5d0 net_sched: remove need_resched() from qdisc_run()
The introduction of this schedule point was done in commit
2ba2506ca7 ("[NET]: Add preemption point in qdisc_run")
at a time the loop was not bounded.

Then later in commit d5b8aa1d24 ("net_sched: fix dequeuer fairness")
we added a limit on the number of packets.

Now is the time to remove the schedule point, since the default
limit of 64 packets matches the number of packets a typical NAPI
poll can process in a row.

This solves a latency problem for most TCP receivers under moderate load :

1) host receives a packet.
   NET_RX_SOFTIRQ is raised by NIC hard IRQ handler

2) __do_softirq() does its first loop, handling NET_RX_SOFTIRQ
   and calling the driver napi->loop() function

3) TCP stores the skb in socket receive queue:

4) TCP calls sk->sk_data_ready() and wakeups a user thread
   waiting for EPOLLIN (as a result, need_resched() might now be true)

5) TCP cooks an ACK and sends it.

6) qdisc_run() processes one packet from qdisc, and sees need_resched(),
   this raises NET_TX_SOFTIRQ (even if there are no more packets in
   the qdisc)

Then we go back to the __do_softirq() in 2), and we see that new
softirqs were raised. Since need_resched() is true, we end up waking
ksoftirqd in this path :

    if (pending) {
            if (time_before(jiffies, end) && !need_resched() &&
                --max_restart)
                    goto restart;

            wakeup_softirqd();
    }

So we have many wakeups of ksoftirqd kernel threads,
and more calls to qdisc_run() with associated lock overhead.

Note that another way to solve the issue would be to change TCP
to first send the ACK packet, then signal the EPOLLIN,
but this changes P99 latencies, as sending the ACK packet
can add a long delay.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-02 14:26:33 -07:00
Cong Wang 6efb971ba8 net_sched: let qdisc_put() accept NULL pointer
When tcf_block_get() fails in sfb_init(), q->qdisc is still a NULL
pointer which leads to a crash in sfb_destroy(). Similar for
sch_dsmark.

Instead of fixing each separately, Linus suggested to just accept
NULL pointer in qdisc_put(), which would make callers easier.

(For sch_dsmark, the bug probably exists long before commit
6529eaba33f0.)

Fixes: 6529eaba33 ("net: sched: introduce tcf block infractructure")
Reported-by: syzbot+d5870a903591faaca4ae@syzkaller.appspotmail.com
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-15 20:54:14 +02:00
Eric Dumazet b88dd52c62 net: sched: fix reordering issues
Whenever MQ is not used on a multiqueue device, we experience
serious reordering problems. Bisection found the cited
commit.

The issue can be described this way :

- A single qdisc hierarchy is shared by all transmit queues.
  (eg : tc qdisc replace dev eth0 root fq_codel)

- When/if try_bulk_dequeue_skb_slow() dequeues a packet targetting
  a different transmit queue than the one used to build a packet train,
  we stop building the current list and save the 'bad' skb (P1) in a
  special queue. (bad_txq)

- When dequeue_skb() calls qdisc_dequeue_skb_bad_txq() and finds this
  skb (P1), it checks if the associated transmit queues is still in frozen
  state. If the queue is still blocked (by BQL or NIC tx ring full),
  we leave the skb in bad_txq and return NULL.

- dequeue_skb() calls q->dequeue() to get another packet (P2)

  The other packet can target the problematic queue (that we found
  in frozen state for the bad_txq packet), but another cpu just ran
  TX completion and made room in the txq that is now ready to accept
  new packets.

- Packet P2 is sent while P1 is still held in bad_txq, P1 might be sent
  at next round. In practice P2 is the lead of a big packet train
  (P2,P3,P4 ...) filling the BQL budget and delaying P1 by many packets :/

To solve this problem, we have to block the dequeue process as long
as the first packet in bad_txq can not be sent. Reordering issues
disappear and no side effects have been seen.

Fixes: a53851e2c3 ("net: sched: explicit locking in gso_cpu fallback")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-06 15:12:33 +02:00
Davide Caratti 092e22e586 net/sched: pfifo_fast: fix wrong dereference in pfifo_fast_enqueue
Now that 'TCQ_F_CPUSTATS' bit can be cleared, depending on the value of
'TCQ_F_NOLOCK' bit in the parent qdisc, we can't assume anymore that
per-cpu counters are there in the error path of skb_array_produce().
Otherwise, the following splat can be seen:

 Unable to handle kernel paging request at virtual address 0000600dea430008
 Mem abort info:
   ESR = 0x96000005
   Exception class = DABT (current EL), IL = 32 bits
   SET = 0, FnV = 0
   EA = 0, S1PTW = 0
 Data abort info:
   ISV = 0, ISS = 0x00000005
   CM = 0, WnR = 0
 user pgtable: 64k pages, 48-bit VAs, pgdp = 000000007b97530e
 [0000600dea430008] pgd=0000000000000000, pud=0000000000000000
 Internal error: Oops: 96000005 [#1] SMP
[...]
 pstate: 10000005 (nzcV daif -PAN -UAO)
 pc : pfifo_fast_enqueue+0x524/0x6e8
 lr : pfifo_fast_enqueue+0x46c/0x6e8
 sp : ffff800d39376fe0
 x29: ffff800d39376fe0 x28: 1ffff001a07d1e40
 x27: ffff800d03e8f188 x26: ffff800d03e8f200
 x25: 0000000000000062 x24: ffff800d393772f0
 x23: 0000000000000000 x22: 0000000000000403
 x21: ffff800cca569a00 x20: ffff800d03e8ee00
 x19: ffff800cca569a10 x18: 00000000000000bf
 x17: 0000000000000000 x16: 0000000000000000
 x15: 0000000000000000 x14: ffff1001a726edd0
 x13: 1fffe4000276a9a4 x12: 0000000000000000
 x11: dfff200000000000 x10: ffff800d03e8f1a0
 x9 : 0000000000000003 x8 : 0000000000000000
 x7 : 00000000f1f1f1f1 x6 : ffff1001a726edea
 x5 : ffff800cca56a53c x4 : 1ffff001bf9a8003
 x3 : 1ffff001bf9a8003 x2 : 1ffff001a07d1dcb
 x1 : 0000600dea430000 x0 : 0000600dea430008
 Process ping (pid: 6067, stack limit = 0x00000000dc0aa557)
 Call trace:
  pfifo_fast_enqueue+0x524/0x6e8
  htb_enqueue+0x660/0x10e0 [sch_htb]
  __dev_queue_xmit+0x123c/0x2de0
  dev_queue_xmit+0x24/0x30
  ip_finish_output2+0xc48/0x1720
  ip_finish_output+0x548/0x9d8
  ip_output+0x334/0x788
  ip_local_out+0x90/0x138
  ip_send_skb+0x44/0x1d0
  ip_push_pending_frames+0x5c/0x78
  raw_sendmsg+0xed8/0x28d0
  inet_sendmsg+0xc4/0x5c0
  sock_sendmsg+0xac/0x108
  __sys_sendto+0x1ac/0x2a0
  __arm64_sys_sendto+0xc4/0x138
  el0_svc_handler+0x13c/0x298
  el0_svc+0x8/0xc
 Code: f9402e80 d538d081 91002000 8b010000 (885f7c03)

Fix this by testing the value of 'TCQ_F_CPUSTATS' bit in 'qdisc->flags',
before dereferencing 'qdisc->cpu_qstats'.

Fixes: 8a53e616de ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too")
CC: Paolo Abeni <pabeni@redhat.com>
CC: Stefano Brivio <sbrivio@redhat.com>
Reported-by: Li Shuang <shuali@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-28 15:57:38 -07:00
Davide Caratti 04d37cf46a net/sched: pfifo_fast: fix wrong dereference when qdisc is reset
Now that 'TCQ_F_CPUSTATS' bit can be cleared, depending on the value of
'TCQ_F_NOLOCK' bit in the parent qdisc, we need to be sure that per-cpu
counters are present when 'reset()' is called for pfifo_fast qdiscs.
Otherwise, the following script:

 # tc q a dev lo handle 1: root htb default 100
 # tc c a dev lo parent 1: classid 1:100 htb \
 > rate 95Mbit ceil 100Mbit burst 64k
 [...]
 # tc f a dev lo parent 1: protocol arp basic classid 1:100
 [...]
 # tc q a dev lo parent 1:100 handle 100: pfifo_fast
 [...]
 # tc q d dev lo root

can generate the following splat:

 Unable to handle kernel paging request at virtual address dfff2c01bd148000
 Mem abort info:
   ESR = 0x96000004
   Exception class = DABT (current EL), IL = 32 bits
   SET = 0, FnV = 0
   EA = 0, S1PTW = 0
 Data abort info:
   ISV = 0, ISS = 0x00000004
   CM = 0, WnR = 0
 [dfff2c01bd148000] address between user and kernel address ranges
 Internal error: Oops: 96000004 [#1] SMP
 [...]
 pstate: 80000005 (Nzcv daif -PAN -UAO)
 pc : pfifo_fast_reset+0x280/0x4d8
 lr : pfifo_fast_reset+0x21c/0x4d8
 sp : ffff800d09676fa0
 x29: ffff800d09676fa0 x28: ffff200012ee22e4
 x27: dfff200000000000 x26: 0000000000000000
 x25: ffff800ca0799958 x24: ffff1001940f332b
 x23: 0000000000000007 x22: ffff200012ee1ab8
 x21: 0000600de8a40000 x20: 0000000000000000
 x19: ffff800ca0799900 x18: 0000000000000000
 x17: 0000000000000002 x16: 0000000000000000
 x15: 0000000000000000 x14: 0000000000000000
 x13: 0000000000000000 x12: ffff1001b922e6e2
 x11: 1ffff001b922e6e1 x10: 0000000000000000
 x9 : 1ffff001b922e6e1 x8 : dfff200000000000
 x7 : 0000000000000000 x6 : 0000000000000000
 x5 : 1fffe400025dc45c x4 : 1fffe400025dc357
 x3 : 00000c01bd148000 x2 : 0000600de8a40000
 x1 : 0000000000000007 x0 : 0000600de8a40004
 Call trace:
  pfifo_fast_reset+0x280/0x4d8
  qdisc_reset+0x6c/0x370
  htb_reset+0x150/0x3b8 [sch_htb]
  qdisc_reset+0x6c/0x370
  dev_deactivate_queue.constprop.5+0xe0/0x1a8
  dev_deactivate_many+0xd8/0x908
  dev_deactivate+0xe4/0x190
  qdisc_graft+0x88c/0xbd0
  tc_get_qdisc+0x418/0x8a8
  rtnetlink_rcv_msg+0x3a8/0xa78
  netlink_rcv_skb+0x18c/0x328
  rtnetlink_rcv+0x28/0x38
  netlink_unicast+0x3c4/0x538
  netlink_sendmsg+0x538/0x9a0
  sock_sendmsg+0xac/0xf8
  ___sys_sendmsg+0x53c/0x658
  __sys_sendmsg+0xc8/0x140
  __arm64_sys_sendmsg+0x74/0xa8
  el0_svc_handler+0x164/0x468
  el0_svc+0x10/0x14
 Code: 910012a0 92400801 d343fc03 11000c21 (38fb6863)

Fix this by testing the value of 'TCQ_F_CPUSTATS' bit in 'qdisc->flags',
before dereferencing 'qdisc->cpu_qstats'.

Changes since v1:
 - coding style improvements, thanks to Stefano Brivio

Fixes: 8a53e616de ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too")
CC: Paolo Abeni <pabeni@redhat.com>
Reported-by: Li Shuang <shuali@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-28 14:45:46 -07:00
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00
Cong Wang 141b6b2ad7 net: add a generic tracepoint for TX queue timeout
Although devlink health report does a nice job on reporting TX
timeout and other NIC errors, unfortunately it requires drivers
to support it but currently only mlx5 has implemented it.
Before other drivers could catch up, it is useful to have a
generic tracepoint to monitor this kind of TX timeout. We have
been suffering TX timeout with different drivers, we plan to
start to monitor it with rasdaemon which just needs a new tracepoint.

Sample output:

  ksoftirqd/1-16    [001] ..s2   144.043173: net_dev_xmit_timeout: dev=ens3 driver=e1000 queue=0

Cc: Eran Ben Elisha <eranbe@mellanox.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-04 00:41:41 -04:00
Paolo Abeni 73eb628ddf Revert: "net: sched: put back q.qlen into a single location"
This revert commit 46b1c18f9d ("net: sched: put back q.qlen into
a single location").
After the previous patch, when a NOLOCK qdisc is enslaved to a
locking qdisc it switches to global stats accounting. As a consequence,
when a classful qdisc accesses directly a child qdisc's qlen, such
qdisc is not doing per CPU accounting and qlen value is consistent.

In the control path nobody uses directly qlen since commit
e5f0e8f8e4 ("net: sched: introduce and use qdisc tree flush/purge
helpers"), so we can remove the contented atomic ops from the
datapath.

v1 -> v2:
 - complete the qdisc_qstats_atomic_qlen_dec() ->
   qdisc_qstats_cpu_qlen_dec() replacement, fix build issue
 - more descriptive commit message

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-10 12:20:46 -07:00
Paolo Abeni 8a53e616de net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too
Since stats updating is always consistent with TCQ_F_CPUSTATS flag,
we can disable it at qdisc creation time flipping such bit.

In my experiments, if the NOLOCK flag is cleared, per CPU stats
accounting does not give any measurable performance gain, but it
waste some memory.

Let's clear TCQ_F_CPUSTATS together with NOLOCK, when enslaving
a NOLOCK qdisc to 'lock' one.

Use stats update helper inside pfifo_fast, to cope correctly with
TCQ_F_CPUSTATS flag change.

As a side effect, q.qlen value for any child qdiscs is always
consistent for all lock classfull qdiscs.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-10 12:20:46 -07:00
Paolo Abeni 9c01c9f1f2 net: sched: always do stats accounting according to TCQ_F_CPUSTATS
The core sched implementation checks independently for NOLOCK flag
to acquire/release the root spin lock and for qdisc_is_percpu_stats()
to account per CPU values in many places.

This change update the last few places checking the TCQ_F_NOLOCK to
do per CPU stats accounting according to qdisc_is_percpu_stats()
value.

The above allows to clean dev_requeue_skb() implementation a bit
and makes stats update always consistent with a single flag.

v1 -> v2:
 - do not move qdisc_is_empty definition, fix build issue

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-10 12:20:46 -07:00