This changes the handling of an unlikely condition to not stop dequeuing
if taprio failed to dequeue the peeked skb in taprio_dequeue().
I've no idea when this can happen, but the only side effect seems to be
that the atomic_sub_return() call right above will have consumed some
budget. This isn't a big deal, since either that made us remain without
any budget (and therefore, we'd exit on the next peeked skb anyway), or
we could send some packets from other TXQs.
I'm making this change because in a future patch I'll be refactoring the
dequeue procedure to simplify it, and this corner case will have to go
away.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
There isn't any code in the network stack which calls taprio_peek().
We only see qdisc->ops->peek() being called on child qdiscs of other
classful qdiscs, never from the generic qdisc code. Whereas taprio is
never a child qdisc, it is always root.
This snippet of a comment from qdisc_peek_dequeued() seems to confirm:
/* we can reuse ->gso_skb because peek isn't called for root qdiscs */
Since I've been known to be wrong many times though, I'm not completely
removing it, but leaving a stub function in place which emits a warning.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are 2 classes of in-tree drivers currently:
- those who act upon struct tc_taprio_sched_entry :: gate_mask as if it
holds a bit mask of TXQs
- those who act upon the gate_mask as if it holds a bit mask of TCs
When it comes to the standard, IEEE 802.1Q-2018 does say this in the
second paragraph of section 8.6.8.4 Enhancements for scheduled traffic:
| A gate control list associated with each Port contains an ordered list
| of gate operations. Each gate operation changes the transmission gate
| state for the gate associated with each of the Port's traffic class
| queues and allows associated control operations to be scheduled.
In typically obtuse language, it refers to a "traffic class queue"
rather than a "traffic class" or a "queue". But careful reading of
802.1Q clarifies that "traffic class" and "queue" are in fact
synonymous (see 8.6.6 Queuing frames):
| A queue in this context is not necessarily a single FIFO data structure.
| A queue is a record of all frames of a given traffic class awaiting
| transmission on a given Bridge Port. The structure of this record is not
| specified.
i.o.w. their definition of "queue" isn't the Linux TX queue.
The gate_mask really is input into taprio via its UAPI as a mask of
traffic classes, but taprio_sched_to_offload() converts it into a TXQ
mask.
The breakdown of drivers which handle TC_SETUP_QDISC_TAPRIO is:
- hellcreek, felix, sja1105: these are DSA switches, it's not even very
clear what TXQs correspond to, other than purely software constructs.
Only the mqprio configuration with 8 TCs and 1 TXQ per TC makes sense.
So it's fine to convert these to a gate mask per TC.
- enetc: I have the hardware and can confirm that the gate mask is per
TC, and affects all TXQs (BD rings) configured for that priority.
- igc: in igc_save_qbv_schedule(), the gate_mask is clearly interpreted
to be per-TXQ.
- tsnep: Gerhard Engleder clarifies that even though this hardware
supports at most 1 TXQ per TC, the TXQ indices may be different from
the TC values themselves, and it is the TXQ indices that matter to
this hardware. So keep it per-TXQ as well.
- stmmac: I have a GMAC datasheet, and in the EST section it does
specify that the gate events are per TXQ rather than per TC.
- lan966x: again, this is a switch, and while not a DSA one, the way in
which it implements lan966x_mqprio_add() - by only allowing num_tc ==
NUM_PRIO_QUEUES (8) - makes it clear to me that TXQs are a purely
software construct here as well. They seem to map 1:1 with TCs.
- am65_cpsw: from looking at am65_cpsw_est_set_sched_cmds(), I get the
impression that the fetch_allow variable is treated like a prio_mask.
This definitely sounds closer to a per-TC gate mask rather than a
per-TXQ one, and TI documentation does seem to recomment an identity
mapping between TCs and TXQs. However, Roger Quadros would like to do
some testing before making changes, so I'm leaving this driver to
operate as it did before, for now. Link with more details at the end.
Based on this breakdown, we have 5 drivers with a gate mask per TC and
4 with a gate mask per TXQ. So let's make the gate mask per TXQ the
opt-in and the gate mask per TC the default.
Benefit from the TC_QUERY_CAPS feature that Jakub suggested we add, and
query the device driver before calling the proper ndo_setup_tc(), and
figure out if it expects one or the other format.
Link: https://patchwork.kernel.org/project/netdevbpf/patch/20230202003621.2679603-15-vladimir.oltean@nxp.com/#25193204
Cc: Horatiu Vultur <horatiu.vultur@microchip.com>
Cc: Siddharth Vadapalli <s-vadapalli@ti.com>
Cc: Roger Quadros <rogerq@kernel.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Kurt Kanzenbach <kurt@linutronix.de> # hellcreek
Reviewed-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The taprio qdisc does not currently pass the mqprio queue configuration
down to the offloading device driver. So the driver cannot act upon the
TXQ counts/offsets per TC, or upon the prio->tc map. It was probably
assumed that the driver only wants to offload num_tc (see
TC_MQPRIO_HW_OFFLOAD_TCS), which it can get from netdev_get_num_tc(),
but there's clearly more to the mqprio configuration than that.
I've considered 2 mechanisms to remedy that. First is to pass a struct
tc_mqprio_qopt_offload as part of the tc_taprio_qopt_offload. The second
is to make taprio actually call TC_SETUP_QDISC_MQPRIO, *in addition to*
TC_SETUP_QDISC_TAPRIO.
The difference is that in the first case, existing drivers (offloading
or not) all ignore taprio's mqprio portion currently, whereas in the
second case, we could control whether to call TC_SETUP_QDISC_MQPRIO,
based on a new capability. The question is which approach would be
better.
I'm afraid that calling TC_SETUP_QDISC_MQPRIO unconditionally (not based
on a taprio capability bit) would risk introducing regressions. For
example, taprio doesn't populate (or validate) qopt->hw, as well as
mqprio.flags, mqprio.shaper, mqprio.min_rate, mqprio.max_rate.
In comparison, adding a capability is functionally equivalent to just
passing the mqprio in a way that drivers can ignore it, except it's
slightly more complicated to use it (need to set the capability).
Ultimately, what made me go for the "mqprio in taprio" variant was that
it's easier for offloading drivers to interpret the mqprio qopt slightly
differently when it comes from taprio vs when it comes from mqprio,
should that ever become necessary.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The taprio qdisc will need to reconstruct a struct tc_mqprio_qopt from
netdev settings once more in a future patch, but this code was already
written twice, once in taprio and once in mqprio.
Refactor the code to a helper in the common mqprio library.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a lot of code in taprio which is "borrowed" from mqprio.
It makes sense to put a stop to the "borrowing" and start actually
reusing code.
Because taprio and mqprio are built as part of different kernel modules,
code reuse can only take place either by writing it as static inline
(limiting), putting it in sch_generic.o (not generic enough), or
creating a third auto-selectable kernel module which only holds library
code. I opted for the third variant.
In a previous change, mqprio gained support for reverse TC:TXQ mappings,
something which taprio still denies. Make taprio use the same validation
logic so that it supports this configuration as well.
The taprio code didn't enforce TXQ overlaps in txtime-assist mode and
that looks intentional, even if I've no idea why that might be. Preserve
that, but add a comment.
There isn't any dedicated MAINTAINERS entry for mqprio, so nothing to
update there.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
syzbot reported a nasty crash [1] in net_tx_action() which
made little sense until we got a repro.
This repro installs a taprio qdisc, but providing an
invalid TCA_RATE attribute.
qdisc_create() has to destroy the just initialized
taprio qdisc, and taprio_destroy() is called.
However, the hrtimer used by taprio had already fired,
therefore advance_sched() called __netif_schedule().
Then net_tx_action was trying to use a destroyed qdisc.
We can not undo the __netif_schedule(), so we must wait
until one cpu serviced the qdisc before we can proceed.
Many thanks to Alexander Potapenko for his help.
[1]
BUG: KMSAN: uninit-value in queued_spin_trylock include/asm-generic/qspinlock.h:94 [inline]
BUG: KMSAN: uninit-value in do_raw_spin_trylock include/linux/spinlock.h:191 [inline]
BUG: KMSAN: uninit-value in __raw_spin_trylock include/linux/spinlock_api_smp.h:89 [inline]
BUG: KMSAN: uninit-value in _raw_spin_trylock+0x92/0xa0 kernel/locking/spinlock.c:138
queued_spin_trylock include/asm-generic/qspinlock.h:94 [inline]
do_raw_spin_trylock include/linux/spinlock.h:191 [inline]
__raw_spin_trylock include/linux/spinlock_api_smp.h:89 [inline]
_raw_spin_trylock+0x92/0xa0 kernel/locking/spinlock.c:138
spin_trylock include/linux/spinlock.h:359 [inline]
qdisc_run_begin include/net/sch_generic.h:187 [inline]
qdisc_run+0xee/0x540 include/net/pkt_sched.h:125
net_tx_action+0x77c/0x9a0 net/core/dev.c:5086
__do_softirq+0x1cc/0x7fb kernel/softirq.c:571
run_ksoftirqd+0x2c/0x50 kernel/softirq.c:934
smpboot_thread_fn+0x554/0x9f0 kernel/smpboot.c:164
kthread+0x31b/0x430 kernel/kthread.c:376
ret_from_fork+0x1f/0x30
Uninit was created at:
slab_post_alloc_hook mm/slab.h:732 [inline]
slab_alloc_node mm/slub.c:3258 [inline]
__kmalloc_node_track_caller+0x814/0x1250 mm/slub.c:4970
kmalloc_reserve net/core/skbuff.c:358 [inline]
__alloc_skb+0x346/0xcf0 net/core/skbuff.c:430
alloc_skb include/linux/skbuff.h:1257 [inline]
nlmsg_new include/net/netlink.h:953 [inline]
netlink_ack+0x5f3/0x12b0 net/netlink/af_netlink.c:2436
netlink_rcv_skb+0x55d/0x6c0 net/netlink/af_netlink.c:2507
rtnetlink_rcv+0x30/0x40 net/core/rtnetlink.c:6108
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0xf3b/0x1270 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x1288/0x1440 net/netlink/af_netlink.c:1921
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
____sys_sendmsg+0xabc/0xe90 net/socket.c:2482
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2536
__sys_sendmsg net/socket.c:2565 [inline]
__do_sys_sendmsg net/socket.c:2574 [inline]
__se_sys_sendmsg net/socket.c:2572 [inline]
__x64_sys_sendmsg+0x367/0x540 net/socket.c:2572
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
CPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 6.0.0-rc2-syzkaller-47461-gac3859c02d7f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Fixes: 5a781ccbd1 ("tc: Add support for configuring the taprio scheduler")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
taprio_attach() has this logic at the end, which should have been
removed with the blamed patch (which is now being reverted):
/* access to the child qdiscs is not needed in offload mode */
if (FULL_OFFLOAD_IS_ENABLED(q->flags)) {
kfree(q->qdiscs);
q->qdiscs = NULL;
}
because otherwise, we make use of q->qdiscs[] even after this array was
deallocated, namely in taprio_leaf(). Therefore, whenever one would try
to attach a valid child qdisc to a fully offloaded taprio root, one
would immediately dereference a NULL pointer.
$ tc qdisc replace dev eno0 handle 8001: parent root taprio \
num_tc 8 \
map 0 1 2 3 4 5 6 7 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
max-sdu 0 0 0 0 0 200 0 0 \
base-time 200 \
sched-entry S 80 20000 \
sched-entry S a0 20000 \
sched-entry S 5f 60000 \
flags 2
$ max_frame_size=1500
$ data_rate_kbps=20000
$ port_transmit_rate_kbps=1000000
$ idleslope=$data_rate_kbps
$ sendslope=$(($idleslope - $port_transmit_rate_kbps))
$ locredit=$(($max_frame_size * $sendslope / $port_transmit_rate_kbps))
$ hicredit=$(($max_frame_size * $idleslope / $port_transmit_rate_kbps))
$ tc qdisc replace dev eno0 parent 8001:7 cbs \
idleslope $idleslope \
sendslope $sendslope \
hicredit $hicredit \
locredit $locredit \
offload 0
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030
pc : taprio_leaf+0x28/0x40
lr : qdisc_leaf+0x3c/0x60
Call trace:
taprio_leaf+0x28/0x40
tc_modify_qdisc+0xf0/0x72c
rtnetlink_rcv_msg+0x12c/0x390
netlink_rcv_skb+0x5c/0x130
rtnetlink_rcv+0x1c/0x2c
The solution is not as obvious as the problem. The code which deallocates
q->qdiscs[] is in fact copied and pasted from mqprio, which also
deallocates the array in mqprio_attach() and never uses it afterwards.
Therefore, the identical cleanup logic of priv->qdiscs[] that
mqprio_destroy() has is deceptive because it will never take place at
qdisc_destroy() time, but just at raw ops->destroy() time (otherwise
said, priv->qdiscs[] do not last for the entire lifetime of the mqprio
root), but rather, this is just the twisted way in which the Qdisc API
understands error path cleanup should be done (Qdisc_ops :: destroy() is
called even when Qdisc_ops :: init() never succeeded).
Side note, in fact this is also what the comment in mqprio_init() says:
/* pre-allocate qdisc, attachment can't fail */
Or reworded, mqprio's priv->qdiscs[] scheme is only meant to serve as
data passing between Qdisc_ops :: init() and Qdisc_ops :: attach().
[ this comment was also copied and pasted into the initial taprio
commit, even though taprio_attach() came way later ]
The problem is that taprio also makes extensive use of the q->qdiscs[]
array in the software fast path (taprio_enqueue() and taprio_dequeue()),
but it does not keep a reference of its own on q->qdiscs[i] (you'd think
that since it creates these Qdiscs, it holds the reference, but nope,
this is not completely true).
To understand the difference between taprio_destroy() and mqprio_destroy()
one must look before commit 13511704f8 ("net: taprio offload: enforce
qdisc to netdev queue mapping"), because that just muddied the waters.
In the "original" taprio design, taprio always attached itself (the root
Qdisc) to all netdev TX queues, so that dev_qdisc_enqueue() would go
through taprio_enqueue().
It also called qdisc_refcount_inc() on itself for as many times as there
were netdev TX queues, in order to counter-balance what tc_get_qdisc()
does when destroying a Qdisc (simplified for brevity below):
if (n->nlmsg_type == RTM_DELQDISC)
err = qdisc_graft(dev, parent=NULL, new=NULL, q, extack);
qdisc_graft(where "new" is NULL so this deletes the Qdisc):
for (i = 0; i < num_q; i++) {
struct netdev_queue *dev_queue;
dev_queue = netdev_get_tx_queue(dev, i);
old = dev_graft_qdisc(dev_queue, new);
if (new && i > 0)
qdisc_refcount_inc(new);
qdisc_put(old);
~~~~~~~~~~~~~~
this decrements taprio's refcount once for each TX queue
}
notify_and_destroy(net, skb, n, classid,
rtnl_dereference(dev->qdisc), new);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
and this finally decrements it to zero,
making qdisc_put() call qdisc_destroy()
The q->qdiscs[] created using qdisc_create_dflt() (or their
replacements, if taprio_graft() was ever to get called) were then
privately freed by taprio_destroy().
This is still what is happening after commit 13511704f8 ("net: taprio
offload: enforce qdisc to netdev queue mapping"), but only for software
mode.
In full offload mode, the per-txq "qdisc_put(old)" calls from
qdisc_graft() now deallocate the child Qdiscs rather than decrement
taprio's refcount. So when notify_and_destroy(taprio) finally calls
taprio_destroy(), the difference is that the child Qdiscs were already
deallocated.
And this is exactly why the taprio_attach() comment "access to the child
qdiscs is not needed in offload mode" is deceptive too. Not only the
q->qdiscs[] array is not needed, but it is also necessary to get rid of
it as soon as possible, because otherwise, we will also call qdisc_put()
on the child Qdiscs in qdisc_destroy() -> taprio_destroy(), and this
will cause a nasty use-after-free/refcount-saturate/whatever.
In short, the problem is that since the blamed commit, taprio_leaf()
needs q->qdiscs[] to not be freed by taprio_attach(), while qdisc_destroy()
-> taprio_destroy() does need q->qdiscs[] to be freed by taprio_attach()
for full offload. Fixing one problem triggers the other.
All of this can be solved by making taprio keep its q->qdiscs[i] with a
refcount elevated at 2 (in offloaded mode where they are attached to the
netdev TX queues), both in taprio_attach() and in taprio_graft(). The
generic qdisc_graft() would just decrement the child qdiscs' refcounts
to 1, and taprio_destroy() would give them the final coup de grace.
However the rabbit hole of changes is getting quite deep, and the
complexity increases. The blamed commit was supposed to be a bug fix in
the first place, and the bug it addressed is not so significant so as to
justify further rework in stable trees. So I'd rather just revert it.
I don't know enough about multi-queue Qdisc design to make a proper
judgement right now regarding what is/isn't idiomatic use of Qdisc
concepts in taprio. I will try to study the problem more and come with a
different solution in net-next.
Fixes: 1461d212ab ("net/sched: taprio: make qdisc_leaf() see the per-netdev-queue pfifo child qdiscs")
Reported-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Reported-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Link: https://lore.kernel.org/r/20221004220100.1650558-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
IEEE 802.1Q clause 12.29.1.1 "The queueMaxSDUTable structure and data
types" and 8.6.8.4 "Enhancements for scheduled traffic" talk about the
existence of a per traffic class limitation of maximum frame sizes, with
a fallback on the port-based MTU.
As far as I am able to understand, the 802.1Q Service Data Unit (SDU)
represents the MAC Service Data Unit (MSDU, i.e. L2 payload), excluding
any number of prepended VLAN headers which may be otherwise present in
the MSDU. Therefore, the queueMaxSDU is directly comparable to the
device MTU (1500 means L2 payload sizes are accepted, or frame sizes of
1518 octets, or 1522 plus one VLAN header). Drivers which offload this
are directly responsible of translating into other units of measurement.
To keep the fast path checks optimized, we keep 2 arrays in the qdisc,
one for max_sdu translated into frame length (so that it's comparable to
skb->len), and another for offloading and for dumping back to the user.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
taprio_dev_notifier() subscribes to netdev state changes in order to
determine whether interfaces which have a taprio root qdisc have changed
their link speed, so the internal calculations can be adapted properly.
The 'qdev' temporary variable serves no purpose, because we just use it
only once, and can just as well use qdisc_dev(q->root) directly (or the
"dev" that comes from the netdev notifier; this is because qdev is only
interesting if it was the subject of the state change, _and_ its root
qdisc belongs in the taprio list).
The 'found' variable also doesn't really serve too much of a purpose
either; we can just call taprio_set_picos_per_byte() within the loop,
and exit immediately afterwards.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Link: https://lore.kernel.org/r/20220923145921.3038904-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
use tc_qdisc_stats_dump() in qdisc.
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Tested-by: Victor Nogueira <victor@mojatatu.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The 3 functions that want access to the taprio_list:
taprio_dev_notifier(), taprio_destroy() and taprio_init() are all called
with the rtnl_mutex held, therefore implicitly serialized with respect
to each other. A spin lock serves no purpose.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Link: https://lore.kernel.org/r/20220921095632.1379251-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The WARN_ON_ONCE() checks introduced in commit 13511704f8 ("net:
taprio offload: enforce qdisc to netdev queue mapping") take a small
toll on performance, but otherwise, the conditions are never expected to
happen. Replace them with comments, such that the information is still
conveyed to developers.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stop contributing to the proverbial user unfriendliness of tc, and tell
the user what is wrong wherever possible.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Since commit 13511704f8 ("net: taprio offload: enforce qdisc to netdev
queue mapping"), taprio_dequeue_soft() and taprio_peek_soft() are de
facto the only implementations for Qdisc_ops :: dequeue and Qdisc_ops ::
peek that taprio provides.
This is because in full offload mode, __dev_queue_xmit() will select a
txq->qdisc which is never root taprio qdisc. So if nothing is enqueued
in the root qdisc, it will never be run and nothing will get dequeued
from it.
Therefore, we can remove the private indirection from taprio, and always
point Qdisc_ops :: dequeue to taprio_dequeue_soft (now simply named
taprio_dequeue) and Qdisc_ops :: peek to taprio_peek_soft (now simply
named taprio_peek).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Since commit 13511704f8 ("net: taprio offload: enforce qdisc to netdev
queue mapping"), __dev_queue_xmit() will select a txq->qdisc for the
full offload case of taprio which isn't the root taprio qdisc, so
qdisc enqueues will never pass through taprio_enqueue().
That commit already introduced one safety precaution check for
FULL_OFFLOAD_IS_ENABLED(); a second one is really not needed, so
simplify the conditional for entering into the GSO segmentation logic.
Also reword the comment a little, to appear more natural after the code
change.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Sparse complains that taprio_destroy() dereferences q->oper_sched and
q->admin_sched without rcu_dereference(), since they are marked as __rcu
in the taprio private structure.
1671:28: warning: incorrect type in argument 1 (different address spaces)
1671:28: expected struct callback_head *head
1671:28: got struct callback_head [noderef] __rcu *
1674:28: warning: incorrect type in argument 1 (different address spaces)
1674:28: expected struct callback_head *head
1674:28: got struct callback_head [noderef] __rcu *
To silence that build warning, do actually use rtnl_dereference(), since
we know the rtnl_mutex is held at the time of q->destroy().
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Since the writer-side lock is taken here, we do not need to open an RCU
read-side critical section, instead we can use rtnl_dereference() to
tell lockdep we are serialized with concurrent writes.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The locking in taprio_offload_config_changed() is wrong (but also
inconsequentially so). The current_entry_lock does not serialize changes
to the admin and oper schedules, only to the current entry. In fact, the
rtnl_mutex does that, and that is taken at the time when taprio_change()
is called.
Replace the rcu_dereference_protected() method with the proper RCU
annotation, and drop the unnecessary spin lock.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
taprio can only operate as root qdisc, and to that end, there exists the
following check in taprio_init(), just as in mqprio:
if (sch->parent != TC_H_ROOT)
return -EOPNOTSUPP;
And indeed, when we try to attach taprio to an mqprio child, it fails as
expected:
$ tc qdisc add dev swp0 root handle 1: mqprio num_tc 8 \
map 0 1 2 3 4 5 6 7 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 hw 0
$ tc qdisc replace dev swp0 parent 1:2 taprio num_tc 8 \
map 0 1 2 3 4 5 6 7 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
base-time 0 sched-entry S 0x7f 990000 sched-entry S 0x80 100000 \
flags 0x0 clockid CLOCK_TAI
Error: sch_taprio: Can only be attached as root qdisc.
(extack message added by me)
But when we try to attach a taprio child to a taprio root qdisc,
surprisingly it doesn't fail:
$ tc qdisc replace dev swp0 root handle 1: taprio num_tc 8 \
map 0 1 2 3 4 5 6 7 queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
base-time 0 sched-entry S 0x7f 990000 sched-entry S 0x80 100000 \
flags 0x0 clockid CLOCK_TAI
$ tc qdisc replace dev swp0 parent 1:2 taprio num_tc 8 \
map 0 1 2 3 4 5 6 7 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
base-time 0 sched-entry S 0x7f 990000 sched-entry S 0x80 100000 \
flags 0x0 clockid CLOCK_TAI
This is because tc_modify_qdisc() behaves differently when mqprio is
root, vs when taprio is root.
In the mqprio case, it finds the parent qdisc through
p = qdisc_lookup(dev, TC_H_MAJ(clid)), and then the child qdisc through
q = qdisc_leaf(p, clid). This leaf qdisc q has handle 0, so it is
ignored according to the comment right below ("It may be default qdisc,
ignore it"). As a result, tc_modify_qdisc() goes through the
qdisc_create() code path, and this gives taprio_init() a chance to check
for sch_parent != TC_H_ROOT and error out.
Whereas in the taprio case, the returned q = qdisc_leaf(p, clid) is
different. It is not the default qdisc created for each netdev queue
(both taprio and mqprio call qdisc_create_dflt() and keep them in
a private q->qdiscs[], or priv->qdiscs[], respectively). Instead, taprio
makes qdisc_leaf() return the _root_ qdisc, aka itself.
When taprio does that, tc_modify_qdisc() goes through the qdisc_change()
code path, because the qdisc layer never finds out about the child qdisc
of the root. And through the ->change() ops, taprio has no reason to
check whether its parent is root or not, just through ->init(), which is
not called.
The problem is the taprio_leaf() implementation. Even though code wise,
it does the exact same thing as mqprio_leaf() which it is copied from,
it works with different input data. This is because mqprio does not
attach itself (the root) to each device TX queue, but one of the default
qdiscs from its private array.
In fact, since commit 13511704f8 ("net: taprio offload: enforce qdisc
to netdev queue mapping"), taprio does this too, but just for the full
offload case. So if we tried to attach a taprio child to a fully
offloaded taprio root qdisc, it would properly fail too; just not to a
software root taprio.
To fix the problem, stop looking at the Qdisc that's attached to the TX
queue, and instead, always return the default qdiscs that we've
allocated (and to which we privately enqueue and dequeue, in software
scheduling mode).
Since Qdisc_class_ops :: leaf is only called from tc_modify_qdisc(),
the risk of unforeseen side effects introduced by this change is
minimal.
Fixes: 5a781ccbd1 ("tc: Add support for configuring the taprio scheduler")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In an incredibly strange API design decision, qdisc->destroy() gets
called even if qdisc->init() never succeeded, not exclusively since
commit 87b60cfacf ("net_sched: fix error recovery at qdisc creation"),
but apparently also earlier (in the case of qdisc_create_dflt()).
The taprio qdisc does not fully acknowledge this when it attempts full
offload, because it starts off with q->flags = TAPRIO_FLAGS_INVALID in
taprio_init(), then it replaces q->flags with TCA_TAPRIO_ATTR_FLAGS
parsed from netlink (in taprio_change(), tail called from taprio_init()).
But in taprio_destroy(), we call taprio_disable_offload(), and this
determines what to do based on FULL_OFFLOAD_IS_ENABLED(q->flags).
But looking at the implementation of FULL_OFFLOAD_IS_ENABLED()
(a bitwise check of bit 1 in q->flags), it is invalid to call this macro
on q->flags when it contains TAPRIO_FLAGS_INVALID, because that is set
to U32_MAX, and therefore FULL_OFFLOAD_IS_ENABLED() will return true on
an invalid set of flags.
As a result, it is possible to crash the kernel if user space forces an
error between setting q->flags = TAPRIO_FLAGS_INVALID, and the calling
of taprio_enable_offload(). This is because drivers do not expect the
offload to be disabled when it was never enabled.
The error that we force here is to attach taprio as a non-root qdisc,
but instead as child of an mqprio root qdisc:
$ tc qdisc add dev swp0 root handle 1: \
mqprio num_tc 8 map 0 1 2 3 4 5 6 7 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 hw 0
$ tc qdisc replace dev swp0 parent 1:1 \
taprio num_tc 8 map 0 1 2 3 4 5 6 7 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 base-time 0 \
sched-entry S 0x7f 990000 sched-entry S 0x80 100000 \
flags 0x0 clockid CLOCK_TAI
Unable to handle kernel paging request at virtual address fffffffffffffff8
[fffffffffffffff8] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Call trace:
taprio_dump+0x27c/0x310
vsc9959_port_setup_tc+0x1f4/0x460
felix_port_setup_tc+0x24/0x3c
dsa_slave_setup_tc+0x54/0x27c
taprio_disable_offload.isra.0+0x58/0xe0
taprio_destroy+0x80/0x104
qdisc_create+0x240/0x470
tc_modify_qdisc+0x1fc/0x6b0
rtnetlink_rcv_msg+0x12c/0x390
netlink_rcv_skb+0x5c/0x130
rtnetlink_rcv+0x1c/0x2c
Fix this by keeping track of the operations we made, and undo the
offload only if we actually did it.
I've added "bool offloaded" inside a 4 byte hole between "int clockid"
and "atomic64_t picos_per_byte". Now the first cache line looks like
below:
$ pahole -C taprio_sched net/sched/sch_taprio.o
struct taprio_sched {
struct Qdisc * * qdiscs; /* 0 8 */
struct Qdisc * root; /* 8 8 */
u32 flags; /* 16 4 */
enum tk_offsets tk_offset; /* 20 4 */
int clockid; /* 24 4 */
bool offloaded; /* 28 1 */
/* XXX 3 bytes hole, try to pack */
atomic64_t picos_per_byte; /* 32 0 */
/* XXX 8 bytes hole, try to pack */
spinlock_t current_entry_lock; /* 40 0 */
/* XXX 8 bytes hole, try to pack */
struct sched_entry * current_entry; /* 48 8 */
struct sched_gate_list * oper_sched; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
Fixes: 9c66d15646 ("taprio: Add support for hardware offloading")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
qdisc_reset() is clearing qdisc->q.qlen and qdisc->qstats.backlog
_after_ calling qdisc->ops->reset. There is no need to clear them
again in the specific reset function.
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Link: https://lore.kernel.org/r/20220824005231.345727-1-shaozhengchao@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Time-sensitive networking code needs to work with PTP times expressed in
nanoseconds, and with packet transmission times expressed in
picoseconds, since those would be fractional at higher than gigabit
speed when expressed in nanoseconds.
Convert the existing uses in tc-taprio and the ocelot/felix DSA driver
to a PSEC_PER_NSEC macro. This macro is placed in include/linux/time64.h
as opposed to its relatives (PSEC_PER_SEC etc) from include/vdso/time64.h
because the vDSO library does not (yet) need/use it.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> # for the vDSO parts
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
A user may set the SO_TXTIME socket option to ensure a packet is send
at a given time. The taprio scheduler has to confirm, that it is allowed
to send a packet at that given time, by a check against the packet time
schedule. The scheduler drop the packet, if the gates are closed at the
given send time.
The check, if SO_TXTIME is set, may fail since sk_flags are part of an
union and the union is used otherwise. This happen, if a socket is not
a full socket, like a request socket for example.
Add a check to verify, if the union is used for sk_flags.
Fixes: 4cfd5779bd ("taprio: Add support for txtime-assist mode")
Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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>
syzbot report an array-index-out-of-bounds in taprio_change
index 16 is out of range for type '__u16 [16]'
that's because mqprio->num_tc is lager than TC_MAX_QUEUE,so we check
the return value of netdev_set_num_tc.
Reported-by: syzbot+2b3e5fb6c7ef285a94f6@syzkaller.appspotmail.com
Signed-off-by: Haimin Zhang <tcs_kernel@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 13511704f8 ("net: taprio offload: enforce qdisc to netdev queue mapping")
resulted in duplicate entries in the qdisc hash.
While this did not impact the overall operation of the qdisc and taprio
code paths, it did result in an infinite loop when dumping the qdisc
properties, at least on one target (NXP LS1028 ARDB).
Removing the duplicate call to qdisc_hash_add() solves the problem.
Fixes: 13511704f8 ("net: taprio offload: enforce qdisc to netdev queue mapping")
Signed-off-by: Yannick Vignon <yannick.vignon@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I have checked that the IEEE standard 802.1Q-2018 section 8.6.9.4.5
is called AdminGateStates.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Even though the taprio qdisc is designed for multiqueue devices, all the
queues still point to the same top-level taprio qdisc. This works and is
probably required for software taprio, but at least with offload taprio,
it has an undesirable side effect: because the whole qdisc is run when a
packet has to be sent, it allows packets in a best-effort class to be
processed in the context of a task sending higher priority traffic. If
there are packets left in the qdisc after that first run, the NET_TX
softirq is raised and gets executed immediately in the same process
context. As with any other softirq, it runs up to 10 times and for up to
2ms, during which the calling process is waiting for the sendmsg call (or
similar) to return. In my use case, that calling process is a real-time
task scheduled to send a packet every 2ms, so the long sendmsg calls are
leading to missed timeslots.
By attaching each netdev queue to its own qdisc, as it is done with
the "classic" mq qdisc, each traffic class can be processed independently
without touching the other classes. A high-priority process can then send
packets without getting stuck in the sendmsg call anymore.
Signed-off-by: Yannick Vignon <yannick.vignon@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The rcu_head pointer passed to taprio_free_sched_cb is never NULL.
That means that the result of container_of() operations on it is also
never NULL, even though rcu_head is the first element of the structure
embedding it. On top of that, it is misleading to perform a NULL check
on the result of container_of() because the position of the contained
element could change, which would make the check invalid. Remove the
unnecessary NULL check.
This change was made automatically with the following Coccinelle script.
@@
type t;
identifier v;
statement s;
@@
<+...
(
t v = container_of(...);
|
v = container_of(...);
)
...
when != v
- if (\( !v \| v == NULL \) ) s
...+>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a reproducible sequence from the userland that will trigger a WARN_ON()
condition in taprio_get_start_time, which causes kernel to panic if configured
as "panic_on_warn". Catch this condition in parse_taprio_schedule to
prevent this condition.
Reported as bug on syzkaller:
https://syzkaller.appspot.com/bug?extid=d50710fd0873a9c6b40c
Reported-by: syzbot+d50710fd0873a9c6b40c@syzkaller.appspotmail.com
Signed-off-by: Du Cheng <ducheng2@gmail.com>
Acked-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When using short intervals e.g. below one millisecond, large packets won't be
transmitted at all. The software implementations checks whether the packet can
be fit into the remaining interval. Therefore, it takes the packet length and
the transmission speed into account. That is correct.
However, for large packets it may be that the transmission time exceeds the
interval resulting in no packet transmission. The same situation works fine with
hardware offloading applied.
The problem has been observed with the following schedule and iperf3:
|tc qdisc replace dev lan1 parent root handle 100 taprio \
| num_tc 8 \
| map 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 \
| queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
| base-time $base \
| sched-entry S 0x40 500000 \
| sched-entry S 0xbf 500000 \
| clockid CLOCK_TAI \
| flags 0x00
[...]
|root@tsn:~# iperf3 -c 192.168.2.105
|Connecting to host 192.168.2.105, port 5201
|[ 5] local 192.168.2.121 port 52610 connected to 192.168.2.105 port 5201
|[ ID] Interval Transfer Bitrate Retr Cwnd
|[ 5] 0.00-1.00 sec 45.2 KBytes 370 Kbits/sec 0 1.41 KBytes
|[ 5] 1.00-2.00 sec 0.00 Bytes 0.00 bits/sec 0 1.41 KBytes
After debugging, it seems that the packet length stored in the SKB is about
7000-8000 bytes. Using a 100 Mbit/s link the transmission time is about 600us
which larger than the interval of 500us.
Therefore, segment the SKB into smaller chunks if the packet is too big. This
yields similar results than the hardware offload:
|root@tsn:~# iperf3 -c 192.168.2.105
|Connecting to host 192.168.2.105, port 5201
|- - - - - - - - - - - - - - - - - - - - - - - - -
|[ ID] Interval Transfer Bitrate Retr
|[ 5] 0.00-10.00 sec 48.9 MBytes 41.0 Mbits/sec 0 sender
|[ 5] 0.00-10.02 sec 48.7 MBytes 40.7 Mbits/sec receiver
Furthermore, the segmentation can be skipped for the full offload case, as the
driver or the hardware is expected to handle this.
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix the following coccicheck warnings:
./net/sched/sch_taprio.c:393:3-16: WARNING: Assignment of 0/1 to bool
variable.
./net/sched/sch_taprio.c:375:2-15: WARNING: Assignment of 0/1 to bool
variable.
./net/sched/sch_taprio.c:244:4-19: WARNING: Assignment of 0/1 to bool
variable.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Zhong <abaci-bugfix@linux.alibaba.com>
Link: https://lore.kernel.org/r/1610958662-71166-1-git-send-email-abaci-bugfix@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
taprio_graft() can insert a NULL element in the array of child qdiscs. As
a consquence, taprio_reset() might not reset child qdiscs completely, and
taprio_destroy() might leak resources. Fix it by ensuring that loops that
iterate over q->qdiscs[] don't end when they find the first NULL item.
Fixes: 44d4775ca5 ("net/sched: sch_taprio: reset child qdiscs before freeing them")
Fixes: 5a781ccbd1 ("tc: Add support for configuring the taprio scheduler")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Link: https://lore.kernel.org/r/13edef6778fef03adc751582562fba4a13e06d6a.1608240532.git.dcaratti@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
linux/netdevice.h is included in very many places, touching any
of its dependecies causes large incremental builds.
Drop the linux/ethtool.h include, linux/netdevice.h just needs
a forward declaration of struct ethtool_ops.
Fix all the places which made use of this implicit include.
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Shannon Nelson <snelson@pensando.io>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Link: https://lore.kernel.org/r/20201120225052.1427503-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
It's possible that the user specifies an interval that couldn't allow
any packet to be transmitted. This also avoids the issue of the
hrtimer handler starving the other threads because it's running too
often.
The solution is to reject interval sizes that according to the current
link speed wouldn't allow any packet to be transmitted.
Reported-by: syzbot+8267241609ae8c23b248@syzkaller.appspotmail.com
Fixes: 5a781ccbd1 ("tc: Add support for configuring the taprio scheduler")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit 9c66d15646 ("taprio: Add support for hardware
offloading") there's a bit of inconsistency when offloading schedules
to the hardware:
In software mode, the gate masks are specified in terms of traffic
classes, so if say "sched-entry S 03 20000", it means that the traffic
classes 0 and 1 are open for 20us; when taprio is offloaded to
hardware, the gate masks are specified in terms of hardware queues.
The idea here is to fix hardware offloading, so schedules in hardware
and software mode have the same behavior. What's needed to do is to
map traffic classes to queues when applying the offload to the driver.
Fixes: 9c66d15646 ("taprio: Add support for hardware offloading")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A following patch introduces qevents, points in qdisc algorithm where
packet can be processed by user-defined filters. Should this processing
lead to a situation where a new packet is to be enqueued on the same port,
holding the root lock would lead to deadlocks. To solve the issue, qevent
handler needs to unlock and relock the root lock when necessary.
To that end, add the root lock argument to the qdisc op enqueue, and
propagate throughout.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes. Also, remove unnecessary
variable _size_.
This code was detected with the help of Coccinelle and, audited and
fixed manually.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
There was a bug that was causing packets to be sent to the driver
without first calling dequeue() on the "child" qdisc. And the KASAN
report below shows that sending a packet without calling dequeue()
leads to bad results.
The problem is that when checking the last qdisc "child" we do not set
the returned skb to NULL, which can cause it to be sent to the driver,
and so after the skb is sent, it may be freed, and in some situations a
reference to it may still be in the child qdisc, because it was never
dequeued.
The crash log looks like this:
[ 19.937538] ==================================================================
[ 19.938300] BUG: KASAN: use-after-free in taprio_dequeue_soft+0x620/0x780
[ 19.938968] Read of size 4 at addr ffff8881128628cc by task swapper/1/0
[ 19.939612]
[ 19.939772] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-rc3+ #97
[ 19.940397] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qe4
[ 19.941523] Call Trace:
[ 19.941774] <IRQ>
[ 19.941985] dump_stack+0x97/0xe0
[ 19.942323] print_address_description.constprop.0+0x3b/0x60
[ 19.942884] ? taprio_dequeue_soft+0x620/0x780
[ 19.943325] ? taprio_dequeue_soft+0x620/0x780
[ 19.943767] __kasan_report.cold+0x1a/0x32
[ 19.944173] ? taprio_dequeue_soft+0x620/0x780
[ 19.944612] kasan_report+0xe/0x20
[ 19.944954] taprio_dequeue_soft+0x620/0x780
[ 19.945380] __qdisc_run+0x164/0x18d0
[ 19.945749] net_tx_action+0x2c4/0x730
[ 19.946124] __do_softirq+0x268/0x7bc
[ 19.946491] irq_exit+0x17d/0x1b0
[ 19.946824] smp_apic_timer_interrupt+0xeb/0x380
[ 19.947280] apic_timer_interrupt+0xf/0x20
[ 19.947687] </IRQ>
[ 19.947912] RIP: 0010:default_idle+0x2d/0x2d0
[ 19.948345] Code: 00 00 41 56 41 55 65 44 8b 2d 3f 8d 7c 7c 41 54 55 53 0f 1f 44 00 00 e8 b1 b2 c5 fd e9 07 00 3
[ 19.950166] RSP: 0018:ffff88811a3efda0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
[ 19.950909] RAX: 0000000080000000 RBX: ffff88811a3a9600 RCX: ffffffff8385327e
[ 19.951608] RDX: 1ffff110234752c0 RSI: 0000000000000000 RDI: ffffffff8385262f
[ 19.952309] RBP: ffffed10234752c0 R08: 0000000000000001 R09: ffffed10234752c1
[ 19.953009] R10: ffffed10234752c0 R11: ffff88811a3a9607 R12: 0000000000000001
[ 19.953709] R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000
[ 19.954408] ? default_idle_call+0x2e/0x70
[ 19.954816] ? default_idle+0x1f/0x2d0
[ 19.955192] default_idle_call+0x5e/0x70
[ 19.955584] do_idle+0x3d4/0x500
[ 19.955909] ? arch_cpu_idle_exit+0x40/0x40
[ 19.956325] ? _raw_spin_unlock_irqrestore+0x23/0x30
[ 19.956829] ? trace_hardirqs_on+0x30/0x160
[ 19.957242] cpu_startup_entry+0x19/0x20
[ 19.957633] start_secondary+0x2a6/0x380
[ 19.958026] ? set_cpu_sibling_map+0x18b0/0x18b0
[ 19.958486] secondary_startup_64+0xa4/0xb0
[ 19.958921]
[ 19.959078] Allocated by task 33:
[ 19.959412] save_stack+0x1b/0x80
[ 19.959747] __kasan_kmalloc.constprop.0+0xc2/0xd0
[ 19.960222] kmem_cache_alloc+0xe4/0x230
[ 19.960617] __alloc_skb+0x91/0x510
[ 19.960967] ndisc_alloc_skb+0x133/0x330
[ 19.961358] ndisc_send_ns+0x134/0x810
[ 19.961735] addrconf_dad_work+0xad5/0xf80
[ 19.962144] process_one_work+0x78e/0x13a0
[ 19.962551] worker_thread+0x8f/0xfa0
[ 19.962919] kthread+0x2ba/0x3b0
[ 19.963242] ret_from_fork+0x3a/0x50
[ 19.963596]
[ 19.963753] Freed by task 33:
[ 19.964055] save_stack+0x1b/0x80
[ 19.964386] __kasan_slab_free+0x12f/0x180
[ 19.964830] kmem_cache_free+0x80/0x290
[ 19.965231] ip6_mc_input+0x38a/0x4d0
[ 19.965617] ipv6_rcv+0x1a4/0x1d0
[ 19.965948] __netif_receive_skb_one_core+0xf2/0x180
[ 19.966437] netif_receive_skb+0x8c/0x3c0
[ 19.966846] br_handle_frame_finish+0x779/0x1310
[ 19.967302] br_handle_frame+0x42a/0x830
[ 19.967694] __netif_receive_skb_core+0xf0e/0x2a90
[ 19.968167] __netif_receive_skb_one_core+0x96/0x180
[ 19.968658] process_backlog+0x198/0x650
[ 19.969047] net_rx_action+0x2fa/0xaa0
[ 19.969420] __do_softirq+0x268/0x7bc
[ 19.969785]
[ 19.969940] The buggy address belongs to the object at ffff888112862840
[ 19.969940] which belongs to the cache skbuff_head_cache of size 224
[ 19.971202] The buggy address is located 140 bytes inside of
[ 19.971202] 224-byte region [ffff888112862840, ffff888112862920)
[ 19.972344] The buggy address belongs to the page:
[ 19.972820] page:ffffea00044a1800 refcount:1 mapcount:0 mapping:ffff88811a2bd1c0 index:0xffff8881128625c0 compo0
[ 19.973930] flags: 0x8000000000010200(slab|head)
[ 19.974388] raw: 8000000000010200 ffff88811a2ed650 ffff88811a2ed650 ffff88811a2bd1c0
[ 19.975151] raw: ffff8881128625c0 0000000000190013 00000001ffffffff 0000000000000000
[ 19.975915] page dumped because: kasan: bad access detected
[ 19.976461] page_owner tracks the page as allocated
[ 19.976946] page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NO)
[ 19.978332] prep_new_page+0x24b/0x330
[ 19.978707] get_page_from_freelist+0x2057/0x2c90
[ 19.979170] __alloc_pages_nodemask+0x218/0x590
[ 19.979619] new_slab+0x9d/0x300
[ 19.979948] ___slab_alloc.constprop.0+0x2f9/0x6f0
[ 19.980421] __slab_alloc.constprop.0+0x30/0x60
[ 19.980870] kmem_cache_alloc+0x201/0x230
[ 19.981269] __alloc_skb+0x91/0x510
[ 19.981620] alloc_skb_with_frags+0x78/0x4a0
[ 19.982043] sock_alloc_send_pskb+0x5eb/0x750
[ 19.982476] unix_stream_sendmsg+0x399/0x7f0
[ 19.982904] sock_sendmsg+0xe2/0x110
[ 19.983262] ____sys_sendmsg+0x4de/0x6d0
[ 19.983660] ___sys_sendmsg+0xe4/0x160
[ 19.984032] __sys_sendmsg+0xab/0x130
[ 19.984396] do_syscall_64+0xe7/0xae0
[ 19.984761] page last free stack trace:
[ 19.985142] __free_pages_ok+0x432/0xbc0
[ 19.985533] qlist_free_all+0x56/0xc0
[ 19.985907] quarantine_reduce+0x149/0x170
[ 19.986315] __kasan_kmalloc.constprop.0+0x9e/0xd0
[ 19.986791] kmem_cache_alloc+0xe4/0x230
[ 19.987182] prepare_creds+0x24/0x440
[ 19.987548] do_faccessat+0x80/0x590
[ 19.987906] do_syscall_64+0xe7/0xae0
[ 19.988276] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 19.988775]
[ 19.988930] Memory state around the buggy address:
[ 19.989402] ffff888112862780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 19.990111] ffff888112862800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
[ 19.990822] >ffff888112862880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 19.991529] ^
[ 19.992081] ffff888112862900: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
[ 19.992796] ffff888112862980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
Fixes: 5a781ccbd1 ("tc: Add support for configuring the taprio scheduler")
Reported-by: Michael Schmidt <michael.schmidt@eti.uni-siegen.de>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Acked-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add missing attribute validation for TCA_TAPRIO_ATTR_TXTIME_DELAY
to the netlink policy.
Fixes: 4cfd5779bd ("taprio: Add support for txtime-assist mode")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When using taprio offloading together with ETF offloading, configured
like this, for example:
$ tc qdisc replace dev $IFACE parent root handle 100 taprio \
num_tc 4 \
map 2 2 1 0 3 2 2 2 2 2 2 2 2 2 2 2 \
queues 1@0 1@1 1@2 1@3 \
base-time $BASE_TIME \
sched-entry S 01 1000000 \
sched-entry S 0e 1000000 \
flags 0x2
$ tc qdisc replace dev $IFACE parent 100:1 etf \
offload delta 300000 clockid CLOCK_TAI
During enqueue, it works out that the verification added for the
"txtime" assisted mode is run when using taprio + ETF offloading, the
only thing missing is initializing the 'next_txtime' of all the cycle
entries. (if we don't set 'next_txtime' all packets from SO_TXTIME
sockets are dropped)
Fixes: 4cfd5779bd ("taprio: Add support for txtime-assist mode")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When destroying the current taprio instance, which can happen when the
creation of one fails, we should reset the traffic class configuration
back to the default state.
netdev_reset_tc() is a better way because in addition to setting the
number of traffic classes to zero, it also resets the priority to
traffic classes mapping to the default value.
Fixes: 5a781ccbd1 ("tc: Add support for configuring the taprio scheduler")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netlink policy validation for the 'flags' argument was missing.
Fixes: 4cfd5779bd ("taprio: Add support for txtime-assist mode")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the driver implementing taprio offloading depends on the value of
the network device number of traffic classes (dev->num_tc) for
whatever reason, it was going to receive the value zero. The value was
only set after the offloading function is called.
So, moving setting the number of traffic classes to before the
offloading function is called fixes this issue. This is safe because
this only happens when taprio is instantiated (we don't allow this
configuration to be changed without first removing taprio).
Fixes: 9c66d15646 ("taprio: Add support for hardware offloading")
Reported-by: Po Liu <po.liu@nxp.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Acked-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The taprio qdisc allows to set mqprio setting but only once. In case
if mqprio settings are provided next time the error is returned as
it's not allowed to change traffic class mapping in-flignt and that
is normal. But if configuration is absolutely the same - no need to
return error. It allows to provide same command couple times,
changing only base time for instance, or changing only scheds maps,
but leaving mqprio setting w/o modification. It more corresponds the
message: "Changing the traffic mapping of a running schedule is not
supported", so reject mqprio if it's really changed.
Also corrected TC_BITMASK + 1 for consistency, as proposed.
Fixes: a3d43c0d56 ("taprio: Add support adding an admin schedule")
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Tested-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Don't swap oper and admin schedules too early, it's not correct and
causes crash.
Steps to reproduce:
1)
tc qdisc replace dev eth0 parent root handle 100 taprio \
num_tc 3 \
map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \
queues 1@0 1@1 1@2 \
base-time $SOME_BASE_TIME \
sched-entry S 01 80000 \
sched-entry S 02 15000 \
sched-entry S 04 40000 \
flags 2
2)
tc qdisc replace dev eth0 parent root handle 100 taprio \
base-time $SOME_BASE_TIME \
sched-entry S 01 90000 \
sched-entry S 02 20000 \
sched-entry S 04 40000 \
flags 2
3)
tc qdisc replace dev eth0 parent root handle 100 taprio \
base-time $SOME_BASE_TIME \
sched-entry S 01 150000 \
sched-entry S 02 200000 \
sched-entry S 04 40000 \
flags 2
Do 2 3 2 .. steps more times if not happens and observe:
[ 305.832319] Unable to handle kernel write to read-only memory at
virtual address ffff0000087ce7f0
[ 305.910887] CPU: 0 PID: 0 Comm: swapper/0 Not tainted
[ 305.919306] Hardware name: Texas Instruments AM654 Base Board (DT)
[...]
[ 306.017119] x1 : ffff800848031d88 x0 : ffff800848031d80
[ 306.022422] Call trace:
[ 306.024866] taprio_free_sched_cb+0x4c/0x98
[ 306.029040] rcu_process_callbacks+0x25c/0x410
[ 306.033476] __do_softirq+0x10c/0x208
[ 306.037132] irq_exit+0xb8/0xc8
[ 306.040267] __handle_domain_irq+0x64/0xb8
[ 306.044352] gic_handle_irq+0x7c/0x178
[ 306.048092] el1_irq+0xb0/0x128
[ 306.051227] arch_cpu_idle+0x10/0x18
[ 306.054795] do_idle+0x120/0x138
[ 306.058015] cpu_startup_entry+0x20/0x28
[ 306.061931] rest_init+0xcc/0xd8
[ 306.065154] start_kernel+0x3bc/0x3e4
[ 306.068810] Code: f2fbd5b7 f2fbd5b6 d503201f f9400422 (f9000662)
[ 306.074900] ---[ end trace 96c8e2284a9d9d6e ]---
[ 306.079507] Kernel panic - not syncing: Fatal exception in interrupt
[ 306.085847] SMP: stopping secondary CPUs
[ 306.089765] Kernel Offset: disabled
Try to explain one of the possible crash cases:
The "real" admin list is assigned when admin_sched is set to
new_admin, it happens after "swap", that assigns to oper_sched NULL.
Thus if call qdisc show it can crash.
Farther, next second time, when sched list is updated, the admin_sched
is not NULL and becomes the oper_sched, previous oper_sched was NULL so
just skipped. But then admin_sched is assigned new_admin, but schedules
to free previous assigned admin_sched (that already became oper_sched).
Farther, next third time, when sched list is updated,
while one more swap, oper_sched is not null, but it was happy to be
freed already (while prev. admin update), so while try to free
oper_sched the kernel panic happens at taprio_free_sched_cb().
So, move the "swap emulation" where it should be according to function
comment from code.
Fixes: 9c66d15646 ("taprio: Add support for hardware offloading")
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We get one warnings when build kernel W=1:
net/sched/sch_taprio.c:1155:6: warning: no previous prototype for ‘taprio_offload_config_changed’ [-Wmissing-prototypes]
Make the function static to fix this.
Fixes: 9c66d15646 ("taprio: Add support for hardware offloading")
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
When configuring a taprio instance if "flags" is not specified (or
it's zero), taprio currently replies with an "Invalid argument" error.
So, set the return value to zero after we are done with all the
checks.
Fixes: 9c66d15646 ("taprio: Add support for hardware offloading")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Acked-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
The check in taprio_set_picos_per_byte is currently not robust enough
and will trigger this division by zero, due to e.g. PHYLINK not setting
kset->base.speed when there is no PHY connected:
[ 27.109992] Division by zero in kernel.
[ 27.113842] CPU: 1 PID: 198 Comm: tc Not tainted 5.3.0-rc5-01246-gc4006b8c2637-dirty #212
[ 27.121974] Hardware name: Freescale LS1021A
[ 27.126234] [<c03132e0>] (unwind_backtrace) from [<c030d8b8>] (show_stack+0x10/0x14)
[ 27.133938] [<c030d8b8>] (show_stack) from [<c10b21b0>] (dump_stack+0xb0/0xc4)
[ 27.141124] [<c10b21b0>] (dump_stack) from [<c10af97c>] (Ldiv0_64+0x8/0x18)
[ 27.148052] [<c10af97c>] (Ldiv0_64) from [<c0700260>] (div64_u64+0xcc/0xf0)
[ 27.154978] [<c0700260>] (div64_u64) from [<c07002d0>] (div64_s64+0x4c/0x68)
[ 27.161993] [<c07002d0>] (div64_s64) from [<c0f3d890>] (taprio_set_picos_per_byte+0xe8/0xf4)
[ 27.170388] [<c0f3d890>] (taprio_set_picos_per_byte) from [<c0f3f614>] (taprio_change+0x668/0xcec)
[ 27.179302] [<c0f3f614>] (taprio_change) from [<c0f2bc24>] (qdisc_create+0x1fc/0x4f4)
[ 27.187091] [<c0f2bc24>] (qdisc_create) from [<c0f2c0c8>] (tc_modify_qdisc+0x1ac/0x6f8)
[ 27.195055] [<c0f2c0c8>] (tc_modify_qdisc) from [<c0ee9604>] (rtnetlink_rcv_msg+0x268/0x2dc)
[ 27.203449] [<c0ee9604>] (rtnetlink_rcv_msg) from [<c0f4fef0>] (netlink_rcv_skb+0xe0/0x114)
[ 27.211756] [<c0f4fef0>] (netlink_rcv_skb) from [<c0f4f6cc>] (netlink_unicast+0x1b4/0x22c)
[ 27.219977] [<c0f4f6cc>] (netlink_unicast) from [<c0f4fa84>] (netlink_sendmsg+0x284/0x340)
[ 27.228198] [<c0f4fa84>] (netlink_sendmsg) from [<c0eae5fc>] (sock_sendmsg+0x14/0x24)
[ 27.235988] [<c0eae5fc>] (sock_sendmsg) from [<c0eaedf8>] (___sys_sendmsg+0x214/0x228)
[ 27.243863] [<c0eaedf8>] (___sys_sendmsg) from [<c0eb015c>] (__sys_sendmsg+0x50/0x8c)
[ 27.251652] [<c0eb015c>] (__sys_sendmsg) from [<c0301000>] (ret_fast_syscall+0x0/0x54)
[ 27.259524] Exception stack(0xe8045fa8 to 0xe8045ff0)
[ 27.264546] 5fa0: b6f608c8 000000f8 00000003 bed7e2f0 00000000 00000000
[ 27.272681] 5fc0: b6f608c8 000000f8 004ce54c 00000128 5d3ce8c7 00000000 00000026 00505c9c
[ 27.280812] 5fe0: 00000070 bed7e298 004ddd64 b6dd1e64
Russell King points out that the ethtool API says zero is a valid return
value of __ethtool_get_link_ksettings:
* If it is enabled then they are read-only; if the link
* is up they represent the negotiated link mode; if the link is down,
* the speed is 0, %SPEED_UNKNOWN or the highest enabled speed and
* @duplex is %DUPLEX_UNKNOWN or the best enabled duplex mode.
So, it seems that taprio is not following the API... I'd suggest either
fixing taprio, or getting agreement to change the ethtool API.
The chosen path was to fix taprio.
Fixes: 7b9eba7ba0 ("net/sched: taprio: fix picos_per_byte miscalculation")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The speed divisor is used in a context expecting an s64, but it is
evaluated using 32-bit arithmetic.
To avoid that happening, instead of multiplying by 1,000,000 in the
first place, simplify the fraction and do a standard 32 bit division
instead.
Fixes: f04b514c0c ("taprio: Set default link speed to 10 Mbps in taprio_set_picos_per_byte")
Reported-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This allows taprio to offload the schedule enforcement to capable
network cards, resulting in more precise windows and less CPU usage.
The gate mask acts on traffic classes (groups of queues of same
priority), as specified in IEEE 802.1Q-2018, and following the existing
taprio and mqprio semantics.
It is up to the driver to perform conversion between tc and individual
netdev queues if for some reason it needs to make that distinction.
Full offload is requested from the network interface by specifying
"flags 2" in the tc qdisc creation command, which in turn corresponds to
the TCA_TAPRIO_ATTR_FLAG_FULL_OFFLOAD bit.
The important detail here is the clockid which is implicitly /dev/ptpN
for full offload, and hence not configurable.
A reference counting API is added to support the use case where Ethernet
drivers need to keep the taprio offload structure locally (i.e. they are
a multi-port switch driver, and configuring a port depends on the
settings of other ports as well). The refcount_t variable is kept in a
private structure (__tc_taprio_qopt_offload) and not exposed to drivers.
In the future, the private structure might also be expanded with a
backpointer to taprio_sched *q, to implement the notification system
described in the patch (of when admin became oper, or an error occurred,
etc, so the offload can be monitored with 'tc qdisc show').
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Voon Weifeng <weifeng.voon@intel.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The taprio budget needs to be adapted at runtime according to interface
link speed. But that handling is problematic.
For one thing, installing a qdisc on an interface that doesn't have
carrier is not illegal. But taprio prints the following stack trace:
[ 31.851373] ------------[ cut here ]------------
[ 31.856024] WARNING: CPU: 1 PID: 207 at net/sched/sch_taprio.c:481 taprio_dequeue+0x1a8/0x2d4
[ 31.864566] taprio: dequeue() called with unknown picos per byte.
[ 31.864570] Modules linked in:
[ 31.873701] CPU: 1 PID: 207 Comm: tc Not tainted 5.3.0-rc5-01199-g8838fe023cd6 #1689
[ 31.881398] Hardware name: Freescale LS1021A
[ 31.885661] [<c03133a4>] (unwind_backtrace) from [<c030d8cc>] (show_stack+0x10/0x14)
[ 31.893368] [<c030d8cc>] (show_stack) from [<c10ac958>] (dump_stack+0xb4/0xc8)
[ 31.900555] [<c10ac958>] (dump_stack) from [<c0349d04>] (__warn+0xe0/0xf8)
[ 31.907395] [<c0349d04>] (__warn) from [<c0349d64>] (warn_slowpath_fmt+0x48/0x6c)
[ 31.914841] [<c0349d64>] (warn_slowpath_fmt) from [<c0f38db4>] (taprio_dequeue+0x1a8/0x2d4)
[ 31.923150] [<c0f38db4>] (taprio_dequeue) from [<c0f227b0>] (__qdisc_run+0x90/0x61c)
[ 31.930856] [<c0f227b0>] (__qdisc_run) from [<c0ec82ac>] (net_tx_action+0x12c/0x2bc)
[ 31.938560] [<c0ec82ac>] (net_tx_action) from [<c0302298>] (__do_softirq+0x130/0x3c8)
[ 31.946350] [<c0302298>] (__do_softirq) from [<c03502a0>] (irq_exit+0xbc/0xd8)
[ 31.953536] [<c03502a0>] (irq_exit) from [<c03a4808>] (__handle_domain_irq+0x60/0xb4)
[ 31.961328] [<c03a4808>] (__handle_domain_irq) from [<c0754478>] (gic_handle_irq+0x58/0x9c)
[ 31.969638] [<c0754478>] (gic_handle_irq) from [<c0301a8c>] (__irq_svc+0x6c/0x90)
[ 31.977076] Exception stack(0xe8167b20 to 0xe8167b68)
[ 31.982100] 7b20: e9d4bd80 00000cc0 000000cf 00000000 e9d4bd80 c1f38958 00000cc0 c1f38960
[ 31.990234] 7b40: 00000001 000000cf 00000004 e9dc0800 00000000 e8167b70 c0f478ec c0f46d94
[ 31.998363] 7b60: 60070013 ffffffff
[ 32.001833] [<c0301a8c>] (__irq_svc) from [<c0f46d94>] (netlink_trim+0x18/0xd8)
[ 32.009104] [<c0f46d94>] (netlink_trim) from [<c0f478ec>] (netlink_broadcast_filtered+0x34/0x414)
[ 32.017930] [<c0f478ec>] (netlink_broadcast_filtered) from [<c0f47cec>] (netlink_broadcast+0x20/0x28)
[ 32.027102] [<c0f47cec>] (netlink_broadcast) from [<c0eea378>] (rtnetlink_send+0x34/0x88)
[ 32.035238] [<c0eea378>] (rtnetlink_send) from [<c0f25890>] (notify_and_destroy+0x2c/0x44)
[ 32.043461] [<c0f25890>] (notify_and_destroy) from [<c0f25e08>] (qdisc_graft+0x398/0x470)
[ 32.051595] [<c0f25e08>] (qdisc_graft) from [<c0f27a00>] (tc_modify_qdisc+0x3a4/0x724)
[ 32.059470] [<c0f27a00>] (tc_modify_qdisc) from [<c0ee4c84>] (rtnetlink_rcv_msg+0x260/0x2ec)
[ 32.067864] [<c0ee4c84>] (rtnetlink_rcv_msg) from [<c0f4a988>] (netlink_rcv_skb+0xb8/0x110)
[ 32.076172] [<c0f4a988>] (netlink_rcv_skb) from [<c0f4a170>] (netlink_unicast+0x1b4/0x22c)
[ 32.084392] [<c0f4a170>] (netlink_unicast) from [<c0f4a5e4>] (netlink_sendmsg+0x33c/0x380)
[ 32.092614] [<c0f4a5e4>] (netlink_sendmsg) from [<c0ea9f40>] (sock_sendmsg+0x14/0x24)
[ 32.100403] [<c0ea9f40>] (sock_sendmsg) from [<c0eaa780>] (___sys_sendmsg+0x214/0x228)
[ 32.108279] [<c0eaa780>] (___sys_sendmsg) from [<c0eabad0>] (__sys_sendmsg+0x50/0x8c)
[ 32.116068] [<c0eabad0>] (__sys_sendmsg) from [<c0301000>] (ret_fast_syscall+0x0/0x54)
[ 32.123938] Exception stack(0xe8167fa8 to 0xe8167ff0)
[ 32.128960] 7fa0: b6fa68c8 000000f8 00000003 bea142d0 00000000 00000000
[ 32.137093] 7fc0: b6fa68c8 000000f8 0052154c 00000128 5d6468a2 00000000 00000028 00558c9c
[ 32.145224] 7fe0: 00000070 bea14278 00530d64 b6e17e64
[ 32.150659] ---[ end trace 2139c9827c3e5177 ]---
This happens because the qdisc ->dequeue callback gets called. Which
again is not illegal, the qdisc will dequeue even when the interface is
up but doesn't have carrier (and hence SPEED_UNKNOWN), and the frames
will be dropped further down the stack in dev_direct_xmit().
And, at the end of the day, for what? For calculating the initial budget
of an interface which is non-operational at the moment and where frames
will get dropped anyway.
So if we can't figure out the link speed, default to SPEED_10 and move
along. We can also remove the runtime check now.
Cc: Leandro Dorileo <leandro.maciel.dorileo@intel.com>
Fixes: 7b9eba7ba0 ("net/sched: taprio: fix picos_per_byte miscalculation")
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
taprio_init may fail earlier than this line:
list_add(&q->taprio_list, &taprio_list);
i.e. due to the net device not being multi queue.
Attempting to remove q from the global taprio_list when it is not part
of it will result in a kernel panic.
Fix it by matching list_add and list_del better to one another in the
order of operations. This way we can keep the deletion unconditional
and with lower complexity - O(1).
Cc: Leandro Dorileo <leandro.maciel.dorileo@intel.com>
Fixes: 7b9eba7ba0 ("net/sched: taprio: fix picos_per_byte miscalculation")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/sched/sch_taprio.c:680:32: warning:
entry_list_policy defined but not used [-Wunused-const-variable=]
One of the points of commit a3d43c0d56 ("taprio: Add support adding
an admin schedule") is that it removes support (it now returns "not
supported") for schedules using the TCA_TAPRIO_ATTR_SCHED_SINGLE_ENTRY
attribute (which were never used), the parsing of those types of schedules
was the only user of this policy. So removing this policy should be fine.
Reported-by: Hulk Robot <hulkci@huawei.com>
Suggested-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In error case, all entries should be freed from the sched list
before deleting it. For simplicity use rcu way.
Fixes: 5a781ccbd1 ("tc: Add support for configuring the taprio scheduler")
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
During the review of the iproute2 patches for txtime-assist mode, it was
pointed out that it does not make sense for the txtime-delay parameter to
be negative. So, change the type of the parameter from s32 to u32.
Fixes: 4cfd5779bd ("taprio: Add support for txtime-assist mode")
Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When the taprio qdisc is running in "txtime offload" mode, it will
set the launchtime value (in skb->tstamp) for all the packets which do
not have the SO_TXTIME socket option. But, the TCP packets already have
this value set and it indicates the earliest departure time represented
in CLOCK_MONOTONIC clock.
We need to respect the timestamp set by the TCP subsystem. So, convert
this time to the clock which taprio is using and ensure that the packet
is not transmitted before the deadline set by TCP.
Signed-off-by: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Later in this series we will need to transform from
CLOCK_MONOTONIC (used in TCP) to the clock reference used in TAPRIO.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, we are seeing non-critical packets being transmitted outside of
their timeslice. We can confirm that the packets are being dequeued at the
right time. So, the delay is induced in the hardware side. The most likely
reason is the hardware queues are starving the lower priority queues.
In order to improve the performance of taprio, we will be making use of the
txtime feature provided by the ETF qdisc. For all the packets which do not
have the SO_TXTIME option set, taprio will set the transmit timestamp (set
in skb->tstamp) in this mode. TAPrio Qdisc will ensure that the transmit
time for the packet is set to when the gate is open. If SO_TXTIME is set,
the TAPrio qdisc will validate whether the timestamp (in skb->tstamp)
occurs when the gate corresponding to skb's traffic class is open.
Following two parameters added to support this mode:
- flags: used to enable txtime-assist mode. Will also be used to enable
other modes (like hardware offloading) later.
- txtime-delay: This indicates the minimum time it will take for the packet
to hit the wire. This is useful in determining whether we can transmit
the packet in the remaining time if the gate corresponding to the packet is
currently open.
An example configuration for enabling txtime-assist:
tc qdisc replace dev eth0 parent root handle 100 taprio \\
num_tc 3 \\
map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \\
queues 1@0 1@0 1@0 \\
base-time 1558653424279842568 \\
sched-entry S 01 300000 \\
sched-entry S 02 300000 \\
sched-entry S 04 400000 \\
flags 0x1 \\
txtime-delay 40000 \\
clockid CLOCK_TAI
tc qdisc replace dev $IFACE parent 100:1 etf skip_sock_check \\
offload delta 200000 clockid CLOCK_TAI
Note that all the traffic classes are mapped to the same queue. This is
only possible in taprio when txtime-assist is enabled. Also, note that the
ETF Qdisc is enabled with offload mode set.
In this mode, if the packet's traffic class is open and the complete packet
can be transmitted, taprio will try to transmit the packet immediately.
This will be done by setting skb->tstamp to current_time + the time delta
indicated in the txtime-delay parameter. This parameter indicates the time
taken (in software) for packet to reach the network adapter.
If the packet cannot be transmitted in the current interval or if the
packet's traffic is not currently transmitting, the skb->tstamp is set to
the next available timestamp value. This is tracked in the next_launchtime
parameter in the struct sched_entry.
The behaviour w.r.t admin and oper schedules is not changed from what is
present in software mode.
The transmit time is already known in advance. So, we do not need the HR
timers to advance the schedule and wakeup the dequeue side of taprio. So,
HR timer won't be run when this mode is enabled.
Signed-off-by: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove inline directive from length_to_duration(). We will let the compiler
make the decisions.
Signed-off-by: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
cycle time for a particular schedule is calculated only when it is first
installed. So, it makes sense to just calculate it once right after the
'cycle_time' parameter has been parsed and store it in cycle_time.
Signed-off-by: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The call to nla_nest_start_noflag can return a null pointer and currently
this is not being checked and this can lead to a null pointer dereference
when the null pointer sched_nest is passed to function nla_nest_end. Fix
this by adding in a null pointer check.
Addresses-Coverity: ("Dereference null return value")
Fixes: a3d43c0d56 ("taprio: Add support adding an admin schedule")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
IEEE 802.1Q-2018 defines the concept of a cycle-time-extension, so the
last entry of a schedule before the start of a new schedule can be
extended, so "too-short" entries can be avoided.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
IEEE 802.1Q-2018 defines that a the cycle-time of a schedule may be
overridden, so the schedule is truncated to a determined "width".
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The IEEE 802.1Q-2018 defines two "types" of schedules, the "Oper" (from
operational?) and "Admin" ones. Up until now, 'taprio' only had
support for the "Oper" one, added when the qdisc is created. This adds
support for the "Admin" one, which allows the .change() operation to
be supported.
Just for clarification, some quick (and dirty) definitions, the "Oper"
schedule is the currently (as in this instant) running one, and it's
read-only. The "Admin" one is the one that the system configurator has
installed, it can be changed, and it will be "promoted" to "Oper" when
it's 'base-time' is reached.
The idea behing this patch is that calling something like the below,
(after taprio is already configured with an initial schedule):
$ tc qdisc change taprio dev IFACE parent root \
base-time X \
sched-entry <CMD> <GATES> <INTERVAL> \
...
Will cause a new admin schedule to be created and programmed to be
"promoted" to "Oper" at instant X. If an "Admin" schedule already
exists, it will be overwritten with the new parameters.
Up until now, there was some code that was added to ease the support
of changing a single entry of a schedule, but was ultimately unused.
Now, that we have support for "change" with more well thought
semantics, updating a single entry seems to be less useful.
So we remove what is in practice dead code, and return a "not
supported" error if the user tries to use it. If changing a single
entry would make the user's life easier we may ressurrect this idea,
but at this point, removing it simplifies the code.
For now, only the schedule specific bits are allowed to be added for a
new schedule, that means that 'clockid', 'num_tc', 'map' and 'queues'
cannot be modified.
Example:
$ tc qdisc change dev IFACE parent root handle 100 taprio \
base-time $BASE_TIME \
sched-entry S 00 500000 \
sched-entry S 0f 500000 \
clockid CLOCK_TAI
The only change in the netlink API introduced by this change is the
introduction of an "admin" type in the response to a dump request,
that type allows userspace to separate the "oper" schedule from the
"admin" schedule. If userspace doesn't support the "admin" type, it
will only display the "oper" schedule.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Right now, this isn't a problem, but the next commit allows schedules
to be added during runtime. When a new schedule transitions from the
inactive to the active state ("admin" -> "oper") the previous one can
be freed, if it's freed just after the RCU read lock is released, we
may access an invalid entry.
So, we should take care to protect the dequeue() flow, so all the
places that access the entries are protected by the RCU read lock.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We currently have two levels of strict validation:
1) liberal (default)
- undefined (type >= max) & NLA_UNSPEC attributes accepted
- attribute length >= expected accepted
- garbage at end of message accepted
2) strict (opt-in)
- NLA_UNSPEC attributes accepted
- attribute length >= expected accepted
Split out parsing strictness into four different options:
* TRAILING - check that there's no trailing data after parsing
attributes (in message or nested)
* MAXTYPE - reject attrs > max known type
* UNSPEC - reject attributes with NLA_UNSPEC policy entries
* STRICT_ATTRS - strictly validate attribute size
The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().
Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.
We end up with the following renames:
* nla_parse -> nla_parse_deprecated
* nla_parse_strict -> nla_parse_deprecated_strict
* nlmsg_parse -> nlmsg_parse_deprecated
* nlmsg_parse_strict -> nlmsg_parse_deprecated_strict
* nla_parse_nested -> nla_parse_nested_deprecated
* nla_validate_nested -> nla_validate_nested_deprecated
Using spatch, of course:
@@
expression TB, MAX, HEAD, LEN, POL, EXT;
@@
-nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
+nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)
@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)
@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
@@
expression TB, MAX, NLA, POL, EXT;
@@
-nla_parse_nested(TB, MAX, NLA, POL, EXT)
+nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)
@@
expression START, MAX, POL, EXT;
@@
-nla_validate_nested(START, MAX, POL, EXT)
+nla_validate_nested_deprecated(START, MAX, POL, EXT)
@@
expression NLH, HDRLEN, MAX, POL, EXT;
@@
-nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
+nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)
For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.
Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.
Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.
In effect then, this adds fully strict validation for any new command.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.
Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().
Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:
@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)
@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In case we don't have 'guard' or 'budget' to transmit the skb, we should
continue traversing the qdisc list since the remaining guard/budget
might be enough to transmit a skb from other children qdiscs.
Fixes: 5a781ccbd1 (“tc: Add support for configuring the taprio scheduler”)
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While traversing taprio's children qdisc list, if the gate is closed for
a given traffic class, we should continue traversing the list since the
remaining qdiscs may have skb ready for transmission.
This patch also takes this opportunity and changes the function to use
the TAPRIO_ALL_GATES_OPEN macro instead of the magic number '-1'.
Fixes: 5a781ccbd1 (“tc: Add support for configuring the taprio scheduler”)
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The 'entry' argument from should_restart_cycle() cannot be NULL since it
is already checked by the caller so the WARN_ON() within should_
restart_cycle() could be removed. By doing that, that function becomes
a dummy wrapper on list_is_last() so this patch simply gets rid of it
and call list_is_last() within advance_sched() instead.
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch does a code refactoring to taprio_get_start_time() function
to improve readability and report error properly.
If 'base' time is later than 'now', the start time is equal to 'base'
and taprio_get_start_time() is done. That's the natural case so we move
that code to the beginning of the function. Also, if 'cycle' calculation
is zero, something went really wrong with taprio and we should log that
internal error properly.
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes a pointless variable assigment in taprio_change().
The 'err' variable is not used from this assignment to the next one so
this patch removes it.
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Recent changes to taprio did not use the correct div64 helpers,
leading to:
net/sched/sch_taprio.o: In function `taprio_dequeue':
sch_taprio.c:(.text+0x34a): undefined reference to `__divdi3'
net/sched/sch_taprio.o: In function `advance_sched':
sch_taprio.c:(.text+0xa0b): undefined reference to `__divdi3'
net/sched/sch_taprio.o: In function `taprio_init':
sch_taprio.c:(.text+0x1450): undefined reference to `__divdi3'
/home/jkicinski/devel/linux/Makefile:1032: recipe for target 'vmlinux' failed
Use math64 helpers.
Fixes: 7b9eba7ba0 ("net/sched: taprio: fix picos_per_byte miscalculation")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The Time Aware Priority Scheduler is heavily dependent to link speed,
it relies on it to calculate transmission bytes per cycle, we can't
properly calculate the so called budget if the device has failed
to report the link speed.
In that case we can't dequeue packets assuming a wrong budget.
This patch makes sure we fail to dequeue case:
1) __ethtool_get_link_ksettings() reports error or 2) the ethernet
driver failed to set the ksettings' speed value (setting link speed
to SPEED_UNKNOWN).
Additionally we re calculate the budget whenever the link speed is
changed.
Fixes: 5a781ccbd1 ("tc: Add support for configuring the taprio scheduler")
Signed-off-by: Leandro Dorileo <leandro.maciel.dorileo@intel.com>
Reviewed-by: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Classful qdiscs can't access directly the child qdiscs backlog
length: if such qdisc is NOLOCK, per CPU values should be
accounted instead.
Most qdiscs no not respect the above. As a result, qstats fetching
for most classful qdisc is currently incorrect: if the child qdisc is
NOLOCK, it always reports 0 len backlog.
This change introduces a pair of helpers to safely fetch
both backlog and qlen and use them in stats class dumping
functions, fixing the above issue and cleaning a bit the code.
DRR needs also to access the child qdisc queue length, so it
needs custom handling.
Fixes: c5ad119fb6 ("net: sched: pfifo_fast use skb_array")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This traffic scheduler allows traffic classes states (transmission
allowed/not allowed, in the simplest case) to be scheduled, according
to a pre-generated time sequence. This is the basis of the IEEE
802.1Qbv specification.
Example configuration:
tc qdisc replace dev enp3s0 parent root handle 100 taprio \
num_tc 3 \
map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \
queues 1@0 1@1 2@2 \
base-time 1528743495910289987 \
sched-entry S 01 300000 \
sched-entry S 02 300000 \
sched-entry S 04 300000 \
clockid CLOCK_TAI
The configuration format is similar to mqprio. The main difference is
the presence of a schedule, built by multiple "sched-entry"
definitions, each entry has the following format:
sched-entry <CMD> <GATE MASK> <INTERVAL>
The only supported <CMD> is "S", which means "SetGateStates",
following the IEEE 802.1Qbv-2015 definition (Table 8-6). <GATE MASK>
is a bitmask where each bit is a associated with a traffic class, so
bit 0 (the least significant bit) being "on" means that traffic class
0 is "active" for that schedule entry. <INTERVAL> is a time duration
in nanoseconds that specifies for how long that state defined by <CMD>
and <GATE MASK> should be held before moving to the next entry.
This schedule is circular, that is, after the last entry is executed
it starts from the first one, indefinitely.
The other parameters can be defined as follows:
- base-time: specifies the instant when the schedule starts, if
'base-time' is a time in the past, the schedule will start at
base-time + (N * cycle-time)
where N is the smallest integer so the resulting time is greater
than "now", and "cycle-time" is the sum of all the intervals of the
entries in the schedule;
- clockid: specifies the reference clock to be used;
The parameters should be similar to what the IEEE 802.1Q family of
specification defines.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
