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>
Eric Dumazet