Since 20dd3850 ("can: Speed up CAN frame receiption by using
ml_priv") the CAN framework uses per device specific data in the AF_CAN
protocol. For this purpose the struct net_device->ml_priv is used. Later
the ml_priv usage in CAN was extended for other users, one of them being
CAN_J1939.

Later in the kernel ml_priv was converted to an union, used by other
drivers. E.g. the tun driver started storing it's stats pointer.

Since tun devices can claim to be a CAN device, CAN specific protocols
will wrongly interpret this pointer, which will cause system crashes.
Mostly this issue is visible in the CAN_J1939 stack.

To fix this issue, we request a dedicated CAN pointer within the
net_device struct.

Reported-by: syzbot+5138c4dd15a0401bec7b@syzkaller.appspotmail.com
Fixes: 20dd3850 ("can: Speed up CAN frame receiption by using ml_priv")
Fixes: ffd956ee ("can: introduce CAN midlayer private and allocate it automatically")
Fixes: 9d71dd0c ("can: add support of SAE J1939 protocol")
Fixes: 497a5757 ("tun: switch to net core provided statistics counters")
Signed-off-by: NOleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20210223070127.4538-1-o.rempel@pengutronix.deSigned-off-by: NJakub Kicinski <kuba@kernel.org>

The use-case for dropping the MTU check when TC-BPF does redirect to
ingress, is described by Eyal Birger in email[0]. The summary is the
ability to increase packet size (e.g. with IPv6 headers for NAT64) and
ingress redirect packet and let normal netstack fragment packet as needed.

[0] https://lore.kernel.org/netdev/CAHsH6Gug-hsLGHQ6N0wtixdOa85LDZ3HNRHVd0opR=19Qo4W4Q@mail.gmail.com/

V15:
 - missing static for function declaration

V9:
 - Make net_device "up" (IFF_UP) check explicit in skb_do_redirect

V4:
 - Keep net_device "up" (IFF_UP) check.
 - Adjustment to handle bpf_redirect_peer() helper
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/161287790971.790810.11785274340154740591.stgit@firesoul

dev_ifsioc_locked() is called with only RCU read lock, so when
there is a parallel writer changing the mac address, it could
get a partially updated mac address, as shown below:

Thread 1			Thread 2
// eth_commit_mac_addr_change()
memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
				// dev_ifsioc_locked()
				memcpy(ifr->ifr_hwaddr.sa_data,
					dev->dev_addr,...);

Close this race condition by guarding them with a RW semaphore,
like netdev_get_name(). We can not use seqlock here as it does not
allow blocking. The writers already take RTNL anyway, so this does
not affect the slow path. To avoid bothering existing
dev_set_mac_address() callers in drivers, introduce a new wrapper
just for user-facing callers on ioctl and rtnetlink paths.

Note, bonding also changes slave mac addresses but that requires
a separate patch due to the complexity of bonding code.

Fixes: 3710becf ("net: RCU locking for simple ioctl()")
Reported-by: N"Gong, Sishuai" <sishuai@purdue.edu>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a new sysfs attribute to the network device class.
Said attribute provides a per-device control to enable/disable the
threaded mode for all the napi instances of the given network device,
without the need for a device up/down.
User sets it to 1 or 0 to enable or disable threaded mode.
Note: when switching between threaded and the current softirq based mode
for a napi instance, it will not immediately take effect if the napi is
currently being polled. The mode switch will happen for the next time
napi_schedule() is called.
Co-developed-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Co-developed-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Co-developed-by: NFelix Fietkau <nbd@nbd.name>
Signed-off-by: NFelix Fietkau <nbd@nbd.name>
Signed-off-by: NWei Wang <weiwan@google.com>
Reviewed-by: NAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch allows running each napi poll loop inside its own
kernel thread.
The kthread is created during netif_napi_add() if dev->threaded
is set. And threaded mode is enabled in napi_enable(). We will
provide a way to set dev->threaded and enable threaded mode
without a device up/down in the following patch.

Once that threaded mode is enabled and the kthread is
started, napi_schedule() will wake-up such thread instead
of scheduling the softirq.

The threaded poll loop behaves quite likely the net_rx_action,
but it does not have to manipulate local irqs and uses
an explicit scheduling point based on netdev_budget.
Co-developed-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Co-developed-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Co-developed-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NWei Wang <weiwan@google.com>
Reviewed-by: NAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Prevent netif_tx_disable() running concurrently with dev_watchdog() by
taking the device global xmit lock. Otherwise, the recommended:

	netif_carrier_off(dev);
	netif_tx_disable(dev);

driver shutdown sequence can happen after the watchdog has already
checked carrier, resulting in possible false alarms. This is because
netif_tx_lock() only sets the frozen bit without maintaining the locks
on the individual queues.

Fixes: c3f26a26 ("netdev: Fix lockdep warnings in multiqueue configurations.")
Signed-off-by: NEdwin Peer <edwin.peer@broadcom.com>
Reviewed-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current layout of net_device is not optimal for cacheline usage.

The member adj_list.lower linked list is split between cacheline 2 and 3.
The ifindex is placed together with stats (struct net_device_stats),
although most modern drivers don't update this stats member.

The members netdev_ops, mtu and hard_header_len are placed on three
different cachelines. These members are accessed for XDP redirect into
devmap, which were noticeably with perf tool. When not using the map
redirect variant (like TC-BPF does), then ifindex is also used, which is
placed on a separate fourth cacheline. These members are also accessed
during forwarding with regular network stack. The members priv_flags and
flags are on fast-path for network stack transmit path in __dev_queue_xmit
(currently located together with mtu cacheline).

This patch creates a read mostly cacheline, with the purpose of keeping the
above mentioned members on the same cacheline.

Some netdev_features_t members also becomes part of this cacheline, which is
on purpose, as function netif_skb_features() is on fast-path via
validate_xmit_skb().
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/r/161168277983.410784.12401225493601624417.stgit@firesoulSigned-off-by: NJakub Kicinski <kuba@kernel.org>

HTB doesn't scale well because of contention on a single lock, and it
also consumes CPU. This patch adds support for offloading HTB to
hardware that supports hierarchical rate limiting.

In the offload mode, HTB passes control commands to the driver using
ndo_setup_tc. The driver has to replicate the whole hierarchy of classes
and their settings (rate, ceil) in the NIC. Every modification of the
HTB tree caused by the admin results in ndo_setup_tc being called.

After this setup, the HTB algorithm is done completely in the NIC. An SQ
(send queue) is created for every leaf class and attached to the
hierarchy, so that the NIC can calculate and obey aggregated rate
limits, too. In the future, it can be changed, so that multiple SQs will
back a single leaf class.

ndo_select_queue is responsible for selecting the right queue that
serves the traffic class of each packet.

The data path works as follows: a packet is classified by clsact, the
driver selects a hardware queue according to its class, and the packet
is enqueued into this queue's qdisc.

This solution addresses two main problems of scaling HTB:

1. Contention by flow classification. Currently the filters are attached
to the HTB instance as follows:

    # tc filter add dev eth0 parent 1:0 protocol ip flower dst_port 80
    classid 1:10

It's possible to move classification to clsact egress hook, which is
thread-safe and lock-free:

    # tc filter add dev eth0 egress protocol ip flower dst_port 80
    action skbedit priority 1:10

This way classification still happens in software, but the lock
contention is eliminated, and it happens before selecting the TX queue,
allowing the driver to translate the class to the corresponding hardware
queue in ndo_select_queue.

Note that this is already compatible with non-offloaded HTB and doesn't
require changes to the kernel nor iproute2.

2. Contention by handling packets. HTB is not multi-queue, it attaches
to a whole net device, and handling of all packets takes the same lock.
When HTB is offloaded, it registers itself as a multi-queue qdisc,
similarly to mq: HTB is attached to the netdev, and each queue has its
own qdisc.

Some features of HTB may be not supported by some particular hardware,
for example, the maximum number of classes may be limited, the
granularity of rate and ceil parameters may be different, etc. - so, the
offload is not enabled by default, a new parameter is used to enable it:

    # tc qdisc replace dev eth0 root handle 1: htb offload
Signed-off-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@nvidia.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

This comes from an end-user request, where they're running multiple VMs on
hosts with bonded interfaces connected to some interest switch topologies,
where 802.3ad isn't an option. They're currently running a proprietary
solution that effectively achieves load-balancing of VMs and bandwidth
utilization improvements with a similar form of transmission algorithm.

Basically, each VM has it's own vlan, so it always sends its traffic out
the same interface, unless that interface fails. Traffic gets split
between the interfaces, maintaining a consistent path, with failover still
available if an interface goes down.

Unlike bond_eth_hash(), this hash function is using the full source MAC
address instead of just the last byte, as there are so few components to
the hash, and in the no-vlan case, we would be returning just the last
byte of the source MAC as the hash value. It's entirely possible to have
two NICs in a bond with the same last byte of their MAC, but not the same
MAC, so this adjustment should guarantee distinct hashes in all cases.

This has been rudimetarily tested to provide similar results to the
proprietary solution it is aiming to replace. A patch for iproute2 is also
posted, to properly support the new mode there as well.

Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Cc: Thomas Davis <tadavis@lbl.gov>
Signed-off-by: NJarod Wilson <jarod@redhat.com>
Link: https://lore.kernel.org/r/20210119010927.1191922-1-jarod@redhat.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

ndo_sk_get_lower_dev returns the lower netdev that corresponds to
a given socket.
Additionally, we implement a helper netdev_sk_get_lowest_dev() to get
the lowest one in chain.
Signed-off-by: NTariq Toukan <tariqt@nvidia.com>
Reviewed-by: NBoris Pismenny <borisp@nvidia.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

GRO_DROP can only be returned from napi_gro_frags()
if the skb has not been allocated by a prior napi_get_frags()

Since drivers must use napi_get_frags() and test its result
before populating the skb with metadata, we can safely remove
GRO_DROP since it offers no practical use.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Acked-by: NEdward Cree <ecree.xilinx@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

All UDP tunnel port management is now routed via udp_tunnel_nic
infra directly. Remove the old callbacks.
Reviewed-by: NAlexander Duyck <alexanderduyck@fb.com>
Reviewed-by: NJacob Keller <jacob.e.keller@intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

There are some use cases for netdev_notify_peers in the context
when rtnl lock is already held. Introduce lockless version
of netdev_notify_peers call to save the extra code to call
	call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
	call_netdevice_notifiers(NETDEV_RESEND_IGMP, dev);
After that, convert netdev_notify_peers to call the new helper.
Suggested-by: NNathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: NLijun Pan <ljp@linux.ibm.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

The last user of the RTNL brother of dev_getfirstbyhwtype (the latter
being synchronized under RCU) has been deleted in commit b4db2b35
("afs: Use core kernel UUID generation").

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20201129200550.2433401-1-vladimir.oltean@nxp.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

The existing busy-polling mode, enabled by the SO_BUSY_POLL socket
option or system-wide using the /proc/sys/net/core/busy_read knob, is
an opportunistic. That means that if the NAPI context is not
scheduled, it will poll it. If, after busy-polling, the budget is
exceeded the busy-polling logic will schedule the NAPI onto the
regular softirq handling.

One implication of the behavior above is that a busy/heavy loaded NAPI
context will never enter/allow for busy-polling. Some applications
prefer that most NAPI processing would be done by busy-polling.

This series adds a new socket option, SO_PREFER_BUSY_POLL, that works
in concert with the napi_defer_hard_irqs and gro_flush_timeout
knobs. The napi_defer_hard_irqs and gro_flush_timeout knobs were
introduced in commit 6f8b12d6 ("net: napi: add hard irqs deferral
feature"), and allows for a user to defer interrupts to be enabled and
instead schedule the NAPI context from a watchdog timer. When a user
enables the SO_PREFER_BUSY_POLL, again with the other knobs enabled,
and the NAPI context is being processed by a softirq, the softirq NAPI
processing will exit early to allow the busy-polling to be performed.

If the application stops performing busy-polling via a system call,
the watchdog timer defined by gro_flush_timeout will timeout, and
regular softirq handling will resume.

In summary; Heavy traffic applications that prefer busy-polling over
softirq processing should use this option.

Example usage:

  $ echo 2 | sudo tee /sys/class/net/ens785f1/napi_defer_hard_irqs
  $ echo 200000 | sudo tee /sys/class/net/ens785f1/gro_flush_timeout

Note that the timeout should be larger than the userspace processing
window, otherwise the watchdog will timeout and fall back to regular
softirq processing.

Enable the SO_BUSY_POLL/SO_PREFER_BUSY_POLL options on your socket.
Signed-off-by: NBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NJakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/bpf/20201130185205.196029-2-bjorn.topel@gmail.com

Commit 642e450b ("xsk: Do not discard packet when NETDEV_TX_BUSY")
addressed the problem that packets were discarded from the Tx AF_XDP
ring, when the driver returned NETDEV_TX_BUSY. Part of the fix was
bumping the skbuff reference count, so that the buffer would not be
freed by dev_direct_xmit(). A reference count larger than one means
that the skbuff is "shared", which is not the case.

If the "shared" skbuff is sent to the generic XDP receive path,
netif_receive_generic_xdp(), and pskb_expand_head() is entered the
BUG_ON(skb_shared(skb)) will trigger.

This patch adds a variant to dev_direct_xmit(), __dev_direct_xmit(),
where a user can select the skbuff free policy. This allows AF_XDP to
avoid bumping the reference count, but still keep the NETDEV_TX_BUSY
behavior.

Fixes: 642e450b ("xsk: Do not discard packet when NETDEV_TX_BUSY")
Reported-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201123175600.146255-1-bjorn.topel@gmail.com

In the patchset merged by commit b9fcf0a0
("Merge branch 'support-AF_PACKET-for-layer-3-devices'") L3 devices which
did not have header_ops were given one for the purpose of protocol parsing
on af_packet transmit path.

That change made af_packet receive path regard these devices as having a
visible L3 header and therefore aligned incoming skb->data to point to the
skb's mac_header. Some devices, such as ipip, xfrmi, and others, do not
reset their mac_header prior to ingress and therefore their incoming
packets became malformed.

Ideally these devices would reset their mac headers, or af_packet would be
able to rely on dev->hard_header_len being 0 for such cases, but it seems
this is not the case.

Fix by changing af_packet RX ll visibility criteria to include the
existence of a '.create()' header operation, which is used when creating
a device hard header - via dev_hard_header() - by upper layers, and does
not exist in these L3 devices.

As this predicate may be useful in other situations, add it as a common
dev_has_header() helper in netdevice.h.

Fixes: b9fcf0a0 ("Merge branch 'support-AF_PACKET-for-layer-3-devices'")
Signed-off-by: NEyal Birger <eyal.birger@gmail.com>
Acked-by: NJason A. Donenfeld <Jason@zx2c4.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20201121062817.3178900-1-eyal.birger@gmail.comSigned-off-by: NJakub 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: NJohannes Berg <johannes@sipsolutions.net>
Acked-by: NShannon Nelson <snelson@pensando.io>
Reviewed-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Link: https://lore.kernel.org/r/20201120225052.1427503-1-kuba@kernel.orgSigned-off-by: NJakub Kicinski <kuba@kernel.org>

Some identifiers have different names between their prototypes
and the kernel-doc markup.

In the specific case of netif_subqueue_stopped(), keep the
current markup for __netif_subqueue_stopped(), adding a
new one for netif_subqueue_stopped().
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

It's a frequent pattern to use netdev->stats for the less frequently
accessed counters and per-cpu counters for the frequently accessed
counters (rx/tx bytes/packets). Add a default ndo_get_stats64()
implementation for this use case.
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

We have netdev_alloc_pcpu_stats(), and we have devm_alloc_percpu().
Add a managed version of netdev_alloc_pcpu_stats, e.g. for allocating
the per-cpu stats in the probe() callback of a driver. It needs to be
a macro for dealing properly with the type argument.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Add dev_sw_netstats_tx_add(), complementing already existing
dev_sw_netstats_rx_add(). Other than dev_sw_netstats_rx_add allow to
pass the number of packets as function argument.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

In several places the same code is used to populate rtnl_link_stats64
fields with data from pcpu_sw_netstats. Therefore factor out this code
to a new function dev_fetch_sw_netstats().

v2:
- constify argument netstats
- don't ignore netstats being NULL or an ERRPTR
- switch to EXPORT_SYMBOL_GPL
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/6d16a338-52f5-df69-0020-6bc771a7d498@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

Add an efficient ingress to ingress netns switch that can be used out of tc BPF
programs in order to redirect traffic from host ns ingress into a container
veth device ingress without having to go via CPU backlog queue [0]. For local
containers this can also be utilized and path via CPU backlog queue only needs
to be taken once, not twice. On a high level this borrows from ipvlan which does
similar switch in __netif_receive_skb_core() and then iterates via another_round.
This helps to reduce latency for mentioned use cases.

Pod to remote pod with redirect(), TCP_RR [1]:

  # percpu_netperf 10.217.1.33
          RT_LATENCY:         122.450         (per CPU:         122.666         122.401         122.333         122.401 )
        MEAN_LATENCY:         121.210         (per CPU:         121.100         121.260         121.320         121.160 )
      STDDEV_LATENCY:         120.040         (per CPU:         119.420         119.910         125.460         115.370 )
         MIN_LATENCY:          46.500         (per CPU:          47.000          47.000          47.000          45.000 )
         P50_LATENCY:         118.500         (per CPU:         118.000         119.000         118.000         119.000 )
         P90_LATENCY:         127.500         (per CPU:         127.000         128.000         127.000         128.000 )
         P99_LATENCY:         130.750         (per CPU:         131.000         131.000         129.000         132.000 )

    TRANSACTION_RATE:       32666.400         (per CPU:        8152.200        8169.842        8174.439        8169.897 )

Pod to remote pod with redirect_peer(), TCP_RR:

  # percpu_netperf 10.217.1.33
          RT_LATENCY:          44.449         (per CPU:          43.767          43.127          45.279          45.622 )
        MEAN_LATENCY:          45.065         (per CPU:          44.030          45.530          45.190          45.510 )
      STDDEV_LATENCY:          84.823         (per CPU:          66.770          97.290          84.380          90.850 )
         MIN_LATENCY:          33.500         (per CPU:          33.000          33.000          34.000          34.000 )
         P50_LATENCY:          43.250         (per CPU:          43.000          43.000          43.000          44.000 )
         P90_LATENCY:          46.750         (per CPU:          46.000          47.000          47.000          47.000 )
         P99_LATENCY:          52.750         (per CPU:          51.000          54.000          53.000          53.000 )

    TRANSACTION_RATE:       90039.500         (per CPU:       22848.186       23187.089       22085.077       21919.130 )

  [0] https://linuxplumbersconf.org/event/7/contributions/674/attachments/568/1002/plumbers_2020_cilium_load_balancer.pdf
  [1] https://github.com/borkmann/netperf_scripts/blob/master/percpu_netperfSigned-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201010234006.7075-3-daniel@iogearbox.net

some drivers/network protocols update rx bytes/packets under
u64_stats_update_begin/end sequence.
Add a specific helper like dev_lstats_add()
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

NETDEV_HW_ADDR_T_SLAVE is not used anymore, remove it.
Signed-off-by: NTaehee Yoo <ap420073@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As warned by "make htmldocs", there are two new struct elements
that aren't documented:

	../include/linux/netdevice.h:2159: warning: Function parameter or member 'unlink_list' not described in 'net_device'
	../include/linux/netdevice.h:2159: warning: Function parameter or member 'nested_level' not described in 'net_device'

Fixes: 1fc70edb ("net: core: add nested_level variable in net_device")
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Quite some drivers make conditional decisions based on in_interrupt() to
invoke either netif_rx() or netif_rx_ni().

Conditionals based on in_interrupt() or other variants of preempt count
checks in drivers should not exist for various reasons and Linus clearly
requested to either split the code pathes or pass an argument to the
common functions which provides the context.

This is obviously the correct solution, but for some of the affected
drivers this needs a major rewrite due to their convoluted structure.

As in_interrupt() usage in drivers needs to be phased out, provide
netif_rx_any_context() as a stop gap for these drivers.

This confines the in_interrupt() conditional to core code which in turn
allows to remove the access to this check for driver code and provides one
central place to do further modifications once the driver maze is cleaned
up.
Suggested-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to add a new variable 'nested_level' into the net_device
structure.
This variable will be used as a parameter of spin_lock_nested() of
dev->addr_list_lock.

netif_addr_lock() can be called recursively so spin_lock_nested() is
used instead of spin_lock() and dev->lower_level is used as a parameter
of spin_lock_nested().
But, dev->lower_level value can be updated while it is being used.
So, lockdep would warn a possible deadlock scenario.

When a stacked interface is deleted, netif_{uc | mc}_sync() is
called recursively.
So, spin_lock_nested() is called recursively too.
At this moment, the dev->lower_level variable is used as a parameter of it.
dev->lower_level value is updated when interfaces are being unlinked/linked
immediately.
Thus, After unlinking, dev->lower_level shouldn't be a parameter of
spin_lock_nested().

    A (macvlan)
    |
    B (vlan)
    |
    C (bridge)
    |
    D (macvlan)
    |
    E (vlan)
    |
    F (bridge)

    A->lower_level : 6
    B->lower_level : 5
    C->lower_level : 4
    D->lower_level : 3
    E->lower_level : 2
    F->lower_level : 1

When an interface 'A' is removed, it releases resources.
At this moment, netif_addr_lock() would be called.
Then, netdev_upper_dev_unlink() is called recursively.
Then dev->lower_level is updated.
There is no problem.

But, when the bridge module is removed, 'C' and 'F' interfaces
are removed at once.
If 'F' is removed first, a lower_level value is like below.
    A->lower_level : 5
    B->lower_level : 4
    C->lower_level : 3
    D->lower_level : 2
    E->lower_level : 1
    F->lower_level : 1

Then, 'C' is removed. at this moment, netif_addr_lock() is called
recursively.
The ordering is like this.
C(3)->D(2)->E(1)->F(1)
At this moment, the lower_level value of 'E' and 'F' are the same.
So, lockdep warns a possible deadlock scenario.

In order to avoid this problem, a new variable 'nested_level' is added.
This value is the same as dev->lower_level - 1.
But this value is updated in rtnl_unlock().
So, this variable can be used as a parameter of spin_lock_nested() safely
in the rtnl context.

Test commands:
   ip link add br0 type bridge vlan_filtering 1
   ip link add vlan1 link br0 type vlan id 10
   ip link add macvlan2 link vlan1 type macvlan
   ip link add br3 type bridge vlan_filtering 1
   ip link set macvlan2 master br3
   ip link add vlan4 link br3 type vlan id 10
   ip link add macvlan5 link vlan4 type macvlan
   ip link add br6 type bridge vlan_filtering 1
   ip link set macvlan5 master br6
   ip link add vlan7 link br6 type vlan id 10
   ip link add macvlan8 link vlan7 type macvlan

   ip link set br0 up
   ip link set vlan1 up
   ip link set macvlan2 up
   ip link set br3 up
   ip link set vlan4 up
   ip link set macvlan5 up
   ip link set br6 up
   ip link set vlan7 up
   ip link set macvlan8 up
   modprobe -rv bridge

Splat looks like:
[   36.057436][  T744] WARNING: possible recursive locking detected
[   36.058848][  T744] 5.9.0-rc6+ #728 Not tainted
[   36.059959][  T744] --------------------------------------------
[   36.061391][  T744] ip/744 is trying to acquire lock:
[   36.062590][  T744] ffff8c4767509280 (&vlan_netdev_addr_lock_key){+...}-{2:2}, at: dev_set_rx_mode+0x19/0x30
[   36.064922][  T744]
[   36.064922][  T744] but task is already holding lock:
[   36.066626][  T744] ffff8c4767769280 (&vlan_netdev_addr_lock_key){+...}-{2:2}, at: dev_uc_add+0x1e/0x60
[   36.068851][  T744]
[   36.068851][  T744] other info that might help us debug this:
[   36.070731][  T744]  Possible unsafe locking scenario:
[   36.070731][  T744]
[   36.072497][  T744]        CPU0
[   36.073238][  T744]        ----
[   36.074007][  T744]   lock(&vlan_netdev_addr_lock_key);
[   36.075290][  T744]   lock(&vlan_netdev_addr_lock_key);
[   36.076590][  T744]
[   36.076590][  T744]  *** DEADLOCK ***
[   36.076590][  T744]
[   36.078515][  T744]  May be due to missing lock nesting notation
[   36.078515][  T744]
[   36.080491][  T744] 3 locks held by ip/744:
[   36.081471][  T744]  #0: ffffffff98571df0 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x236/0x490
[   36.083614][  T744]  #1: ffff8c4767769280 (&vlan_netdev_addr_lock_key){+...}-{2:2}, at: dev_uc_add+0x1e/0x60
[   36.085942][  T744]  #2: ffff8c476c8da280 (&bridge_netdev_addr_lock_key/4){+...}-{2:2}, at: dev_uc_sync+0x39/0x80
[   36.088400][  T744]
[   36.088400][  T744] stack backtrace:
[   36.089772][  T744] CPU: 6 PID: 744 Comm: ip Not tainted 5.9.0-rc6+ #728
[   36.091364][  T744] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[   36.093630][  T744] Call Trace:
[   36.094416][  T744]  dump_stack+0x77/0x9b
[   36.095385][  T744]  __lock_acquire+0xbc3/0x1f40
[   36.096522][  T744]  lock_acquire+0xb4/0x3b0
[   36.097540][  T744]  ? dev_set_rx_mode+0x19/0x30
[   36.098657][  T744]  ? rtmsg_ifinfo+0x1f/0x30
[   36.099711][  T744]  ? __dev_notify_flags+0xa5/0xf0
[   36.100874][  T744]  ? rtnl_is_locked+0x11/0x20
[   36.101967][  T744]  ? __dev_set_promiscuity+0x7b/0x1a0
[   36.103230][  T744]  _raw_spin_lock_bh+0x38/0x70
[   36.104348][  T744]  ? dev_set_rx_mode+0x19/0x30
[   36.105461][  T744]  dev_set_rx_mode+0x19/0x30
[   36.106532][  T744]  dev_set_promiscuity+0x36/0x50
[   36.107692][  T744]  __dev_set_promiscuity+0x123/0x1a0
[   36.108929][  T744]  dev_set_promiscuity+0x1e/0x50
[   36.110093][  T744]  br_port_set_promisc+0x1f/0x40 [bridge]
[   36.111415][  T744]  br_manage_promisc+0x8b/0xe0 [bridge]
[   36.112728][  T744]  __dev_set_promiscuity+0x123/0x1a0
[   36.113967][  T744]  ? __hw_addr_sync_one+0x23/0x50
[   36.115135][  T744]  __dev_set_rx_mode+0x68/0x90
[   36.116249][  T744]  dev_uc_sync+0x70/0x80
[   36.117244][  T744]  dev_uc_add+0x50/0x60
[   36.118223][  T744]  macvlan_open+0x18e/0x1f0 [macvlan]
[   36.119470][  T744]  __dev_open+0xd6/0x170
[   36.120470][  T744]  __dev_change_flags+0x181/0x1d0
[   36.121644][  T744]  dev_change_flags+0x23/0x60
[   36.122741][  T744]  do_setlink+0x30a/0x11e0
[   36.123778][  T744]  ? __lock_acquire+0x92c/0x1f40
[   36.124929][  T744]  ? __nla_validate_parse.part.6+0x45/0x8e0
[   36.126309][  T744]  ? __lock_acquire+0x92c/0x1f40
[   36.127457][  T744]  __rtnl_newlink+0x546/0x8e0
[   36.128560][  T744]  ? lock_acquire+0xb4/0x3b0
[   36.129623][  T744]  ? deactivate_slab.isra.85+0x6a1/0x850
[   36.130946][  T744]  ? __lock_acquire+0x92c/0x1f40
[   36.132102][  T744]  ? lock_acquire+0xb4/0x3b0
[   36.133176][  T744]  ? is_bpf_text_address+0x5/0xe0
[   36.134364][  T744]  ? rtnl_newlink+0x2e/0x70
[   36.135445][  T744]  ? rcu_read_lock_sched_held+0x32/0x60
[   36.136771][  T744]  ? kmem_cache_alloc_trace+0x2d8/0x380
[   36.138070][  T744]  ? rtnl_newlink+0x2e/0x70
[   36.139164][  T744]  rtnl_newlink+0x47/0x70
[ ... ]

Fixes: 845e0ebb ("net: change addr_list_lock back to static key")
Signed-off-by: NTaehee Yoo <ap420073@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Functions related to nested interface infrastructure such as
netdev_walk_all_{ upper | lower }_dev() pass both private functions
and "data" pointer to handle their own things.
At this point, the data pointer type is void *.
In order to make it easier to expand common variables and functions,
this new netdev_nested_priv structure is added.

In the following patch, a new member variable will be added into this
struct to fix the lockdep issue.
Signed-off-by: NTaehee Yoo <ap420073@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Earlier commit 316cdaa1 ("net: add option to not create fall-back
tunnels in root-ns as well") removed the CONFIG_SYSCTL to enable the
kernel-commandline to work. However, this variable gets defined only
when CONFIG_SYSCTL option is selected.

With this change the behavior would default to creating fall-back
tunnels in all namespaces when CONFIG_SYSCTL is not selected and
the kernel commandline option will be ignored.

Fixes: 316cdaa1 ("net: add option to not create fall-back tunnels in root-ns as well")
Signed-off-by: NMahesh Bandewar <maheshb@google.com>
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Reported-by: Nkernel test robot <lkp@intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is no callers in tree, so can remove it.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Reviewed-by: NSaeed Mahameed <saeedm@nvidia.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To RCUify napi->dev_list we need to replace list_del_init()
with list_del_rcu(). There is no _init() version for RCU for
obvious reasons. Up until now netif_napi_del() was idempotent
so to make sure it remains such add a bit which is set when
NAPI is listed, and cleared when it removed. Since we don't
expect multiple calls to netif_napi_add() to be correct,
add a warning on that side.

Now that napi_hash_add / napi_hash_del are only called by
napi_add / del we can actually steal its bit. We just need
to make sure hash node is initialized correctly.
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We allow drivers to call napi_hash_del() before calling
netif_napi_del() to batch RCU grace periods. This makes
the API asymmetric and leaks internal implementation details.
Soon we will want the grace period to protect more than just
the NAPI hash table.

Restructure the API and have drivers call a new function -
__netif_napi_del() if they want to take care of RCU waits.

Note that only core was checking the return status from
napi_hash_del() so the new helper does not report if the
NAPI was actually deleted.

Some notes on driver oddness:
 - veth observed the grace period before calling netif_napi_del()
   but that should not matter
 - myri10ge observed normal RCU flavor
 - bnx2x and enic did not actually observe the grace period
   (unless they did so implicitly)
 - virtio_net and enic only unhashed Rx NAPIs

The last two points seem to indicate that the calls to
napi_hash_del() were a left over rather than an optimization.
Regardless, it's easy enough to correct them.

This patch may introduce extra synchronize_net() calls for
interfaces which set NAPI_STATE_NO_BUSY_POLL and depend on
free_netdev() to call netif_napi_del(). This seems inevitable
since we want to use RCU for netpoll dev->napi_list traversal,
and almost no drivers set IFF_DISABLE_NETPOLL.
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix kernel-doc warning in <linux/netdevice.h>:

../include/linux/netdevice.h:2158: warning: Function parameter or member 'xdp_state' not described in 'net_device'

Fixes: 7f0a8382 ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Fix kernel-doc warning in <linux/netdevice.h>:

../include/linux/netdevice.h:2158: warning: Function parameter or member 'proto_down_reason' not described in 'net_device'

Fixes: 829eb208 ("rtnetlink: add support for protodown reason")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Acked-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Replace the explicit umem reference passed to the driver in AF_XDP
zero-copy mode with the buffer pool instead. This in preparation for
extending the functionality of the zero-copy mode so that umems can be
shared between queues on the same netdev and also between netdevs. In
this commit, only an umem reference has been added to the buffer pool
struct. But later commits will add other entities to it. These are
going to be entities that are different between different queue ids
and netdevs even though the umem is shared between them.
Signed-off-by: NMagnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NBjörn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/1598603189-32145-2-git-send-email-magnus.karlsson@intel.com

The sysctl that was added  earlier by commit 79134e6c ("net: do
not create fallback tunnels for non-default namespaces") to create
fall-back only in root-ns. This patch enhances that behavior to provide
option not to create fallback tunnels in root-ns as well. Since modules
that create fallback tunnels could be built-in and setting the sysctl
value after booting is pointless, so added a kernel cmdline options to
change this default. The default setting is preseved for backward
compatibility. The kernel command line option of fb_tunnels=initns will
set the sysctl value to 1 and will create fallback tunnels only in initns
while kernel cmdline fb_tunnels=none will set the sysctl value to 2 and
fallback tunnels are skipped in every netns.
Signed-off-by: NMahesh Bandewar <maheshb@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Maciej Zenczykowski <maze@google.com>
Cc: Jian Yang <jianyang@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Many device drivers use the same prefetch code structure to
deal with small L1 cacheline size.
Take this code into a function and call it from the drivers.
Suggested-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Reviewed-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, processes sending traffic to a local bridge with an
encapsulation device as a port don't get ICMP errors if they exceed
the PMTU of the encapsulated link.

David Ahern suggested this as a hack, but it actually looks like
the correct solution: when we update the PMTU for a given destination
by means of updating or creating a route exception, the encapsulation
might trigger this because of PMTU discovery happening either on the
encapsulation device itself, or its lower layer. This happens on
bridged encapsulations only.

The output interface shouldn't matter, because we already have a
valid destination. Drop the output interface restriction from the
associated route lookup.

For UDP tunnels, we will now have a route exception created for the
encapsulation itself, with a MTU value reflecting its headroom, which
allows a bridge forwarding IP packets originated locally to deliver
errors back to the sending socket.

The behaviour is now consistent with IPv6 and verified with selftests
pmtu_ipv{4,6}_br_{geneve,vxlan}{4,6}_exception introduced later in
this series.

v2:
- reset output interface only for bridge ports (David Ahern)
- add and use netif_is_any_bridge_port() helper (David Ahern)
Suggested-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>