This patch adds hardware channel APIs support between
VF and PF for tunnelling configuration for the VFs.
According to that configuration VFs can run VXLAN/GENEVE/GRE
tunnels over it with tunnel features offloaded.

Using these APIs VF can also request for UDP ports configuration
to the PF, although PF and it's child VFs share the same port.
Signed-off-by: NManish Chopra <manish.chopra@cavium.com>
Signed-off-by: NYuval Mintz <yuval.mintz@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds support for UDP ports in bulletin board
to notify UDP ports change to the VFs
Signed-off-by: NManish Chopra <manish.chopra@cavium.com>
Signed-off-by: NYuval Mintz <yuval.mintz@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch configures UDP ports locally instead of
configuring them in deferred context which would be
helpful in synchronizing UDP ports configuration for VFs
which will be enabled in further patches.
Signed-off-by: NManish Chopra <manish.chopra@cavium.com>
Signed-off-by: NYuval Mintz <yuval.mintz@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch disables tunnel offloads via ndo_features_check()
if given UDP port is not offloaded to hardware. This in turn
allows to run multiple tunnel interfaces using different UDP ports.
Signed-off-by: NManish Chopra <manish.chopra@cavium.com>
Signed-off-by: NYuval Mintz <yuval.mintz@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch enables tunnel feature offloads based on hw configuration
at initialization time instead of enabling them always.
Signed-off-by: NManish Chopra <manish.chopra@cavium.com>
Signed-off-by: NYuval Mintz <yuval.mintz@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch changes the tunnel APIs to use per tunnel
info instead of using bitmasks for all tunnels and also
uses single struct to hold the data to prepare multiple
variant of tunnel configuration ramrods to be sent to the hardware.
Signed-off-by: NManish Chopra <manish.chopra@cavium.com>
Signed-off-by: NYuval Mintz <yuval.mintz@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Guillaume Nault says:

====================
l2tp: add informations about l2tpeth interfaces in /sys

Patch #1 lets userspace retrieve the naming scheme of an l2tpeth
interface, using /sys/class/net/<iface>/name_assign_type.

Patch #2 adds the DEVTYPE field in /sys/class/net/<iface>/uevent so
that userspace can reliably know if a device is an l2tpeth interface.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Export type of l2tpeth interfaces to userspace
(/sys/class/net/<iface>/uevent).
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>
Acked-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Export naming scheme used when creating l2tpeth interfaces
(/sys/class/net/<iface>/name_assign_type). This let userspace know if
the device's name has been generated automatically or defined manually.
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>
Acked-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

per discussion at netconf/netdev:
When we have an action that is capable of branching (example a policer),
we can achieve a continuation of the action graph by programming a
"continue" where we find an exact replica of the same filter rule with a lower
priority and the remainder of the action graph. When you have 100s of thousands
of filters which require such a feature it gets very inefficient to do two
lookups.

This patch completes a leftover feature of action codes. Its time has come.

Example below where a user labels packets with a different skbmark on ingress
of a port depending on whether they have/not exceeded the configured rate.
This mark is then used to make further decisions on some egress port.

 #rate control, very low so we can easily see the effect
sudo $TC actions add action police rate 1kbit burst 90k \
conform-exceed pipe/jump 2 index 10
 # skbedit index 11 will be used if the user conforms
sudo $TC actions add action skbedit mark 11 ok index 11
 # skbedit index 12 will be used if the user does not conform
sudo $TC actions add action skbedit mark 12 ok index 12

 #lets bind the user ..
sudo $TC filter add dev $ETH parent ffff: protocol ip prio 8 u32 \
match ip dst 127.0.0.8/32 flowid 1:10 \
action police index 10 \
action skbedit index 11 \
action skbedit index 12

 #run a ping -f and see what happens..
 #
jhs@foobar:~$ sudo $TC -s filter ls dev $ETH parent ffff: protocol ip
filter pref 8 u32
filter pref 8 u32 fh 800: ht divisor 1
filter pref 8 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:10  (rule hit 2800 success 1005)
  match 7f000008/ffffffff at 16 (success 1005 )
	action order 1:  police 0xa rate 1Kbit burst 23440b mtu 2Kb action pipe/jump 2 overhead 0b
	ref 2 bind 1 installed 207 sec used 122 sec
	Action statistics:
	Sent 84420 bytes 1005 pkt (dropped 0, overlimits 721 requeues 0)
	backlog 0b 0p requeues 0

	action order 2:  skbedit mark 11 pass
	 index 11 ref 2 bind 1 installed 204 sec used 122 sec
 	Action statistics:
	Sent 60564 bytes 721 pkt (dropped 0, overlimits 0 requeues 0)
	backlog 0b 0p requeues 0

	action order 3:  skbedit mark 12 pass
	 index 12 ref 2 bind 1 installed 201 sec used 122 sec
 	Action statistics:
	Sent 23856 bytes 284 pkt (dropped 0, overlimits 0 requeues 0)
	backlog 0b 0p requeues 0

Not bad, about 28% non-conforming packets..
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Merge tag 'linux-can-next-for-4.12-20170425' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next

Marc Kleine-Budde says:

====================
pull-request: can-next 2017-04-25

this is a pull request of 21 patches for net-next/master.

There are 4 patches by Stephane Grosjean for the PEAK PCAN-PCIe FD
CAN-FD boards. The next 7 patches are by Mario Huettel, which add
support for M_CAN IP version >= v3.1.x to the m_can driver. A patch by
Remigiusz Kołłątaj adds support for the Microchip CAN BUS Analyzer. 8
patches by Oliver Hartkopp complete the initial CAN network namespace
support. Wei Yongjun's patch for the ti_hecc driver fixes the return
value check in the probe function.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 4fbae7d8 ("ipvlan: Introduce l3s mode") added
registration of netfilter hooks via nf_register_hooks().

This API provides the illusion of 'global' netfilter hooks by placing the
hooks in all current and future network namespaces.

In case of ipvlan the hook appears to be only needed in the namespace
that contains the ipvlan master device (i.e., usually init_net), so
placing them in all namespaces is not needed.

This switches ipvlan driver to pernet operations, and then only registers
hooks in namespaces where a ipvlan master device is set to l3s mode.

Extra care has to be taken when the master device is moved to another
namespace, as we might have to 'move' the netfilter hooks too.

This is done by storing the namespace the ipvlan port was created in.
On REGISTER event, do (un)register operations in the old/new namespaces.

This will also allow removal of the nf_register_hooks() in a future patch.

Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case of error, the function devm_ioremap_resource() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR().

Fixes: dabf54dd ("can: ti_hecc: Convert TI HECC driver to DT only driver")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Autoload the vcan module when a vcan instance is to be created by
'ip link add type vcan'
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Similar to the virtual ethernet driver veth, vxcan implements a
local CAN traffic tunnel between two virtual CAN network devices.
See Kconfig entry for details.
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The CAN gateway was not implemented as per-net in the initial network
namespace support by Mario Kicherer (8e8cda6d).
This patch enables the CAN gateway to be used in different namespaces.
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The CAN_BCM protocol and its procfs entries were not implemented as per-net
in the initial network namespace support by Mario Kicherer (8e8cda6d).
This patch adds the missing per-net functionality for the CAN BCM.
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The statistics and its proc output was not implemented as per-net in the
initial network namespace support by Mario Kicherer (8e8cda6d).
This patch adds the missing per-net statistics for the CAN subsystem.
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

can_rx_alldev_list is a per-net data structure now. Remove it's definition
here and can_rx_dev_list too.
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The namespace support for the CAN subsystem does not need any additional
memory. So when ".size = 0" there's no extra memory allocated by the system.
And therefore ".id" is obsolete too.
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The can_rx_alldev_list is a per-net data structure now and allocated in
can_pernet_init(). Make sure the memory is free'd in can_pernet_exit() too.
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

SocketCAN driver for Microchip CAN BUS Analyzer
(http://www.microchip.com/development-tools/)

Changes in v4:
- possible memory leak fixed in mcba_usb_write_bulk_callback
- LED support added
- failure handling in mcba_usb_probe improved
- C99 initializers for structs on stack

Changes in v3:
- improved/simplified CAN ID conversion
- functions for transmission of skb and cmd separated
- fixed/improved netif_stop_queue handling
- style/cosmetic corrections

Changes in v2:
- Termination handling reimplemented to fit new netlink API
(IFLA_CAN_TERMINATION)
- Bitrate handling reimplemented to fit new netlink API
(IFLA_CAN_BITRATE)
- CAN ID conversion refactored (changed from macro to inline functions)
- CAN DLC handling using get_can_dlc()
- Endianness handling for can_speed introduced
- Debugging removed
- Redundant error prints removed
- Style/cosmetic corrections (i.e. macro names, redefs, inits etc.)
Signed-off-by: NRemigiusz Kołłątaj <remigiusz.kollataj@mobica.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

* Added defines for TX Event FIFO Element
* Adapted ndo_start_xmit function.
  For versions >= v3.1.x it uses the TX FIFO to optimize the data
  throughput. It stores the echo skb at the same index as in the
  M_CAN's TX FIFO. The frame's message marker is set to this index.
  This message marker is received in the TX Event FIFO after
  the message was successfully transmitted. It is used to echo the
  correct echo skb back to the network stack.
* Added m_can_echo_tx_event function. It reads all received
  message markers in the TX Event FIFO and loops back the
  corresponding echo skbs.
* ISR checks for new TX Event Entry interrupt for version >= 3.1.x.
Signed-off-by: NMario Huettel <mario.huettel@gmx.net>
Reviewed-by: NOliver Hartkopp <socketcan@hartkopp.net>
Tested-by: NQuentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

* TX/TX Event FIFO sizes are configured for version >= v3.1.x
Signed-off-by: NMario Huettel <mario.huettel@gmx.net>
Tested-by: NQuentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

This patch adapts the initialization of the M_CAN. So it can be used
with all versions >= 3.0.x.

Changes:
* Added version element to m_can_priv structure to hold M_CAN version.
* Renamed bittiming structs for version 3.0.x
* Added new bittiming structs for version >= 3.1.x
* Function alloc_m_can_dev takes 2 new arguments. The TX FIFO size and the
  base address of the module.
* Chip configuration for CAN_CTRLMODE_LOOPBACK is changed: Enabled
  CCCR_MON bit. In combination with TEST_LBCK it activates the internal
  loopback mode. Leaving CCCR_MON '0' results in external loopback mode.
* Clocks are temporarily enabled by platform_propbe function in order to
  allow read access to the Core Release register and the Control Register.
  Registers are used to detect M_CAN version and optional Non-ISO Feature.

Initialization of M_CAN for version >= 3.1.x:
* TX FIFO of M_CAN is used to transmit frames. The driver does not need to
  stop the tx queue after each frame sent.
* Initialization of TX Event FIFO is added.
* NON-ISO is fixed for all M_CAN versions < 3.2.x. Version 3.2.x _can_ have
  the NISO (Non-ISO) bit which can switch the mode of the M_CAN to Non-ISO
  mode. This bit does not have to be writeable. Therefore it is checked.
  If it is writable Non-ISO support is added to the controllers supported
  CAN modes.

New Functions:
* Function to check the Core Release version. The read value determines the
  behaviour of the driver.
* Function to check if the NISO bit for version >= 3.2.x is implemented.
Signed-off-by: NMario Huettel <mario.huettel@gmx.net>
Reviewed-by: NOliver Hartkopp <socketcan@hartkopp.net>
Tested-by: NQuentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

* Updated register defines to newest M_CAN version (v3.2.1).
* Changed defines in the whole code.
Signed-off-by: NMario Huettel <mario.huettel@gmx.net>
Reviewed-by: NOliver Hartkopp <socketcan@hartkopp.net>
Tested-by: NQuentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The virtual address of the device was printed. I removed it because it
leaks internal information.
Signed-off-by: NMario Huettel <mario.huettel@gmx.net>
Tested-by: NQuentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

FIFO water marks disabled because the driver doesn't handle water mark
events.
Signed-off-by: NMario Huettel <mario.huettel@gmx.net>
Reviewed-by: NOliver Hartkopp <socketcan@hartkopp.net>
Tested-by: NQuentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

* Disabled interrupt line 1. The driver didn't use it.
Signed-off-by: NMario Huettel <mario.huettel@gmx.net>
Tested-by: NQuentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

This patch adds the support of the PCAN-PCI Express FD boards made
by PEAK-System, for computers using the PCI Express slot.

The PCAN-PCI Express FD has one or two CAN FD channels, depending
on the model. A galvanic isolation of the CAN ports protects
the electronics of the card and the respective computer against
disturbances of up to 500 Volts. The PCAN-PCI Express FD can be operated
with ambient temperatures in a range of -40 to +85 °C.

Such boards run an extented version of the CAN-FD IP running into USB
CAN-FD interfaces from PEAK-System, so this patch adds several new commands
and their corresponding data types to the PEAK CAN-FD common definitions
header file too.
Signed-off-by: NStephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The CAN-FD IP from PEAK-System runs into several kinds of PC CAN-FD
interfaces. Up to now, only the USB CAN-FD adapters were supported by
the Kernel. In order to prepare the adding of some new non-USB CAN-FD
interfaces, this patch moves - and rename - the IP definitions file
from its private (usb) sub-directory into a - newly created - CAN specific
one.
Signed-off-by: NStephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Fixes the usage of the const qualifier in the memory pointer arguments
of the declared inline functions. By changing the line containing "const",
this patch also changes the name of the arg into a more usual one.
Signed-off-by: NStephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

This patch fixes the wrong usage of a specific USB data type into a common
header file. This common header file is intended to define the common data
types and values that define access to the PEAK-System CAN-FD IP, whatever
the PC interface is.
Signed-off-by: NStephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Willem de Bruijn says:

====================
virtio-net tx napi

Add napi for virtio-net transmit completion processing.

Changes:
  v2 -> v3:
    - convert __netif_tx_trylock to __netif_tx_lock on tx napi poll
          ensure that the handler always cleans, to avoid deadlock
    - unconditionally clean in start_xmit
          avoid adding an unnecessary "if (use_napi)" branch
    - remove virtqueue_disable_cb in patch 5/5
          a noop in the common event_idx based loop
    - document affinity_hint_set constraint

  v1 -> v2:
    - disable by default
    - disable unless affinity_hint_set
          because cache misses add up to a third higher cycle cost,
	  e.g., in TCP_RR tests. This is not limited to the patch
	  that enables tx completion cleaning in rx napi.
    - use trylock to avoid contention between tx and rx napi
    - keep interrupts masked during xmit_more (new patch 5/5)
          this improves cycles especially for multi UDP_STREAM, which
	  does not benefit from cleaning tx completions on rx napi.
    - move free_old_xmit_skbs (new patch 3/5)
          to avoid forward declaration

    not changed:
    - deduplicate virnet_poll_tx and virtnet_poll_txclean
          they look similar, but have differ too much to make it
	  worthwhile.
    - delay netif_wake_subqueue for more than 2 + MAX_SKB_FRAGS
          evaluated, but made no difference
    - patch 1/5

  RFC -> v1:
    - dropped vhost interrupt moderation patch:
          not needed and likely expensive at light load
    - remove tx napi weight
        - always clean all tx completions
        - use boolean to toggle tx-napi, instead
    - only clean tx in rx if tx-napi is enabled
        - then clean tx before rx
    - fix: add missing braces in virtnet_freeze_down
    - testing: add 4KB TCP_RR + UDP test results

Based on previous patchsets by Jason Wang:

  [RFC V7 PATCH 0/7] enable tx interrupts for virtio-net
  http://lkml.iu.edu/hypermail/linux/kernel/1505.3/00245.html

Before commit b0c39dbd ("virtio_net: don't free buffers in xmit
ring") the virtio-net driver would free transmitted packets on
transmission of new packets in ndo_start_xmit and, to catch the edge
case when no new packet is sent, also in a timer at 10HZ.

A timer can cause long stalls. VIRTIO_F_NOTIFY_ON_EMPTY avoids stalls
due to low free descriptor count. It does not address a stalls due to
low socket SO_SNDBUF. Increasing timer frequency decreases that stall
time, but increases interrupt rate and, thus, cycle count.

Currently, with no timer, packets are freed only at ndo_start_xmit.
Latency of consume_skb is now unbounded. To avoid a deadlock if a sock
reaches SO_SNDBUF, packets are orphaned on tx. This breaks TCP small
queues.

Reenable TCP small queues by removing the orphan. Instead of using a
timer, convert the driver to regular tx napi. This does not have the
unresolved stall issue and does not have any frequency to tune.

By keeping interrupts enabled by default, napi increases tx
interrupt rate. VIRTIO_F_EVENT_IDX avoids sending an interrupt if
one is already unacknowledged, so makes this more feasible today.
Combine that with an optimization that brings interrupt rate
back in line with the existing version for most workloads:

Tx completion cleaning on rx interrupts elides most explicit tx
interrupts by relying on the fact that many rx interrupts fire.

Tested by running {1, 10, 100} {TCP, UDP} STREAM, RR, 4K_RR benchmarks
from a guest to a server on the host, on an x86_64 Haswell. The guest
runs 4 vCPUs pinned to 4 cores. vhost and the test server are
pinned to a core each.

All results are the median of 5 runs, with variance well < 10%.
Used neper (github.com/google/neper) as test process.

Napi increases single stream throughput, but increases cycle cost.
The optimizations bring this down. The previous patchset saw a
regression with UDP_STREAM, which does not benefit from cleaning tx
interrupts in rx napi. This regression is now gone for 10x, 100x.
Remaining difference is higher 1x TCP_STREAM, lower 1x UDP_STREAM.

The latest results are with process, rx napi and tx napi affine to
the same core. All numbers are lower than the previous patchset.

             upstream     napi
TCP_STREAM:
1x:
  Mbps          27816    39805
  Gcycles         274      285

10x:
  Mbps          42947    42531
  Gcycles         300      296

100x:
  Mbps          31830    28042
  Gcycles         279      269

TCP_RR Latency (us):
1x:
  p50              21       21
  p99              27       27
  Gcycles         180      167

10x:
  p50              40       39
  p99              52       52
  Gcycles         214      211

100x:
  p50             281      241
  p99             411      337
  Gcycles         218      226

TCP_RR 4K:
1x:
  p50              28       29
  p99              34       36
  Gcycles         177      167

10x:
  p50              70       71
  p99              85      134
  Gcycles         213      214

100x:
  p50             442      611
  p99             802      785
  Gcycles         237      216

UDP_STREAM:
1x:
  Mbps          29468    26800
  Gcycles         284      293

10x:
  Mbps          29891    29978
  Gcycles         285      312

100x:
  Mbps          30269    30304
  Gcycles         318      316

UDP_RR:
1x:
  p50              19       19
  p99              23       23
  Gcycles         180      173

10x:
  p50              35       40
  p99              54       64
  Gcycles         245      237

100x:
  p50             234      286
  p99             484      473
  Gcycles         224      214

Note that GSO is enabled, so 4K RR still translates to one packet
per request.

Lower throughput at 100x vs 10x can be (at least in part)
explained by looking at bytes per packet sent (nstat). It likely
also explains the lower throughput of 1x for some variants.

upstream:

 N=1   bytes/pkt=16581
 N=10  bytes/pkt=61513
 N=100 bytes/pkt=51558

at_rx:

 N=1   bytes/pkt=65204
 N=10  bytes/pkt=65148
 N=100 bytes/pkt=56840
====================
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

Tx napi mode increases the rate of transmit interrupts. Suppress some
by masking interrupts while more packets are expected. The interrupts
will be reenabled before the last packet is sent.

This optimization reduces the througput drop with tx napi for
unidirectional flows such as UDP_STREAM that do not benefit from
cleaning tx completions in the the receive napi handler.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Amortize the cost of virtual interrupts by doing both rx and tx work
on reception of a receive interrupt if tx napi is enabled. With
VIRTIO_F_EVENT_IDX, this suppresses most explicit tx completion
interrupts for bidirectional workloads.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

An upcoming patch will call free_old_xmit_skbs indirectly from
virtnet_poll. Move the function above this to avoid having to
introduce a forward declaration.

This is a pure move: no code changes.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Convert virtio-net to a standard napi tx completion path. This enables
better TCP pacing using TCP small queues and increases single stream
throughput.

The virtio-net driver currently cleans tx descriptors on transmission
of new packets in ndo_start_xmit. Latency depends on new traffic, so
is unbounded. To avoid deadlock when a socket reaches its snd limit,
packets are orphaned on tranmission. This breaks socket backpressure,
including TSQ.

Napi increases the number of interrupts generated compared to the
current model, which keeps interrupts disabled as long as the ring
has enough free descriptors. Keep tx napi optional and disabled for
now. Follow-on patches will reduce the interrupt cost.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Prepare virtio-net for tx napi by converting existing napi code to
use helper functions. This also deduplicates some logic.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Doing a full 64-bit decomposition is really stupid especially for
simple values like 0 and -1.

But if we are going to optimize this, go all the way and try for all 2
and 3 instruction sequences not requiring a temporary register as
well.

First we do the easy cases where it's a zero or sign extended 32-bit
number (sethi+or, sethi+xor, respectively).

Then we try to find a range of set bits we can load simply then shift
up into place, in various ways.

Then we try negating the constant and see if we can do a simple
sequence using that with a xor at the end.  (f.e. the range of set
bits can't be loaded simply, but for the negated value it can)

The final optimized strategy involves 4 instructions sequences not
needing a temporary register.

Otherwise we sadly fully decompose using a temp..

Example, from ALU64_XOR_K: 0x0000ffffffff0000 ^ 0x0 = 0x0000ffffffff0000:

0000000000000000 <foo>:
   0:   9d e3 bf 50     save  %sp, -176, %sp
   4:   01 00 00 00     nop
   8:   90 10 00 18     mov  %i0, %o0
   c:   13 3f ff ff     sethi  %hi(0xfffffc00), %o1
  10:   92 12 63 ff     or  %o1, 0x3ff, %o1     ! ffffffff <foo+0xffffffff>
  14:   93 2a 70 10     sllx  %o1, 0x10, %o1
  18:   15 3f ff ff     sethi  %hi(0xfffffc00), %o2
  1c:   94 12 a3 ff     or  %o2, 0x3ff, %o2     ! ffffffff <foo+0xffffffff>
  20:   95 2a b0 10     sllx  %o2, 0x10, %o2
  24:   92 1a 60 00     xor  %o1, 0, %o1
  28:   12 e2 40 8a     cxbe  %o1, %o2, 38 <foo+0x38>
  2c:   9a 10 20 02     mov  2, %o5
  30:   10 60 00 03     b,pn   %xcc, 3c <foo+0x3c>
  34:   01 00 00 00     nop
  38:   9a 10 20 01     mov  1, %o5     ! 1 <foo+0x1>
  3c:   81 c7 e0 08     ret
  40:   91 eb 40 00     restore  %o5, %g0, %o0
Signed-off-by: NDavid S. Miller <davem@davemloft.net>