RFC4960, section 8.3 says:

  On an idle destination address that is allowed to heartbeat,
  it is recommended that a HEARTBEAT chunk is sent once per RTO
  of that destination address plus the protocol parameter
  'HB.interval', with jittering of +/- 50% of the RTO value,
  and exponential backoff of the RTO if the previous HEARTBEAT
  is unanswered.

Currently, we calculate jitter via sctp_jitter() function first,
and then add its result to the current RTO for the new timeout:

  TMO = RTO + (RAND() % RTO) - (RTO / 2)
              `------------------------^-=> sctp_jitter()

Instead, we can just simplify all this by directly calculating:

  TMO = (RTO / 2) + (RAND() % RTO)

With the help of prandom_u32_max(), we don't need to open code
our own global PRNG, but can instead just make use of the per
CPU implementation of prandom with better quality numbers. Also,
we can now spare us the conditional for divide by zero check
since no div or mod operation needs to be used. Note that
prandom_u32_max() won't emit the same result as a mod operation,
but we really don't care here as we only want to have a random
number scaled into RTO interval.

Note, exponential RTO backoff is handeled elsewhere, namely in
sctp_do_8_2_transport_strike().
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Sathya Perla says:

====================
be2net: patch set

v2 change: merged 2 lines into one in patch 4

Patch 1 refactors be_cmd_get_profile_config() routine to reduce
code duplication by using the be_cmd_notify_wait() routine, instead
of using a separate variant of the code for MBOX and MCCQ.

Patch 2 introduces the required FW-cmd code in the PF to query
RSS support on a VF. This is in preparation for patch 3.

Patch 3 adds support for the PF driver to re-configure the resource
distribution in FW based on the number of VFs enabled by the user. When
the user is not interested in enabling VFs, all resources of a port are
set-aside for the PF. If less than maximum number of VFs are enabled, then
each VF gets a better share of the resources and can now enable RSS (if
the interface supports it.)

Patch 4 is a minor fix to re-enable HW vlan filtering as soon as the number
of vlans programmed is within the HW limit.

Please consider applying to net-next tree. Thanks!
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

While adding vlans, when the HW limit of vlan filters is reached, the
driver enables vlan promiscuous mode.
Similarily, while removing vlans, the driver must re-enable HW filtering
as soon as the number of vlan filters is within the HW limit.
Signed-off-by: Kalesh AP <kalesh.purayil@emulex.com>
Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If SR-IOV is enabled in the adapter, the FW distributes queue resources
evenly across the PF and it's VFs. If the user is not interested in enabling
VFs, the queues set aside for VFs are wasted.
This patch adds support for the PF driver to re-configure the resource
distribution in FW based on the number of VFs enabled by the user.
This also allows for supporting RSS queues on VFs, when less number of VFs
are enabled per PF. When maximum number of VFs are enabled, each VF typically
gets only one RXQ.
Signed-off-by: Vasundhara Volam <vasundhara.volam@emulex.com>
Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The PF driver must query the FW for VF's interface capabilities
to know if the VF is RSS capable or not.
This patch is in preparation for enabling RSS on VFs on Skyhawk-R.
Signed-off-by: Vasundhara Volam <vasundhara.volam@emulex.com>
Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix be_cmd_get_profile_cmd() to use be_cmd_notify_wait() routine,
which uses MBOX if MCCQ has not been created. Doing this reduces
code duplication; we don't need the _mbox/_mccq() variants anymore.
Signed-off-by: Vasundhara Volam <vasundhara.volam@emulex.com>
Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix checkpatch warning:
WARNING: kfree(NULL) is safe this check is probably not required

Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since consume_skb() (and hence dev_kfree_skb() macro) checks the passed pointer
for NULL, there's no need to check for NULL before invoking dev_kfree_skb().
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Prashant Sreedharan <prashant@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Harish Patil says:

====================
qlcnic: Enhance Tx timeout debug data collection.

The following set of patches are for enhancing Tx timeout debug collection

- Collect a firmware dump on first Tx timeout if netif_msg_tx_err() is set
- Log Receive and Status ring info on Tx timeout, in addition to Tx ring info
- Log additional Tx ring info if netif_msg_tx_err() is set
- Update driver version to 5.3.61

Please apply this series to net-next.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Harish Patil <harish.patil@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

- Collect a firmware dump on first Tx timeout if netif_msg_tx_err() is set
- Log Receive and Status ring info on Tx timeout, in addition to Tx ring info
- Log additional Tx ring info if netif_msg_tx_err() is set
Signed-off-by: Harish Patil <harish.patil@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

based on checkpatch:
"debugfs_remove_recursive(NULL) is safe this check is probably not required"

Cc: Dmitry Tarnyagin <dmitry.tarnyagin@lockless.no>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c: remove unnecessary null test before debugfs_remove_recursive

Fix checkpatch warning:
"WARNING: debugfs_remove_recursive(NULL) is safe this check is probably not required"

Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

When an UDP application switches from AF_INET to AF_INET6 sockets, we
have a small performance degradation for IPv4 communications because of
extra cache line misses to access ipv6only information.

This can also be noticed for TCP listeners, as ipv6_only_sock() is also
used from __inet_lookup_listener()->compute_score()

This is magnified when SO_REUSEPORT is used.

Move ipv6only into struct sock_common so that it is available at
no extra cost in lookups.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jeff Kirsher says:

====================
Intel Wired LAN Driver Updates 2014-07-01

This series contains updates to i40e, i40evf, igb and ixgbe.

Shannon adds the Base Address High and Low to the admin queue structure
to simplify the logic in the configuration routines.  Also adds code to
clear all queues and interrupts to help clean up after a PXE or other
early boot activity.

Kevin fixes mask assignment value since -1 cannot be used for unsigned
integer types.

Mitch fixes an issue where in some circumstances the reply from the PF
would come back before we were able to properly modify the admin queue
pending and required flags.  This would mess up the flags and put the
driver in an indeterminate state, so fix this by simply setting the flags
before sending the request to the admin queue.  Also changes the branding
string for i40evf to reduce confusion and to match up with our other
marketing materials.

Kamil adds a new variable defining admin send queue (ASQ) command write
back timeout to allow for dynamic modification of this timeout.

Anjali fix a bug in the flow director filter replay logic, so that we
call a replay after a sideband reset correctly.

Jesse adds code to initialize all members of the context descriptor to
prevent possible stale data.

Christopher fixes i40e to prevent writing to reserved bits, since the
queue index is only 0-127.

Jacob removes the unneeded header export.h from the i40e PTP code.
Fixes ixgbe PTP code where the PPS signal was not correct, as it
generates a one half HZ clock signal, it only generates one level
change per second.  To generate a full clock, we need two level changes
per second.

Todd provides a fix for igb to bring up link when the PHY has powered
up, which was reported by Jeff Westfahl.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This limitation maybe had some reason in the past, but now there is not
one -> removing this.
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Veaceslav Falico <vfalico@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Hariprasad Shenai says:

====================
cxgb4: Fix for PCI passthrough and some Misc. fixes

This patch series fixes probe failure in VM when PF is exposed through PCI
Passthrough. Adds support to use firmware interface to get BAR0 value.
Replace the backdoor mechanism to access the HW memory with PCIe Window method
which fixes memory I/O. Also adds device ID of few more adapters for cxgb4 and
cxgb4vf driver.

The patches series is created against 'net-next' tree.
And includes patches on cxgb4, cxgb4vf and iw_cxgb4 driver.

Since this patch-series contains mainly cxgb4 related changes, we would like to
request this patch series to get merged via David Miller's 'net-next' tree.

We have included all the maintainers of respective drivers. Kindly review the
change and let us know in case of any review comments.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Rip out a bunch of redundant PCI-E Memory Window Read/Write routines,
collapse the more general purpose routines into a single routine
thereby eliminating the need for a large stack frame (and extra data
copying) in the outer routine, change everything to use the improved
routine t4_memory_rw.

Based on origninal work by Casey Leedom <leedom@chelsio.com> and
Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use the firmware interface to get the BAR0 value since we really don't want
to use the PCI-E Configuration Space Backdoor access which is owned by the
firmware.

Set up PCI-E Memory Window registers using the true values programmed into
BAR registers.  When the PF4 "Master Function" is exported to a Virtual
Machine, the values returned by pci_resource_start() will be for the
synthetic PCI-E Configuration Space and not the real addresses. But we need
to program the PCI-E Memory Window address decoders with the real addresses
that we're going to be using in order to have accesses through the Memory
Windows work.

Based on origninal work by Casey Leedom <leedom@chelsio.com>
Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Change logic which determines our Physical Function at PCI Probe time.
Now we read the PL_WHOAMI register and get the Physical Function.

Pass Physical Function to Upper Layer Drivers in lld_info structure in the
new field "pf" added to lld_info.  This is useful for the cases where the
PF, say PF4, is attached to a Virtual Machine via some form of "PCI
Pass Through" technology and the PCI Function shows up as PF0 in the VM.

Based on original work by Casey Leedom <leedom@chelsio.com>
Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stefan Sørensen says:

====================
dp83640: Increase support perout pins

This patch series increases the number of periodic output pins supported
on the dp83640 to 7, and allows for reprogramming the calibration pin.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The ptp pin function programming does not allow calibration pin to change
function. This is problematic on hardware that uses the default calibration
pin for other purposes.

Removing this limitation does not impact calibration if userspace does not
reprogram the calibration pin.
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

For consistency, use the ptp_find_pin function to get the calibration pin,
not gpio_tab.
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This constraints the pin assignment to not allow the calibration function to
be reassigned and only allow reassigning the calibratin pin if only one phy is
connected.
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch increases the number of supported periodic output pins from
1 to 7. The last pin is reserved for sync.
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Periodic output triggers 0 and 1 of the dp83640 has a programmable
duty-cycle which is controlled by the Pulsewidth2 field of the trigger
data register.  This field is not documented in the datasheet, but it
is described in the "PHYTER Software Development Guide" section
3.1.4.1. Failing to set the field can result in unstable/no trigger
output.

Add programming of the Pulsewidth2 field, setting it to the same value
as the Pulsewidth field for a 50% duty cycle.
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Yuval Mintz says:

====================
bnx2x: Enhancement patch series

This patch series introduces the ability to propagate link parameters
to VFs as well as control the VF link via hypervisor.

In addition, it contains 2 small improvements [one IOV-related and the
other improves performance on machines with short cache lines].

Please consider applying these patches to `net-next'.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

There are linux distributions where the inbox bnx2x driver contains SRIOV
support but doesn't contain the changes introduced in b9871bcf
"bnx2x: VF RSS support - PF side".

A VF in a VM running that distribution over a new hypervisor will access
incorrect addresses when trying to transmit packets, causing an attention
in the hypervisor and making that VF inactive until FLRed.

The driver in the VM has to ne upgraded [no real way to overcome this], but
due to the HW attention currently arising upgrading the driver in the VM
would not suffice [since the VF needs also be FLRed if the previous driver
was already loaded].

This patch causes the PF to fail the acquire message from a VF running an
old problematic driver; The VF will then gracefully fail it's probe preventing
the HW attention [and allow clean upgrade of driver in VM].
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This improves the performance of driver on machine with L1_CACHE_SHIFT of at
most 32 bytes [HW was planned for 64-byte aligned fastpath data].
Signed-off-by: Dmitry Kravkov <Dmitry.Kravkov@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Until now VFs were oblvious to the actual configured link parameters.
This patch does 2 things:

  1. It enables a PF to inform its VF using the bulletin board of the link
     configured, and allows the VF to present that information.

  2. It adds support of `ndo_set_vf_link_state', allowing the hypervisor
     to set the VF link state.
Signed-off-by: Dmitry Kravkov <Dmitry.Kravkov@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jesper Dangaard Brouer says:

====================
Optimizing pktgen for single CPU performance

This series focus on optimizing "pktgen" for single CPU performance.

V2-series:
 - Removed some patches
 - Doc real reason for TX ring buffer filling up

NIC tuning for pktgen:
 http://netoptimizer.blogspot.dk/2014/06/pktgen-for-network-overload-testing.html

General overload setup according to:
 http://netoptimizer.blogspot.dk/2014/04/basic-tuning-for-network-overload.html

Hardware:
 System: CPU E5-2630
 NIC: Intel ixgbe/82599 chip

Testing done with net-next git tree on top of
 commit 6623b419 ("Merge branch 'master' of...jkirsher/net-next")

Pktgen script exercising race condition:
 https://github.com/netoptimizer/network-testing/blob/master/pktgen/unit_test01_race_add_rem_device_loop.sh

Tool for measuring LOCK overhead:
 https://github.com/netoptimizer/network-testing/blob/master/src/overhead_cmpxchg.c
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The if_lock()/if_unlock() in next_to_run() adds a significant
overhead, because its called for every packet in busy loop of
pktgen_thread_worker().  (Thomas Graf originally pointed me
at this lock problem).

Removing these two "LOCK" operations should in theory save us approx
16ns (8ns x 2), as illustrated below we do save 16ns when removing
the locks and introducing RCU protection.

Performance data with CLONE_SKB==100000, TX-size=512, rx-usecs=30:
 (single CPU performance, ixgbe 10Gbit/s, E5-2630)
 * Prev   : 5684009 pps --> 175.93ns (1/5684009*10^9)
 * RCU-fix: 6272204 pps --> 159.43ns (1/6272204*10^9)
 * Diff   : +588195 pps --> -16.50ns

To understand this RCU patch, I describe the pktgen thread model
below.

In pktgen there is several kernel threads, but there is only one CPU
running each kernel thread.  Communication with the kernel threads are
done through some thread control flags.  This allow the thread to
change data structures at a know synchronization point, see main
thread func pktgen_thread_worker().

Userspace changes are communicated through proc-file writes.  There
are three types of changes, general control changes "pgctrl"
(func:pgctrl_write), thread changes "kpktgend_X"
(func:pktgen_thread_write), and interface config changes "etcX@N"
(func:pktgen_if_write).

Userspace "pgctrl" and "thread" changes are synchronized via the mutex
pktgen_thread_lock, thus only a single userspace instance can run.
The mutex is taken while the packet generator is running, by pgctrl
"start".  Thus e.g. "add_device" cannot be invoked when pktgen is
running/started.

All "pgctrl" and all "thread" changes, except thread "add_device",
communicate via the thread control flags.  The main problem is the
exception "add_device", that modifies threads "if_list" directly.

Fortunately "add_device" cannot be invoked while pktgen is running.
But there exists a race between "rem_device_all" and "add_device"
(which normally don't occur, because "rem_device_all" waits 125ms
before returning). Background'ing "rem_device_all" and running
"add_device" immediately allow the race to occur.

The race affects the threads (list of devices) "if_list".  The if_lock
is used for protecting this "if_list".  Other readers are given
lock-free access to the list under RCU read sections.

Note, interface config changes (via proc) can occur while pktgen is
running, which worries me a bit.  I'm assuming proc_remove() takes
appropriate locks, to assure no writers exists after proc_remove()
finish.

I've been running a script exercising the race condition (leading me
to fix the proc_remove order), without any issues.  The script also
exercises concurrent proc writes, while the interface config is
getting removed.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Avoid calling set_current_state() inside the busy-loop in
pktgen_thread_worker().  In case of pkt_dev->delay, then it is still
used/enabled in pktgen_xmit() via the spin() call.

The set_current_state(TASK_INTERRUPTIBLE) uses a xchg, which implicit
is LOCK prefixed.  I've measured the asm LOCK operation to take approx
8ns on this E5-2630 CPU.  Performance increase corrolate with this
measurement.

Performance data with CLONE_SKB==100000, rx-usecs=30:
 (single CPU performance, ixgbe 10Gbit/s, E5-2630)
 * Prev:  5454050 pps --> 183.35ns (1/5454050*10^9)
 * Now:   5684009 pps --> 175.93ns (1/5684009*10^9)
 * Diff:  +229959 pps -->  -7.42ns
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Using pktgen I'm seeing the ixgbe driver "push-back", due TX ring
running full.  Thus, the TX ring is artificially limiting pktgen.
(Diagnose via "ethtool -S", look for "tx_restart_queue" or "tx_busy"
counters.)

Using ixgbe, the real reason behind the TX ring running full, is due
to TX ring not being cleaned up fast enough. The ixgbe driver combines
TX+RX ring cleanups, and the cleanup interval is affected by the
ethtool --coalesce setting of parameter "rx-usecs".

Do not increase the default NIC TX ring buffer or default cleanup
interval.  Instead simply document that pktgen needs special NIC
tuning for maximum packet per sec performance.

Performance results with pktgen with clone_skb=100000.
TX ring size 512 (default), adjusting "rx-usecs":
 (Single CPU performance, E5-2630, ixgbe)
 - 3935002 pps - rx-usecs:  1 (irqs:  9346)
 - 5132350 pps - rx-usecs: 10 (irqs: 99157)
 - 5375111 pps - rx-usecs: 20 (irqs: 50154)
 - 5454050 pps - rx-usecs: 30 (irqs: 33872)
 - 5496320 pps - rx-usecs: 40 (irqs: 26197)
 - 5502510 pps - rx-usecs: 50 (irqs: 21527)

TX ring size adjusting (ethtool -G), "rx-usecs==1" (default):
 - 3935002 pps - tx-size:  512
 - 5354401 pps - tx-size:  768
 - 5356847 pps - tx-size: 1024
 - 5327595 pps - tx-size: 1536
 - 5356779 pps - tx-size: 2048
 - 5353438 pps - tx-size: 4096

Notice after commit 6f25cd47 (pktgen: fix xmit test for BQL enabled
devices) pktgen uses netif_xmit_frozen_or_drv_stopped() and ignores
the BQL "stack" pause (QUEUE_STATE_STACK_XOFF) flag.  This allow us to put
more pressure on the TX ring buffers.

It is the ixgbe_maybe_stop_tx() call that stops the transmits, and
pktgen respecting this in the call to netif_xmit_frozen_or_drv_stopped(txq).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This stub now allows userspace to see IFLA_INFO_KIND for ovs master and
IFLA_INFO_SLAVE_KIND for slave.
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

So far, it is assumed that ops->setup is filled up. But there might be
case that ops might make sense even without ->setup. In that case,
forbid to newlink and dellink.

This allows to register simple rtnl link ops containing only ->kind.
That allows consistent way of passing device kind (either device-kind or
slave-kind) to userspace.
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

In commit 37112105("net:
QDISC_STATE_RUNNING dont need atomic bit ops") the
__QDISC_STATE_RUNNING is renamed to __QDISC___STATE_RUNNING,
but the old names existing in comment are not replaced with
the new name completely.
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>