Claudiu Manoil says:

====================
gianfar: Tx timeout issue

There's an older Tx timeout issue showing up on etsec2 devices
with 2 CPUs.  I pinned this issue down to processing overhead
incurred by supporting multiple Tx/Rx rings, as explained in
the 2nd patch below.  But before this, there's also a concurency
issue leading to Rx/Tx spurrious interrupts, addressed by the
'Tx NAPI' patch below.
The Tx timeout can be triggered with multiple Tx flows,
'iperf -c -N 8' commands, on a 2 CPUs etsec2 based (P1020) board.

Before the patches:
"""
root@p1020rdb-pc:~# iperf -c 172.16.1.3 -n 1000M -P 8 &
[...]
root@p1020rdb-pc:~# NETDEV WATCHDOG: eth1 (fsl-gianfar): transmit queue 1 timed out
WARNING: at net/sched/sch_generic.c:279
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.13.0-rc3-03386-g89ea59c #23
task: ed84ef40 ti: ed868000 task.ti: ed868000
NIP: c04627a8 LR: c04627a8 CTR: c02fb270
REGS: ed869d00 TRAP: 0700   Not tainted  (3.13.0-rc3-03386-g89ea59c)
MSR: 00029000 <CE,EE,ME>  CR: 44000022  XER: 20000000
[...]

root@p1020rdb-pc:~# [ ID] Interval       Transfer     Bandwidth
[  5]  0.0-19.3 sec  1000 MBytes    434 Mbits/sec
[  8]  0.0-39.7 sec  1000 MBytes    211 Mbits/sec
[  9]  0.0-40.1 sec  1000 MBytes    209 Mbits/sec
[  3]  0.0-40.2 sec  1000 MBytes    209 Mbits/sec
[ 10]  0.0-59.0 sec  1000 MBytes    142 Mbits/sec
[  7]  0.0-74.6 sec  1000 MBytes    112 Mbits/sec
[  6]  0.0-74.7 sec  1000 MBytes    112 Mbits/sec
[  4]  0.0-74.7 sec  1000 MBytes    112 Mbits/sec
[SUM]  0.0-74.7 sec  7.81 GBytes    898 Mbits/sec

root@p1020rdb-pc:~# ifconfig eth1
eth1      Link encap:Ethernet  HWaddr 00:04:9f:00:13:01
          inet addr:172.16.1.1  Bcast:172.16.255.255  Mask:255.255.0.0
          inet6 addr: fe80::204:9fff:fe00:1301/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:708722 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8717849 errors:6 dropped:0 overruns:1470 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:58118018 (55.4 MiB)  TX bytes:274069482 (261.3 MiB)
          Base address:0xa000

"""

After applying the patches:
"""
root@p1020rdb-pc:~# iperf -c 172.16.1.3 -n 1000M -P 8 &
[...]
root@p1020rdb-pc:~# [ ID] Interval       Transfer     Bandwidth
[  9]  0.0-70.5 sec  1000 MBytes    119 Mbits/sec
[  5]  0.0-70.5 sec  1000 MBytes    119 Mbits/sec
[  6]  0.0-70.7 sec  1000 MBytes    119 Mbits/sec
[  4]  0.0-71.0 sec  1000 MBytes    118 Mbits/sec
[  8]  0.0-71.1 sec  1000 MBytes    118 Mbits/sec
[  3]  0.0-71.2 sec  1000 MBytes    118 Mbits/sec
[ 10]  0.0-71.3 sec  1000 MBytes    118 Mbits/sec
[  7]  0.0-71.3 sec  1000 MBytes    118 Mbits/sec
[SUM]  0.0-71.3 sec  7.81 GBytes    942 Mbits/sec

root@p1020rdb-pc:~# ifconfig eth1
eth1      Link encap:Ethernet  HWaddr 00:04:9f:00:13:01
          inet addr:172.16.1.1  Bcast:172.16.255.255  Mask:255.255.0.0
          inet6 addr: fe80::204:9fff:fe00:1301/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:728446 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8690057 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:59732650 (56.9 MiB)  TX bytes:271554306 (258.9 MiB)
          Base address:0xa000
"""
v2: PATCH 2:
    Replaced CPP check with run-time condition to
    limit the number of queues. Updated comments.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

For the "fsl,etsec2" compatible models the driver currently
supports 8 Tx and Rx DMA rings (aka HW queues).  However, there
are only 2 pairs of Rx/Tx interrupt lines, as these controllers
are integrated in low power SoCs with 2 CPUs at most.  As a result,
there are at most 2 NAPI instances that have to service multiple
Tx and Rx queues for these devices.  This complicates the NAPI
polling routine having to iterate over the mutiple Rx/Tx queues
hooked to the same interrupt lines.  And there's also an overhead
at HW level, as the controller needs to service all the 8 Tx rings
in a round robin manner.  The combined overhead shows up for multi
parallel Tx flows transmitted by the kernel stack, when the driver
usually starts returning NETDEV_TX_BUSY leading to NETDEV WATCHDOG
Tx timeout triggering if the Tx path is congested for too long.

As an alternative, this patch makes the driver support only one
Tx/Rx DMA ring per NAPI instance (per interrupt group or pair
of Tx/Rx interrupt lines) by default.  The simplified single queue
polling routine (gfar_poll_sq) will be the default napi poll routine
for the etsec2 devices too.  Some adjustments needed to be made to
link the Tx/Rx HW queues with each NAPI instance (2 in this case).
The gfar_poll_sq() is already successfully used by older SQ_SG_MODE
(single interrupt group) controllers.
This patch fixes Tx timeout triggering under heavy Tx traffic load
(i.e. iperf -c -P 8) for the "fsl,etsec2" (currently the only
MQ_MG_MODE devices).  There's also a significant memory footprint
reduction by supporting 2 Rx/Tx DMA rings (at most), instead of 8,
for these devices.
Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There are some concurrency issues on devices w/ 2 CPUs related
to the handling of Rx and Tx interrupts.  eTSEC has separate
interrupt lines for Rx and Tx but a single imask register
to mask these interrupts and a single NAPI instance to handle
both Rx and Tx work.  As a result, the Rx and Tx ISRs are
identical, both are invoking gfar_schedule_cleanup(), however
both handlers can be entered at the same time when the Rx and
Tx interrupts are taken by different CPUs.  In this case
spurrious interrupts (SPU) show up (in /proc/interrupts)
indicating a concurrency issue.  Also, Tx overruns followed
by Tx timeout have been observed under heavy Tx traffic load.

To address these issues, the schedule cleanup ISR part has
been changed to handle the Rx and Tx interrupts independently.
The patch adds a separate NAPI poll routine for Tx cleanup to
be triggerred independently by the Tx confirmation interrupts
only.  Existing poll functions are modified to handle only
the Rx path processing.  The Tx poll routine does not need a
budget, since Tx processing doesn't consume NAPI budget, and
hence it is registered with minimum NAPI weight.
NAPI scheduling does not require locking since there are
different NAPI instances between the Rx and Tx confirmation
paths now.
So, the patch fixes the occurence of spurrious Rx/Tx interrupts.
Tx overruns also occur less frequently now.
Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Ether_addr_equal_64bits is more efficient than ether_addr_equal, and
can be used when each argument is an array within a structure that
contains at least two bytes of data beyond the array, so it is safe
to use it for vlan, and make sense for fast path.

Cc: Joe Perches <joe@perches.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

According Joe's suggestion, maybe it'd be faster to add an unlikely to
the test for PCKET_OTHERHOST, so I add it and see whether the performance
could be better, although the differences is so small and negligible, but
it is hard to catch that any lower device would set the skb type to
PACKET_OTHERHOST, so most of time, I think it make sense to add unlikely
for the test.

Cc: Joe Perches <joe@perches.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Resizing fq hash table allocates memory while holding qdisc spinlock,
with BH disabled.

This is definitely not good, as allocation might sleep.

We can drop the lock and get it when needed, we hold RTNL so no other
changes can happen at the same time.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: afe4fd06 ("pkt_sched: fq: Fair Queue packet scheduler")
Signed-off-by: David S. Miller <davem@davemloft.net>

Jeff Kirsher says:

====================
Intel Wired LAN Driver Updates

This series contains updates to e1000e, ixgbevf and igb.

Majority of this series contains fixes and cleanups to e1000e,
most notably are:

Todd provides a fix to PTP in e1000e which adds a lock in e1000e_phc_adjfreq
to prevent concurrent changes to TIMINCA and SYSTIMH/L.  Then provides an
igb fix to use ARRAY_SIZE for array size calculation.

David provides the remaining e1000e which contain:
 - cleanup of pointer references that are no longer used
 - fix an issue on systems with Management Engine enabled with the
   ethernet cable unplugged
 - fix an issue on 82579 where enabling EEE LPI sooner than one second
   after link up causes link issues on some switches
 - refactor the power management flows to prevent the suspend path from
   being executed twice when hibernating
 - refactor the runtime power management to fix interfering with the
   functionality of Energy Efficient Ethernet when enabled and to fix
   the device from repeatedly flip between suspend and resume with the
   interface administratively downed
 - enable the feature PHY Ultra Low Power Mode which is a power saving
   feature that reduces the power consumption of the PHY when a cable is
   not connected
 - fix the ethtool offline tests for 82579 parts
 - fix SHRA register access for 82579 parts which was introduced by
   previous commit c3a0dce3 "e1000e: fix overrun of PHY RAR array"

Florian provides a fix for ixgbevf where skb->pkt_type was being checked
like a bitmask, but it is not a bitmask.

Fix an issue reported by Stephen Hemminger where there was a warning
about code defined but never used if IGB_HWMON is not defined.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix warning about code defined but never used if IGB_HWMON not defined.
Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Use ARRAY_SIZE for array size calculation.
Signed-off-by: Todd Fujinaka <todd.fujinaka@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

skb->pkt_type is not a bitmask, but contains only value at a time from
the range defined in include/uapi/linux/if_packet.h.

Checking it like if it was a bitmask of values would also cause
PACKET_OTHERHOST, PACKET_LOOPBACK and PACKET_FASTROUTE to be matched by
this check since their lower 2 bits are also set, although that does not
fix a real bug, it is still potentially confusing.

This bogus check was introduced in commit 815cccbf ("ixgbe: add setlink,
getlink support to ixgbe and ixgbevf").
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Previous commit c3a0dce3 fixed an overrun for the RAR on i218 devices.
This commit also attempted to homogenize the RAR/SHRA access for all parts
accessed by the e1000e driver.  This change introduced an error for
assigning MAC addresses to guest OS's for 82579 devices.

Only RAR[0] is accessible to the driver for 82579 parts, and additional
addresses must be placed into the SHRA[L|H] registers.  The rar_entry_count
was changed in the previous commit to an inaccurate value that accounted
for all RAR and SHRA registers, not just the ones usable by the driver.

This patch fixes the count to the correct value and adjusts the
e1000_rar_set_pch2lan() function to user the correct index.

Cc: John Greene <jogreene@redhat.com>
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Changes to the rar_entry_count value require a change to the indexing
used to access the SHRA[H|L] registers when testing them with
'ethtool -t <iface> offline'
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Valid values for InterruptThrottleRate are 10-100000, or one of
0, 1, 3, 4.  '2' is not valid.  This is a legacy from the branching
from the e1000 driver code that e1000e was based from.

Prior to this patch, if the e1000e driver  was loaded with a forced
invalid InterruptThrottleRate of '2', then no throttle rate would be
set and no error message generated.

Now, a message will be generated that an invalid value was used and the
value for InterruptThrottleRate will be set to the default value.
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

ULP is a power saving feature that reduces the power consumption of the
PHY when a cable is not connected.

ULP is gated on the following conditions:
1) The hardware must support ULP.  Currently this is only I218
   devices from Intel
2) ULP is initiated by the driver, so, no driver results in no ULP.
3) ULP's implementation utilizes Runtime Power Management to toggle its
   execution.  ULP is enabled/disabled based on the state of Runtime PM.
4) ULP is not active when wake-on-unicast, multicast or broadcast is active
   as these features are mutually-exclusive.

Since the PHY is in an unavailable state while ULP is active, any access
of the PHY registers will fail.  This is resolved by utilizing kernel
calls that cause the device to exit Runtime PM (e.g. pm_runtime_get_sync)
and then, after PHY access is complete,  allow the device to resume
Runtime PM (e.g. pm_runtime_put_sync).

Under certain conditions, toggling the LANPHYPC is necessary to disable
ULP mode.  Break out existing code to toggle LANPHYPC to a new function
to avoid code duplication.
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Cc: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Fix issues with:
RuntimePM causing the device to repeatedly flip between suspend and resume
with the interface administratively downed.
Having RuntimePM enabled interfering with the functionality of Energy
Efficient Ethernet.

Added checks to disallow functions that should not be executed if the
device is currently runtime suspended

Make runtime_idle callback to use same deterministic behavior as the igb
driver.
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Acked-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Refactor the system power management flows to prevent the suspend path from
being executed twice when hibernating since both the freeze and
poweroff callbacks were set to e1000_suspend() via SET_SYSTEM_SLEEP_PM_OPS.
There are HW workarounds that are performed during this flow and calling
them twice was causing erroneous behavior.

Re-arrange the code to take advantage of common code paths and explicitly
set the individual dev_pm_ops callbacks for suspend, resume, freeze,
thaw, poweroff and restore.

Add a boolean parameter (reset) to the e1000e_down function to allow
for cases when the HW should not be reset when downed during a PM event.

Now that all suspend/shutdown paths result in a call to __e1000_shutdown()
that checks Wake on Lan status, removing redundant check for WoL in
e1000_power_down_phy().
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Acked-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Branding strings from recently released and soon to be released
hardware configurations that are supported by e1000e.
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Acked-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

This patch is to update the GPL header by removing the portion that
refers to the Free Software Foundation address.

Change the copyright date for 2014.

Reformat the header comments to conform to kernel networking coding norms
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Enabling EEE LPI sooner than one second after link up on 82579 causes link
issues with some switches.

Remove EEE enablement for 82579 parts from the link initialization flow to
avoid initializing too early.  EEE initialization for 82579 will be done
in e1000e_update_phy_task.
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Acked-by: Bruce W Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

On a ME enabled system with the cable out, the driver init flow would
generate an erroneous message indicating that resets were being blocked
by an active ME session.  Cause was ME clearing the semaphore bit to
block further PHY resets for up to 50 msec during power-on/cycle.  After
this interval, ME would re-set the bit and allow PHY resets.

To resolve this, change the flow of e1000e_phy_hw_reset_generic() to
utilize a delay and retry method.  Poll the FWSM register to minimize
any extra time added to the flow.  If the delay times out at 100ms
(checked in 10msec increments), then return the value E1000_BLK_PHY_RESET,
as this is the accurate state of the PHY.  Attempting to alter just the
call to e1000e_phy_hw_reset_generic() in e1000_init_phy_workarounds_pchlan()
just caused the problem to move further down the flow.
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Acked-by: Bruce W. Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Cleaning up some pointer references that are no longer necessary
Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Add lock in e1000e_phc_adjfreq to prevent concurrent changes to TIMINCA
and SYSTIMH/L.
Signed-off-by: Todd Fujinaka <todd.fujinaka@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

This patch adds a missing return after fragmentation init. Otherwise we
register a sysctl interface and deregister it afterwards which makes no
sense.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Marc Kleine-Budde says:

====================
pull-request: can-next 2014-02-12

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

Alexander Shiyan contributes two patches for the mcp251x, one making
the driver more quiet and the other one improves the compile time
coverage by removing the #ifdef CONFIG_PM_SLEEP. Then two patches for
the flexcan driver by me, one removing the #ifdef CONFIG_PM_SLEEP, too,
the other one making use of platform_get_device_id(). Another patch by
me which converts the janz-ican3 driver to use netdev_<level>(). The
remaining 7 patches are by Oliver Hartkopp, they add CAN FD support to
the netlink configuration interface.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Hayes Wang says:

====================
r8152: tx/rx improvement

 - Select the suitable spin lock for each function.
 - Add additional check to reduce the spin lock.
 - Up the priority of the tx to avoid interrupted by rx.
 - Support rx checksum, large send, and IPv6 hw checksum.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Support hw IPv6 checksum for TCP and UDP packets.

Note that the hw has the limitation of the range of the transport
offset. Besides, the TCP Pseudo Header of the IPv6 TSO of the hw
bases on the Microsoft document which excludes the packet length.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Support scatter gather and TSO.

Adjust the tx checksum function and set the max gso size to fix the
size of the tx aggregation buffer.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Support hw rx checksum for TCP and UDP packets.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Continue dealing with the remain rx packets, even though the allocation
of the skb fail. This could calculate the correct dropped packets.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

move the tx_bottom() from delayed_work to tasklet. It makes the rx
and tx balanced. If the device is in runtime suspend when getting
the tx packet, wakeup the device before trasmitting.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Check tx agg list before spin lock to avoid doing spin lock every
times.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use spin_lock and spin_unlock in interrupt context.

The ndo_start_xmit would not be called in interrupt context, so
replace the relative spin_lock_irqsave and spin_unlock_irqrestore
with spin_lock_bh and spin_unlock_bh.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jeff Kirsher says:

====================
Intel Wired LAN Driver Updates

This series contains updates to i40e and i40evf.

Most notable are:
Joseph completes the implementation of the ethtool ntuple rule
management interface by adding the get, update and delete interface
reset.

Akeem provides a fix to prevent a possible overflow due to multiplication
of number and size by using kzalloc, so use kcalloc.

Jesse provides an implementation for skb_set_hash() and adds the L4 type
return when we know it is an L4 hash.  He also adds a counter to
statistics for Tx timeouts to help users.  Lastly he provides a change
to stay away from the cache line where the done bit may be getting
written back for the transmit ring since the hardware may be writing the
whole cache line for a partial update.

Shannon cleans up code comments.

Anjali removes a firmware workaround for newer firmware since the number
of MSIx vectors are being reported correctly.

v2:
 -  dropped patch 01 of the series based on feedback from the author
    Joe Perches and Shannon Nelson.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

David Howells says:

====================
net-next: AF_RXRPC fixes and development

Here are some AF_RXRPC fixes:

 (1) Fix to remove incorrect checksum calculation made during recvmsg().  It's
     unnecessary to try to do this there since we check the checksum before
     reading the RxRPC header from the packet.

 (2) Fix to prevent the sending of an ABORT packet in response to another
     ABORT packet and inducing a storm.

 (3) Fix UDP MTU calculation from parsing ICMP_FRAG_NEEDED packets where we
     don't handle the ICMP packet not specifying an MTU size.

And development patches:

 (4) Add sysctls for configuring RxRPC parameters, specifically various delays
     pertaining to ACK generation, the time before we resend a packet for
     which we don't receive an ACK, the maximum time a call is permitted to
     live and the amount of time transport, connection and dead call
     information is cached.

 (5) Improve ACK packet production by adjusting the handling of ACK_REQUESTED
     packets, ignoring the MORE_PACKETS flag, delaying the production of
     otherwise immediate ACK_IDLE packets and delaying all ACK_IDLE production
     (barring the call termination) to half a second.

 (6) Add more sysctl parameters to expose the Rx window size, the maximum
     packet size that we're willing to receive and the number of jumbo rxrpc
     packets we're willing to handle in a single UDP packet.

 (7) Request ACKs on alternate DATA packets so that the other side doesn't
     wait till we fill up the Tx window.

 (8) Use a RCU hash table to look up the rxrpc_call for an incoming packet
     rather than stepping through a hierarchy involving several spinlocks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Zoltan Kiss says:

====================
xen-netback: TX grant mapping with SKBTX_DEV_ZEROCOPY instead of copy

A long known problem of the upstream netback implementation that on the TX
path (from guest to Dom0) it copies the whole packet from guest memory into
Dom0. That simply became a bottleneck with 10Gb NICs, and generally it's a
huge perfomance penalty. The classic kernel version of netback used grant
mapping, and to get notified when the page can be unmapped, it used page
destructors. Unfortunately that destructor is not an upstreamable solution.
Ian Campbell's skb fragment destructor patch series [1] tried to solve this
problem, however it seems to be very invasive on the network stack's code,
and therefore haven't progressed very well.
This patch series use SKBTX_DEV_ZEROCOPY flags to tell the stack it needs to
know when the skb is freed up. That is the way KVM solved the same problem,
and based on my initial tests it can do the same for us. Avoiding the extra
copy boosted up TX throughput from 6.8 Gbps to 7.9 (I used a slower AMD
Interlagos box, both Dom0 and guest on upstream kernel, on the same NUMA node,
running iperf 2.0.5, and the remote end was a bare metal box on the same 10Gb
switch)
Based on my investigations the packet get only copied if it is delivered to
Dom0 IP stack through deliver_skb, which is due to this [2] patch. This affects
DomU->Dom0 IP traffic and when Dom0 does routing/NAT for the guest. That's a bit
unfortunate, but luckily it doesn't cause a major regression for this usecase.
In the future we should try to eliminate that copy somehow.
There are a few spinoff tasks which will be addressed in separate patches:
- grant copy the header directly instead of map and memcpy. This should help
  us avoiding TLB flushing
- use something else than ballooned pages
- fix grant map to use page->index properly
I've tried to broke it down to smaller patches, with mixed results, so I
welcome suggestions on that part as well:
1: Use skb->cb to store pending_idx
2: Some refactoring
3: Change RX path for mapped SKB fragments (moved here to keep bisectability,
review it after #4)
4: Introduce TX grant mapping
5: Remove old TX grant copy definitons and fix indentations
6: Add stat counters for zerocopy
7: Handle guests with too many frags
8: Timeout packets in RX path
9: Aggregate TX unmap operations

v2: I've fixed some smaller things, see the individual patches. I've added a
few new stat counters, and handling the important use case when an older guest
sends lots of slots. Instead of delayed copy now we timeout packets on the RX
path, based on the assumption that otherwise packets should get stucked
anywhere else. Finally some unmap batching to avoid too much TLB flush

v3: Apart from fixing a few things mentioned in responses the important change
is the use the hypercall directly for grant [un]mapping, therefore we can
avoid m2p override.

v4: Now we are using a new grant mapping API to avoid m2p_override. The RX queue
timeout logic changed also.

v5: Only minor fixes based on Wei's comments

v6: Important bugfixes for xenvif_poll exit path and zerocopy callback, see
first 2 patches. Also rework of handling packets with too many slots, and
reorder the series a bit.

v7: Small fixes in comments/log messages/error paths, and merging the frag
overflow stats patch into its parent.

[1] http://lwn.net/Articles/491522/
[2] https://lkml.org/lkml/2012/7/20/363
====================
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Unmapping causes TLB flushing, therefore we should make it in the largest
possible batches. However we shouldn't starve the guest for too long. So if
the guest has space for at least two big packets and we don't have at least a
quarter ring to unmap, delay it for at most 1 milisec.
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

A malicious or buggy guest can leave its queue filled indefinitely, in which
case qdisc start to queue packets for that VIF. If those packets came from an
another guest, it can block its slots and prevent shutdown. To avoid that, we
make sure the queue is drained in every 10 seconds.
The QDisc queue in worst case takes 3 round to flush usually.
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Xen network protocol had implicit dependency on MAX_SKB_FRAGS. Netback has to
handle guests sending up to XEN_NETBK_LEGACY_SLOTS_MAX slots. To achieve that:
- create a new skb
- map the leftover slots to its frags (no linear buffer here!)
- chain it to the previous through skb_shinfo(skb)->frag_list
- map them
- copy and coalesce the frags into a brand new one and send it to the stack
- unmap the 2 old skb's pages

It's also introduces new stat counters, which help determine how often the guest
sends a packet with more than MAX_SKB_FRAGS frags.

NOTE: if bisect brought you here, you should apply the series up until
"xen-netback: Timeout packets in RX path", otherwise malicious guests can block
other guests by not releasing their sent packets.
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

These counters help determine how often the buffers had to be copied. Also
they help find out if packets are leaked, as if "sent != success + fail",
there are probably packets never freed up properly.

NOTE: if bisect brought you here, you should apply the series up until
"xen-netback: Timeout packets in RX path", otherwise Windows guests can't work
properly and malicious guests can block other guests by not releasing their sent
packets.
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

These became obsolete with grant mapping. I've left intentionally the
indentations in this way, to improve readability of previous patches.

NOTE: if bisect brought you here, you should apply the series up until
"xen-netback: Timeout packets in RX path", otherwise Windows guests can't work
properly and malicious guests can block other guests by not releasing their sent
packets.
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>