Jeff Kirsher says:

====================
100GbE Intel Wired LAN Driver Updates 2017-10-02

This series contains updates to fm10k only.

Jake provides all but one of the changes in this series.  Most are small
fixes, starting with ensuring prompt transmission of messages queued up
after each VF message is received and handled.  Fix a possible race
condition between the watchdog task and the processing of mailbox
messages by just checking whether the mailbox is still open.  Fix a
couple of GCC v7 warnings, including misspelled "fall through" comments
and warnings about possible truncation of calls to snprintf().  Cleaned
up a convoluted bitshift and read for the PFVFLRE register.  Fixed a
potential divide by zero when finding the proper r_idx.

Markus Elfring fixes an issue which was found using Coccinelle, where
we should have been using seq_putc() instead of seq_puts().
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Mika Westerberg says:

====================
Thunderbolt networking

In addition of tunneling PCIe, Display Port and USB traffic, Thunderbolt
allows connecting two hosts (domains) over a Thunderbolt cable. It is
possible to tunnel arbitrary data packets over such connection using
high-speed DMA rings available in the Thunderbolt host controller.

In order to discover Thunderbolt services the other host supports, there is
a software protocol running on top of the automatically configured control
channel (ring 0). This protocol is called XDomain discovery protocol and it
uses XDomain properties to describe the host (domain) and the services it
supports.

Once both sides have agreed what services are supported they can enable
high-speed DMA rings to transfer data over the cable.

This series adds support for the XDomain protocol so that we expose each
remote connection as Thunderbolt XDomain device and each service as
Thunderbolt service device. On top of that we create an API that allows
writing drivers for these services and finally we provide an example
Thunderbolt service driver that creates virtual ethernet inferface that
allows tunneling networking packets over Thunderbolt cable. The API could
be used for creating other future Thunderbolt services, such as tunneling
SCSI over Thunderbolt, for example.

The XDomain protocol and networking support is also available in macOS and
Windows so this makes it possible to connect Linux to macOS and Windows as
well.

The patches are based on previous Thunderbolt networking patch series by
Amir Levy and Michael Jamet, that can be found here:

  https://lwn.net/Articles/705998/

The main difference to that patch series is that we have the XDomain
protocol running in the kernel now so there is no need for a separate
userspace daemon.

Note this does not affect the existing functionality, so security levels
and NVM firmware upgrade continue to work as before (with the small
exception that now sysfs also shows the XDomain connections and services in
addition to normal Thunderbolt devices). It is also possible to connect up
to 5 Thunderbolt devices and then another host, and the network driver
works exactly the same.

This is third version of the patch series. The previous versions can be
be found here:

  v2: https://lkml.org/lkml/2017/9/25/225
  v1: https://lwn.net/Articles/734019/

Changes from the v2:

  * Add comment regarding calculation of interrupt throttling value
  * Add UUIDs as strings in comments on top of each declaration
  * Add a patch removing __packed from existing ICM messages. They are all
    32-bit aligned and should pack fine without the __packed.
  * Move adding MAINTAINERS entries to a separate patches
  * Added Michael and Yehezkel to be maintainers of the network driver
  * Remove __packed from the new ICM messages. They should pack fine as
    well without it.
  * Call register_netdev() after all other initialization is done in the
    network driver.
  * Use build_skb() instead of copying. We allocate order 1 page here to
    leave room for SKB shared info required by build_skb(). However, we do
    not leave room for full NET_SKB_PAD because the NHI hardware does not
    cope well if a frame crosses 4kB boundary. According comments in
    __build_skb() that should still be fine.
  * Added Reviewed-by tag from Andy.

Changes from the v1:

  * Add include/linux/thunderbolt.h to MAINTAINERS
  * Correct Linux version and date of new sysfs entries in
    Documentation/ABI/testing/sysfs-bus-thunderbolt
  * Move network driver from drivers/thunderbolt/net.c to
    drivers/net/thunderbolt.c and update it to follow coding style in
    drivers/net/*.
  * Add MAINTAINERS entry for the network driver
  * Minor cleanups

In case someone wants to try this out, the last patch adds documentation
how the networking driver can be used. In short, if you connect Linux to a
macOS or Windows, everything is done automatically (as those systems have
the networking service enabled by default). For Linux to Linux connection
one host needs to load the networking driver first (so that the other side
can locate the networking service and load the corresponding driver).
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

I will be maintaining the Thunderbolt network driver along with Michael
and Yehezkel.
Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ThunderboltIP is a protocol created by Apple to tunnel IP/ethernet
traffic over a Thunderbolt cable. The protocol consists of configuration
phase where each side sends ThunderboltIP login packets (the protocol is
determined by UUID in the XDomain packet header) over the configuration
channel. Once both sides get positive acknowledgment to their login
packet, they configure high-speed DMA path accordingly. This DMA path is
then used to transmit and receive networking traffic.

This patch creates a virtual ethernet interface the host software can
use in the same way as any other networking interface. Once the
interface is brought up successfully network packets get tunneled over
the Thunderbolt cable to the remote host and back.

The connection is terminated by sending a ThunderboltIP logout packet
over the configuration channel. We do this when the network interface is
brought down by user or the driver is unloaded.
Signed-off-by: Amir Levy <amir.jer.levy@intel.com>
Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The new API header (include/linux/thunderbolt.h) is maintained by the
Thunderbolt driver maintainers.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Thunderbolt services should not care which HopID (ring) they use for
sending and receiving packets over the high-speed DMA path, so make
tb_ring_alloc_rx() and tb_ring_alloc_tx() accept negative HopID. This
means that the NHI will allocate next available HopID for the caller
automatically.

These HopIDs will be allocated from the range which is not reserved for
the Thunderbolt protocol (8 .. hop_count - 1).

The allocated HopID can be retrieved from ring->hop field after the ring
has been allocated successfully if needed.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This is needed when Thunderbolt service drivers need to DMA map memory
before it is passed down to the ring.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In order to support things like networking over Thunderbolt cable, there
needs to be a way to switch the ring to a mode where it can be polled
with the interrupt masked. We implement such mode so that the caller can
allocate a ring by passing pointer to a function that is then called
when an interrupt is triggered. Completed frames can be fetched using
tb_ring_poll() and the interrupt can be re-enabled when the caller is
finished with polling by using tb_ring_poll_complete().
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This is needed because ring polling functionality can be called from
atomic contexts when networking and other high-speed traffic is
transferred over a Thunderbolt cable.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This makes it possible to enqueue frames also from atomic context which
is needed for example, when networking packets are sent over a
Thunderbolt cable.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

A Thunderbolt service driver might need to check if there was an error
with the descriptor when in frame mode. We also add two Rx specific
error flags RING_DESC_CRC_ERROR and RING_DESC_BUFFER_OVERRUN.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

These are used by Thunderbolt services to send and receive frames over
the high-speed DMA rings.

We also put the functions to tb_ namespace to make sure we do not
collide with others and add missing kernel-doc comments for the exported
functions.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When high-speed DMA paths are used to transfer arbitrary data over a
Thunderbolt link, DMA rings should be in frame mode instead of raw mode.
The latter is used by the control channel (ring 0). In frame mode each
data frame can hold up to 4kB payload.

This patch modifies the DMA ring code to allow configuring a ring to be
in frame mode by passing a new flag (RING_FLAG_FRAME) to the ring when
it is allocated. In addition there might be need to enable end-to-end
(E2E) workaround for the ring to prevent losing Rx frames in certain
situations. We add another flag (RING_FLAG_E2E) that can be used for
this purpose.

This code is based on the work done by Amir Levy and Michael Jamet.
Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This will keep the interrupt delivery rate reasonable. The value used
here (128 us) is a recommendation from the hardware people.

This code is based on the work done by Amir Levy and Michael Jamet.
Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When two hosts are connected over a Thunderbolt cable, there is a
protocol they can use to communicate capabilities supported by the host.
The discovery protocol uses automatically configured control channel
(ring 0) and is build on top of request/response transactions using
special XDomain primitives provided by the Thunderbolt base protocol.

The capabilities consists of a root directory block of basic properties
used for identification of the host, and then there can be zero or more
directories each describing a Thunderbolt service and its capabilities.

Once both sides have discovered what is supported the two hosts can
setup high-speed DMA paths and transfer data to the other side using
whatever protocol was agreed based on the properties. The software
protocol used to communicate which DMA paths to enable is service
specific.

This patch adds support for the XDomain discovery protocol to the
Thunderbolt bus. We model each remote host connection as a Linux XDomain
device. For each Thunderbolt service found supported on the XDomain
device, we create Linux Thunderbolt service device which Thunderbolt
service drivers can then bind to based on the protocol identification
information retrieved from the property directory describing the
service.

This code is based on the work done by Amir Levy and Michael Jamet.
Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

A Thunderbolt service might need to find the physical port from a link
the cable is connected to. For instance networking driver uses this
information to generate MAC address according the Apple ThunderboltIP
protocol.

Move this function to thunderbolt.h and rename it to
tb_phy_port_from_link() to reflect the fact that it does not take switch
as parameter.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

These are needed by Thunderbolt services so move them to thunderbolt.h
to make sure they are available outside of drivers/thunderbolt.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

These will be needed by Thunderbolt services when sending and receiving
XDomain control messages. While there change TB_CFG_PKG_PREPARE_TO_SLEEP
value to be decimal in order to be consistent with other members.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Thunderbolt XDomain discovery protocol uses directories which contain
properties and other directories to exchange information about what
capabilities the remote host supports. This also includes identification
information like device ID and name.

This adds support for parsing and formatting these properties and
establishes an API drivers can use in addition to the core Thunderbolt
driver. This API is exposed in a new header: include/linux/thunderbolt.h.

This code is based on the work done by Amir Levy and Michael Jamet.
Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

These messages are all 32-bit aligned and they should be packed without
the __packed attribute just fine. It also allows compiler to generate
better code on some architectures.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We will be using these when communicating XDomain discovery protocol
over Thunderbolt link but they might be useful for other drivers as
well.

Make them available through byteorder/generic.h.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jiri Pirko says:

====================
mlxsw: Fixlets

Couple of small nit fixes from Petr
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

fou test lifted from ip-fou man page.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Simon Horman says:

====================
flow_dissector: dissect tunnel info

Move dissection of tunnel info from the flower classifier to the flow
dissector where all other dissection occurs.  This should not have any
behavioural affect on other users of the flow dissector.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Move dissection of tunnel info from the flower classifier to the flow
dissector where all other dissection occurs.  This should not have any
behavioural affect on other users of the flow dissector.
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Make the skb parameter of skb_metadata_dst() and skb_tunnel_info()
const as they are not modified. This is in preparation for using
them in call-sites where skb is const.
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Although very unlikely, it is possible that cancel_work_sync() may stop
the service_task before it actually started. In this case, the
__FM10K_SERVICE_SCHED bit will never be cleared. This results in the
service task being unable to reschedule in the future. Add a helper
function which sets the service disable bit, waits for the service task
to stop and clears the schedule bit, thus avoiding the race condition.
We know the schedule bit is safe to clear because the cancel_work_sync()
guarantees the service task is not running.

Add a helper function also to restart the service task, for symmetry.
This is not strictly needed but helps the mental model of how to stop
and start the service task.

This race could only happen in fm10k_suspend/fm10k_resume as this is the
only place where the service task is actually restarted. Thus,
suspend/resume testing would be ideal. However, note that the chance of
this happening is very slim as the service event is scheduled for
immediate execution, and you would have to trigger a suspend at almost
the exact same time as the service task was scheduled.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

A future patch needs these functions defined earlier in the file. Move
them closer to above where they will be called.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

It is possible that under rare circumstances the device is undergoing
a reset, such as when a PFLR occurs, and the device may be transmitting
simultaneously. In this case, we might attempt to divide by zero when
finding the proper r_idx. Instead, lets read the num_tx_queues once,
and make sure it's non-zero.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

We've always had a really weird looping construction for resetting VFs.
We read the VFLRE register and reset the VF if the corresponding bit is
set, which makes sense. However we loop continuously until we no longer
have any bits left unset. At first this makes sense, as a sort of "keep
trying until we succeed" concept.

Unfortunately this causes a problem if we happen to surprise remove
while this code is executing, because in this case we'll always read all
1s for the VFLRE register. This results in a hard lockup on the CPU
because the loop will never terminate.

Because our own reset function will clear the VFLR event register
always, (except when we've lost PCIe link obviously) there is no real
reason to loop. In practice, we'll loop over once and find that no VFs
are pending anymore.

Lets just check once. Since we're clear the notification when we reset
there's no benefit to the loop. Additionally, there shouldn't be a race
as future VLFRE events should trigger an interrupt. Additionally, we
didn't warn or do anything in the looped case anyways.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

We're doing a really convoluted bitshift and read for the PFVFLRE
register. Just reading the PFVFLRE(1), shifting it by 32, then reading
PFVFLRE(0) should be sufficient.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

When we load the driver, we set the last_reset to be in the future,
which delays the initial driver reset. Additionally, the service task
isn't scheduled to run automatically until the timer runs out. This
causes a needless delay of the first reset to begin talking to the
switch manager.

We can avoid this by simply not setting last_reset and immediately
scheduling the service task while in probe. This allows the device to
wake up faster, and avoids this delay.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Newer versions of GCC starting with 7 now additionally warn when a case
statement may fall through without an explicit comment mentioning it.
Add such a comment to silence the warning, as this is expected.

Unfortunately the comment must come directly before the next case
statement, so we put it outside the #ifdef. Otherwise, the compiler
cannot properly detect it and thus the warning is displayed regardless.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

New versions of GCC since version 7 began warning about possible
truncation of calls to snprintf. We can fix this and avoid false
positives. First, we should pass the full buffer size to snprintf,
because it guarantees a NULL character as part of its passed length, so
passing len-1 is simply wasting a byte of possible storage.

Second, if we make the ri and ti variables unsigned, the compiler is
able to correctly reason that the value never gets larger than 256, so
it doesn't need to warn about the full space required to print a signed
integer.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Newer versions of GCC since version 7 now warn when a case statement may
fall through without an explicit comment. "Fallthough" does not count as
it is misspelled. Fix the typos for these comments to appease the new
warnings.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

In fm10k_get_host_state_generic, we check the mailbox tx_read() function
to ensure that the mailbox is still open. This function also checks to
make sure we have space to transmit another message. Unfortunately, if
we just recently sent a bunch of messages (such as enabling hundreds of
VLANs on a VF) this can result in a race where the watchdog task thinks
the link went down just because we haven't had time to process all these
messages yet.

Instead, lets just check whether the mailbox is still open. This ensures
that we don't race with the Tx FIFO, and we only link down once the
mailbox is not open.

This is safe, because if the FIFO fills up and we're unable to send
a message for too long, we'll end up triggering the timeout detection
which results in a reset. Additionally, since we still check to ensure
the mailbox state is OPEN, we'll transition to link down whenever the
mailbox closes as well.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Two single characters should be put into a sequence.
Thus use the corresponding function "seq_putc".

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

When we are handling PF<->VF mailbox messages, it is possible that the
VF will send us so many messages that the PF<->SM FIFO will fill up. In
this case, we stop the loop and wait until the service event is
rescheduled.

Normally this should happen due to an interrupt. But it is possible that
we don't get another interrupt for a while and it isn't until the
service timer actually reschedules us. Instead, simply reschedule
immediately which will cause the service event to be run again as soon
as we exit.

This ensures that we promptly handle all of the PF<->VF messages with
minimal delay, while still giving time for the SM mailbox to drain.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>