Configure flow control correctly, and based on the receive fifo size read
as a property from the devicetree since the Synopsys stmmac fifo sizes are
configurable based on a particular chip's implementation. This patch maintains
the previous incorrect behavior unless the receive fifo size is found in the
devicetree.
Signed-off-by: NVince Bridgers <vbridger@opensource.altera.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Unicast pause frame detect was not being enabled for the Synopsys stmmac. This
patch sets Unicast pause frame detect in MAC register 6 so that pause frame
detection by the stmmac conforms to IEEE 802.3, Annex 31B.3.3 Receive
Operation - Specifically, a MAC shall respond to pause frames containing
either the reserved multicast address or the unique physical address
associated with this station.
Signed-off-by: NVince Bridgers <vbridger@opensource.altera.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Read the tx-fifo-depth and rx-fifo-depth from the devicetree. The Synopsys
stmmac controller fifos are configurable per product instance, and the fifo
sizes are needed to configure certain features correctly such as flow control.
Signed-off-by: NVince Bridgers <vbridger@opensource.altera.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add defines and documentation for enabling flow control on the stmmac. Flow
control was not implemented correctly on the stmmac driver and is currently
non-functional as a result. This is the first in a series of small patches
to correctly implement this feature.
Signed-off-by: NVince Bridgers <vbridger@opensource.altera.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

An oops exists in the flow of stmmac_release().
phy_ethtool_get_wol() depends on phydev->drv.
phydev->drv will be null after stmmac_mdio_unreg() completes.

Steps to reproduce on Quark X1000:

1. ifconfig eth0 192.168.0.1
2. rmmod stmmac_pci

To fix this stmmac_mdio_unreg() should be run after unregister_netdev().
Signed-off-by: NBryan O'Donoghue <pure.logic@nexus-software.ie>
Reported-by: NDan O'Donovan <dan.odonovan@emutex.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A duplicate declaration of 'ret' can result in hiding an error code.
Drop it.

Fixes: 17ee3e04 ("net: dsa: Provide additional RMON statistics")
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove including <linux/version.h> that don't need it.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix to return -EINVAL from the invalid PCI region size error
handling case instead of 0, as done elsewhere in this function.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Return correct error code if _mv88e6xxx_reg_read returns an error.

Fixes: facd95b2 ("net: dsa: mv88e6xxx: Add Hardware bridging support")
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

set_filter_wr is requesting __GFP_NOFAIL allocation although it can return
ENOMEM without any problems obviously (t4_l2t_set_switching does that
already).  So the non-failing requirement is too strong without any
obvious reason.  Drop __GFP_NOFAIL and reorganize the code to have the
failure paths easier.

The same applies to _c4iw_write_mem_dma_aligned which uses __GFP_NOFAIL
and then checks the return value and returns -ENOMEM on failure.  This
doesn't make any sense what so ever.  Either the allocation cannot fail or
it can.

del_filter_wr seems to be safe as well because the filter entry is not
marked as pending and the return value is propagated up the stack up to
c4iw_destroy_listen.
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 9a2620c8 ("bnx2x: prevent WARN during driver unload")
switched the napi/busy_lock locking mechanism from spin_lock() into
spin_lock_bh(), breaking inter-operability with netconsole, as netpoll
disables interrupts prior to calling our napi mechanism.

This switches the driver into using atomic assignments instead of the
spinlock mechanisms previously employed.

Based on initial patch from Yuval Mintz & Ariel Elior

I basically added softirq starvation avoidance, and mixture
of atomic operations, plain writes and barriers.

Note this slightly reduces the overhead for this driver when no
busy_poll sockets are in use.

Fixes: 9a2620c8 ("bnx2x: prevent WARN during driver unload")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The code sets the expiry value of the timer to a relative value and
starts it with hrtimer_start_expires. That's fine, but that only works
once. The timer is started in relative mode, so the expiry value gets
overwritten with the absolut expiry time (now + expiry).

So once the timer expired, a new call to hrtimer_start_expires results
in an immidiately expired timer, because the expiry value is
already in the past.

Use the proper mechanisms to (re)start the timer in the intended way.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: dingtianhong <dingtianhong@huawei.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Zhangfei Gao <zhangfei.gao@linaro.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: netdev@vger.kernel.org
Acked-by: NDing Tianhong <dingtianhong@huawei.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Bump.

Change-ID: Id14baae72332d0f1a9bc5d351ea1a85cb0295ec3
Signed-off-by: NCatherine Sullivan <catherine.sullivan@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

The kernel has added SPEED_40000 for ethtool.
Go ahead and use the new #define.

Change-ID: Ic7e16e5c9e91085afe539f11ee1b7668adc4d0ef
Signed-off-by: NGreg Rose <gregory.v.rose@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

These changes just remove unused variables and any code that uses them
as the results of storing into these variables doesn't have any
side effects that I can see or provide any benefit.

Change-ID: I8a5ec7132ff1443d23aae729cef94beaaaf19e3a
Signed-off-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

The init_interrupt_scheme function had a possible failure
path to allocate memory that was found by smatch.

This adds the correct handling to the function to abort
probe if the memory allocation fails.

Change-ID: I2bf1d826a244209619da4c452d0d58b3eb5e26a3
Signed-off-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Store the 8 bytes of the WR_CSR_PROT field returned as part of the get
device/function capabilities AQ command.

Change-ID: Ifcaeea2ff29885fa769e4f384c7db88a25e8afd0
Signed-off-by: NKevin Scott <kevin.c.scott@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

This is a feature to enable better debugging of user reported issues by
allowing a bash script to acquire information about the internal hardware
state. The data output to the kernel log is collected by the script and can
then be sent to Intel. This is a critical debugging feature for helping us
interpret and reproduce complex customer setups.

Change-ID: Ie8b3ab09086d6870a709015f51ada05af10b41bb
Signed-off-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

This is to allow quick check for FCoE capability is enabled or not
in device function before any SW overrides.

Change-ID: I5f78ba798d566f143161273156916c6f4074496e
Signed-off-by: NVasu Dev <vasu.dev@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

With a HW issue that was recently discovered, after a VFLR HW might be
indicating to us a reset completion little too early. So wait another 10
msec for cache to be cleaned up.

Change-ID: I6a24dcf5dd7ffcd6500246e717411ef58532d1e9
Signed-off-by: NAnjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Move the VF notification functions to the top of the file. This
eliminates an unnecessary declaration.

Change-ID: I036171f14180ee9f0ce4e0a21334d6a217d06c94
Signed-off-by: NMitch Williams <mitch.a.williams@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Gratuitously notify VFs of link state when they activate their queues.
In general, this is the last thing that a VF driver will do as it opens
its interface, so this is a good time to notify the VF.

Currently, VF devices assume link is up unless told otherwise, which
means that VFs instantiated on a PF with no link will report the wrong
state. This change corrects that issue.

Change-ID: Iea53622904ecc681ac3f8938d81c30033ef9a0a6
Signed-off-by: NMitch Williams <mitch.a.williams@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

The aq_pending field in the adapter structure is actually redundant with
the current_op field. Remove the aq_pending field and expunge all traces
of it from the official record. This simplifies the code significantly,
especially in the virtual channel completion routine.

Change-ID: Ib2957c8c19882bd0cecc6fcd133912c24b46a1ff
Signed-off-by: NMitch Williams <mitch.a.williams@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

With this patch we can now add Flow director Sideband rules for a VF from
it's PF. Here is an example on how it can be done when VF id = 5 and
queue = 2:

"ethtool -N ethx flow-type udp4 src-ip x.x.x.x dst-ip y.y.y.y src-port p1 dst-port p2 action 2 user-def 5"

User-def specifies VF id and action specifies queue.

Change-ID: Ib37d6dff3823a4d85caffde638473891c38c2b89
Signed-off-by: NAnjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Not sure how this slipped through. Cosmetic change only.
Signed-off-by: NMitch Williams <mitch.a.williams@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Explicitly stop the rings belonging to each VF when disabling SR-IOV.
Even though the VFs were gone, and the associated VSIs were removed,
the rings were not stopped, and in some circumstances the hardware would
continue to access the memory formerly used by the rings, causing
memory corruption or DMAR errors, both of which would lead to general
malaise of the kernel.

To relieve this condition, explicitly stop all the rings associated with
each VF before releasing its resources.
Signed-off-by: NMitch Williams <mitch.a.williams@intel.com>
Tested-by: NJim Young <james.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Allocating a large number of elements in atomic context could quickly
deplete memory reserves, so just disallow atomic resizing entirely.

Nothing currently uses mempool_resize() with anything other than
GFP_KERNEL, so convert existing callers to drop the gfp_mask.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Acked-by: Steffen Maier <maier@linux.vnet.ibm.com>	[zfcp]
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, cleancache_register_ops returns the previous value of
cleancache_ops to allow chaining.  However, chaining, as it is
implemented now, is extremely dangerous due to possible pool id
collisions.  Suppose, a new cleancache driver is registered after the
previous one assigned an id to a super block.  If the new driver assigns
the same id to another super block, which is perfectly possible, we will
have two different filesystems using the same id.  No matter if the new
driver implements chaining or not, we are likely to get data corruption
with such a configuration eventually.

This patch therefore disables the ability to override cleancache_ops
altogether as potentially dangerous.  If there is already cleancache
driver registered, all further calls to cleancache_register_ops will
return EBUSY.  Since no user of cleancache implements chaining, we only
need to make minor changes to the code outside the cleancache core.
Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch replaces cancel_dirty_page() with a helper function
account_page_cleaned() which only updates counters.  It's called from
truncate_complete_page() and from try_to_free_buffers() (hack for ext3).
Page is locked in both cases, page-lock protects against concurrent
dirtiers: see commit 2d6d7f98 ("mm: protect set_page_dirty() from
ongoing truncation").

Delete_from_page_cache() shouldn't be called for dirty pages, they must
be handled by caller (either written or truncated).  This patch treats
final dirty accounting fixup at the end of __delete_from_page_cache() as
a debug check and adds WARN_ON_ONCE() around it.  If something removes
dirty pages without proper handling that might be a bug and unwritten
data might be lost.

Hugetlbfs has no dirty pages accounting, ClearPageDirty() is enough
here.

cancel_dirty_page() in nfs_wb_page_cancel() is redundant.  This is
helper for nfs_invalidate_page() and it's called only in case complete
invalidation.

The mess was started in v2.6.20 after commits 46d2277c ("Clean up
and make try_to_free_buffers() not race with dirty pages") and
3e67c098 ("truncate: clear page dirtiness before running
try_to_free_buffers()") first was reverted right in v2.6.20 in commit
ecdfc978 ("Resurrect 'try_to_free_buffers()' VM hackery"), second in
v2.6.25 commit a2b34564 ("Fix dirty page accounting leak with ext3
data=journal").

Custom fixes were introduced between these points.  NFS in v2.6.23, commit
1b3b4a1a ("NFS: Fix a write request leak in nfs_invalidate_page()").
Kludge in __delete_from_page_cache() in v2.6.24, commit 3a692790 ("Do
dirty page accounting when removing a page from the page cache").  Since
v2.6.25 all of them are redundant.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's a deadlock when concurrently hot-adding memory through the probe
interface and switching a memory block from offline to online.

When hot-adding memory via the probe interface, add_memory() first takes
mem_hotplug_begin() and then device_lock() is later taken when registering
the newly initialized memory block.  This creates a lock dependency of (1)
mem_hotplug.lock (2) dev->mutex.

When switching a memory block from offline to online, dev->mutex is first
grabbed in device_online() when the write(2) transitions an existing
memory block from offline to online, and then online_pages() will take
mem_hotplug_begin().

This creates a lock inversion between mem_hotplug.lock and dev->mutex.
Vitaly reports that this deadlock can happen when kworker handling a probe
event races with systemd-udevd switching a memory block's state.

This patch requires the state transition to take mem_hotplug_begin()
before dev->mutex.  Hot-adding memory via the probe interface creates a
memory block while holding mem_hotplug_begin(), there is no way to take
dev->mutex first in this case.

online_pages() and offline_pages() are only called when transitioning
memory block state.  We now require that mem_hotplug_begin() is taken
before calling them -- this requires exporting the mem_hotplug_begin() and
mem_hotplug_done() to generic code.  In all hot-add and hot-remove cases,
mem_hotplug_begin() is done prior to device_online().  This is all that is
needed to avoid the deadlock.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Reported-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zhang Zhen <zhenzhang.zhang@huawei.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Wang Nan <wangnan0@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use macro section_nr_to_pfn() to switch between section and pfn, instead
of open-coding it.  No semantic changes.
Signed-off-by: NSheng Yong <shengyong1@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the recent driver changes, bump the version.
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: NKrishneil Singh <krishneil.k.singh@intel.com>

VFs were being improperly added to the switch's multicast group. The
error stems from the fact that incorrect arguments were passed to the
"update_mc_addr" function. It would seem to be a copy paste error since
the parameters are similar to the "update_uc_addr" function.
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NNgai-Mint Kwan <ngai-mint.kwan@intel.com>
Acked-by: NMatthew Vick <matthew.vick@intel.com>
Tested-by: NKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

When we call update_max_size it does not drop all oversized messages.
This is due to the difficulty in performing this operation, since it is
a FIFO which makes updating anything other than head or tail very
difficult. To fix this, modify validate_msg_size to ensure that we error
out later when trying to transmit the message that could be oversized.
This will generally be a rare condition, as it requires the FIFO to
include a message larger than the max_size negotiated during mailbox
connect. Note that max_size is always smaller than rx.size so it should
be safe to use here.

Also, update the update_max_size function header comment to clearly
indicate that it does not drop all oversized messages, but only those at
the head of the FIFO.
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Acked-by: NMatthew Vick <matthew.vick@intel.com>
Tested-by: NKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

When we forcefully shutdown the mailbox, we then go about resetting max
size to 0, and clearing all messages in the FIFO. Instead, we should
just reset the head pointer so that the FIFO becomes empty, rather than
changing the max size to 0. This helps prevent increment in tx_dropped
counter during mailbox negotiation, which is confusing to viewers of
Linux ethtool statistics output.
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Acked-by: NMatthew Vick <matthew.vick@intel.com>
Tested-by: NKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

The use of dropped doesn't really mean dropped mailbox messages, but
rather specifically messages which were too large to fit in the remote
Rx FIFO. Rename the stat to more clearly indicate what it means.
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Acked-by: NMatthew Vick <matthew.vick@intel.com>
Tested-by: NKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

When the PF receives a request to update a multicast address for the VF,
it checks the enabled multicast mode first. Fix a bug where the VF tried
to set a multicast address before requesting the required xcast mode.
This ensures the multicast addresses are honored as long as the xcast
mode was allowed.
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Acked-by: NMatthew Vick <matthew.vick@intel.com>
Tested-by: NKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Since the service task handles varying work that doesn't all require the
interface to be up, launch the service timer immediately. This ensures
that we continually check the mailbox, as well as handle other tasks
while the device is down.
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Acked-by: NMatthew Vick <matthew.vick@intel.com>
Tested-by: NKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

The header comment included a miscopy of a C-code line, and also
mis-used Rx FIFO when it clearly meant Tx FIFO
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Acked-by: NMatthew Vick <matthew.vick@intel.com>
Tested-by: NKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Add a header comment explaining why we have the somewhat crazy mailbox
flow. This flow is necessary as it prevents the PF<->SM mailbox from
being flooded by the VF messages, which normally trigger a message to
the PF. This helps prevent the case where we see a PF mailbox timeout.
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Acked-by: NMatthew Vick <matthew.vick@intel.com>
Tested-by: NKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>