This will be used by the set_rx_mode callback.

Also move a comment about multicast filtering in this new function.
Signed-off-by: Olivier Blin <olivier.blin@softathome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

To delegate promiscuous mode and multicast filtering to the subdriver.
Signed-off-by: Olivier Blin <olivier.blin@softathome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Florian Fainelli says:

====================
net: systemport: RX path and suspend fixes

These two patches fix a race condition where we have our RX interrupts
enabled, but not NAPI for the RX path, and the second patch fixes an
issue for packets stuck in RX fifo during a suspend/resume cycle.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

bcm_sysport_resume() was missing an UniMAC reset which can lead to
various receive FIFO corruptions coming out of a suspend cycle. If the
RX FIFO is stuck, it will deliver corrupted/duplicate packets towards
the host CPU interface.

This could be reproduced on crowded network and when Wake-on-LAN is
enabled for this particular interface because the switch still forwards
packets towards the host CPU interface (SYSTEMPORT), and we had to leave
the UniMAC RX enable bit on to allow matching MagicPackets.

Once we re-enter the resume function, there is a small window during
which the UniMAC receive is still enabled, and we start queueing
packets, but the RDMA and RBUF engines are not ready, which leads to
having packets stuck in the UniMAC RX FIFO, ultimately delivered towards
the host CPU as corrupted.

Fixes: 40755a0f ("net: systemport: add suspend and resume support")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There is currently a small window during which the SYSTEMPORT adapter
enables its RX interrupts without having enabled its NAPI handler, which
can result in packets to be discarded during interface bringup.

A similar but more serious window exists in bcm_sysport_resume() during
which we can have the RDMA engine not fully prepared to receive packets
and yet having RX interrupts enabled.

Fix this my moving the RX interrupt enable down to
bcm_sysport_netif_start() after napi_enable() for the RX path is called,
which fixes both call sites: bcm_sysport_open() and
bcm_sysport_resume().

Fixes: b02e6d9b ("net: systemport: add bcm_sysport_netif_{enable,stop}")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix kernel-doc warning in <linux/skbuff.h> by making both headers_start
and headers_end private fields.

Warning(..//include/linux/skbuff.h:654): No description found for parameter 'headers_end[0]'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Marvell phy 88E1145 configuration & initialization was missing a case
for initializing SGMII mode. This patch adds that case.
Signed-off-by: Vince Bridgers <vbridger@opensource.altera.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

when slave 0 has no phy and slave 1 connected to phy, driver probe will
fail as there is no phy id present for slave 0 device tree, so continuing
even though no phy-id found, also moving mac-id read later to ensure
mac-id is read from device tree even when phy-id entry in not found.
Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

John W. Linville says:

====================
pull request: wireless 2014-10-28

Please pull this batch of fixes intended for the 3.18 stream!

For the mac80211 bits, Johannes says:

"Here are a few fixes for the wireless stack: one fixes the
RTS rate, one for a debugfs file, one to return the correct
channel to userspace, a sanity check for a userspace value
and the remaining two are just documentation fixes."

For the iwlwifi bits, Emmanuel says:

"I revert here a patch that caused interoperability issues.
dvm gets a fix for a bug that was reported by many users.
Two minor fixes for BT Coex and platform power fix that helps
reducing latency when the PCIe link goes to low power states."

In addition...

Felix Fietkau adds a couple of ath code fixes related to regulatory
rule enforcement.

Hauke Mehrtens fixes a build break with bcma when CONFIG_OF_ADDRESS
is not set.

Karsten Wiese provides a trio of minor fixes for rtl8192cu.

Kees Cook prevents a potential information leak in rtlwifi.

Larry Finger also brings a trio of minor fixes for rtlwifi.

Rafał Miłecki adds a device ID to the bcma bus driver.

Rickard Strandqvist offers some strn* -> strl* changes in brcmfmac
to eliminate non-terminated string issues.

Sujith Manoharan avoids some ath9k stalls by enabling HW queue control
only for MCC.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Andrew Lunn says:

====================
DSA tagging mismatches

The second patch is a fix, which should be applied to -rc. It is
possible to get a DSA configuration which does not work. The patch
stops this happening.

The first patch detects this situation, and errors out the probe of
DSA, making it more obvious something is wrong. It is not required to
apply it -rc.

v2 fixes the use case pointed out by Florian, that a switch driver
may use DSA_TAG_PROTO_NONE which the patch did not correctly handle.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The mv88e6171 can support two different tagging protocols, DSA and
EDSA. The switch driver structure only allows one protocol to be
enumerated, and DSA was chosen. However the Kconfig entry ensures the
EDSA tagging code is built. With a minimal configuration, we then end
up with a mismatch. The probe is successful, EDSA tagging is used, but
the switch is configured for DSA, resulting in mangled packets.

Change the switch driver structure to enumerate EDSA, fixing the
mismatch.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Fixes: 42f27253 ("net: DSA: Marvell mv88e6171 switch driver")
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If there is a mismatch between enabled tagging protocols and the
protocol the switch supports, error out, rather than continue with a
situation which is unlikely to work.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
cc: alexander.h.duyck@intel.com
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

introduce two configs:
- hidden CONFIG_BPF to select eBPF interpreter that classic socket filters
  depend on
- visible CONFIG_BPF_SYSCALL (default off) that tracing and sockets can use

that solves several problems:
- tracing and others that wish to use eBPF don't need to depend on NET.
  They can use BPF_SYSCALL to allow loading from userspace or select BPF
  to use it directly from kernel in NET-less configs.
- in 3.18 programs cannot be attached to events yet, so don't force it on
- when the rest of eBPF infra is there in 3.19+, it's still useful to
  switch it off to minimize kernel size

bloat-o-meter on x64 shows:
add/remove: 0/60 grow/shrink: 0/2 up/down: 0/-15601 (-15601)

tested with many different config combinations. Hopefully didn't miss anything.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Anish Bhatt says:

====================
cxgb4 : DCBx fixes for apps/host lldp agents

This patchset  contains some minor fixes for cxgb4 DCBx code. Chiefly, cxgb4
was not cleaning up any apps added to kernel app table when link was lost.
Disabling DCBx in firmware would automatically set DCBx state to host-managed
and enabled, we now wait for an explicit enable call from an lldp agent instead

First patch was originally sent to net-next, but considering it applies to
correcting behaviour of code already in net, I think it qualifies as a bug fix.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Disabling DCBx in firmware automatically enables DCBx for control via host
lldp agents. Wait for an explicit setstate call from an lldp agents to enable
 DCBx instead.

Fixes: 76bcb31e ("cxgb4 : Add DCBx support codebase and dcbnl_ops")
Signed-off-by: Anish Bhatt <anish@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Clear out any DCB apps we might have added to kernel table when we lose DCB
sync (or IEEE equivalent event). These were previously left behind and not
cleaned up correctly. IEEE allows individual components to work independently,
 so improve check for IEEE completion by specifying individual components.

Fixes: 10b00466 ("cxgb4: IEEE fixes for DCBx state machine")
Signed-off-by: Anish Bhatt <anish@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for your net tree,
they are:

1) Allow to recycle a TCP port in conntrack when the change role from
   server to client, from Marcelo Leitner.

2) Fix possible off by one access in ip_set_nfnl_get_byindex(), patch
   from Dan Carpenter.

3) alloc_percpu returns NULL on error, no need for IS_ERR() in nf_tables
   chain statistic updates. From Sabrina Dubroca.

4) Don't compile ip options in bridge netfilter, this mangles the packet
   and bridge should not alter layer >= 3 headers when forwarding packets.
   Patch from Herbert Xu and tested by Florian Westphal.

5) Account the final NLMSG_DONE message when calculating the size of the
   nflog netlink batches. Patch from Florian Westphal.

6) Fix a possible netlink attribute length overflow with large packets.
   Again from Florian Westphal.

7) Release the skbuff if nfnetlink_log fails to put the final
   NLMSG_DONE message. This fixes a leak on error. This shouldn't ever
   happen though, otherwise this means we miscalculate the netlink batch
   size, so spot a warning if this ever happens so we can track down the
   problem. This patch from Houcheng Lin.

8) Look at the right list when recycling targets in the nft_compat,
   patch from Arturo Borrero.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The code looks for an already loaded target, and the correct list to search
is nft_target_list, not nft_match_list.
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Merge tag 'mac80211-for-john-2014-10-23' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211

Johannes Berg <johannes@sipsolutions.net> says:

"Here are a few fixes for the wireless stack: one fixes the
RTS rate, one for a debugfs file, one to return the correct
channel to userspace, a sanity check for a userspace value
and the remaining two are just documentation fixes."
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Merge tag 'iwlwifi-for-john-2014-10-23' of git://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/iwlwifi-fixes

Emmanuel Grumbach <egrumbach@gmail.com> says:

"I revert here a patch that caused interoperability issues.
dvm gets a fix for a bug that was reported by many users.
Two minor fixes for BT Coex and platform power fix that helps
reducing latency when the PCIe link goes to low power states."
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Do not reuse skb if it was pfmemalloc tainted, otherwise
future frame might be dropped anyway.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

Eli Cohen says:

====================
irq sync fixes

This two patch series fixes a race where an interrupt handler could access a
freed memory.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

After moving the EQ ownership to software effectively destroying it, call
synchronize_irq() to ensure that any handler routines running on other CPU
cores finish execution. Only then free the EQ buffer.
The same thing is done when we destroy a CQ which is one of the sources
generating interrupts. In the case of CQ we want to avoid completion handlers
on a CQ that was destroyed. In the case we do the same to avoid receiving
asynchronous events after the EQ has been destroyed and its buffers freed.
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

After destroying the EQ, the object responsible for generating interrupts, call
synchronize_irq() to ensure that any handler routines running on other CPU
cores finish execution. Only then free the EQ buffer. This patch solves a very
rare case when we get panic on driver unload.
The same thing is done when we destroy a CQ which is one of the sources
generating interrupts. In the case of CQ we want to avoid completion handlers
on a CQ that was destroyed. In the case we do the same to avoid receiving
asynchronous events after the EQ has been destroyed and its buffers freed.
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c: In function ‘xgene_enet_ecc_init’:
drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c:126: warning: ‘data’ may be used uninitialized in this function

Depending on the arbitrary value on the stack, the loop may terminate
too early, and cause a bogus -ENODEV failure.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

We accidentally mask by the _SHIFT variable.  It means that "event" is
always zero.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Tested-by: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We need to cancel the work queue after rcu grace period,
otherwise it can be rescheduled by incoming packets.

We need to purge queue if some skbs are still in it.

We can use __skb_queue_head_init() variant in
macvlan_process_broadcast()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 412ca155 ("macvlan: Move broadcasts into a work queue")
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

percpu tcp_md5sig_pool contains memory blobs that ultimately
go through sg_set_buf().

-> sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));

This requires that whole area is in a physically contiguous portion
of memory. And that @buf is not backed by vmalloc().

Given that alloc_percpu() can use vmalloc() areas, this does not
fit the requirements.

Replace alloc_percpu() by a static DEFINE_PER_CPU() as tcp_md5sig_pool
is small anyway, there is no gain to dynamically allocate it.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 765cf997 ("tcp: md5: remove one indirection level in tcp_md5sig_pool")
Reported-by: Crestez Dan Leonard <cdleonard@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

David Vrabel says:

====================
xen-netback: guest Rx queue drain and stall fixes

This series fixes two critical xen-netback bugs.

1. Netback may consume all of host memory by queuing an unlimited
   number of skb on the internal guest Rx queue.  This behaviour is
   guest triggerable.

2. Carrier flapping under high traffic rates which reduces
   performance.

The first patch is a prerequite.  Removing support for frontends with
feature-rx-notify makes it easier to reason about the correctness of
netback since it no longer has to support this outdated and broken
mode.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

If a frontend not receiving packets it is useful to detect this and
turn off the carrier so packets are dropped early instead of being
queued and drained when they expire.

A to-guest queue is stalled if it doesn't have enough free slots for a
an extended period of time (default 60 s).

If at least one queue is stalled, the carrier is turned off (in the
expectation that the other queues will soon stall as well).  The
carrier is only turned on once all queues are ready.

When the frontend connects, all the queues start in the stalled state
and only become ready once the frontend queues enough Rx requests.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Netback needs to discard old to-guest skb's (guest Rx queue drain) and
it needs detect guest Rx stalls (to disable the carrier so packets are
discarded earlier), but the current implementation is very broken.

1. The check in hard_start_xmit of the slot availability did not
   consider the number of packets that were already in the guest Rx
   queue.  This could allow the queue to grow without bound.

   The guest stops consuming packets and the ring was allowed to fill
   leaving S slot free.  Netback queues a packet requiring more than S
   slots (ensuring that the ring stays with S slots free).  Netback
   queue indefinately packets provided that then require S or fewer
   slots.

2. The Rx stall detection is not triggered in this case since the
   (host) Tx queue is not stopped.

3. If the Tx queue is stopped and a guest Rx interrupt occurs, netback
   will consider this an Rx purge event which may result in it taking
   the carrier down unnecessarily.  It also considers a queue with
   only 1 slot free as unstalled (even though the next packet might
   not fit in this).

The internal guest Rx queue is limited by a byte length (to 512 Kib,
enough for half the ring).  The (host) Tx queue is stopped and started
based on this limit.  This sets an upper bound on the amount of memory
used by packets on the internal queue.

This allows the estimatation of the number of slots for an skb to be
removed (it wasn't a very good estimate anyway).  Instead, the guest
Rx thread just waits for enough free slots for a maximum sized packet.

skbs queued on the internal queue have an 'expires' time (set to the
current time plus the drain timeout).  The guest Rx thread will detect
when the skb at the head of the queue has expired and discard expired
skbs.  This sets a clear upper bound on the length of time an skb can
be queued for.  For a guest being destroyed the maximum time needed to
wait for all the packets it sent to be dropped is still the drain
timeout (10 s) since it will not be sending new packets.

Rx stall detection is reintroduced in a later commit.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Frontends that do not provide feature-rx-notify may stall because
netback depends on the notification from frontend to wake the guest Rx
thread (even if can_queue is false).

This could be fixed but feature-rx-notify was introduced in 2006 and I
am not aware of any frontends that do not implement this.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch brings back the makefile called testptp.mk which was removed
in commit adb19fb6 (Documentation: add makefiles for more targets).

While the idea of that commit was to improve build coverage of the
examples, the new Makefile is unable to cross compile the testptp program.
In contrast, the deleted makefile was able to do this just fine.

This patch fixes the regression by restoring the original makefile.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Peter Foley <pefoley2@pefoley.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The kernel should reserve enough room in the skb so that the DONE
message can always be appended.  However, in case of e.g. new attribute
erronously not being size-accounted for, __nfulnl_send() will still
try to put next nlmsg into this full skbuf, causing the skb to be stuck
forever and blocking delivery of further messages.

Fix issue by releasing skb immediately after nlmsg_put error and
WARN() so we can track down the cause of such size mismatch.

[ fw@strlen.de: add tailroom/len info to WARN ]
Signed-off-by: Houcheng Lin <houcheng@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

don't try to queue payloads > 0xffff - NLA_HDRLEN, it does not work.
The nla length includes the size of the nla struct, so anything larger
results in u16 integer overflow.

This patch is similar to
9cefbbc9 (netfilter: nfnetlink_queue: cleanup copy_range usage).
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

We currently neither account for the nlattr size, nor do we consider
the size of the trailing NLMSG_DONE when allocating nlmsg skb.

This can result in nflog to stop working, as __nfulnl_send() re-tries
sending forever if it failed to append NLMSG_DONE (which will never
work if buffer is not large enough).
Reported-by: Houcheng Lin <houcheng@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Commit 462fb2af

	bridge : Sanitize skb before it enters the IP stack

broke when IP options are actually used because it mangles the
skb as if it entered the IP stack which is wrong because the
bridge is supposed to operate below the IP stack.

Since nobody has actually requested for parsing of IP options
this patch fixes it by simply reverting to the previous approach
of ignoring all IP options, i.e., zeroing the IPCB.

If and when somebody who uses IP options and actually needs them
to be parsed by the bridge complains then we can revisit this.
Reported-by: David Newall <davidn@davidnewall.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

iwl_poll_bit may return a strictly positive value when the
poll doesn't match on the first try.
This was caught when WoWLAN started failing upon resume
even if the poll_bit actually succeeded.

Also change a wrong print. If we reach the end of
iwl_pcie_prepare_card_hw, it means that we couldn't
get the devices.
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

This reverts commit aa11bbf3.
This commit was causing connection issues and is not needed
if IWL_MVM_RS_RSSI_BASED_INIT_RATE is set to false by default.

Regardless of the issues mentioned above, this patch added the
following WARNING:

WARNING: CPU: 0 PID: 3946 at drivers/net/wireless/iwlwifi/mvm/tx.c:190 iwl_mvm_set_tx_params+0x60a/0x6f0 [iwlmvm]()
Got an HT rate for a non data frame 0x8
CPU: 0 PID: 3946 Comm: wpa_supplicant Tainted: G           O   3.17.0+ #6
Hardware name: LENOVO 20ANCTO1WW/20ANCTO1WW, BIOS GLET71WW (2.25 ) 07/02/2014
 0000000000000009 ffffffff814fa911 ffff8804288db8f8 ffffffff81064f52
 0000000000001808 ffff8804288db948 ffff88040add8660 ffff8804291b5600
 0000000000000000 ffffffff81064fb7 ffffffffa07b73d0 0000000000000020
Call Trace:
 [<ffffffff814fa911>] ? dump_stack+0x41/0x51
 [<ffffffff81064f52>] ? warn_slowpath_common+0x72/0x90
 [<ffffffff81064fb7>] ? warn_slowpath_fmt+0x47/0x50
 [<ffffffffa07a39ea>] ? iwl_mvm_set_tx_params+0x60a/0x6f0 [iwlmvm]
 [<ffffffffa07a3cf8>] ? iwl_mvm_tx_skb+0x48/0x3c0 [iwlmvm]
 [<ffffffffa079cb9b>] ? iwl_mvm_mac_tx+0x7b/0x180 [iwlmvm]
 [<ffffffffa0746ce9>] ? __ieee80211_tx+0x2b9/0x3c0 [mac80211]
 [<ffffffffa07492f3>] ? ieee80211_tx+0xb3/0x100 [mac80211]
 [<ffffffffa0749c49>] ? ieee80211_subif_start_xmit+0x459/0xca0 [mac80211]
 [<ffffffff814116e7>] ? dev_hard_start_xmit+0x337/0x5f0
 [<ffffffff81430d46>] ? sch_direct_xmit+0x96/0x1f0
 [<ffffffff81411ba3>] ? __dev_queue_xmit+0x203/0x4f0
 [<ffffffff8142f670>] ? ether_setup+0x70/0x70
 [<ffffffff814e96a1>] ? packet_sendmsg+0xf81/0x1110
 [<ffffffff8140625c>] ? skb_free_datagram+0xc/0x40
 [<ffffffff813f7538>] ? sock_sendmsg+0x88/0xc0
 [<ffffffff813f7274>] ? move_addr_to_kernel.part.20+0x14/0x60
 [<ffffffff811c47c2>] ? __inode_wait_for_writeback+0x62/0xb0
 [<ffffffff813f7a91>] ? SYSC_sendto+0xf1/0x180
 [<ffffffff813f88f9>] ? __sys_recvmsg+0x39/0x70
 [<ffffffff8150066d>] ? system_call_fastpath+0x1a/0x1f
---[ end trace cc19a150d311fc63 ]---

which was reported here: https://bugzilla.kernel.org/show_bug.cgi?id=85691

CC: <stable@vger.kernel.org> [3.13+]
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

When mac80211 wants to ensure that a frame is sent, it calls
the flush() callback. Until now, iwldvm implemented this by
waiting that all the frames are sent (ACKed or timeout).
In case of weak signal, this can take a significant amount
of time, delaying the next connection (in case of roaming).
Many users have reported that the flush would take too long
leading to the following error messages to be printed:

iwlwifi 0000:03:00.0: fail to flush all tx fifo queues Q 2
iwlwifi 0000:03:00.0: Current SW read_ptr 161 write_ptr 201
iwl data: 00000000: 00 00 00 00 00 00 00 00 fe ff 01 00 00 00 00 00
[snip]
iwlwifi 0000:03:00.0: FH TRBs(0) = 0x00000000
[snip]
iwlwifi 0000:03:00.0: Q 0 is active and mapped to fifo 3 ra_tid 0x0000 [9,9]
[snip]

Instead of waiting for these packets, simply drop them. This
significantly improves the responsiveness of the network.
Note that all the queues are flushed, but the VO one. This
is not typically used by the applications and it likely
contains management frames that are useful for connection
or roaming.

This bug is tracked here:
https://bugzilla.kernel.org/show_bug.cgi?id=56581

But it is duplicated in distributions' trackers.
A simple search in Ubuntu's database led to these bugs:

https://bugs.launchpad.net/ubuntu/+source/linux-firmware/+bug/1270808
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1305406
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1356236
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1360597
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1361809

Cc: <stable@vger.kernel.org>
Depends-on: 77be2c54 ("mac80211: add vif to flush call")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>