The oif has already been checked that it is non-zero; the 2 additional
checks on oif within that if (oif) {...} block are redundant.

CC: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

lan78xx_suspend() may return non-zero from lan78xx_write_reg() in some scenario.
Fix to return 0 when lan78xx_suspend() has no error.
Signed-off-by: Woojung Huh <woojung.huh@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Or Gerlitz says:

====================
Mellanox mlx5 driver update

Bunch of changes from the team, while warming engines for the
upcoming SRIOV support.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Update new health monitored syndromes and their descriptions.
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The name refers to syndrome so uset ext_synd instread of ext_sync.
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In the new flow, we separate the pci initialization and teardown from the
initialization and teardown of the other resources.

init_one calls mlx5_pci_init that handles the pci resources initialization.
It then calls mlx5_load_one to initialize the remainder of the resources.

When removing a device, remove_one is invoked. However, now remove_one
calls mlx5_unload_one to free all the resources except the pci resources.
When mlx5_unload_one returns, mlx5_pci_close is called to free the pci
resources.

The above separation will allow us to implement the pci error handlers and
suspend and resume callbacks.
Signed-off-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Some errors did not result with notifying firmware that the page request
could not be fulfilled. Fix this and put the notification logic into a
separate function.
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In case of async command completion, the error code returned should take
into account the command completion status.
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Cosmetic change.
Do not use the an err variable just to assign and return it.
Signed-off-by: Achiad Shochat <achiad@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Used the output mailbox format for input mailbox.
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The private mlx5 state flag that indicates that the netdev is
opened is set at the beginning of the netdev open flow.
In case an error occured later in the mlx5 netdev open flow, this
flag was not cleared, remaining set although the actual set is
closed.
Signed-off-by: Achiad Shochat <achiad@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The function returns always non-negative values.

The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/assign_signed_to_unsigned.cocci [1].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2046107Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We found that a TCP Fast Open passive connection was vulnerable
to reorders, as the exchange might look like

[1] C -> S S <FO ...> <request>
[2] S -> C S. ack request <options>
[3] S -> C . <answer>

packets [2] and [3] can be generated at almost the same time.

If C receives the 3rd packet before the 2nd, it will drop it as
the socket is in SYN_SENT state and expects a SYNACK.

S will have to retransmit the answer.

Current OOO avoidance in linux is defeated because SYNACK
packets are attached to the LISTEN socket, while DATA packets
are attached to the children. They might be sent by different cpus,
and different TX queues might be selected.

It turns out that for TFO, we created a child, which is a
full blown socket in TCP_SYN_RECV state, and we simply can attach
the SYNACK packet to this socket.

This means that at the time tcp_sendmsg() pushes DATA packet,
skb->ooo_okay will be set iff the SYNACK packet had been sent
and TX completed.

This removes the reorder source at the host level.

We also removed the export of tcp_try_fastopen(), as it is no
longer called from IPv6.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jeff Kirsher says:

====================
Intel Wired LAN Driver Updates 2015-09-28

This series contains updates to i40e, i40evf and igb to resolve issues
seen and reported by Red Hat.

Kiran moves i40e_get_head() in preparation for the refactor of the Tx
timeout logic, so that it can be used in other areas of the driver.
Refactored the driver timeout logic by issuing a writeback request via
a software interrupt to the hardware the first time the driver detects
a hang.  This was due to the driver being too aggressive in resetting a
hung queue.

Shannon adds the GRE protocol to the transmit checksum encoding.

Anjali fixes an issue of forcing writeback too often, which caused us to
not benefit from NAPI.  We now disable force writeback in the clean
routine for X710 and XL710 adapters.  The X722 adapters do not enable
interrupt to force a writeback and benefit from WB_ON_ITR and so force
WB is left enabled for those adapters.  Fixed a possible deadlock issue
where sync_vsi_filters() can be called directly under RTNL or through
the timer subtask without RTNL.  So update the flow to see if we are
already under RTNL before trying to grab it.

Stefan Assmann provides a fix for igb where SR-IOV was not getting
enabled properly and we ran into a NULL pointer if the max_vfs module
parameter is specified.  This is prevented by setting the
IGB_FLAG_HAS_MSIX bit before calling igb_probe_vfs().

v2: added "i40e: Fix for recursive RTNL lock during PROMISC change" patch
    to the series, as it resolves another issues seen and reported by
    Red Hat.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

In igb_sw_init() the sequence of calls was changed from
igb_init_queue_configuration()
igb_init_interrupt_scheme()
igb_probe_vfs()
to
igb_probe_vfs()
igb_init_queue_configuration()
igb_init_interrupt_scheme()

This results in adapter->flags not having the IGB_FLAG_HAS_MSIX bit set
during igb_probe_vfs()->igb_enable_sriov(). Therefore SR-IOV does not
get enabled properly and we run into a NULL pointer if the max_vfs
module parameter is specified (adapter->vf_data does not get allocated,
crash on accessing the structure).

[    7.419348] BUG: unable to handle kernel NULL pointer dereference at 0000000000000048
[    7.419367] IP: [<ffffffffa02161c6>] igb_reset+0xe6/0x5d0 [igb]
[    7.419370] PGD 0
[    7.419373] Oops: 0002 [#1] SMP
[    7.419381] Modules linked in: ahci(+) libahci igb(+) i40e(+) vxlan ip6_udp_tunnel udp_tunnel megaraid_sas(+) ixgbe(+) mdio
[    7.419385] CPU: 0 PID: 4 Comm: kworker/0:0 Not tainted 4.2.0+ #153
[    7.419387] Hardware name: Dell Inc. PowerEdge R720/0C4Y3R, BIOS 1.6.0 03/07/2013
[...]
[    7.419431] Call Trace:
[    7.419442]  [<ffffffffa0217236>] igb_probe+0x8b6/0x1340 [igb]
[    7.419447]  [<ffffffff814c7f15>] local_pci_probe+0x45/0xa0

Prevent this by setting the IGB_FLAG_HAS_MSIX bit before calling
igb_probe_vfs(). The real interrupt capabilities will be checked during
igb_init_interrupt_scheme() so this is safe to do.
Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

The sync_vsi_filters function can be called directly under RTNL
or through the timer subtask without one. This was causing a deadlock.

If sync_vsi_filters is called from a thread which held the lock,
and in another thread the PROMISC setting got changed we would
be executing the PROMISC change in the thread which already held
the lock alongside the other filter update. The PROMISC change
requires a reset if we are on a VEB, which requires it to be called
under RTNL.

Earlier the driver would call reset for PROMISC change without
checking if we were already under RTNL and would try to grab it
causing a deadlock. This patch changes the flow to see if we are
already under RTNL before trying to grab it.
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: Kiran Patil <kiran.patil@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

This patch fixes the issue of forcing WB too often causing us to not
benefit from NAPI.

Without this patch we were forcing WB/arming interrupt too often taking
away the benefits of NAPI and causing a performance impact.

With this patch we disable force WB in the clean routine for X710
and XL710 adapters. X722 adapters do not enable interrupt to force
a WB and benefit from WB_ON_ITR and hence force WB is left enabled
for those adapters.
For XL710 and X710 adapters if we have less than 4 packets pending
a software Interrupt triggered from service task will force a WB.

This patch also changes the conditions for setting RS bit as described
in code comments. This optimizes when the HW does a tail bump and when
it does a WB. It also optimizes when we do a wmb.
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Make sure the Tx checksum encoder knows about GRE protocol and sets the
descriptor flag appropriately.
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

This patch modifies the driver timeout logic by issuing a writeback
request via a software interrupt to the hardware the first time the
driver detects a hang. The driver was too aggressive in resetting a hung
queue, so back that off by removing logic to down the netdevice after
too many hangs, and move the function to the service task.

Change-ID: Ife100b9d124cd08cbdb81ab659008c1b9abbedea
Signed-off-by: Kiran Patil <kiran.patil@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

i40e_get_head needs to be called in multiple files in a further patch,
prepare by moving the function into a header file.
Signed-off-by: Kiran Patil <kiran.patil@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Allow bridge forward delay to be configured when Spanning Tree is enabled.
Signed-off-by: Ian Wilson <iwilson@brocade.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jiri Benc says:

====================
vxlan: support both IPv4 and IPv6 sockets

Note: this needs net merged into net-next in order to apply.

It's currently not easy enough to work with metadata based vxlan tunnels. In
particular, it's necessary to create separate network interfaces for IPv4
and IPv6 tunneling. Assigning an IPv6 address to an IPv4 interface is
allowed yet won't do what's expected. With route based tunneling, one has to
pay attention to use the vxlan interface opened with the correct family.
Other users of this (openvswitch) would need to always create two vxlan
interfaces.

Furthermore, there's no sane API for creating an IPv6 vxlan metadata based
interface.

This patchset simplifies this by opening both IPv4 and IPv6 socket if the
vxlan interface has the metadata flag (IFLA_VXLAN_COLLECT_METADATA) set.
Assignment of addresses etc. works as expected after this.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

For metadata based vxlan interface, open both IPv4 and IPv6 socket. This is
much more user friendly: it's not necessary to create two vxlan interfaces
and pay attention to using the right one in routing rules.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Make vxlan_sock_add both alloc the socket and attach it to vxlan_dev. Let
vxlan_sock_release accept vxlan_dev as its parameter instead of vxlan_sock.

This makes vxlan_sock_add and vxlan_sock release complementary. It reduces
code duplication in the next patch.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When fixing the TSO support I noticed we just mask ->gso_size with the
MSSMask value and don't care about the consequences.

Provide a .ndo_features_check() method which drops the NETIF_F_TSO
feature for any skb which would exceed the maximum, and thus forces it
to be segmented by software.

Then we can stop the masking in cp_start_xmit(), and just WARN if the
maximum is exceeded, which should now never happen.

Finally, Francois Romieu noticed that we didn't even have the right
value for MSSMask anyway; it should be 0x7ff (11 bits) not 0xfff.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

I fixed TSO. Hardware checksum and scatter/gather also appear to be
working correctly both on real hardware and in QEMU's emulation.

Let's enable them by default and see if anyone screams...
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:
	net/ipv4/arp.c

The net/ipv4/arp.c conflict was one commit adding a new
local variable while another commit was deleting one.
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull networking fixes from David Miller:

 1) When we run a tap on netlink sockets, we have to copy mmap'd SKBs
    instead of cloning them.  From Daniel Borkmann.

 2) When converting classical BPF into eBPF, fix the setting of the
    source reg to BPF_REG_X.  From Tycho Andersen.

 3) Fix igmpv3/mldv2 report parsing in the bridge multicast code, from
    Linus Lussing.

 4) Fix dst refcounting for ipv6 tunnels, from Martin KaFai Lau.

 5) Set NLM_F_REPLACE flag properly when replacing ipv6 routes, from
    Roopa Prabhu.

 6) Add some new cxgb4 PCI device IDs, from Hariprasad Shenai.

 7) Fix headroom tests and SKB leaks in ipv6 fragmentation code, from
    Florian Westphal.

 8) Check DMA mapping errors in bna driver, from Ivan Vecera.

 9) Several 8139cp bug fixes (dev_kfree_skb_any in interrupt context,
    misclearing of interrupt status in TX timeout handler, etc.) from
    David Woodhouse.

10) In tipc, reset SKB header pointer after skb_linearize(), from Erik
    Hugne.

11) Fix autobind races et al. in netlink code, from Herbert Xu with
    help from Tejun Heo and others.

12) Missing SET_NETDEV_DEV in sunvnet driver, from Sowmini Varadhan.

13) Fix various races in timewait timer and reqsk_queue_hadh_req, from
    Eric Dumazet.

14) Fix array overruns in mac80211, from Johannes Berg and Dan
    Carpenter.

15) Fix data race in rhashtable_rehash_one(), from Dmitriy Vyukov.

16) Fix race between poll_one_napi and napi_disable, from Neil Horman.

17) Fix byte order in geneve tunnel port config, from John W Linville.

18) Fix handling of ARP replies over lightweight tunnels, from Jiri
    Benc.

19) We can loop when fib rule dumps cross multiple SKBs, fix from Wilson
    Kok and Roopa Prabhu.

20) Several reference count handling bug fixes in the PHY/MDIO layer
    from Russel King.

21) Fix lockdep splat in ppp_dev_uninit(), from Guillaume Nault.

22) Fix crash in icmp_route_lookup(), from David Ahern.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (116 commits)
  net: Fix panic in icmp_route_lookup
  net: update docbook comment for __mdiobus_register()
  ppp: fix lockdep splat in ppp_dev_uninit()
  net: via/Kconfig: GENERIC_PCI_IOMAP required if PCI not selected
  phy: marvell: add link partner advertised modes
  net: fix net_device refcounting
  phy: add phy_device_remove()
  phy: fixed-phy: properly validate phy in fixed_phy_update_state()
  net: fix phy refcounting in a bunch of drivers
  of_mdio: fix MDIO phy device refcounting
  phy: add proper phy struct device refcounting
  phy: fix mdiobus module safety
  net: dsa: fix of_mdio_find_bus() device refcount leak
  phy: fix of_mdio_find_bus() device refcount leak
  ip6_tunnel: Reduce log level in ip6_tnl_err() to debug
  ip6_gre: Reduce log level in ip6gre_err() to debug
  fib_rules: fix fib rule dumps across multiple skbs
  bnx2x: byte swap rss_key to comply to Toeplitz specs
  net: revert "net_sched: move tp->root allocation into fw_init()"
  lwtunnel: remove source and destination UDP port config option
  ...

Andrey reported a panic:

[ 7249.865507] BUG: unable to handle kernel pointer dereference at 000000b4
[ 7249.865559] IP: [<c16afeca>] icmp_route_lookup+0xaa/0x320
[ 7249.865598] *pdpt = 0000000030f7f001 *pde = 0000000000000000
[ 7249.865637] Oops: 0000 [#1]
...
[ 7249.866811] CPU: 0 PID: 0 Comm: swapper/0 Not tainted
4.3.0-999-generic #201509220155
[ 7249.866876] Hardware name: MSI MS-7250/MS-7250, BIOS 080014  08/02/2006
[ 7249.866916] task: c1a5ab00 ti: c1a52000 task.ti: c1a52000
[ 7249.866949] EIP: 0060:[<c16afeca>] EFLAGS: 00210246 CPU: 0
[ 7249.866981] EIP is at icmp_route_lookup+0xaa/0x320
[ 7249.867012] EAX: 00000000 EBX: f483ba48 ECX: 00000000 EDX: f2e18a00
[ 7249.867045] ESI: 000000c0 EDI: f483ba70 EBP: f483b9ec ESP: f483b974
[ 7249.867077]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[ 7249.867108] CR0: 8005003b CR2: 000000b4 CR3: 36ee07c0 CR4: 000006f0
[ 7249.867141] Stack:
[ 7249.867165]  320310ee 00000000 00000042 320310ee 00000000 c1aeca00
f3920240 f0c69180
[ 7249.867268]  f483ba04 f855058b a89b66cd f483ba44 f8962f4b 00000000
e659266c f483ba54
[ 7249.867361]  8004753c f483ba5c f8962f4b f2031140 000003c1 ffbd8fa0
c16b0e00 00000064
[ 7249.867448] Call Trace:
[ 7249.867494]  [<f855058b>] ? e1000_xmit_frame+0x87b/0xdc0 [e1000e]
[ 7249.867534]  [<f8962f4b>] ? tcp_in_window+0xeb/0xb10 [nf_conntrack]
[ 7249.867576]  [<f8962f4b>] ? tcp_in_window+0xeb/0xb10 [nf_conntrack]
[ 7249.867615]  [<c16b0e00>] ? icmp_send+0xa0/0x380
[ 7249.867648]  [<c16b102f>] icmp_send+0x2cf/0x380
[ 7249.867681]  [<f89c8126>] nf_send_unreach+0xa6/0xc0 [nf_reject_ipv4]
[ 7249.867714]  [<f89cd0da>] reject_tg+0x7a/0x9f [ipt_REJECT]
[ 7249.867746]  [<f88c29a7>] ipt_do_table+0x317/0x70c [ip_tables]
[ 7249.867780]  [<f895e0a6>] ? __nf_conntrack_find_get+0x166/0x3b0
[nf_conntrack]
[ 7249.867838]  [<f895eea8>] ? nf_conntrack_in+0x398/0x600 [nf_conntrack]
[ 7249.867889]  [<f84c0035>] iptable_filter_hook+0x35/0x80 [iptable_filter]
[ 7249.867933]  [<c16776a1>] nf_iterate+0x71/0x80
[ 7249.867970]  [<c1677715>] nf_hook_slow+0x65/0xc0
[ 7249.868002]  [<c1681811>] __ip_local_out_sk+0xc1/0xd0
[ 7249.868034]  [<c1680f30>] ? ip_forward_options+0x1a0/0x1a0
[ 7249.868066]  [<c1681836>] ip_local_out_sk+0x16/0x30
[ 7249.868097]  [<c1684054>] ip_send_skb+0x14/0x80
[ 7249.868129]  [<c16840f4>] ip_push_pending_frames+0x34/0x40
[ 7249.868163]  [<c16844a2>] ip_send_unicast_reply+0x282/0x310
[ 7249.868196]  [<c16a0863>] tcp_v4_send_reset+0x1b3/0x380
[ 7249.868227]  [<c16a1b63>] tcp_v4_rcv+0x323/0x990
[ 7249.868257]  [<c16776a1>] ? nf_iterate+0x71/0x80
[ 7249.868289]  [<c167dc2b>] ip_local_deliver_finish+0x8b/0x230
[ 7249.868322]  [<c167df4c>] ip_local_deliver+0x4c/0xa0
[ 7249.868353]  [<c167dba0>] ? ip_rcv_finish+0x390/0x390
[ 7249.868384]  [<c167d88c>] ip_rcv_finish+0x7c/0x390
[ 7249.868415]  [<c167e280>] ip_rcv+0x2e0/0x420
...

Prior to the VRF change the oif was not set in the flow struct, so the
VRF support should really have only added the vrf_master_ifindex lookup.

Fixes: 613d09b3 ("net: Use VRF device index for lookups on TX")
Cc: Andrey Melnikov <temnota.am@gmail.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Update the docbook comment for __mdiobus_register() to include the new
module owner argument.  This resolves a warning found by the 0-day
builder.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull another cgroup fix from Tejun Heo:
 "The cgroup writeback support got inadvertently enabled for traditional
  hierarchies revealing two regressions which are currently being worked
  on.  It shouldn't have been enabled on traditional hierarchies, so
  disable it on them.  This is enough to make the regressions go away
  for people who aren't experimenting with cgroup"

* 'for-4.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup, writeback: don't enable cgroup writeback on traditional hierarchies

Eric Dumazet says:

====================
dccp/tcp: constify listener sock

Another patch bomb to prepare lockless TCP/DCCP LISTEN handling.

SYNACK retransmits are built and sent without listener socket
being locked. Soon, initial SYNACK packets will have same property.

This series makes sure we did not something wrong with this model,
by adding a const qualifier in all the paths taken from synack building
and transmit, for IPv4/IPv6 and TCP/dccp.

The only potential problem was the rewrite of ecn bits for connections
with DCTCP as congestion module, but this was a very minor one.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

SYNACK packets are sent on behalf on unlocked listeners
or fastopen sockets. Mark socket as const to catch future changes
that might break the assumption.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This is done to make sure we do not change listener socket
while sending SYNACK packets while socket lock is not held.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Like tcp_make_synack() the only time we might change the socket is
when calling sock_wmalloc(), which is using atomic operation to
update sk->sk_wmem_alloc

Also use MAX_DCCP_HEADER as both IPv4/IPv6 use this value for max_header.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This documents fact that listener lock might not be held
at the time SYNACK are sent.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This is to document that socket lock might not be held at this point.

skb_set_owner_w() and ipv6_local_error() are using proper atomic ops
or spinlocks, so we promote the socket to non const when calling them.

netfilter hooks should never assume socket lock is held,
we also promote the socket to non const.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

listener socket is not locked when tcp_make_synack() is called.

We better make sure no field is written.

There is one exception : Since SYNACK packets are attached to the listener
at this moment (or SYN_RECV child in case of Fast Open),
sock_wmalloc() needs to update sk->sk_wmem_alloc, but this is done using
atomic operations so this is safe.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

SYNACK packets might be sent without holding socket lock.

For DCTCP/ECN sake, we should call INET_ECN_xmit() while
socket lock is owned, and only when we init/change congestion control.

This also fixies a bug if congestion module is changed from
dctcp to another one on a listener : we now clear ECN bits
properly.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We do not use the socket in this function.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>