bpf_tail_call() arguments:

 - ctx......: Context pointer
 - jmp_table: One of BPF_MAP_TYPE_PROG_ARRAY maps used as the jump table
 - index....: Index in the jump table

In this implementation s390x JIT does stack unwinding and jumps into the
callee program prologue. Caller and callee use the same stack.

With this patch a tail call generates the following code on s390x:

 if (index >= array->map.max_entries)
         goto out
 000003ff8001c7e4: e31030100016   llgf    %r1,16(%r3)
 000003ff8001c7ea: ec41001fa065   clgrj   %r4,%r1,10,3ff8001c828

 if (tail_call_cnt++ > MAX_TAIL_CALL_CNT)
         goto out;
 000003ff8001c7f0: a7080001       lhi     %r0,1
 000003ff8001c7f4: eb10f25000fa   laal    %r1,%r0,592(%r15)
 000003ff8001c7fa: ec120017207f   clij    %r1,32,2,3ff8001c828

 prog = array->prog[index];
 if (prog == NULL)
         goto out;
 000003ff8001c800: eb140003000d   sllg    %r1,%r4,3
 000003ff8001c806: e31310800004   lg      %r1,128(%r3,%r1)
 000003ff8001c80c: ec18000e007d   clgij   %r1,0,8,3ff8001c828

 Restore registers before calling function
 000003ff8001c812: eb68f2980004   lmg     %r6,%r8,664(%r15)
 000003ff8001c818: ebbff2c00004   lmg     %r11,%r15,704(%r15)

 goto *(prog->bpf_func + tail_call_start);
 000003ff8001c81e: e31100200004   lg      %r1,32(%r1,%r0)
 000003ff8001c824: 47f01006       bc      15,6(%r1)
Reviewed-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pull networking fixes from David Miller:

 1) Fix stack allocation in s390 BPF JIT, from Michael Holzheu.

 2) Disable LRO on openvswitch paths, from Jiri Benc.

 3) UDP early demux doesn't handle multicast group membership properly,
    fix from Shawn Bohrer.

 4) Fix TX queue hang due to incorrect handling of mixed sized fragments
    and linearlization in i40e driver, from Anjali Singhai Jain.

 5) Cannot use disable_irq() in timer handler of AMD xgbe driver, from
    Thomas Lendacky.

 6) b2net driver improperly assumes pci_alloc_consistent() gives zero'd
    out memory, use dma_zalloc_coherent().  From Sriharsha Basavapatna.

 7) Fix use-after-free in MPLS and ipv6, from Robert Shearman.

 8) Missing neif_napi_del() calls in cleanup paths of b44 driver, from
    Hauke Mehrtens.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  net: replace last open coded skb_orphan_frags with function call
  net: bcmgenet: power on MII block for all MII modes
  ipv6: Fix protocol resubmission
  ipv6: fix possible use after free of dev stats
  b44: call netif_napi_del()
  bridge: disable softirqs around br_fdb_update to avoid lockup
  Revert "bridge: use _bh spinlock variant for br_fdb_update to avoid lockup"
  mpls: fix possible use after free of device
  be2net: Replace dma/pci_alloc_coherent() calls with dma_zalloc_coherent()
  bridge: use _bh spinlock variant for br_fdb_update to avoid lockup
  amd-xgbe: Use disable_irq_nosync from within timer function
  rhashtable: add missing import <linux/export.h>
  i40e: Make sure to be in VEB mode if SRIOV is enabled at probe
  i40e: start up in VEPA mode by default
  i40e/i40evf: Fix mixed size frags and linearization
  ipv4/udp: Verify multicast group is ours in upd_v4_early_demux()
  openvswitch: disable LRO
  s390/bpf: fix bpf frame pointer setup
  s390/bpf: fix stack allocation

Pull last-minute virtio fix from Michael Tsirkin:
 "This fixes a minor issue affecting multiqueue virtio net when user
  keeps changing the number of active queues and CPUs are added and
  removed by hotplug"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_pci: Clear stale cpumask when setting irq affinity

Fix the device tree entries to modify the '_' to '-'.
Also changes the names of the internal delay properties
from -int- to -internal- as the -int- appeared as a keyword.
Signed-off-by: NDan Murphy <dmurphy@ti.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

API compliance scanning with coccinelle flagged:
./drivers/atm/iphase.c:2621:4-20:
        WARNING: timeout (50) seems HZ dependent

Numeric constants passed to schedule_timeout() make the effective
timeout HZ dependent which does not seem intended.
Fixed up by converting the constant to jiffies with msecs_to_jiffies()
As this driver was introduced in the early 2.3 series it is most
likely assuming HZ=100 so the constant 50 is converted to 500ms.
Signed-off-by: NNicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pull ARM SoC fixes from Kevin Hilman:
 "About 10 days worth of small bug fixes, and the (hopefully) final
  round fixes for from arm-soc land for the -rc cycle.  Nothing special
  to note, but here's a brief summary of fixes by SoC type:

   - OMAP:
        small set of misc DT fixes; boot fix for THUMB2 kernel

   - mediatek:
        PMIC fixes; DT fix for model name

   - exynos:
        wakeup interupt fixes for 3250

   - mvebu:
        revert mbus patch which broke DMA masters

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  ARM: dts: am335x-boneblack: disable RTC-only sleep to avoid hardware damage
  ARM: dts: AM35xx: fix system control module clocks
  arm64: dts: mt8173-evb: fix model name
  ARM: exynos: Fix wake-up interrupts for Exynos3250
  ARM: dts: Fix n900 dts file to work around 4.1 touchscreen regression on n900
  ARM: dts: Fix dm816x to use right compatible flag for MUSB
  ARM: OMAP3: Fix booting with thumb2 kernel
  Revert "bus: mvebu-mbus: make sure SDRAM CS for DMA don't overlap the MBus bridge window"
  bus: mvebu-mbus: do not set WIN_CTRL_SYNCBARRIER on non io-coherent platforms.
  ARM: mvebu: armada-xp-linksys-mamba: Disable internal RTC
  soc: mediatek: Add compile dependency to pmic-wrapper
  soc: mediatek: PMIC wrap: Fix register state machine handling
  soc: mediatek: PMIC wrap: Fix clock rate handling

Update the AFE_TX_CONFIG value to solve marginal rise/fall issues
observed when the link is operating in 100BaseT. This workaround applies
to GPHY revisions D0, E0 and newer.
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 70008aa5 ("skbuff: convert to skb_orphan_frags") replaced
open coded tests of SKBTX_DEV_ZEROCOPY and skb_copy_ubufs with calls
to helper function skb_orphan_frags. Apply that to the last remaining
open coded site.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The RGMII block is currently only powered on when using RGMII or
RGMII_NO_ID, which is not correct when using the GENET interface in MII
or Reverse MII modes. We always need to power on the RGMII interface for
this block to properly work, regardless of the MII mode in which we
operate.

Fixes: aa09677c ("net: bcmgenet: add MDIO routines")
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

UDP encapsulation is broken on IPv6. This is because the logic to resubmit
the nexthdr is inverted, checking for a ret value > 0 instead of < 0. Also,
the resubmit label is in the wrong position since we already get the
nexthdr value when performing decapsulation. In addition the skb pull is no
longer necessary either.

This changes the return value check to look for < 0, using it for the
nexthdr on the next iteration, and moves the resubmit label to the proper
location.

With these changes the v6 code now matches what we do in the v4 ip input
code wrt resubmitting when decapsulating.
Signed-off-by: NJosh Hunt <johunt@akamai.com>
Acked-by: N"Tom Herbert" <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The memory pointed to by idev->stats.icmpv6msgdev,
idev->stats.icmpv6dev and idev->stats.ipv6 can each be used in an RCU
read context without taking a reference on idev. For example, through
IP6_*_STATS_* calls in ip6_rcv. These memory blocks are freed without
waiting for an RCU grace period to elapse. This could lead to the
memory being written to after it has been freed.

Fix this by using call_rcu to free the memory used for stats, as well
as idev after an RCU grace period has elapsed.
Signed-off-by: NRobert Shearman <rshearma@brocade.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Merge tag 'omap-for-v4.1/fixes-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into fixes

Merge omap fixes for v4.1, urgent fix to avoid potential hardware damage From Tony Lindgren:

Omap fixes for the -rc cycle, including a fix for potential hardware
breakage on BeagleBones:

- BeagleBones don't support RTC-only mode, it can cause hardware
  damage if system-power-controller is specified without
  ti,pmic-shutdown-controller

- Fix a recent regression to am3517 SoCs caused by the recent clock
  move that was not noticed until now despite automated boot
  testing

- Fix a regression for n900 touchscreen triggered by recent
  recent input changes

- Fix compatible property for dm816x USB to avoid errors with
  USB Ethernet

- Fix oops for omap3 when built with CONFIG_THUMB2_KERNEL

* tag 'omap-for-v4.1/fixes-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
  ARM: dts: am335x-boneblack: disable RTC-only sleep to avoid hardware damage
  ARM: dts: AM35xx: fix system control module clocks
  ARM: dts: Fix n900 dts file to work around 4.1 touchscreen regression on n900
  ARM: dts: Fix dm816x to use right compatible flag for MUSB
  ARM: OMAP3: Fix booting with thumb2 kernel

Pull Intel IOMMU fix from David Woodhouse:
 "This fixes an oops when attempting to enable 1:1 passthrough mode for
  devices on which VT-d translation was disabled anyway.

  It's actually a long-standing bug but recent changes (commit
  18436afd: "iommu/vt-d: Allow RMRR on graphics devices too") have
  made it much easier to trigger with 'iommu=pt intel_iommu=igfx_off' on
  the command line"

* git://git.infradead.org/intel-iommu:
  iommu/vt-d: Fix passthrough mode with translation-disabled devices

Pull libata fixes from Tejun Heo:
 "Two driver fixes.  One is for an ahci_mvebu controller config bug and
  the other fixes pata_octeon_cf build issue"

* 'for-4.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
  pata_octeon_cf: fix broken build
  ata: ahci_mvebu: Fix wrongly set base address for the MBus window setting

MODULE_DEVICE_TABLE is referring to wrong driver's table and breaks the
build. Fix that.

Cc: stable@vger.kernel.org
Signed-off-by: NAaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Jaeden Amero says:

====================
net/phy: micrel: Center FLP timing at 16ms

In v2, we add an additional cleanup commit to make an array of strings
static const and to improve const correctness generally. We also no longer
unnecessarily initialize the result variable in
ksz9031_center_flp_timing().

In v3, we remove the unnecessary result variable from ksz9031_config_init()
introduced by a previous version of "net/phy: micrel: Center FLP timing at
16ms".

In v4, we modify the commit message of "net/phy: micrel: Center FLP timing
at 16ms" to replace the awkward quotation of the data sheet's programming
procedure with an explanation of why we program the FLP burst registers and
restart auto-negotiation where we do (config_init).
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Link failures have been observed when using the KSZ9031 with HP 1810-8G
and HP 1910-8G network switches. Center the FLP timing at 16ms to help
avoid intermittent link failures.

>From the KSZ9031RNX and KSZ9031MNX data sheets revision 2.2, section
"Auto-Negotiation Timing":
	The KSZ9031[RNX or MNX] Fast Link Pulse (FLP) burst-to-burst
	transmit timing for Auto-Negotiation defaults to 8ms. IEEE 802.3
	Standard specifies this timing to be 16ms +/-8ms. Some PHY link
	partners need to receive the FLP with 16ms centered timing;
	otherwise, there can be intermittent link failures and long
	link-up times.

The PHY data sheet recommends configuring the FLP burst registers after
power-up/reset and immediately thereafter restarting auto-negotiation, so
we center the FLP timing at 16ms and then restart auto-negotiation in the
config_init for KSZ9031.
Signed-off-by: NJaeden Amero <jaeden.amero@ni.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are some defines for a few pad skew related extended registers.
Specify for which MMD Address (dev_addr) they are for.
Signed-off-by: NJaeden Amero <jaeden.amero@ni.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In a few places in this driver, we weren't using const where we could
have. Use const more.

In addition, change the arrays of strings in ksz9031_config_init() to be
not only const, but also static.
Signed-off-by: NJaeden Amero <jaeden.amero@ni.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As Alexander Duyck pointed out that:
struct tnode {
        ...
        struct key_vector kv[1];
}
The kv[1] member of struct tnode is an arry that refernced by
a null pointer will not crash the system, like this:
struct tnode *p = NULL;
struct key_vector *kv = p->kv;
As such p->kv doesn't actually dereference anything, it is simply a
means for getting the offset to the array from the pointer p.

This patch make the code more regular to avoid making people feel
odd when they look at the code.
Signed-off-by: NFiro Yang <firogm@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

API compliance scanning with coccinelle flagged:
./drivers/net/wan/dscc4.c:1036:1-33:
        WARNING: timeout (10) seems HZ dependent
./drivers/net/wan/dscc4.c:554:2-34:
        WARNING: timeout (10) seems HZ dependent
./drivers/net/wan/dscc4.c:599:2-34:
        WARNING: timeout (10) seems HZ dependent

Numeric constants passed to schedule_timeout_*() make the effective
timeout HZ dependent which does not seem to be the intent here.
Fixed up by converting the constant to jiffies with msecs_to_jiffies(),
passing 100ms (assuming HZ==100 in the original code).
Signed-off-by: NNicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

API compliance scanning with coccinelle flagged:
./drivers/net/wan/cosa.c:520:2-18: WARNING:
	timeout (30) seems HZ dependent

Numeric constants passed to schedule_timeout() make the effective
timeout HZ dependent which makes little sense in a device probe.
Fixed up by converting the constant to jiffies with msecs_to_jiffies()
Signed-off-by: NNicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix static checker warnings in the flow of system guid query.

Fixes: 707c4602 ('net/mlx5_core: Add new query HCA vport commands')
Signed-off-by: NMajd Dibbiny <majd@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the driver gets unregistered a call to netif_napi_del() was
missing, this all was also missing in the error paths of
b44_init_one().
Signed-off-by: NHauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

br_fdb_update() can be called in process context in the following way:
br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set)
so we need to disable softirqs because there are softirq users of the
hash_lock. One easy way to reproduce this is to modify the bridge utility
to set NTF_USE, enable stp and then set maxageing to a low value so
br_fdb_cleanup() is called frequently and then just add new entries in
a loop. This happens because br_fdb_cleanup() is called from timer/softirq
context. The spin locks in br_fdb_update were _bh before commit f8ae737d
("[BRIDGE]: forwarding remove unneeded preempt and bh diasables")
and at the time that commit was correct because br_fdb_update() couldn't be
called from process context, but that changed after commit:
292d1398 ("bridge: add NTF_USE support")
Using local_bh_disable/enable around br_fdb_update() allows us to keep
using the spin_lock/unlock in br_fdb_update for the fast-path.
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Fixes: 292d1398 ("bridge: add NTF_USE support")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 1d7c4903.

Nikolay Aleksandrov has a better version of this fix.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In big endian cases, macro cpu_to_le16 unfolds to __swab16 which
provides special case for constants. In little endian cases,
__constant_cpu_to_le16 and cpu_to_le16 expand directly to the
same expression. So, replace __constant_cpu_to_le16 with
cpu_to_le16 with the goal of getting rid of the definition of
__constant_cpu_to_le16 completely.

The semantic patch that performs this transformation is as follows:

@@expression x;@@

- __constant_cpu_to_le16(x)
+ cpu_to_le16(x)
Signed-off-by: NVaishali Thakkar <vthakkar1994@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The mpls device is used in an RCU read context without a lock being
held. As the memory is freed without waiting for the RCU grace period
to elapse, the freed memory could still be in use.

Address this by using kfree_rcu to free the memory for the mpls device
after the RCU grace period has elapsed.

Fixes: 03c57747 ("mpls: Per-device MPLS state")
Signed-off-by: NRobert Shearman <rshearma@brocade.com>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

use time_is_before_eq_jiffies macro for time comparison
Signed-off-by: NAntonio Murdaca <antonio.murdaca@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pull MIPS updates from Ralf Baechle:
 "Eight fixes across arch/mips.  Nothing stands particuarly out nor is
  complicated but fixes keep coming in at a higher than comfortable
  rate"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: KVM: Do not sign extend on unsigned MMIO load
  MIPS: BPF: Fix stack pointer allocation
  MIPS: Loongson-3: Fix a cpu-hotplug issue in loongson3_ipi_interrupt()
  MIPS: Fix enabling of DEBUG_STACKOVERFLOW
  MIPS: c-r4k: Fix typo in probe_scache()
  MIPS: Avoid an FPE exception in FCSR mask probing
  MIPS: ath79: Add a missing new line in log message
  MIPS: ralink: Fix clearing the illegal access interrupt

There are several places in the driver (all in control paths) where
coherent dma memory is being allocated using either dma_alloc_coherent()
or the deprecated pci_alloc_consistent(). All these calls should be
changed to use dma_zalloc_coherent() to avoid uninitialized fields in
data structures backed by this memory.
Reported-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NSriharsha Basavapatna <sriharsha.basavapatna@avagotech.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current driver adjust freq formula is:
fe * diff = ppb * pc
Note:
  fe: ENET ref clock frequency in Hz
  diff = inc_corr - inc: difference between default increment and correction increment
  ppb: parts per billion adjustment from base
  pc: correction period (in number of fe clock cycles)

The correction increment will be used after N cycles of regular increments,
not every N cycles (with N being the correction period). For example, set ENET_ATCOR=4,
INC=8, INC_CORR=9, there will be 4 increments of 8 (ENET_ATINC[INC]) , followed by 1
increment of 9 (ENET_ATINC[INC_CORR]).

So, the correct formula is:
	fe * diff = ppb * (pc + 1)

For ENET_ATCOR, a value 0 disables the correction counter and no corrections occur.
So base on the origin formula, set pc = pc > 1 ? pc - 1 : pc.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NFrank Li <Frank.Li@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

br_fdb_update() can be called in process context in the following way:
br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set)
so we need to use spin_lock_bh because there are softirq users of the
hash_lock. One easy way to reproduce this is to modify the bridge utility
to set NTF_USE, enable stp and then set maxageing to a low value so
br_fdb_cleanup() is called frequently and then just add new entries in
a loop. This happens because br_fdb_cleanup() is called from timer/softirq
context. These locks were _bh before commit f8ae737d
("[BRIDGE]: forwarding remove unneeded preempt and bh diasables")
and at the time that commit was correct because br_fdb_update() couldn't be
called from process context, but that changed after commit:
292d1398 ("bridge: add NTF_USE support")
Signed-off-by: NWilson Kok <wkok@cumulusnetworks.com>
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Fixes: 292d1398 ("bridge: add NTF_USE support")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove sparse warnings:
drivers/net/ethernet/xilinx/ll_temac_main.c:65:16: warning: cast removes
address space of expression
drivers/net/ethernet/xilinx/ll_temac_main.c:70:9: warning: cast removes
address space of expression
drivers/net/ethernet/xilinx/ll_temac_main.c:127:16: warning: cast
removes address space of expression
drivers/net/ethernet/xilinx/ll_temac_main.c:137:9: warning: cast removes
address space of expression
drivers/net/ethernet/xilinx/ll_temac_main.c:409:3: warning: symbol
'temac_options' was not declared. Should it be static?
drivers/net/ethernet/xilinx/ll_temac_main.c:590:6: warning: symbol
'temac_adjust_link' was not declared. Should it be static?
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPv4 and IPv6 share same implementation of get_cookie_sock(),
and there is no point inlining it.

We add tcp_ prefix to the common helper name and export it.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dump useful ring statistics along with interrupt status, software
maintained pointers and hardware registers to help troubleshoot TX queue
stalls.

When a timeout occurs, disable TX NAPI for the rings, dump their states
while interrupts are disabled, re-enable interrupts, NAPI and queue flow
control to help with the recovery.
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ethtool -S on a DSA interface can deadlock for some switches because
the same lock is taken twice. Use the register read function which
expects the lock to be already held.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Fixes: 31888234 ("net: dsa: mv88e6xxx: Replace stats mutex with SMI mutex")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

allow programs read/write skb->mark, tc_index fields and
((struct qdisc_skb_cb *)cb)->data.

mark and tc_index are generically useful in TC.
cb[0]-cb[4] are primarily used to pass arguments from one
program to another called via bpf_tail_call() which can
be seen in sockex3_kern.c example.

All fields of 'struct __sk_buff' are readable to socket and tc_cls_act progs.
mark, tc_index are writeable from tc_cls_act only.
cb[0]-cb[4] are writeable by both sockets and tc_cls_act.

Add verifier tests and improve sample code.
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>