dsa_slave_phy_setup() finds the phy for the port via device tree and
using of_phy_connect(), or it uses the fall back of taking a phy from
the switch internal mdio bus and calling phy_connect_direct(). Either
way, if a phy is found, phy_attach_direct() is called to attach the
phy to the slave device.

In dsa_slave_create(), a second call to phy_attach() is made. This
results in the warning "PHY already attached". Remove this second,
redundant attaching of the phy.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Tested-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

src_ip is a pointer to a union vxlan_addr, one member of which is a
struct sockaddr. Passing a pointer to src_ip is wrong; one should pass
the value of src_ip itself. Since %pIS formally expects something of
type struct sockaddr*, let's pass a pointer to the appropriate union
member, though this of course doesn't change the generated code.

Fixes: e4c7ed41 ("vxlan: add ipv6 support")
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When using per channel DMA interrupts the transmit interrupt (TI) and the
receive interrupt (RI) are masked off so as to not generate an interrupt
to the main ISR. However, should another interrupt fire for the DMA channel
that is handled by the main ISR the TI/RI bits can still be set. This
will cause the wrong and uninitialized napi structure to be used causing a
panic. Add a check to be sure per channel DMA interrupts are not enabled
before acting on those bit flags.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Hotpluging a cpu might be rare, yet we have to use proper
handlers when taking over packets found in backlog queues.

dev_cpu_callback() runs from process context, thus we should
call netif_rx_ni() to properly invoke softirq handler.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ifla_vf_policy[] is wrong in advertising its individual member types as
NLA_BINARY since .type = NLA_BINARY in combination with .len declares the
len member as *max* attribute length [0, len].

The issue is that when do_setvfinfo() is being called to set up a VF
through ndo handler, we could set corrupted data if the attribute length
is less than the size of the related structure itself.

The intent is exactly the opposite, namely to make sure to pass at least
data of minimum size of len.

Fixes: ebc08a6f ("rtnetlink: Add VF config code to rtnetlink")
Cc: Mitch Williams <mitch.a.williams@intel.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The number of connected switches was sourced from the number of
children to the DSA node, change it to the number of available
children, skipping any disabled switches.

Fixes: 5e95329b ("dsa: add device tree bindings to register DSA switches")
Signed-off-by: NTobias Waldekranz <tobias@waldekranz.com>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the case where there is only one switch, no routing table will have
been allocated, so do not dereference it in this case.
Signed-off-by: NTobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We still need a validate_link_af() handler with an appropriate nla policy,
similarly as we have in IPv4 case, otherwise size validations are not being
done properly in that case.

Fixes: f53adae4 ("net: ipv6: add tokenized interface identifier support")
Fixes: bc91b0f0 ("ipv6: addrconf: implement address generation modes")
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are a couple bugs with the error handling in this function.

1) If we can't allocate "rx_ring->rx_skbuff" then we should call
   dma_free_coherent() but we don't.
2) free_rx_ring() frees "rx_ring->rx_skbuff_dma" and "rx_ring->rx_skbuff"
   so calling it in a loop causes a double free.

Also it was a bit confusing how we sometimes freed things before doing
the goto.  I've cleaned it up so it does error handling in normal kernel
style.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch add a missing check on the return value of devm_kzalloc,
which would cause a NULL pointer dereference in a OOM situation.
Signed-off-by: NKiran Padwal <kiran.padwal@smartplayin.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes two issues in UDP checksum computation in pktgen.

First, the pseudo-header uses the source and destination IP
addresses. Currently, the ports are used for IPv4.

Second, the UDP checksum covers both header and data.  So we need to
generate the data earlier (move pktgen_finalize_skb up), and compute
the checksum for UDP header + data.

Fixes: c26bf4a5 ("pktgen: Add UDPCSUM flag to support UDP checksums")
Signed-off-by: NSabrina Dubroca <sd@queasysnail.net>
Acked-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RFC 4429 ("Optimistic DAD") states that optimistic addresses
should be treated as deprecated addresses.  From section 2.1:

   Unless noted otherwise, components of the IPv6 protocol stack
   should treat addresses in the Optimistic state equivalently to
   those in the Deprecated state, indicating that the address is
   available for use but should not be used if another suitable
   address is available.

Optimistic addresses are indeed avoided when other addresses are
available (i.e. at source address selection time), but they have
not heretofore been available for things like explicit bind() and
sendmsg() with struct in6_pktinfo, etc.

This change makes optimistic addresses treated more like
deprecated addresses than tentative ones.
Signed-off-by: NErik Kline <ek@google.com>
Acked-by: NLorenzo Colitti <lorenzo@google.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

flow_cache_flush_task references a structure member flow_cache_gc_work
where it should reference flow_cache_flush_task instead.

Kernel panic occurs on kernels using IPsec during XFRM garbage
collection. The garbage collection interval can be shortened using the
following sysctl settings:

net.ipv4.xfrm4_gc_thresh=4
net.ipv6.xfrm6_gc_thresh=4

With the default settings, our productions servers crash approximately
once a week. With the settings above, they crash immediately.

Fixes: ca925cf1 ("flowcache: Make flow cache name space aware")
Reported-by: NTomáš Charvát <tc@excello.cz>
Tested-by: NJan Hejl <jh@excello.cz>
Signed-off-by: NMiroslav Urbanek <mu@miroslavurbanek.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pull networking fixes from David Miller:

 1) Stretch ACKs can kill performance with Reno and CUBIC congestion
    control, largely due to LRO and GRO.  Fix from Neal Cardwell.

 2) Fix userland breakage because we accidently emit zero length netlink
    messages from the bridging code.  From Roopa Prabhu.

 3) Carry handling in generic csum_tcpudp_nofold is broken, fix from
    Karl Beldan.

 4) Remove bogus dev_set_net() calls from CAIF driver, from Nicolas
    Dichtel.

 5) Make sure PPP deflation never returns a length greater then the
    output buffer, otherwise we overflow and trigger skb_over_panic().
    Fix from Florian Westphal.

 6) COSA driver needs VIRT_TO_BUS Kconfig dependencies, from Arnd
    Bergmann.

 7) Don't increase route cached MTU on datagram too big ICMPs.  From Li
    Wei.

 8) Fix error path leaks in nf_tables, from Pablo Neira Ayuso.

 9) Fix bitmask handling regression in netlink that broke things like
    acpi userland tools.  From Pablo Neira Ayuso.

10) Wrong header pointer passed to param_type2af() in SCTP code, from
    Saran Maruti Ramanara.

11) Stacked vlans not handled correctly by vlan_get_protocol(), from
    Toshiaki Makita.

12) Add missing DMA memory barrier to xgene driver, from Iyappan
    Subramanian.

13) Fix crash in rate estimators, from Eric Dumazet.

14) We've been adding various workarounds, one after another, for the
    change which added the per-net tcp_sock.  It was meant to reduce
    socket contention but added lots of problems.

    Reduce this instead to a proper per-cpu socket and that rids us of
    all the daemons.

    From Eric Dumazet.

15) Fix memory corruption and OOPS in mlx4 driver, from Jack
    Morgenstein.

16) When we disabled UFO in the virtio_net device, it introduces some
    serious performance regressions.  The orignal problem was IPV6
    fragment ID generation, so fix that properly instead.  From Vlad
    Yasevich.

17) sr9700 driver build breaks on xtensa because it defines macros with
    the same name as those used by the arch code.  Use more unique
    names.  From Chen Gang.

18) Fix endianness in new virio 1.0 mode of the vhost net driver, from
    Michael S Tsirkin.

19) Several sysctls were setting the maxlen attribute incorrectly, from
    Sasha Levin.

20) Don't accept an FQ scheduler quantum of zero, that leads to crashes.
    From Kenneth Klette Jonassen.

21) Fix dumping of non-existing actions in the packet scheduler
    classifier.  From Ignacy Gawędzki.

22) Return the write work_done value when doing TX work in the qlcnic
    driver.

23) ip6gre_err accesses the info field with the wrong endianness, from
    Sabrina Dubroca.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (54 commits)
  sit: fix some __be16/u16 mismatches
  ipv6: fix sparse errors in ip6_make_flowlabel()
  net: remove some sparse warnings
  flow_keys: n_proto type should be __be16
  ip6_gre: fix endianness errors in ip6gre_err
  qlcnic: Fix NAPI poll routine for Tx completion
  amd-xgbe: Set RSS enablement based on hardware features
  amd-xgbe: Adjust for zero-based traffic class count
  cls_api.c: Fix dumping of non-existing actions' stats.
  pkt_sched: fq: avoid hang when quantum 0
  net: rds: use correct size for max unacked packets and bytes
  vhost/net: fix up num_buffers endian-ness
  gianfar: correct the bad expression while writing bit-pattern
  net: usb: sr9700: Use 'SR_' prefix for the common register macros
  Revert "drivers/net: Disable UFO through virtio"
  Revert "drivers/net, ipv6: Select IPv6 fragment idents for virtio UFO packets"
  ipv6: Select fragment id during UFO segmentation if not set.
  xen-netback: stop the guest rx thread after a fatal error
  net/mlx4_core: Fix kernel Oops (mem corruption) when working with more than 80 VFs
  isdn: off by one in connect_res()
  ...

Pull SCSI fixes from James Bottomley:
 "This patch set is fixing two serious problems which have turned up
  late in the release cycle.

  The first fixes a problem with 4k sector disks where the transfer
  length (amount of data sent to the disk) was getting increased every
  time the disk was revalidated leading to potential for overflows.

  The other is a regression oops fix for some of our last merge window
  code"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  sd: Fix max transfer length for 4k disks
  scsi: fix device handler detach oops

Pull drm fixes from Dave Airlie:
 "Radeon and amdkfd fixes.

  Radeon ones mostly for oops in some test/benchmark functions since
  fencing changes, and one regression fix for old GPUs,

  There is one cirrus regression fix, the 32bpp broke userspace, so this
  hides it behind a module option for the few users who care.

  I'm off for a few days, so this is probably the final pull I have, if
  I see fixes from Intel I'll forward the pull as I should have email"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/cirrus: Limit modes depending on bpp option
  drm/radeon: fix the crash in test functions
  drm/radeon: fix the crash in benchmark functions
  drm/radeon: properly set vm fragment size for TN/RL
  drm/radeon: don't init gpuvm if accel is disabled (v3)
  drm/radeon: fix PLLs on RS880 and older v2
  drm/amdkfd: Don't create BUG due to incorrect user parameter
  drm/amdkfd: max num of queues can't be 0
  drm/amdkfd: Fix bug in accounting of queues

Pull spi fixes from Mark Brown:
 "A couple of driver specific fixes:

   - Disable DMA mode for i.MX6DL chips due to a hardware bug.

   - Don't use devm_kzalloc() outside of bind/unbind paths in the
     fsl-dspi driver, fixing memory leaks"

* tag 'spi-v3.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: imx: use pio mode for i.mx6dl
  spi: spi-fsl-dspi: Remove usage of devm_kzalloc

Pull ACPI power management fix from Rafael  Wysocki:
 "This is a revert of an ACPI Low-power Subsystem (LPSS) driver change
  that was supposed to improve power management of the LPSS DMA
  controller, but introduced more serious problems.

  Since fixing them turns out to be non-trivial, it is better to revert
  the commit in question at this point and try to fix the original issue
  differently in the next cycle"

* tag 'pm+acpi-3.19-fin' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "ACPI / LPSS: introduce a 'proxy' device to power on LPSS for DMA"

Pull PCI fixes from Bjorn Helgaas:
 "Enumeration
    - Scan all device numbers on NEC as well as Stratus (Charlotte Richardson)

  Resource management
    - Handle read-only BARs on AMD CS553x devices (Myron Stowe)

  Synopsys DesignWare
    - Reject MSI-X IRQs (Lucas Stach)"

* tag 'pci-v3.19-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: Handle read-only BARs on AMD CS553x devices
  PCI: Add NEC variants to Stratus ftServer PCIe DMI check
  PCI: designware: Reject MSI-X IRQs

Fixes following sparse warnings :

net/ipv6/sit.c:1509:32: warning: incorrect type in assignment (different base types)
net/ipv6/sit.c:1509:32:    expected restricted __be16 [usertype] sport
net/ipv6/sit.c:1509:32:    got unsigned short
net/ipv6/sit.c:1514:32: warning: incorrect type in assignment (different base types)
net/ipv6/sit.c:1514:32:    expected restricted __be16 [usertype] dport
net/ipv6/sit.c:1514:32:    got unsigned short
net/ipv6/sit.c:1711:38: warning: incorrect type in argument 3 (different base types)
net/ipv6/sit.c:1711:38:    expected unsigned short [unsigned] [usertype] value
net/ipv6/sit.c:1711:38:    got restricted __be16 [usertype] sport
net/ipv6/sit.c:1713:38: warning: incorrect type in argument 3 (different base types)
net/ipv6/sit.c:1713:38:    expected unsigned short [unsigned] [usertype] value
net/ipv6/sit.c:1713:38:    got restricted __be16 [usertype] dport
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/ipv6.h:713:22: warning: incorrect type in assignment (different base types)
include/net/ipv6.h:713:22:    expected restricted __be32 [usertype] hash
include/net/ipv6.h:713:22:    got unsigned int
include/net/ipv6.h:719:25: warning: restricted __be32 degrades to integer
include/net/ipv6.h:719:22: warning: invalid assignment: ^=
include/net/ipv6.h:719:22:    left side has type restricted __be32
include/net/ipv6.h:719:22:    right side has type unsigned int
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

netdev_adjacent_add_links() and netdev_adjacent_del_links()
are static.

queue->qdisc has __rcu annotation, need to use RCU_INIT_POINTER()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

(struct flow_keys)->n_proto is in network order, use
proper type for this.

Fixes following sparse errors :

net/core/flow_dissector.c:139:39: warning: incorrect type in assignment (different base types)
net/core/flow_dissector.c:139:39:    expected unsigned short [unsigned] [usertype] n_proto
net/core/flow_dissector.c:139:39:    got restricted __be16 [assigned] [usertype] proto
net/core/flow_dissector.c:237:23: warning: incorrect type in assignment (different base types)
net/core/flow_dissector.c:237:23:    expected unsigned short [unsigned] [usertype] n_proto
net/core/flow_dissector.c:237:23:    got restricted __be16 [assigned] [usertype] proto
Signed-off-by: NEric Dumazet <edumazet@google.com>
Fixes: e0f31d84 ("flow_keys: Record IP layer protocol in skb_flow_dissect()")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

info is in network byte order, change it back to host byte order
before use. In particular, the current code sets the MTU of the tunnel
to a wrong (too big) value.

Fixes: c12b395a ("gre: Support GRE over IPv6")
Signed-off-by: NSabrina Dubroca <sd@queasysnail.net>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After d75b1ade ("net: less interrupt masking in NAPI")
driver's NAPI poll routine is expected to return
exact budget value if it wants to be re-called.
Signed-off-by: NShahed Shaikh <shahed.shaikh@qlogic.com>
Fixes: d75b1ade ("net: less interrupt masking in NAPI")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The RSS support requires enablement based on the features reported by
the hardware. The setting of this flag is missing. Add support to
set the RSS enablement flag based on the reported hardware features.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The number of traffic classes reported by the hardware is zero-based
so increment the value returned to get an actual count.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In tcf_exts_dump_stats(), ensure that exts->actions is not empty before
accessing the first element of that list and calling tcf_action_copy_stats()
on it.  This fixes some random segvs when adding filters of type "basic" with
no particular action.

This also fixes the dumping of those "no-action" filters, which more often
than not made calls to tcf_action_copy_stats() fail and consequently netlink
attributes added by the caller to be removed by a call to nla_nest_cancel().

Fixes: 33be6271 ("net_sched: act: use standard struct list_head")
Signed-off-by: NIgnacy Gawędzki <ignacy.gawedzki@green-communications.fr>
Acked-by: NCong Wang <cwang@twopensource.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Configuring fq with quantum 0 hangs the system, presumably because of a
non-interruptible infinite loop. Either way quantum 0 does not make sense.

Reproduce with:
sudo tc qdisc add dev lo root fq quantum 0 initial_quantum 0
ping 127.0.0.1
Signed-off-by: NKenneth Klette Jonassen <kennetkl@ifi.uio.no>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit [8975626e: drm/cirrus: allow 32bpp framebuffers for
cirrus drm] broke X modesetting driver because cirrus driver still
provides the full list of modes up to 1280x1024 while the 32bpp can
support only up to 800x600.

We might be able to filter out the invalid modes in mode_valid
callback, but unfortunately the bpp in question can't be referred
there for now (let me know if there is a better way to retrieve the
bpp for the probed fb).

So, instead, this patch adds the bpp module option to specify the
maximal bpp explicitly and limits the resolutions in get_modes
depending on its value.

The default value is set to 24 so that the existing stuff keeps
working.  If you need a new 32bpp feature, specify cirrus.bpp=32
option explicitly.

Fixes: 8975626e ('drm/cirrus: allow 32bpp framebuffers for cirrus drm')
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Max unacked packets/bytes is an int while sizeof(long) was used in the
sysctl table.

This means that when they were getting read we'd also leak kernel memory
to userspace along with the timeout values.
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In virtio 1.0 mode, when mergeable buffers are enabled on a big-endian
host, num_buffers wasn't byte-swapped correctly, so large incoming
packets got corrupted.

To fix, fill it in within hdr - this also makes sure it gets
the correct type.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch correct the bad expression while writing the
bit-pattern from software's buffer to hardware registers.
Signed-off-by: NSanjeev Sharma <Sanjeev_Sharma@mentor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commone register macors (e.g. RSR) is too commont to drivers, it may
be conflict with the architectures (e.g. xtensa, sh).

The related warnings (with allmodconfig under xtensa):

    CC [M]  drivers/net/usb/sr9700.o
  In file included from drivers/net/usb/sr9700.c:24:0:
  drivers/net/usb/sr9700.h:65:0: warning: "RSR" redefined
   #define RSR   0x06
   ^
  In file included from ./arch/xtensa/include/asm/bitops.h:22:0,
                   from include/linux/bitops.h:36,
                   from include/linux/kernel.h:10,
                   from include/linux/list.h:8,
                   from include/linux/module.h:9,
                   from drivers/net/usb/sr9700.c:13:
  ./arch/xtensa/include/asm/processor.h:190:0: note: this is the location of the previous definition
   #define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v));
   ^
Signed-off-by: NChen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pull cifs fixes from Steve French:
 "Three small cifs fixes.  One fixes a hang under stress, and the other
  two are security related"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix MUST SecurityFlags filtering
  Complete oplock break jobs before closing file handle
  cifs: use memzero_explicit to clear stack buffer

Pull ARM fixes from Russell King:
 "A number of ARM fixes, the biggest is fixing a regression caused by
  appended DT blobs exceeding 64K, causing the decompressor fixup code
  to fail to patch the DT blob.  Another important fix is for the ASID
  allocator from Will Deacon which prevents some rare crashes seen on
  some systems.  Lastly, there's a build fix for v7M systems when printk
  support is disabled.

  The last two remaining fixes are more cosmetic - the IOMMU one
  prevents an annoying harmless warning message, and we disable the
  kernel strict memory permissions on non-MMU which can't support it
  anyway"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8299/1: mm: ensure local active ASID is marked as allocated on rollover
  ARM: 8298/1: ARM_KERNMEM_PERMS only works with MMU enabled
  ARM: 8295/1: fix v7M build for !CONFIG_PRINTK
  ARM: 8294/1: ATAG_DTB_COMPAT: remove the DT workspace's hardcoded 64KB size
  ARM: 8288/1: dma-mapping: don't detach devices without an IOMMU during teardown

Vladislav Yasevich says:

====================
Restore UFO support to virtio_net devices

commit 3d0ad094
Author: Ben Hutchings <ben@decadent.org.uk>
Date:   Thu Oct 30 18:27:12 2014 +0000

    drivers/net: Disable UFO through virtio

Turned off UFO support to virtio-net based devices due to issues
with IPv6 fragment id generation for UFO packets.  The issue
was that IPv6 UFO/GSO implementation expects the fragment id
to be supplied in skb_shinfo().  However, for packets generated
by the VMs, the fragment id is not supplied which causes all
IPv6 fragments to have the id of 0.

The problem is that turning off UFO support on tap/macvtap
as well as virtio devices caused issues with migrations.
Migrations would fail when moving a vm from a kernel supporting
expecting UFO to work to the newer kernels that disabled UFO.

This series provides a partial solution to address the migration
issue.  The series allows us to track whether skb_shinfo()->ip6_frag_id
has been set by treating value of 0 as unset.
This lets GSO code to generate fragment ids if they are necessary
(ex: packet was generated by VM or packet socket).

Since v3:
  - Resolved build issue when IPv6 is a module.
  - Removed trailing white space.

Since v2:
  - Rebase and rebuild to make sure everything works.  No changes
    to the patches were done.

Since v1:
  - Removed the skb bit and use value of 0 as tracker.
  - Used Eric's suggestion to set fragment id as 0x80000000 if id
    generation procedure yeilded a 0 result.
  - Consolidated ipv6 id genration code.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 3d0ad094.

Now that GSO functionality can correctly track if the fragment
id has been selected and select a fragment id if necessary,
we can re-enable UFO on tap/macvap and virtio devices.
Signed-off-by: NVladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 5188cd44.

Now that GSO layer can track if fragment id has been selected
and can allocate one if necessary, we don't need to do this in
tap and macvtap.  This reverts most of the code and only keeps
the new ipv6 fragment id generation function that is still needed.

Fixes: 3d0ad094 (drivers/net: Disable UFO through virtio)
Signed-off-by: NVladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>