On the platforms which are x2apic and interrupt-remapping
capable, Linux kernel is enabling x2apic even if the BIOS
doesn't. This is to take advantage of the features that x2apic
brings in.

Some of the OEM platforms are running into issues because of
this, as their bios is not x2apic aware. For example, this was
resulting in interrupt migration issues on one of the platforms.
Also if the BIOS SMI handling uses APIC interface to send SMI's,
then the BIOS need to be aware of x2apic mode that OS has
enabled.

On some of these platforms, BIOS doesn't have a HW mechanism to
turnoff the x2apic feature to prevent OS from enabling it.

To resolve this mess, recent changes to the VT-d2 specification:

 http://download.intel.com/technology/computing/vptech/Intel(r)_VT_for_Direct_IO.pdf

includes a mechanism that provides BIOS a way to request system
software to opt out of enabling x2apic mode.

Look at the x2apic optout flag in the DMAR tables before
enabling the x2apic mode in the platform. Also print a warning
that we have disabled x2apic based on the BIOS request.

Kernel boot parameter "intremap=no_x2apic_optout" can be used to
override the BIOS x2apic optout request.
Signed-off-by: NYouquan Song <youquan.song@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: yinghai@kernel.org
Cc: joerg.roedel@amd.com
Cc: tony.luck@intel.com
Cc: dwmw2@infradead.org
Link: http://lkml.kernel.org/r/20110824001456.171766616@sbsiddha-desk.sc.intel.comSigned-off-by: NIngo Molnar <mingo@elte.hu>

* 'irq-fixes-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip:
  x86, iommu: Mark DMAR IRQ as non-threaded
  genirq: Make irq_shutdown() symmetric vs. irq_startup again

* 'for-linus' of git://github.com/chrismason/linux:
  Btrfs: only clear the need lookup flag after the dentry is setup
  BTRFS: Fix lseek return value for error
  Btrfs: don't change inode flag of the dest clone file
  Btrfs: don't make a file partly checksummed through file clone
  Btrfs: fix pages truncation in btrfs_ioctl_clone()
  btrfs: fix d_off in the first dirent

When a xHC host is unable to handle isochronous transfer in the
interval, it reports a Missed Service Error event and skips some tds.

Currently xhci driver handles MSE event in the following ways:

1. When encounter a MSE event, set ep->skip flag, update event ring
   dequeue pointer and return.

2. When encounter the next event on this ep, the driver will run the
   do-while loop, fetch td from ep's td_list to find the td
   corresponding to this event.  All tds missed are marked as short
   transfer(-EXDEV).

The do-while loop will end in two ways:

1. If the td pointed by the event trb is found;

2. If the ep ring's td_list is empty.

However, if a buggy HW reports some unpredicted event (for example, an
overrun event following a MSE event while the ep ring is actually not
empty), the driver will never find the td, and it will loop until the
td_list is empty.

Unfortunately, the spinlock is dropped when give back a urb in the
do-while loop.  During the spinlock released period, the class driver
may still submit urbs and add tds to the td_list.  This may cause
disaster, since the td_list will never be empty and the loop never ends,
and the system hangs.

To fix this, count the number of TDs on the ep ring before skipping TDs,
and quit the loop when skipped that number of tds.  This guarantees the
do-while loop will end after certain number of cycles, and driver will
not be trapped in an infinite loop.
Signed-off-by: NAndiry Xu <andiry.xu@amd.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Sometimes, when a USB 3.0 device is disconnected, the Intel Panther
Point xHCI host controller will report a link state change with the
state set to "SS.Inactive".  This causes the xHCI host controller to
issue a warm port reset, which doesn't finish before the USB core times
out while waiting for it to complete.

When the warm port reset does complete, and the xHC gives back a port
status change event, the xHCI driver kicks khubd.  However, it fails to
set the bit indicating there is a change event for that port because the
logic in xhci-hub.c doesn't check for the warm port reset bit.

After that, the warm port status change bit is never cleared by the USB
core, and the xHC stops reporting port status change bits.  (The xHCI
spec says it shouldn't report more port events until all change bits are
cleared.) This means any port changes when a new device is connected
will never be reported, and the port will seem "dead" until the xHCI
driver is unloaded and reloaded, or the computer is rebooted.  Fix this
by making the xHCI driver set the port change bit when a warm port reset
change bit is set.

A better solution would be to make the USB core handle warm port reset
in differently, merging the current code with the standard port reset
code that does an incremental backoff on the timeout, and tries to
complete the port reset two more times before giving up.  That more
complicated fix will be merged next window, and this fix will be
backported to stable.

This should be backported to kernels as old as 3.0, since that was the
first kernel with commit a11496eb ("xHCI: warm reset support").
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix build when CONFIG_ISA_DMA_API is enabled but
CONFIG_COMEDI_PCI[_DRIVERS] is not enabled.

Fixes these build errors:

  drivers/staging/comedi/drivers/ni_labpc.c: In function 'labpc_ai_cmd':
  drivers/staging/comedi/drivers/ni_labpc.c:1351: error: implicit declaration of function 'labpc_suggest_transfer_size'
  drivers/staging/comedi/drivers/ni_labpc.c: At top level:
  drivers/staging/comedi/drivers/ni_labpc.c:1802: error: conflicting types for 'labpc_suggest_transfer_size'
  drivers/staging/comedi/drivers/ni_labpc.c:1351: note: previous implicit declaration of 'labpc_suggest_transfer_size' was here
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Even with just the interface limited to admin, there really is little to
reason to give byte-per-byte counts for taskstats.  So round it down to
something less intrusive.
Acked-by: NBalbir Singh <bsingharora@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Ok, this isn't optimal, since it means that 'iotop' needs admin
capabilities, and we may have to work on this some more.  But at the
same time it is very much not acceptable to let anybody just read
anybody elses IO statistics quite at this level.

Use of the GENL_ADMIN_PERM suggested by Johannes Berg as an alternative
to checking the capabilities by hand.
Reported-by: NVasiliy Kulikov <segoon@openwall.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Acked-by: NBalbir Singh <bsingharora@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'slab/urgent' of git://github.com/penberg/linux:
  slub: add slab with one free object to partial list tail

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon/kms: Make GPU/CPU page size handling consistent in blit code (v2)
  drm/radeon/kms: fix typo in r100_blit_copy
  drm/radeon: Unreference GEM object outside of spinlock in page flip error path.
  drm/radeon: Don't read from CP ring write pointer registers.
  drm/ttm: request zeroed system memory pages for new TT buffer objects

* git://github.com/davem330/net:
  tcp: fix validation of D-SACK
  tcp: fix build error if !CONFIG_SYN_COOKIES

D-SACK is allowed to reside below snd_una. But the corresponding check
in tcp_is_sackblock_valid() is the exact opposite. It looks like a typo.
Signed-off-by: NZheng Yan <zheng.z.yan@intel.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 946cedcc (tcp: Change possible SYN flooding messages)
added a build error if CONFIG_SYN_COOKIES=n
Reported-by: NMarkus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* 'for-linus' of git://git.infradead.org/users/sameo/mfd-2.6:
  mfd: Fix omap-usb-host build failure
  mfd: Make omap-usb-host TLL mode work again
  mfd: Set MAX8997 irq pointer
  mfd: Fix initialisation of tps65910 interrupts
  mfd: Check for twl4030-madc NULL pointer
  mfd: Copy the device pointer to the twl4030-madc structure
  mfd: Rename wm8350 static gpio_set_debounce()
  mfd: Fix value of WM8994_CONFIGURE_GPIO

The BO blit code inconsistenly handled the page size.  This wasn't
an issue on system with 4k pages since the GPU's page size is 4k as
well.  Switch the driver blit callbacks to take num pages in GPU
page units.

Fixes lemote mipsel systems using AMD rs780/rs880 chipsets.

v2: incorporate suggestions from Michel.
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NMichel Dänzer <michel.daenzer@amd.com>
Cc: stable@kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

cur_pages is the number of pages per loop iteration.
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NMichel Dänzer <michel.daenzer@amd.com>
Cc: stable@kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

* git://github.com/davem330/net: (62 commits)
  ipv6: don't use inetpeer to store metrics for routes.
  can: ti_hecc: include linux/io.h
  IRDA: Fix global type conflicts in net/irda/irsysctl.c v2
  net: Handle different key sizes between address families in flow cache
  net: Align AF-specific flowi structs to long
  ipv4: Fix fib_info->fib_metrics leak
  caif: fix a potential NULL dereference
  sctp: deal with multiple COOKIE_ECHO chunks
  ibmveth: Fix checksum offload failure handling
  ibmveth: Checksum offload is always disabled
  ibmveth: Fix issue with DMA mapping failure
  ibmveth: Fix DMA unmap error
  pch_gbe: support ML7831 IOH
  pch_gbe: added the process of FIFO over run error
  pch_gbe: fixed the issue which receives an unnecessary packet.
  sfc: Use 64-bit writes for TX push where possible
  Revert "sfc: Use write-combining to reduce TX latency" and follow-ups
  bnx2x: Fix ethtool advertisement
  bnx2x: Fix 578xx link LED
  bnx2x: Fix XMAC loopback test
  ...

We can race with readdir and the RCU path walking stuff.  This is because we
clear the need lookup flag before actually instantiating the inode.  This will
lead the RCU path walk stuff to find a dentry it thinks is valid without a
d_inode attached.  So instead unhash the dentry when we first start the lookup,
and then clear the flag after we've instantiated the dentry so we're garunteed
to either try the slow lookup, or have the d_inode set properly.
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The recent reworking of btrfs' lseek lead to incorrect
values being returned.  This adds checks for seeking
beyond EOF in SEEK_HOLE and makes sure the error
values come back correct.

Andi Kleen also sent in similar patches.
Signed-off-by: NJie Liu <jeff.liu@oracle.com>
Reported-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The dst file will have the same inode flags with dst file after
file clone, and I think it's unexpected.

For example, the dst file will suddenly become immutable after
getting some share of data with src file, if the src is immutable.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

To reproduce the bug:

  # mount /dev/sda7 /mnt
  # dd if=/dev/zero of=/mnt/src bs=4K count=1
  # umount /mnt

  # mount -o nodatasum /dev/sda7 /mnt
  # dd if=/dev/zero of=/mnt/dst bs=4K count=1
  # clone_range -s 4K -l 4K /mnt/src /mnt/dst

  # echo 3 > /proc/sys/vm/drop_caches
  # cat /mnt/dst
  # dmesg
  ...
  btrfs no csum found for inode 258 start 0
  btrfs csum failed ino 258 off 0 csum 2566472073 private 0

It's because part of the file is checksummed and the other part is not,
and then btrfs will complain checksum is not found when we read the file.

Disallow file clone if src and dst file have different checksum flag,
so we ensure a file is completely checksummed or unchecksummed.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

It's a bug in commit f81c9cdc
(Btrfs: truncate pages from clone ioctl target range)

We should pass the dest range to the truncate function, but not the
src range.

Also move the function before locking extent state.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Since the d_off in the first dirent for "." (that originates from
the 4th argument "offset" of filldir() for the 2nd dirent for "..")
is wrongly assigned in btrfs_real_readdir(), telldir returns same
offset for different locations.

 | # mkfs.btrfs /dev/sdb1
 | # mount /dev/sdb1 fs0
 | # cd fs0
 | # touch file0 file1
 | # ../test
 | telldir: 0
 | readdir: d_off = 2, d_name = "."
 | telldir: 2
 | readdir: d_off = 2, d_name = ".."
 | telldir: 2
 | readdir: d_off = 3, d_name = "file0"
 | telldir: 3
 | readdir: d_off = 2147483647, d_name = "file1"
 | telldir: 2147483647

To fix this problem, pass filp->f_pos (which is loff_t) instead.

 | # ../test
 | telldir: 0
 | readdir: d_off = 1, d_name = "."
 | telldir: 1
 | readdir: d_off = 2, d_name = ".."
 | telldir: 2
 | readdir: d_off = 3, d_name = "file0"
 :

At the moment the "offset" for "." is unused because there is no
preceding dirent, however it is better to pass filp->f_pos to follow
grammatical usage.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

* 'fixes' of git://git.user.in-berlin.de/s5r6/linux1394:
  firewire: ohci: add no MSI quirk for O2Micro controller

* '3.1-rc-fixes' of git://linux-iscsi.org/target-pending:
  iscsi-target: Fix sendpage breakage with proper padding+DataDigest iovec offsets
  iscsi-target: Disable markers + remove dangerous local scope array usage
  target: Skip non hex characters for VPD=0x83 NAA IEEE Registered Extended
  tcm_fc: Work queue based approach instead of managing own thread and event based mechanism
  tcm_fc: Invalidation of DDP context for FCoE target in error conditions
  target: Fix race between multiple invocations of target_qf_do_work()

Current IPv6 implementation uses inetpeer to store metrics for
routes. The problem of inetpeer is that it doesn't take subnet
prefix length in to consideration. If two routes have the same
address but different prefix length, they share same inetpeer.
So changing metrics of one route also affects the other. The
fix is to allocate separate metrics storage for each route.
Signed-off-by: NZheng Yan <zheng.z.yan@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes a bug in the iscsit_fe_sendpage_sg() transmit codepath that
was originally introduced with the v3.1 iscsi-target merge that incorrectly
uses hardcoded cmd->iov_data_count values to determine cmd->iov_data[] offsets
for extra outgoing padding and DataDigest payload vectors.

This code is obviously incorrect for the DataDigest enabled case with sendpage
offload, and this fix ensures correct operation for padding + DataDigest,
padding only, and DataDigest only cases.  The bug was introduced during a
pre-merge change in iscsit_fe_sendpage_sg() to natively use struct scatterlist
instead of the legacy v3.0 struct se_mem logic.

Cc: Andy Grover <agrover@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This fixes a build breakage for OMAP3 boards.
Signed-off-by: NDaniel Mack <zonque@gmail.com>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: netdev@vger.kernel.org
Acked-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The externs here didn't agree with the declarations in qos.c.

Better would be probably to move this into a header, but since it's
common practice to have naked externs with sysctls I left it for now.

Cc: samuel@sortiz.org
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With the conversion of struct flowi to a union of AF-specific structs, some
operations on the flow cache need to account for the exact size of the key.
Signed-off-by: NDavid Ward <david.ward@ll.mit.edu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

AF-specific flowi structs are now passed to flow_key_compare, which must
also be aligned to a long.
Signed-off-by: NDavid Ward <david.ward@ll.mit.edu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 4670994d(net,rcu: convert call_rcu(fc_rport_free_rcu) to
kfree_rcu()) introduced a memory leak. This patch reverts it.
Signed-off-by: NZheng Yan <zheng.z.yan@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit bd30ce4b (caif: Use RCU instead of spin-lock in caif_dev.c)
added a potential NULL dereference in case alloc_percpu() fails.

caif_device_alloc() can also use GFP_KERNEL instead of GFP_ATOMIC.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Sjur Brændeland <sjur.brandeland@stericsson.com>
Acked-by: NSjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Attempt to reduce the number of IP packets emitted in response to single
SCTP packet (2e3216cd) introduced a complication - if a packet contains
two COOKIE_ECHO chunks and nothing else then SCTP state machine corks the
socket while processing first COOKIE_ECHO and then loses the association
and forgets to uncork the socket. To deal with the issue add new SCTP
command which can be used to set association explictly. Use this new
command when processing second COOKIE_ECHO chunk to restore the context
for SCTP state machine.
Signed-off-by: NMax Matveev <makc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* 'for-linus' of git://github.com/dtor/input:
  Input: wacom - fix touch parsing on newer Bamboos
  Input: bcm5974 - add MacBookAir4,1 trackpad support
  Input: wacom - add POINTER and DIRECT device properties
  Input: adp5588-keys - remove incorrect modalias
  Input: cm109 - fix checking return value of usb_control_msg
  Input: wacom - advertise BTN_TOOL_PEN and BTN_STYLUS for PenPartner
  Input: wacom - remove pressure for touch devices

This fixes https://bugs.launchpad.net/ubuntu/+source/linux/+bug/801719 .

An O2Micro PCI Express FireWire controller,
"FireWire (IEEE 1394) [0c00]: O2 Micro, Inc. Device [1217:11f7] (rev 05)"
which is a combination device together with an SDHCI controller and some
sort of storage controller, misses SBP-2 status writes from an attached
FireWire HDD.  This problem goes away if MSI is disabled for this
FireWire controller.

The device reportedly does not require QUIRK_CYCLE_TIMER.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (amended changelog)
Cc: <stable@kernel.org>

This patch makes iscsi-target explictly disable OFMarker=Yes and IFMarker=yes
parameter key usage during iscsi login by setting IFMarkInt_Reject and
OFMarkInt_Reject values in iscsi_enforce_integrity_rules() to effectively
disable iscsi marker usage.  With this patch, an initiator proposer asking
to enable either marker parameter keys will be issued a 'No' response, and
the target sets OFMarkInt + IFMarkInt parameter key response to 'Irrelevant'.

With markers disabled during iscsi login, this patch removes the problematic
on-stack local-scope array for marker intervals in iscsit_do_rx_data() +
iscsit_do_tx_data(), and other related marker code in iscsi_target_util.c.
This fixes a potentional stack smashing scenario with small range markers
enabled and a large MRDSL as reported by DanC here:

[bug report] target: stack can be smashed
http://www.spinics.net/lists/target-devel/msg00453.htmlReported-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds target_parse_naa_6h_vendor_specific() to address a bug where the
conversion of PRODUCT SERIAL NUMBER to use hex2bin() in target_emulate_evpd_83()
was not doing proper isxdigit() checking.  This conversion of the vpd_unit_serial
configifs attribute is done while generating a VPD=0x83 NAA IEEE Registered
Extended DESIGNATOR format's 100 bits of unique VENDOR SPECIFIC IDENTIFIER +
VENDOR SPECIFIC IDENTIFIER EXTENSION area.

This patch allows vpd_unit_serial (VPD=0x80) and the T10 Vendor ID DESIGNATOR
format (VPD=0x83) to continue to use free-form variable length ASCII values,
and now skips any non hex characters for fixed length NAA IEEE Registered Extended
DESIGNATOR format (VPD=0x83) requring the binary conversion.

This was originally reported by Martin after the v3.1-rc1 change to use hex2bin()
in commit 11650b85 where the use of non hex
characters in vpd_unit_serial generated different values than the original
v3.0 internal hex -> binary code.  This v3.1 change caused a problem with
filesystems who write a NAA DESIGNATOR onto it's ondisk metadata, and this patch
will (again) change existing values to ensure that non hex characters are not
included in the fixed length NAA DESIGNATOR.

Note this patch still expects vpd_unit_serial to be set via existing userspace
methods of uuid generation, and does not do strict formatting via configfs input.

The original bug report and thread can be found here:

NAA breakage
http://www.spinics.net/lists/target-devel/msg00477.html

The v3.1-rc1 formatting of VPD=0x83 w/o this patch:

VPD INQUIRY: Device Identification page
  Designation descriptor number 1, descriptor length: 20
    designator_type: NAA,  code_set: Binary
    associated with the addressed logical unit
      NAA 6, IEEE Company_id: 0x1405
      Vendor Specific Identifier: 0xffde35ebf
      Vendor Specific Identifier Extension: 0x3092f498ffa820f9
      [0x6001405ffde35ebf3092f498ffa820f9]
  Designation descriptor number 2, descriptor length: 56
    designator_type: T10 vendor identification,  code_set: ASCII
    associated with the addressed logical unit
      vendor id: LIO-ORG
      vendor specific: IBLOCK:ffde35ec-3092-4980-a820-917636ca54f1

The v3.1-final formatting of VPD=0x83 w/ this patch:

VPD INQUIRY: Device Identification page
  Designation descriptor number 1, descriptor length: 20
    designator_type: NAA,  code_set: Binary
    associated with the addressed logical unit
      NAA 6, IEEE Company_id: 0x1405
      Vendor Specific Identifier: 0xffde35ec3
      Vendor Specific Identifier Extension: 0x924980a82091763
      [0x6001405ffde35ec30924980a82091763]
  Designation descriptor number 2, descriptor length: 56
    designator_type: T10 vendor identification,  code_set: ASCII
    associated with the addressed logical unit
      vendor id: LIO-ORG
      vendor specific: IBLOCK:ffde35ec-3092-4980-a820-917636ca54f1

(v2: Fix parsing code to dereference + check for string terminator instead
     of null pointer to ensure a zeroed payload for vpd_unit_serial less
     than 100 bits of NAA DESIGNATOR VENDOR SPECIFIC area.  Also, remove
     the unnecessary bitwise assignment)
Reported-by: NMartin Svec <martin.svec@zoner.cz>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Fix a number of issues in ibmveth_set_csum_offload:

- set_attr6 and clr_attr6 may be used uninitialised

- We store the result of the IPV4 checksum change in ret but overwrite
  it in a couple of places before checking it again later. Add ret4
  to make it obvious what we are doing.

- We weren't clearing the NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM flags
  if the enable of that hypervisor feature failed.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>