This patch fixes the following sparse warnings. One is fixed by casting return
value to a return type of the function. The others by creating a specific
stmmac_platform.h which provides the bits related to the platform driver.

drivers/net/ethernet/stmicro/stmmac/dwmac-meson.c:59:29: warning: incorrect type in return expression (different address spaces)
drivers/net/ethernet/stmicro/stmmac/dwmac-meson.c:59:29:    expected void *
drivers/net/ethernet/stmicro/stmmac/dwmac-meson.c:59:29:    got void [noderef] <asn:2>*reg

drivers/net/ethernet/stmicro/stmmac/dwmac-meson.c:64:29: warning: symbol 'meson6_dwmac_data' was not declared. Should it be static?
drivers/net/ethernet/stmicro/stmmac/dwmac-sti.c:354:29: warning: symbol 'stih4xx_dwmac_data' was not declared. Should it be static?
drivers/net/ethernet/stmicro/stmmac/dwmac-sti.c:361:29: warning: symbol 'stid127_dwmac_data' was not declared. Should it be static?
drivers/net/ethernet/stmicro/stmmac/dwmac-sunxi.c:133:29: warning: symbol 'sun7i_gmac_data' was not declared. Should it be static?
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is a kernel helper to dump buffers in a hexdecimal format. This patch
substitutes the open coded function by calling that helper.

The output is slightly changed:
 - no lead space
 - ASCII part will be printed along with the dump
 - offset is longer than 3 characters (now 8)
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Herbert Xu says:

====================
Replace skb_copy_datagram_const_iovec with iterator version

This patch series adds the helper skb_copy_datagram_iter, which
is meant to replace both skb_copy_datagram_iovec and its evil
twin skb_copy_datagram_const_iovec.

It then converts tun and macvtap over to the new helper and finally
removes skb_copy_datagram_const_iovec which is only used by tun
and macvtap.

The copy_to_iter return value issue pointed out by Al has now been
fixed.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that both macvtap and tun are using skb_copy_datagram_iter, we
can kill the abomination that is skb_copy_datagram_const_iovec.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch removes the use of skb_copy_datagram_const_iovec in
favour of the iovec iterator-based skb_copy_datagram_iter.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch removes the use of skb_copy_datagram_const_iovec in
favour of the iovec iterator-based skb_copy_datagram_iter.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds skb_copy_datagram_iter, which is identical to
skb_copy_datagram_iovec except that it operates on iov_iter
instead of iovec.

Eventually all users of skb_copy_datagram_iovec should switch
over to iov_iter and then we can remove skb_copy_datagram_iovec.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add definition to vxlan nla_policy for UDP checksum. This is necessary
to enable UDP checksums on VXLAN.

In some instances, enabling UDP checksums can improve performance on
receive for devices that return legacy checksum-unnecessary for UDP/IP.
Also, UDP checksum provides some protection against VNI corruption.

Testing:

Ran 200 instances of TCP_STREAM and TCP_RR on bnx2x.

TCP_STREAM
  IPv4, without UDP checksums
      14.41% TX CPU utilization
      25.71% RX CPU utilization
      9083.4 Mbps
  IPv4, with UDP checksums
      13.99% TX CPU utilization
      13.40% RX CPU utilization
      9095.65 Mbps

TCP_RR
  IPv4, without UDP checksums
      94.08% TX CPU utilization
      156/248/462 90/95/99% latencies
      1.12743e+06 tps
  IPv4, with UDP checksums
      94.43% TX CPU utilization
      158/250/462 90/95/99% latencies
      1.13345e+06 tps
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Tom Lendacky says:

====================
amd-xgbe: AMD XGBE driver updates 2014-11-06

The following series of patches fixes a couple of bugs that slipped
through my last series.

- Free channel structure after freeing the per channel interrupts
- If an skb error allocation occurs during receive processing check
  whether more descriptors are associated with the packet or whether
  to start on a new packet

This patch series is based on net-next.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If the skb allocation fails during receive processing, the driver would
continue reading descriptors without first determining if there were
any more descriptors for the current packet. Update the code to check
whether more descriptors are associated with the current packet or
whether to move on to the next descriptor as a new packet.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The channel structure is freed before freeing the per channel
interrupts resulting in a kernel oops. Move the call to free
the channel structure to after the freeing of the per channel
interrupts.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

o Poll for the link events only if firmware doesn't have capability
  to notify the driver for the link events.
Signed-off-by: NManish Chopra <manish.chopra@qlogic.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we reuse the rx buffer, we need to update the desc. If not hardware sees
stale value.

In the following crash, when mtu is changed, hardware sees old rx buffer value
and crashes on skb_put.

Fix this by using enic_queue_rq_desc helper function which updates the necessary
desc.

[   64.657376] skbuff: skb_over_panic: text:ffffffffa041f55d len:9010 put:9010 head:ffff8800d3ca9fc0 data:ffff8800d3caa000 tail:0x2372 end:0x640 dev:enp0s3
[   64.659965] ------------[ cut here ]------------
[   64.661322] kernel BUG at net/core/skbuff.c:100!
[   64.662644] invalid opcode: 0000 [#1] PREEMPT SMP
[   64.664001] Modules linked in: rpcsec_gss_krb5 auth_rpcgss oid_registry nfsv4 cirrus ttm drm_kms_helper drm enic psmouse microcode evdev serio_raw syscopyarea sysfillrect sysimgblt i2c_piix4 i2c_core pcspkr nfs lockd grace sunrpc fscache ext4 crc16 mbcache jbd2 sd_mod ata_generic virtio_balloon ata_piix libata uhci_hcd virtio_pci virtio_ring usbcore usb_common virtio scsi_mod
[   64.664834] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W      3.17.0-netnext-10335-g942396b0-dirty #273
[   64.664834] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   64.664834] task: ffffffff81a1d580 ti: ffffffff81a00000 task.ti: ffffffff81a00000
[   64.664834] RIP: 0010:[<ffffffff81392cf1>]  [<ffffffff81392cf1>] skb_panic+0x61/0x70
[   64.664834] RSP: 0018:ffff880210603d48  EFLAGS: 00010292
[   64.664834] RAX: 000000000000008c RBX: ffff88020b0f6930 RCX: 0000000000000000
[   64.664834] RDX: 000000000000008c RSI: ffffffff8178b288 RDI: 00000000ffffffff
[   64.664834] RBP: ffff880210603d68 R08: 0000000000000001 R09: 0000000000000001
[   64.664834] R10: 00000000000005ce R11: 0000000000000001 R12: ffff88020b1f0b40
[   64.664834] R13: 000000000000a332 R14: ffff880209a1a000 R15: 0000000000000001
[   64.664834] FS:  0000000000000000(0000) GS:ffff880210600000(0000) knlGS:0000000000000000
[   64.664834] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   64.664834] CR2: 00007f6752935e48 CR3: 0000000035743000 CR4: 00000000000006f0
[   64.664834] Stack:
[   64.664834]  ffff8800d3caa000 0000000000002372 0000000000000640 ffff88020b1f0000
[   64.664834]  ffff880210603d78 ffffffff81392d54 ffff880210603e08 ffffffffa041f55d
[   64.664834]  0000000000000296 ffffffff00000000 00008e7e00008e7e ffff880200002332
[   64.664834] Call Trace:
[   64.664834]  <IRQ>
[   64.664834]
[   64.664834]  [<ffffffff81392d54>] skb_put+0x54/0x60
[   64.664834]  [<ffffffffa041f55d>] enic_rq_service.constprop.47+0x3ad/0x730 [enic]
[   64.664834]  [<ffffffffa041fa79>] enic_poll_msix_rq+0x199/0x370 [enic]
[   64.664834]  [<ffffffff813a5499>] net_rx_action+0x139/0x210
[   64.664834]  [<ffffffff81290db3>] ? __this_cpu_preempt_check+0x13/0x20
[   64.664834]  [<ffffffff8106110e>] __do_softirq+0x14e/0x280
[   64.664834]  [<ffffffff8106152e>] irq_exit+0x8e/0xb0
[   64.664834]  [<ffffffff8100fd21>] do_IRQ+0x61/0x100
[   64.664834]  [<ffffffff814a2bf2>] common_interrupt+0x72/0x72

fixes: a03bb56e ("enic: implement rx_copybreak")
Signed-off-by: NGovindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case of error in rx path, we free the buf->os_buf but we do not make it NULL.
In next iteration we use the skb which is already freed. This causes the
following crash.

[  886.154772] general protection fault: 0000 [#1] PREEMPT SMP
[  886.154851] Modules linked in: rpcsec_gss_krb5 auth_rpcgss oid_registry nfsv4 microcode evdev cirrus ttm drm_kms_helper drm enic syscopyarea sysfillrect sysimgblt psmouse i2c_piix4 serio_raw pcspkr i2c_core nfs lockd grace sunrpc fscache ext4 crc16 mbcache jbd2 sd_mod crc_t10dif crct10dif_common ata_generic ata_piix virtio_balloon libata scsi_mod uhci_hcd usbcore virtio_pci virtio_ring virtio usb_common
[  886.155199] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W      3.17.0-netnext-05668-g876bc7f #272
[  886.155263] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  886.155304] task: ffffffff81a1d580 ti: ffffffff81a00000 task.ti: ffffffff81a00000
[  886.155356] RIP: 0010:[<ffffffff81384030>]  [<ffffffff81384030>] kfree_skb_list+0x10/0x30
[  886.155418] RSP: 0018:ffff880210603d48  EFLAGS: 00010206
[  886.155456] RAX: 0000000000000020 RBX: 0000000000000000 RCX: 0000000000000000
[  886.155504] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 004500084e000017
[  886.155553] RBP: ffff880210603d50 R08: 00000000fe13d1b6 R09: 0000000000000001
[  886.155601] R10: 0000000000000000 R11: 0000000000000000 R12: ffff880209ff2f00
[  886.155650] R13: ffff88020ac0fe40 R14: ffff880209ff2f00 R15: ffff8800da8e3a80
[  886.155699] FS:  0000000000000000(0000) GS:ffff880210600000(0000) knlGS:0000000000000000
[  886.155774] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[  886.155814] CR2: 00007f0e0c925000 CR3: 0000000035e8b000 CR4: 00000000000006f0
[  886.155865] Stack:
[  886.155882]  0000000000000000 ffff880210603d78 ffffffff81383f79 ffff880209ff2f00
[  886.155942]  ffff88020b0c0b40 000000000000c000 ffff880210603d90 ffffffff81383faf
[  886.156001]  ffff880209ff2f00 ffff880210603da8 ffffffff8138406d ffff88020b1b08c0
[  886.156061] Call Trace:
[  886.156080]  <IRQ>
[  886.156095]
[  886.156112]  [<ffffffff81383f79>] skb_release_data+0xa9/0xc0
[  886.157656]  [<ffffffff81383faf>] skb_release_all+0x1f/0x30
[  886.159195]  [<ffffffff8138406d>] consume_skb+0x1d/0x40
[  886.160719]  [<ffffffff813942e5>] __dev_kfree_skb_any+0x35/0x40
[  886.162224]  [<ffffffffa02dc1d5>] enic_rq_service.constprop.47+0xe5/0x5a0 [enic]
[  886.163756]  [<ffffffffa02dc829>] enic_poll_msix_rq+0x199/0x370 [enic]
[  886.164730]  [<ffffffff81397e29>] net_rx_action+0x139/0x210
[  886.164730]  [<ffffffff8105fb2e>] __do_softirq+0x14e/0x280
[  886.164730]  [<ffffffff8105ff2e>] irq_exit+0x8e/0xb0
[  886.164730]  [<ffffffff8100fc1d>] do_IRQ+0x5d/0x100
[  886.164730]  [<ffffffff81496832>] common_interrupt+0x72/0x72

fixes: a03bb56e ("enic: implement rx_copybreak")
Signed-off-by: NGovindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Eli Cohen says:

====================
mlx5_core fixes for 3.18

the following two patches fix races to could lead to kernel panic in some cases.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When events arrive at driver load, the event handler gets called even before
the spinlock and list are initialized. Fix this by moving the initialization
before EQs creation.
Signed-off-by: NEli Cohen <eli@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After the EQ is created, it can possibly generate interrupts and the interrupt
handler is referencing eq->dev. It is therefore required to set eq->dev before
calling request_irq() so if an event is generated before request_irq() returns,
we will have a valid eq->dev field.
Signed-off-by: NEli Cohen <eli@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pravin B Shelar says:

====================
Open vSwitch

First two patches are related to OVS MPLS support. Rest of patches
are mostly refactoring and minor improvements to openvswitch.

v1-v2:
 - Fix conflicts due to "gue: Remote checksum offload"
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sowmini Varadhan says:

====================
sunvnet: bug fixes

This patch series has a coding-style fix and a bug fix.

The coding style fix (patch 1) is the extra indentation flagged by
Ben Hutchings:
  http://marc.info/?l=linux-netdev&m=141529243409594&w=2

The bugfix (patch 2) is the following:
when vnet_event_napi() is  called as part of napi_resume
(i.e., continuation of a previous NAPI read that was truncated
due to budget constraints), and then finds no more packets to read,
the code was trying to avoid an additional trip through ldc_rx
as an optimization. However, when this corner case happens, we would
need to reset a number of dring state bits such as rcv_nxt carefully,
which quickly becomes complex and hacky.  The cleaner solution
is to just roll back to vnet_poll, re-enable interrupts and set up
dring state as was done in the pre-NAPI version of the driver.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

vnet_event_napi() may be called as part of the NAPI ->poll,
to resume reading descriptor rings. When no data is available,
descriptor ring state (e.g., rcv_nxt) needs to be reset
carefully to stay in lock-step with ldc_read(). In the interest
of simplicity, the best way to do this is to return from
vnet_event_napi() when there are no more packets to read.
The next trip through ldc_rx will correctly set up the dring state.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Tested-by: NDavid Stevens <david.stevens@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

remove redundant tab.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Reported-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Hayes Wang says:

====================
r8152: rtl_ops_init modify

Initialize the ops through tp->version. This could skip checking
each VID/PID.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The PIDs are only used in the id table, so the definitions are
unnacessary. Remove them wouldn't have confusion.
Signed-off-by: NHayes Wang <hayeswang@realtek.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace using VID/PID with using tp->version to initialize the ops.
Signed-off-by: NHayes Wang <hayeswang@realtek.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move r8152b_get_version() to the location before rtl_ops_init().
Then, the rtl_ops_init() could use tp->version.
Signed-off-by: NHayes Wang <hayeswang@realtek.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It's unused now, just delete it.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 64ce2073 ("[NET]: Make NETDEBUG pure printk wrappers")
originally had these NETDEBUG printks as always emitting.

Commit a2a316fd ("[NET]: Replace CONFIG_NET_DEBUG with sysctl")
added a net_msg_warn sysctl to these NETDEBUG uses.

Convert these NETDEBUG uses to normal pr_info calls.

This changes the output prefix from "ESP: " to include
"IPSec: " for the ipv4 case and "IPv6: " for the ipv6 case.

These output lines are now like the other messages in the files.

Other miscellanea:

Neaten the arithmetic spacing to be consistent with other
arithmetic spacing in the files.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These messages aren't useful as there's a generic dump_stack()
on OOM.

Neaten the comment and if test above the OOM by separating the
assign in if into an allocation then if test.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The mv88e6172 is very similar to the mv88e6171.  So extend the
mv88e6171 driver to support it.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the ports phys are connected to the switches internal MDIO bus,
we need to connect the phy to the slave netdev, otherwise
auto-negotiation etc, does not work.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes: 4bba3925 ("[PKT_SCHED]: Prefix tc actions with act_")
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NRyo Munakata <ryomnktml@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

when cpsw is build as modulea and simple insert and removal of module
creates a deadlock, due to delete timer. the timer is created and destroyed
in cpsw_ale_start and cpsw_ale_stop which are from device open and close.

root@am437x-evm:~# modprobe -r ti_cpsw
[  158.505333] INFO: trying to register non-static key.
[  158.510623] the code is fine but needs lockdep annotation.
[  158.516448] turning off the locking correctness validator.
[  158.522282] CPU: 0 PID: 1339 Comm: modprobe Not tainted 3.14.23-00445-gd41c88f #44
[  158.530359] [<c0015380>] (unwind_backtrace) from [<c0012088>] (show_stack+0x10/0x14)
[  158.538603] [<c0012088>] (show_stack) from [<c054ad70>] (dump_stack+0x78/0x94)
[  158.546295] [<c054ad70>] (dump_stack) from [<c0088008>] (__lock_acquire+0x176c/0x1b74)
[  158.554711] [<c0088008>] (__lock_acquire) from [<c0088944>] (lock_acquire+0x9c/0x104)
[  158.563043] [<c0088944>] (lock_acquire) from [<c004e520>] (del_timer_sync+0x44/0xd8)
[  158.571289] [<c004e520>] (del_timer_sync) from [<bf2eac1c>] (cpsw_ale_destroy+0x10/0x3c [ti_cpsw])
[  158.580821] [<bf2eac1c>] (cpsw_ale_destroy [ti_cpsw]) from [<bf2eb268>] (cpsw_remove+0x30/0xa0 [ti_cpsw])
[  158.591000] [<bf2eb268>] (cpsw_remove [ti_cpsw]) from [<c035ef44>] (platform_drv_remove+0x18/0x1c)
[  158.600527] [<c035ef44>] (platform_drv_remove) from [<c035d8bc>] (__device_release_driver+0x70/0xc8)
[  158.610236] [<c035d8bc>] (__device_release_driver) from [<c035e0d4>] (driver_detach+0xb4/0xb8)
[  158.619386] [<c035e0d4>] (driver_detach) from [<c035d6e4>] (bus_remove_driver+0x4c/0x90)
[  158.627988] [<c035d6e4>] (bus_remove_driver) from [<c00af2a8>] (SyS_delete_module+0x10c/0x198)
[  158.637144] [<c00af2a8>] (SyS_delete_module) from [<c000e580>] (ret_fast_syscall+0x0/0x48)
[  179.524727] INFO: rcu_sched detected stalls on CPUs/tasks: {} (detected by 0, t=2102 jiffies, g=1487, c=1486, q=6)
[  179.535741] INFO: Stall ended before state dump start
Signed-off-by: NMugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ATM, txq_reclaim will dequeue and free an skb for each tx desc released
by the hw that has TX_LAST_DESC set. However, in case of TSO, each
hw desc embedding the last part of a segment has TX_LAST_DESC set,
losing the one-to-one 'last skb frag'/'TX_LAST_DESC set' correspondance,
which causes data corruption.

Fix this by checking TX_ENABLE_INTERRUPT instead of TX_LAST_DESC, and
warn when trying to dequeue from an empty txq (which can be symptomatic
of releasing skbs prematurely).

Fixes: 3ae8f4e0 ('net: mv643xx_eth: Implement software TSO')
Reported-by: NSlawomir Gajzner <slawomir.gajzner@gmail.com>
Reported-by: NJulien D'Ascenzio <jdascenzio@yahoo.fr>
Signed-off-by: NKarl Beldan <karl.beldan@rivierawaves.com>
Cc: Ian Campbell <ijc@hellion.org.uk>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Shradha Shah says:

====================
sfc: Clean up Siena SR-IOV support in preparation for EF10 SR-IOV support

This patch series provides a base and clean up for the upcoming
EF10 SRIOV patches.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Also add dummy functions where required to avoid NULL pointer dereference.
Signed-off-by: NShradha Shah <sshah@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Patch in preparation for the upcoming EF10 sriov support.
Signed-off-by: NShradha Shah <sshah@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch series provides a base and cleanup for the
upcoming EF10 SRIOV support.

This patch moves the VF state into siena_nic_data as a basis to
save the VF state based on nic type.
Signed-off-by: NShradha Shah <sshah@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Unconditionally pulling 128 bytes into the linear area is not required
for:

- security: Every protocol demux starts with pskb_may_pull() to pull
  frag data into the linear area, if necessary, before looking at
  headers.

- performance: Netback has already grant copied up-to 128 bytes from
  the first slot of a packet into the linear area. The first slot
  normally contain all the IPv4/IPv6 and TCP/UDP headers.

The unconditional pull would often copy frag data unnecessarily.  This
is a performance problem when running on a version of Xen where grant
unmap avoids TLB flushes for pages which are not accessed.  TLB
flushes can now be avoided for > 99% of unmaps (it was 0% before).

Grant unmap TLB flush avoidance will be available in a future version
of Xen (probably 4.6).
Signed-off-by: NMalcolm Crossley <malcolm.crossley@citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>