net: adopt skb_network_offset() and similar helpers

This is a cleanup patch, making code a bit more concise.

1) Use skb_network_offset(skb) in place of
(skb_network_header(skb) - skb->data)

2) Use -skb_network_offset(skb) in place of
(skb->data - skb_network_header(skb))

3) Use skb_transport_offset(skb) in place of
(skb_transport_header(skb) - skb->data)

4) Use skb_inner_transport_offset(skb) in place of
(skb_inner_transport_header(skb) - skb->data)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com> # for sfc
Signed-off-by: David S. Miller <davem@davemloft.net>

sfc: Remove struct efx_special_buffer

The attributes index and entries are no longer needed, so use
struct efx_buffer instead.
next_buffer_table was also Siena specific.
Removed some checkpatch warnings.

Signed-off-by: Martin Habets <habetsm.xilinx@gmail.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: vlan: introduce skb_vlan_eth_hdr()

Similar to skb_eth_hdr() introduced in commit 96cc4b69581d ("macvlan: do
not assume mac_header is set in macvlan_broadcast()"), let's introduce a
skb_vlan_eth_hdr() helper which can be used in TX-only code paths to get
to the VLAN header based on skb->data rather than based on the
skb_mac_header(skb).

We also consolidate the drivers that dereference skb->data to go through
this helper.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sfc: remove EFX_BUG_ON_PARANOID, use EFX_WARN_ON_[ONCE_]PARANOID instead

Logically, EFX_BUG_ON_PARANOID can never be correct. For, BUG_ON should
only be used if it is not possible to continue without potential harm;
and since the non-DEBUG driver will continue regardless (as the BUG_ON is
compiled out), clearly the BUG_ON cannot be needed in the DEBUG driver.
So, replace every EFX_BUG_ON_PARANOID with either an EFX_WARN_ON_PARANOID
or the newly defined EFX_WARN_ON_ONCE_PARANOID.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sfc: remove Software TSO

It gives no advantage over GSO now that xmit_more exists. If we find
ourselves unable to handle a TSO skb (because our TXQ doesn't have a
TSOv2 context and the NIC doesn't support TSOv1), hand it back to GSO.
Also do that if the TSO handler fails with EINVAL for any other reason.
As Falcon-architecture NICs don't support any firmware-assisted TSO,
they no longer advertise TSO feature flags at all.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sfc: Firmware-Assisted TSO version 2

Add support for FATSOv2 to the driver. FATSOv2 offloads far more of the task
of TCP segmentation to the firmware, such that we now just pass a single
super-packet to the NIC. This means TSO has a great deal in common with a
normal DMA transmit, apart from adding a couple of option descriptors.
NIC-specific checks have been moved off the fast path and in to
initialisation where possible.

This also moves FATSOv1/SWTSO to a new file (tx_tso.c). The end of transmit
and some error handling is now outside TSO, since it is common with other
code.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>