The last memory barrier in stmmac_xmit()/stmmac_tso_xmit() is placed
between a coherent memory write and a MMIO write:

The own bit is written in First Desc (TSO: MSS desc or First Desc).
<barrier>
The DMA engine is started by a write to the tx desc tail pointer/
enable dma transmission register, i.e. a MMIO write.

This barrier cannot be a simple dma_wmb(), since a dma_wmb() is only
used to guarantee the ordering, with respect to other writes,
to cache coherent DMA memory.

To guarantee that the cache coherent memory writes have completed
before we attempt to write to the cache incoherent MMIO region,
we need to use the more heavyweight barrier wmb().
Signed-off-by: NNiklas Cassel <niklas.cassel@axis.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A dma_wmb() is used to guarantee the ordering, with respect to
other writes, to cache coherent DMA memory.

There is a dma_wmb() in prepare_tx_desc()/prepare_tso_tx_desc() which
ensures that TDES0/1/2 is written before TDES3 (which contains the own
bit), for First Desc.

However, in the rare case that MSS changes, there will be a MSS
context descriptor in front of the regular DMA descriptors:

<MSS desc> <- DMA Next Descriptor
<First Desc>
<desc n>
<Last Desc>

Thus, for this special case, we need a dma_wmb()
after prepare_tso_tx_desc()/before writing the own bit to the MSS desc,
so that we flush the write to TDES3 for First Desc,
in order to ensure that the MSS descriptor is the last descriptor to
set the own bit.
Signed-off-by: NNiklas Cassel <niklas.cassel@axis.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sowmini Varadhan says:

====================
RDS: optimized notification for zerocopy completion

Resending with acked-by additions: previous attempt does not show
up in Patchwork. This time with a new mail Message-Id.

RDS applications use predominantly request-response, transacation
based IPC, so that ingress and egress traffic are well-balanced,
and it is possible/desirable to reduce system-call overhead by
piggybacking the notifications for zerocopy completion response
with data.

Moreover, it has been pointed out that socket functions block
if sk_err is non-zero, thus if the RDS code does not plan/need
to use sk_error_queue path for completion notification, it
is preferable to remove the sk_errror_queue related paths in
RDS.

Both of these goals are implemented in this series.

v2: removed sk_error_queue support
v3: incorporated additional code review comments (details in each patch)
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

PF_RDS sockets pass up cookies for zerocopy completion as ancillary
data. Update msg_zerocopy to reap this information.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This commit is an optimization over commit 01883eda
("rds: support for zcopy completion notification") for PF_RDS sockets.

RDS applications are predominantly request-response transactions, so
it is more efficient to reduce the number of system calls and have
zerocopy completion notification delivered as ancillary data on the
POLLIN channel.

Cookies are passed up as ancillary data (at level SOL_RDS) in a
struct rds_zcopy_cookies when the returned value of recvmsg() is
greater than, or equal to, 0. A max of RDS_MAX_ZCOOKIES may be passed
with each message.

This commit removes support for zerocopy completion notification on
MSG_ERRQUEUE for PF_RDS sockets.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation for optimized reception of zerocopy completion,
revert the Rx side changes introduced by Commit dfb8434b
("selftests/net: add zerocopy support for PF_RDS test case")
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Jeff Kirsher says:

====================
40GbE Intel Wired LAN Driver Updates 2018-02-26

This series contains updates to i40e and i40evf only.

Mariusz adds a new ethtool private flag for forcing true link state with
the requested changes from Jakub Kicinski.

Paweł fixes an issue where we were double locking the same resource
which would generate a kernel panic after bringing an interface up for
i40evf.

Alan modifies both drivers to use software values to determine if there
are packets stalled on the ring with the added benefit of being less CPU
intensive since we do not need to reach into the hardware to get the
values.

Colin Ian King provides a few fixes detected by Coverity, first was to
pass a struct by reference versus by value to be more efficient.  Then
verify the VSI pointer is not NULL before trying to dereference it.
Cleaned up redundant checks that always return true.

Dan Carpenter fixes over indented lines of code.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch improves few aspects of interrupt handling:
- update to current interrupt allocation API
  (use pci_alloc_irq_vectors() instead of deprecated pci_enable_msi())
- this implicitly will allocate a MSI-X interrupt if available
- get rid of flag RTL_FEATURE_MSI
- remove some dead code, intentionally disabling (unreliable) MSI
  being partially available on old PCI chips.

The patch works fine on a RTL8168evl (chip version 34) and on a
RTL8169SB (chip version 04).
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes: 153e1b84 ("selftests: Add FIB onlink tests")
Reported-by: NIdo Schimmel <idosch@idosch.org>
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Madalin Bucur says:

====================
DPAA Ethernet fixes

Fixed an issue on the Tx path that was visible in netperf
TCP_SENDFILE tests. Addressed another issue with Rx errors
not being always counted. Adding control for allmulti.

v2: rephrased commit message, reduced changes in the SG mapping fix
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds allmulticast option for memac, dtsec
and 10GEC controllers.
Signed-off-by: NRadu Bulie <radu-andrei.bulie@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NMadalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Simplify the code and avoid some Rx errors not being
accounted.
Signed-off-by: NMadalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

An issue in the code mapping the skb fragments into
scatter-gather frames was evidentiated by netperf
TCP_SENDFILE tests. The size was set wrong for all
fragments but the first, affecting the transmission
of any skb with more than one fragment.
Signed-off-by: NMadalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Merge branch 'ieee802154-for-davem-2018-02-26' of git://git.kernel.org/pub/scm/linux/kernel/git/sschmidt/wpan-next

Stefan Schmidt says:

====================
pull-request: ieee802154-next 2018-02-26

An update from ieee802154 for *net-next*

Alexander corrected a setting which got lost during some 6lowpan rework
a while back and Xue Liu provided us with a new driver for the MCR20A
transceiver.

If there are any issues let me know. If not, please pull.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Kirill Tkhai says:

====================
Converting pernet_operations (part #3)

This patchset continues to review and to convert pernet_operations
to async. Where it is possible, they are grouped by type of actions
init/exit methods ([1/28], for example). I hope this will make
the review a little bit easier. The changes are tree-wide: in net, fs,
drivers and security.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations only register and unregister nf hooks.
So, they are able to be marked as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations only register and unregister nf hooks.
So, they are able to be marked as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations only unregister nf hooks.
So, they are able to be marked as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations register and unregister nf hooks.
Also they populate and depopulate ila_net_id-pointed hash
table. The table is changed by hooks during skb processing
and via netlink request. It looks impossible for another
net pernet_operations to force the table reading or writing,
so, they are able to be marked as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations only unregister nf hooks.
So, they are able to be marked as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations register and unregister nf hooks,
and populate and destroy /proc entry. So, they are able
to be marked as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations only unregister nf hooks.
So, they are able to be marked as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations unregister ipvlan net hooks.
nf_unregister_net_hooks() removes hooks one-by-one,
and then frees the memory via rcu. This looks similar
to that happens, when a new hooks is added: allocation
of bigger memory region, copy of old content, and rcu
freeing the old memory. So, all of net code should be
well with this behavior. Also at the time of hook
unregistering, there are no packets, and foreign net
pernet_operations are not interested in others hooks.
So, we mark them as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations have only exit method, which
moves devices from cfg802154_rdev_list to init_net.
This may occur in any time from nl802154_wpan_phy_netns(),
so we are nice with rtnl_lock() synchronization.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: NStefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to ip6_tnl_net_ops. Exit method
unregisters all net sit devices, and it looks like another
pernet_operations are not interested in foreign net sit list.
Init method registers netdevice. So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to ip6_tnl_net_ops. Exit method
unregisters all net vti6 tunnels, and it looks like another
pernet_operations are not interested in foreign net vti6 list.
Init method registers netdevice. So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to ip6gre_net_ops. Exit method
unregisters all net ip6_tnl tunnels, and it looks like another
pernet_operations are not interested in foreign net tunnels list.
So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to bond_net_ops. Exit method
unregisters all net ip6gre devices, and it looks like another
pernet_operations are not interested in foreign net ip6gre list
or net_generic()->tunnels_wc. Init method registers net device.
So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to bond_net_ops. Exit methods
unregisters all net ipgre/ipgre_tap/erspan/vti/ipip devices, and it
looks like another pernet_operations are not interested in foreign
net ipgre/ipgre_tap/erspan/vti/ipip list. Init method also does not
intersect with something pernet-specific. So, it's possible
to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to bond_net_ops. Exit method
unregisters all net bridge devices, and it looks like another
pernet_operations are not interested in foreign net bridge list.
So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to bond_net_ops. Exit method
unregisters all net vlanx devices, and it looks like another
pernet_operations are not interested in foreign net vlanx list.
So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to bond_net_ops. Exit method
unregisters all net ppp devices, and it looks like another
pernet_operations are not interested in foreign net ppp list.
So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to bond_net_ops. Exit method
unregisters all net gtp devices, and it looks like another
pernet_operations are not interested in foreign net gtp list.
So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are similar to bond_net_ops. Exit method
unregisters all net geneve devices, and it looks like another
pernet_operations are not interested in foreign net geneve list.
So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations populate/depopulate /proc and /sys
entries. Exit method unregisters all net bond devices, and
it seems another pernet_operations are not interested in
foreign net bond list. So, it's possible to mark them async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations are from net/sched directory, and they call only
tc_action_net_init() and tc_action_net_exit():

bpf_net_ops
connmark_net_ops
csum_net_ops
gact_net_ops
ife_net_ops
ipt_net_ops
xt_net_ops
mirred_net_ops
nat_net_ops
pedit_net_ops
police_net_ops
sample_net_ops
simp_net_ops
skbedit_net_ops
skbmod_net_ops
tunnel_key_net_ops
vlan_net_ops

1)tc_action_net_init() just allocates and initializes per-net memory.
2)There should not be in-flight packets at the time of tc_action_net_exit()
call, or another pernet_operations send packets to dying net (except
netlink). So, it seems they can be marked as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations create and destroy sysctl tables,
and they are able to be executed in parallel with any others:

ip_vs_lblc_ops
ip_vs_lblcr_ops
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations just create and destroy IDR.
So, we mark them as async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations make pretty simple actions
like variable initialization on init, debug checks
on exit, and so on, and they obviously are able
to be executed in parallel with any others:

vrf_net_ops
lockd_net_ops
grace_net_ops
xfrm6_tunnel_net_ops
kcm_net_ops
tcf_net_ops
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>