dev_init_scheduler() and dev_activate() expect the caller to
hold RTNL. Since we don't want blackhole device to be initialized
per ns, we are initializing at init.

[    3.855027] Call Trace:
[    3.855034]  dump_stack+0x67/0x95
[    3.855037]  lockdep_rcu_suspicious+0xd5/0x110
[    3.855044]  dev_init_scheduler+0xe3/0x120
[    3.855048]  ? net_olddevs_init+0x60/0x60
[    3.855050]  blackhole_netdev_init+0x45/0x6e
[    3.855052]  do_one_initcall+0x6c/0x2fa
[    3.855058]  ? rcu_read_lock_sched_held+0x8c/0xa0
[    3.855066]  kernel_init_freeable+0x1e5/0x288
[    3.855071]  ? rest_init+0x260/0x260
[    3.855074]  kernel_init+0xf/0x180
[    3.855076]  ? rest_init+0x260/0x260
[    3.855078]  ret_from_fork+0x24/0x30

Fixes: 4de83b88 ("loopback: create blackhole net device similar to loopack.")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

Before mlxsw_sp1_ptp_packet_finish() sends the packet back, it validates
whether the corresponding port is still valid. However the condition is
incorrect: when mlxsw_sp_port == NULL, the code dereferences the port to
compare it to skb->dev.

The condition needs to check whether the port is present and skb->dev still
refers to that port (or else is NULL). If that does not hold, bail out.
Add a pair of parentheses to fix the condition.

Fixes: d92e4e6e ("mlxsw: spectrum: PTP: Support timestamping on Spectrum-1")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

It was reported that the GPD MicroPC is broken in a way that no valid
MAC address can be read from the network chip. The vendor driver deals
with this by assigning a random MAC address as fallback. So let's do
the same.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit 759d0957.

The patch was based on a misunderstanding. As Al Viro pointed out [0]
it's simply wrong on big endian. So let's revert it.

[0] https://marc.info/?t=156200975600004&r=1&w=2Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 760f1dc2 ("net: stmmac: add sanity check to
device_property_read_u32_array call") introduced error checking of the
device_property_read_u32_array() call in stmmac_mdio_reset().
This results in the following error when the "snps,reset-delays-us"
property is not defined in devicetree:
  invalid property snps,reset-delays-us

This sanity check made sense until commit 84ce4d0f ("net: stmmac:
initialize the reset delay array") ensured that there are fallback
values for the reset delay if the "snps,reset-delays-us" property is
absent. That was at the cost of making that property mandatory though.

Drop the sanity check for device_property_read_u32_array() and thus make
the "snps,reset-delays-us" property optional again (avoiding the error
message while loading the stmmac driver with a .dtb where the property
is absent).

Fixes: 760f1dc2 ("net: stmmac: add sanity check to device_property_read_u32_array call")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

A bonding master can be up while best_slave is NULL.

[12105.636318] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[12105.638204] mlx4_en: eth1: Linkstate event 1 -> 1
[12105.648984] IP: bond_select_active_slave+0x125/0x250
[12105.653977] PGD 0 P4D 0
[12105.656572] Oops: 0000 [#1] SMP PTI
[12105.660487] gsmi: Log Shutdown Reason 0x03
[12105.664620] Modules linked in: kvm_intel loop act_mirred uhaul vfat fat stg_standard_ftl stg_megablocks stg_idt stg_hdi stg elephant_dev_num stg_idt_eeprom w1_therm wire i2c_mux_pca954x i2c_mux mlx4_i2c i2c_usb cdc_acm ehci_pci ehci_hcd i2c_iimc mlx4_en mlx4_ib ib_uverbs ib_core mlx4_core [last unloaded: kvm_intel]
[12105.685686] mlx4_core 0000:03:00.0: dispatching link up event for port 2
[12105.685700] mlx4_en: eth2: Linkstate event 2 -> 1
[12105.685700] mlx4_en: eth2: Link Up (linkstate)
[12105.724452] Workqueue: bond0 bond_mii_monitor
[12105.728854] RIP: 0010:bond_select_active_slave+0x125/0x250
[12105.734355] RSP: 0018:ffffaf146a81fd88 EFLAGS: 00010246
[12105.739637] RAX: 0000000000000003 RBX: ffff8c62b03c6900 RCX: 0000000000000000
[12105.746838] RDX: 0000000000000000 RSI: ffffaf146a81fd08 RDI: ffff8c62b03c6000
[12105.754054] RBP: ffffaf146a81fdb8 R08: 0000000000000001 R09: ffff8c517d387600
[12105.761299] R10: 00000000001075d9 R11: ffffffffaceba92f R12: 0000000000000000
[12105.768553] R13: ffff8c8240ae4800 R14: 0000000000000000 R15: 0000000000000000
[12105.775748] FS:  0000000000000000(0000) GS:ffff8c62bfa40000(0000) knlGS:0000000000000000
[12105.783892] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[12105.789716] CR2: 0000000000000000 CR3: 0000000d0520e001 CR4: 00000000001626f0
[12105.796976] Call Trace:
[12105.799446]  [<ffffffffac31d387>] bond_mii_monitor+0x497/0x6f0
[12105.805317]  [<ffffffffabd42643>] process_one_work+0x143/0x370
[12105.811225]  [<ffffffffabd42c7a>] worker_thread+0x4a/0x360
[12105.816761]  [<ffffffffabd48bc5>] kthread+0x105/0x140
[12105.821865]  [<ffffffffabd42c30>] ? rescuer_thread+0x380/0x380
[12105.827757]  [<ffffffffabd48ac0>] ? kthread_associate_blkcg+0xc0/0xc0
[12105.834266]  [<ffffffffac600241>] ret_from_fork+0x51/0x60

Fixes: e2a7420d ("bonding/main: convert to using slave printk macros")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: John Sperbeck <jsperbeck@google.com>
Cc: Jarod Wilson <jarod@redhat.com>
CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Veaceslav Falico <vfalico@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Both tipc_udp_enable and tipc_udp_disable are called under rtnl_lock,
ub->ubsock could never be NULL in tipc_udp_disable and cleanup_bearer,
so remove the check.

Also remove the one in tipc_udp_enable by adding "free" label.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In commit ee28906f ("ipv4: Dump route exceptions if requested") I
added a counter of per-node dumped routes (including actual routes and
exceptions), analogous to the existing counter for dumped nodes. Dumping
exceptions means we need to also keep track of how many routes are dumped
for each node: this would be just one route per node, without exceptions.

When netlink strict checking is not enabled, we dump both routes and
exceptions at the same time: the RTM_F_CLONED flag is not used as a
filter. In this case, the per-node counter 'i_fa' is incremented by one
to track the single dumped route, then also incremented by one for each
exception dumped, and then stored as netlink callback argument as skip
counter, 's_fa', to be used when a partial dump operation restarts.

The per-node counter needs to be increased by one also when we skip a
route (exception) due to a previous non-zero skip counter, because it
needs to match the existing skip counter, if we are dumping both routes
and exceptions. I missed this, and only incremented the counter, for
regular routes, if the previous skip counter was zero. This means that,
in case of a mixed dump, partial dump operations after the first one
will start with a mismatching skip counter value, one less than expected.

This means in turn that the first exception for a given node is skipped
every time a partial dump operation restarts, if netlink strict checking
is not enabled (iproute < 5.0).

It turns out I didn't repeat the test in its final version, commit
de755a85 ("selftests: pmtu: Introduce list_flush_ipv4_exception test
case"), which also counts the number of route exceptions returned, with
iproute2 versions < 5.0 -- I was instead using the equivalent of the IPv6
test as it was before commit b964641e ("selftests: pmtu: Make
list_flush_ipv6_exception test more demanding").

Always increment the per-node counter by one if we previously dumped
a regular route, so that it matches the current skip counter.

Fixes: ee28906f ("ipv4: Dump route exceptions if requested")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

No reason to error out on a MT7621 device with DDR2 memory when non
TRGMII mode is selected.
Only MT7621 DDR2 clock setup is not supported for TRGMII mode.
But non TRGMII mode doesn't need any special clock setup.
Signed-off-by: René van Dorst <opensource@vdorst.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

With gcc 4.1:

    net/rxrpc/output.c: In function ‘rxrpc_send_data_packet’:
    net/rxrpc/output.c:338: warning: ‘ret’ may be used uninitialized in this function

Indeed, if the first jump to the send_fragmentable label is made, and
the address family is not handled in the switch() statement, ret will be
used uninitialized.

Fix this by BUG()'ing as is done in other places in rxrpc where internal
support for future address families will need adding.  It should not be
possible to reach this normally as the address families are checked
up-front.

Fixes: 5a924b89 ("rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The variable r is being initialized with a value that is never
read and it is being updated later with a new value. The
initialization is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch removes standard netdev stats in ethtool -S.
Suggested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Xue Chaojing <xuechaojing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We support many speeds and it doesn't make much sense to list them all
in the Kconfig. Let's just call it Multi-Gigabit.
Suggested-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Catherine Sullivan says:

====================
Add gve driver

This patch series adds the gve driver which will support the
Compute Engine Virtual NIC that will be available in the future.

v2:
- Patch 1:
  - Remove gve_size_assert.h and use static_assert instead.
  - Loop forever instead of bugging if the device won't reset
  - Use module_pci_driver
- Patch 2:
  - Use be16_to_cpu in the RX Seq No define
  - Remove unneeded ndo_change_mtu
- Patch 3:
  - No Changes
- Patch 4:
  - Instead of checking netif_carrier_ok in ethtool stats, just make sure

v3:
- Patch 1:
  - Remove X86 dep
- Patch 2:
  - No changes
- Patch 3:
  - No changes
- Patch 4:
  - Remove unneeded memsets in ethtool stats

v4:
- Patch 1:
  - Use io[read|write]32be instead of [read|write]l(cpu_to_be32())
  - Explicitly add padding to gve_adminq_set_driver_parameter
  - Use static where appropriate
- Patch 2:
  - Use u64_stats_sync
  - Explicity add padding to gve_adminq_create_rx_queue
  - Fix some enianness typing issues found by kbuild
  - Use static where appropriate
  - Remove unused variables
- Patch 3:
  - Use io[read|write]32be instead of [read|write]l(cpu_to_be32())
- Patch 4:
  - Use u64_stats_sync
  - Use static where appropriate
Warnings reported by:
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Add support for the following ethtool commands:

ethtool -s|--change devname [msglvl N] [msglevel type on|off]
ethtool -S|--statistics devname
ethtool -i|--driver devname
ethtool -l|--show-channels devname
ethtool -L|--set-channels devname
ethtool -g|--show-ring devname
ethtool --reset devname
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Jon Olson <jonolson@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add support for the workqueue to handle management interrupts and
support for resets.
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Jon Olson <jonolson@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add support for passing traffic.
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Jon Olson <jonolson@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add a driver framework for the Compute Engine Virtual NIC that will be
available in the future.

At this point the only functionality is loading the driver.
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Jon Olson <jonolson@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Mahesh Bandewar says:

====================
blackhole device to invalidate dst

When we invalidate dst or mark it "dead", we assign 'lo' to
dst->dev. First of all this assignment is racy and more over,
it has MTU implications.

The standard dev MTU is 1500 while the Loopback MTU is 64k. TCP
code when dereferencing the dst don't check if the dst is valid
or not. TCP when dereferencing a dead-dst while negotiating a
new connection, may use dst device which is 'lo' instead of
using the correct device. Consider the following scenario:

A SYN arrives on an interface and tcp-layer while processing
SYNACK finds a dst and associates it with SYNACK skb. Now before
skb gets passed to L3 for processing, if that dst gets "dead"
(because of the virtual device getting disappeared & then reappeared),
the 'lo' gets assigned to that dst (lo MTU = 64k). Let's assume
the SYN has ADV_MSS set as 9k while the output device through
which this SYNACK is going to go out has standard MTU of 1500.
The MTU check during the route check passes since MIN(9K, 64K)
is 9k and TCP successfully negotiates 9k MSS. The subsequent
data packet; bigger in size gets passed to the device and it
won't be marked as GSO since the assumed MTU of the device is
9k.

This either crashes the NIC and we have seen fixes that went
into drivers to handle this scenario. 8914a595 ('bnx2x:
disable GSO where gso_size is too big for hardware') and
2b16f048 ('net: create skb_gso_validate_mac_len()') and
with those fixes TCP eventually recovers but not before
few dropped segments.

Well, I'm not a TCP expert and though we have experienced
these corner cases in our environment, I could not reproduce
this case reliably in my test setup to try this fix myself.
However, Michael Chan <michael.chan@broadcom.com> had a setup
where these fixes helped him mitigate the issue and not cause
the crash.

The idea here is to not alter the data-path with additional
locks or smb()/rmb() barriers to avoid racy assignments but
to create a new device that has really low MTU that has
.ndo_start_xmit essentially a kfree_skb(). Make use of this
device instead of 'lo' when marking the dst dead.

First patch implements the blackhole device and second
patch uses it in IPv4 and IPv6 stack while the third patch
is the self test that ensures the sanity of this device.

v1->v2
  fixed the self-test patch to handle the conflict

v2 -> v3
  fixed Kconfig text/string.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Since this is not really a device with all capabilities, this test
ensures that it has *enough* to make it through the data path
without causing unwanted side-effects (read crash!).
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use blackhole_netdev instead of 'lo' device with lower MTU when marking
dst "dead".
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Tested-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Create a blackhole net device that can be used for "dead"
dst entries instead of loopback device. This blackhole device differs
from loopback in few aspects: (a) It's not per-ns. (b)  MTU on this
device is ETH_MIN_MTU (c) The xmit function is essentially kfree_skb().
and (d) since it's not registered it won't have ifindex.

Lower MTU effectively make the device not pass the MTU check during
the route check when a dst associated with the skb is dead.
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Remove unneeded memset as alloc_etherdev is using kvzalloc which uses
__GFP_ZERO flag
Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Ilias Apalodimas says:

====================
net: netsec: Add XDP Support

This is a respin of https://www.spinics.net/lists/netdev/msg526066.html
Since page_pool API fixes are merged into net-next we can now safely use
it's DMA mapping capabilities.

First patch changes the buffer allocation from napi/netdev_alloc_frag()
to page_pool API. Although this will lead to slightly reduced performance
(on raw packet drops only) we can use the API for XDP buffer recycling.
Another side effect is a slight increase in memory usage, due to using a
single page per packet.

The second patch adds XDP support on the driver.
There's a bunch of interesting options that come up due to the single
Tx queue.
Locking is needed(to avoid messing up the Tx queues since ndo_xdp_xmit
and the normal stack can co-exist). We also need to track down the
'buffer type' for TX and properly free or recycle the packet depending
on it's nature.

Changes since RFC:
- Bug fixes from Jesper and Maciej
- Added page pool API to retrieve the DMA direction

Changes since v1:
- Use page_pool_free correctly if xdp_rxq_info_reg() failed
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The interface only supports 1 Tx queue so locking is introduced on
the Tx queue if XDP is enabled to make sure .ndo_start_xmit and
.ndo_xdp_xmit won't corrupt Tx ring

- Performance (SMMU off)

Benchmark   XDP_SKB     XDP_DRV
xdp1        291kpps     344kpps
rxdrop      282kpps     342kpps

- Performance (SMMU on)
Benchmark   XDP_SKB     XDP_DRV
xdp1        167kpps     324kpps
rxdrop      164kpps     323kpps
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since the dma direction is stored in page pool params, offer an API
helper for driver that choose not to keep track of it locally
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use page_pool and it's DMA mapping capabilities for Rx buffers instead
of netdev/napi_alloc_frag()

Although this will result in a slight performance penalty on small sized
packets (~10%) the use of the API will allow to easily add XDP support.
The penalty won't be visible in network testing i.e ipef/netperf etc, it
only happens during raw packet drops.
Furthermore we intend to add recycling capabilities on the API
in the future. Once the recycling is added the performance penalty will
go away.
The only 'real' penalty is the slightly increased memory usage, since we
now allocate a page per packet instead of the amount of bytes we need +
skb metadata (difference is roughly 2kb per packet).
With a minimum of 4BG of RAM on the only SoC that has this NIC the
extra memory usage is negligible (a bit more on 64K pages)
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Roman Mashak says:

====================
Fix batched event generation for mirred action

When adding or deleting a batch of entries, the kernel sends upto
TCA_ACT_MAX_PRIO entries in an event to user space. However it does not
consider that the action sizes may vary and require different skb sizes.

For example :

% cat tc-batch.sh
TC="sudo /mnt/iproute2.git/tc/tc"

$TC actions flush action mirred
for i in `seq 1 $1`;
do
   cmd="action mirred egress redirect dev lo index $i "
   args=$args$cmd
done
$TC actions add $args
%
% ./tc-batch.sh 32
Error: Failed to fill netlink attributes while adding TC action.
We have an error talking to the kernel
%

patch 1 adds callback in tc_action_ops of mirred action, which calculates
the action size, and passes size to tcf_add_notify()/tcf_del_notify().

patch 2 updates the TDC test suite with relevant test cases.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add get_fill_size() routine used to calculate the action size
when building a batch of events.
Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

People are inclined to stuff random things into cb->args[n] because it
looks like an array of integers. Sometimes people even put u64s in there
with comments noting that a certain member takes up two slots. The
horror! Really this should mirror the usage of skb->cb, which are just
48 opaque bytes suitable for casting a struct. Then people can create
their usual casting macros for accessing strongly typed members of a
struct.

As a plus, this also gives us the same amount of space on 32bit and 64bit.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

The macro TIPC_BC_RETR_LIM is always used in combination with 'jiffies',
so we can just as well perform the addition in the macro itself. This
way, we get a few shorter code lines and one less line break.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

/proc/sys/net/ipv6/flowlabel_reflect assumes written value to be in the
range of 0 to 3. Use proc_dointvec_minmax instead of proc_dointvec.

Fixes: 323a53c4 ("ipv6: tcp: enable flowlabel reflection in some RST packets")
Signed-off-by: Eiichi Tsukata <devel@etsukata.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When user has configured a large number of virtual netdev, such
as 4K vlans, the carrier on/off operation of the real netdev
will also cause it's virtual netdev's link state to be processed
in linkwatch. Currently, the processing is done in a work queue,
which may cause rtnl locking starvation problem and worker
starvation problem for other work queue, such as irqfd_inject wq.

This patch releases the cpu when link watch worker has processed
a fixed number of netdev' link watch event, and schedule the
work queue again when there is still link watch event remaining.
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Ido Schimmel says:

====================
mlxsw: PTP timestamping support

This is the second patchset adding PTP support in mlxsw. Next patchset
will add PTP shapers which are required to maintain accuracy under rates
lower than 40Gb/s, while subsequent patchsets will add tracepoints and
selftests.

Petr says:

This patch set introduces support for retrieving and processing hardware
timestamps for PTP packets.

The way PTP timestamping works on Spectrum-1 is that there are two queues
associated with each front panel port. When a packet is timestamped, the
timestamp is put to one of the queues: timestamps for transmitted packets
to one and for received packets to the other. Activity on these queues is
signaled through the events PTP_ING_FIFO and PTP_EGR_FIFO.

Packets themselves arrive through two traps: PTP0 and PTP1. It is possible
to configure which PTP messages should be trapped under which PTP trap. On
Spectrum systems, mlxsw will use PTP0 for event messages (which need
timestamping), and PTP1 for general messages (which do not).

There are therefore four relevant traps: receive of PTP event resp. general
message, and receive of timestamp for a transmitted resp. received PTP
packet. The obvious point where to put the new logic is a custom listener
to the mentioned traps.

Besides handling ingress traffic (be in packets or timestamps), the driver
also needs to handle timestamping of transmitted packets. One option would
be to invoke the relevant logic from mlxsw_core_ptp_transmitted(). However
on Spectrum-2, the timestamps are actually delivered through the completion
queue, and for that reason this patchset opts to invoke the logic from the
PCI code, via core and the driver, to a chip-specific operation. That way
the invocation will be done in a place where a Spectrum-2 implementation
will have an opportunity to extract the timestamp.

As indicated above, the PTP FIFO signaling happens independently from
packet delivery. A packet corresponding to any given timestamp could be
delivered sooner or later than the timestamp itself. Additionally, the
queues are only four elements deep, and it is therefore possible that the
timestamp for a delivered packet never arrives at all. Similarly a PTP
packet might be dropped due to CPU traffic pressure, and never be delivered
even if the corresponding timestamp was.

The driver thus needs to hold a cache of as-yet-unmatched SKBs and
timestamps. The first piece to arrive (be it timestamp or SKB) is put to
this cache. When the other piece arrives, the timestamp is attached to the
SKB and that is passed on. A delayed work is run at regular intervals to
prune the old unmatched entries.

As mentioned above, the mechanism for timestamp delivery changes on
Spectrum-2, where timestamps are part of completion queue elements, and all
packets are timestamped. All this bookkeeping is therefore unnecessary on
Spectrum-2. For this reason, this patchset spends some time introducing
Spectrum-1 specific artifacts such as a possibility to register a given
trap only on Spectrum-1.

Patches #1-#4 describe new registers.

Patches #5 and #6 introduce the possibility to register certain traps
only on some systems. The list of Spectrum-1 specific traps is left empty
at this point.

Patch #7 hooks into packet receive path by registering PTP traps
and appropriate handlers (that however do nothing of substance yet).

Patch #8 adds a helper to allow storing custom data to SKB->cb.

Patch #9 adds a call into the PCI completion queue handler that invokes,
via core and spectrum code, a PTP transmit handler. (Which also does not do
anything interesting yet.)

Patch #10 introduces code to invoke PTP initialization and adds data types
for the cache of unmatched entries.

Patches #11 and #12 implement the timestamping itself. In #11, the PHC
spin_locks are converted to _bh variants, because unlike normal PHC path,
which runs in process context, timestamp processing runs as soft interrupt.
Then #12 introduces the code for saving and retrieval of unmatched entries,
invokes PTP classifier to identify packets of interest, registers timestamp
FIFO events, and handles decoding and attaching timestamps to packets.

Patch #13 introduces a garbage collector for left-behind entries that have
not been matched for about a second.

In patch #14, PTP message types are configured to arrive as PTP0
(events) or PTP1 (everything else) as appropriate. At this point, the PTP
packets start arriving through the traps, but because PTP is disabled and
there is no way to enable it yet, they are always just passed to the usual
receive path right away.

Finally patches #15 and #16 add the plumbing to actually make it possible
to enable this code through SIOCSHWTSTAMP ioctl, and to advertise the
hardware timestamping capabilities through ethtool.

v2:
- Patch #12:
    - In mlxsw_sp1_ptp_fifo_event_func(), post-increment when iterating over PTP
      FIFO records.
- Patch #14:
    - Change namespace of message type enumerators from MLXSW_ to MLXSW_SP_.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The get_ts_info callback is used for obtaining information about
timestamping capabilities of a network device. On Spectrum-1, implement
it to advertise the PHC and the capability to do HW timestamping, and
the supported RX and TX filters.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The SIOCSHWTSTAMP ioctl configures HW timestamping on a given port.
Dispatch the ioctls to per-chip handler (which add to ptp_ops). Find
which PTP messages need to be timestamped and configure MTPPPC
accordingly.

The SIOCGHWTSTAMP ioctl is getter for the current configuration.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Configure MTPTPT to set which message types should arrive under which
PTP trap, and MOGCR to clear the timestamp queue after its contents are
reported through PTP_ING_FIFO or PTP_EGR_FIFO.

With this configuration, PTP packets start arriving through the PTP
traps. However since timestamping is disabled by default and there is
currently no way to enable it, they will not be timestamped.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

On Spectrum-1, timestamped PTP packets and the corresponding timestamps
need to be kept in caches until both are available, at which point they are
matched up and packets forwarded as appropriate. However, not all packets
will ever see their timestamp, and not all timestamps will ever see their
packet. It is therefore necessary to dispose of such abandoned entries.

To that end, introduce a garbage collector to collect entries that have
not had their counterpart turn up within about a second. The GC
maintains a monotonously-increasing value of GC cycle. Every entry that
is put to the hash table is annotated with the GC cycle at which it
should be collected. When the GC runs, it walks the hash table, and
collects the objects according to their GC cycle annotation.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>