Strict priority for the tx scheduler is by default in Linux driver, so the
tx-sched-sp property was removed in commit aed68640 ("net: stmmac:
platform: Delete a redundant condition branch").

This property is still in use in the following DT (and it will be removed
in a separate patch series):

- arch/arm64/boot/dts/freescale/imx8mp-beacon-som.dtsi
- arch/arm64/boot/dts/freescale/imx8mp-evk.dts
- arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi
- arch/arm64/boot/dts/qcom/sa8540p-ride.dts
- arch/arm64/boot/dts/qcom/sa8775p-ride.dts

There is no problem if that property is still used in the DTs above,
since, as seen above, it is a default property of the driver.
Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Adam Ford <aford173@gmail.com>
Link: https://lore.kernel.org/r/20240429092654.31390-2-f.suligoi@asem.itSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Eric Dumazet says:

====================
net: three additions to net_hotdata

This series moves three fast path sysctls to net_hotdata.

To avoid <net/hotdata.h> inclusion from <net/sock.h>,
create <net/proto_memory.h> to hold proto memory definitions.
====================

Link: https://lore.kernel.org/r/20240429134025.1233626-1-edumazet@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

sysctl_mem_pcpu_rsv is used in TCP fast path,
move it to net_hodata for better cache locality.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240429134025.1233626-6-edumazet@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Move some proto memory definitions out of <net/sock.h>

Very few files need them, and following patch
will include <net/hotdata.h> from <net/proto_memory.h>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240429134025.1233626-5-edumazet@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tcp_out_of_memory() has a single caller: tcp_check_oom().

Following patch will also make sk_memory_allocated()
not anymore visible from <net/sock.h> and <net/tcp.h>

Add const qualifier to sock argument of tcp_out_of_memory()
and tcp_check_oom().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240429134025.1233626-4-edumazet@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

sysctl_skb_defer_max is used in TCP fast path,
move it to net_hodata.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240429134025.1233626-3-edumazet@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

sysctl_max_skb_frags is used in TCP and MPTCP fast paths,
move it to net_hodata for better cache locality.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240429134025.1233626-2-edumazet@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

I added dst_rt6_info() in commit
e8dfd42c ("ipv6: introduce dst_rt6_info() helper")

This patch does a similar change for IPv4.

Instead of (struct rtable *)dst casts, we can use :

 #define dst_rtable(_ptr) \
             container_of_const(_ptr, struct rtable, dst)

Patch is smaller than IPv6 one, because IPv4 has skb_rtable() helper.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/20240429133009.1227754-1-edumazet@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Jakub Kicinski says:

====================
selftests: net: page_poll allocation error injection

Add a test for exercising driver memory allocation failure paths.
page pool is a bit tricky to inject errors into at the page allocator
level because of the bulk alloc and recycling, so add explicit error
injection support "in front" of the caches.

Add a test to exercise that using only the standard APIs.
This is the first useful test for the new tests with an endpoint.
There's no point testing netdevsim here, so this is also the first
HW-only test in Python.

I'm not super happy with the traffic generation using iperf3,
my initial approach was to use mausezahn. But it turned out to be
5x slower in terms of PPS. Hopefully this is good enough for now.

v1: https://lore.kernel.org/all/20240426232400.624864-1-kuba@kernel.org/
====================

Link: https://lore.kernel.org/r/20240429144426.743476-1-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Bugs in memory allocation failure paths are quite common.
Add a test exercising those paths based on qstat and page pool
failure hook.

Running on bnxt:

  # ./drivers/net/hw/pp_alloc_fail.py
  KTAP version 1
  1..1
  # ethtool -G change retval: success
  ok 1 pp_alloc_fail.test_pp_alloc
  # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0

I initially wrote this test to validate commit be43b748 ("net/mlx5e:
RX, Fix page_pool allocation failure recovery for striding rq") but mlx5
still doesn't have qstat. So I run it on bnxt, and while bnxt survives
I found the problem fixed in commit 73011773 ("eth: bnxt: fix counting
packets discarded due to OOM and netpoll").
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240429144426.743476-7-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

While we are not very interested in testing performance
it's useful to be able to generate a lot of traffic.
iperf is the simplest way of getting relatively high PPS.
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240429144426.743476-6-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

When picking TCP ports to use, avoid all below 10k.
This should lower the chance of collision or running
afoul whatever random policies may be on the host.
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240429144426.743476-5-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

The main use of the ip() wrapper over cmd() is that it can parse JSON.
cmd("ip -j link show") will return stdout as a string, and test has
to call json.loads(). With ip("link show", json=True) the return value
will be already parsed.

More tools (ethtool, bpftool etc.) support the --json switch.
To avoid having to wrap all of them individually create a tool()
helper.

Switch from -j to --json (for ethtool).
While at it consume the netns attribute at the ip() level.
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240429144426.743476-4-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

We created a separate directory for HW-only tests, recently.
Glue in the Python test library there, Python is a bit annoying
when it comes to using library code located "lower"
in the directory structure.

Reuse the Env class, but let tests require non-nsim setup.
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240429144426.743476-3-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Because of caching / recycling using the general page allocation
failures to induce errors in page pool allocation is very hard.
Add direct error injection support to page_pool_alloc_pages().
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240429144426.743476-2-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Jakub reports that some tests fail on netdev CI when executed in a debug
kernel.

Increase test timeout to 30m, this should hopefully be enough.
Also reduce test duration where possible for "slow" machines.
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20240429105736.22677-1-fw@strlen.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

sfp_select_interface() does not modify its link_modes argument, so
make this a const pointer.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://lore.kernel.org/r/E1s15s0-00AHyq-8E@rmk-PC.armlinux.org.ukSigned-off-by: Paolo Abeni <pabeni@redhat.com>

Allow use of 2500base-X interface mode for PHY modules that support
2500base-T.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://lore.kernel.org/r/E1s15rv-00AHyk-5S@rmk-PC.armlinux.org.ukSigned-off-by: Paolo Abeni <pabeni@redhat.com>

Add a debugging print in phylink_validate_phy() when we detect that the
PHY has not supplied a possible_interfaces bitmap.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://lore.kernel.org/r/E1s15rq-00AHye-22@rmk-PC.armlinux.org.ukSigned-off-by: Paolo Abeni <pabeni@redhat.com>

Convert realtek to provide its own phylink MAC operations, thus
avoiding the shim layer in DSA's port.c. We need to provide a stub for
the mandatory mac_config() method for rtl8366rb.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/E1s11qJ-00AHi0-Kk@rmk-PC.armlinux.org.ukSigned-off-by: Paolo Abeni <pabeni@redhat.com>

DSA initalises the ds->num_ports amount of ports in
dsa_switch_touch_ports(). When the PHY muxing feature is in use, port 5
won't be defined in the device tree. Because of this, the type member of
the dsa_port structure for this port will be assigned DSA_PORT_TYPE_UNUSED.
The dsa_port_setup() function calls ds->ops->port_disable() when the port
type is DSA_PORT_TYPE_UNUSED.

The MT7530_P5_DIS bit is unset in mt7530_setup() when PHY muxing is being
used. mt7530_port_disable() which is assigned to ds->ops->port_disable() is
called afterwards. Currently, mt7530_port_disable() sets MT7530_P5_DIS
which breaks network connectivity when PHY muxing is being used.

Therefore, do not set MT7530_P5_DIS when PHY muxing is being used.

Fixes: 377174c5 ("net: dsa: mt7530: move MT753X_MTRAP operations for MT7530")
Reported-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240428-for-netnext-mt7530-do-not-disable-port5-when-phy-muxing-v2-1-bb7c37d293f8@arinc9.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

Wen Gu says:

====================
net/smc: SMC intra-OS shortcut with loopback-ism

This patch set acts as the second part of the new version of [1] (The first
part can be referred from [2]), the updated things of this version are listed
at the end.

- Background

SMC-D is now used in IBM z with ISM function to optimize network interconnect
for intra-CPC communications. Inspired by this, we try to make SMC-D available
on the non-s390 architecture through a software-implemented Emulated-ISM device,
that is the loopback-ism device here, to accelerate inter-process or
inter-containers communication within the same OS instance.

- Design

This patch set includes 3 parts:

 - Patch #1: some prepare work for loopback-ism.
 - Patch #2-#7: implement loopback-ism device and adapt SMC-D for it.
   loopback-ism now serves only SMC and no userspace interfaces exposed.
 - Patch #8-#11: memory copy optimization for intra-OS scenario.

The loopback-ism device is designed as an ISMv2 device and not be limited to
a specific net namespace, ends of both inter-process connection (1/1' in diagram
below) or inter-container connection (2/2' in diagram below) can find the same
available loopback-ism and choose it during the CLC handshake.

 Container 1 (ns1)                              Container 2 (ns2)
 +-----------------------------------------+    +-------------------------+
 | +-------+      +-------+      +-------+ |    |        +-------+        |
 | | App A |      | App B |      | App C | |    |        | App D |<-+     |
 | +-------+      +---^---+      +-------+ |    |        +-------+  |(2') |
 |     |127.0.0.1 (1')|             |192.168.0.11       192.168.0.12|     |
 |  (1)|   +--------+ | +--------+  |(2)   |    | +--------+   +--------+ |
 |     `-->|   lo   |-` |  eth0  |<-`      |    | |   lo   |   |  eth0  | |
 +---------+--|---^-+---+-----|--+---------+    +-+--------+---+-^------+-+
              |   |           |                                  |
 Kernel       |   |           |                                  |
 +----+-------v---+-----------v----------------------------------+---+----+
 |    |                            TCP                               |    |
 |    |                                                              |    |
 |    +--------------------------------------------------------------+    |
 |                                                                        |
 |                           +--------------+                             |
 |                           | smc loopback |                             |
 +---------------------------+--------------+-----------------------------+

loopback-ism device creates DMBs (shared memory) for each connection peer.
Since data transfer occurs within the same kernel, the sndbuf of each peer
is only a descriptor and point to the same memory region as peer DMB, so that
the data copy from sndbuf to peer DMB can be avoided in loopback-ism case.

 Container 1 (ns1)                              Container 2 (ns2)
 +-----------------------------------------+    +-------------------------+
 | +-------+                               |    |        +-------+        |
 | | App C |-----+                         |    |        | App D |        |
 | +-------+     |                         |    |        +-^-----+        |
 |               |                         |    |          |              |
 |           (2) |                         |    |     (2') |              |
 |               |                         |    |          |              |
 +---------------|-------------------------+    +----------|--------------+
                 |                                         |
 Kernel          |                                         |
 +---------------|-----------------------------------------|--------------+
 | +--------+ +--v-----+                           +--------+ +--------+  |
 | |dmb_desc| |snd_desc|                           |dmb_desc| |snd_desc|  |
 | +-----|--+ +--|-----+                           +-----|--+ +--------+  |
 | +-----|--+    |                                 +-----|--+             |
 | | DMB C  |    +---------------------------------| DMB D  |             |
 | +--------+                                      +--------+             |
 |                                                                        |
 |                           +--------------+                             |
 |                           | smc loopback |                             |
 +---------------------------+--------------+-----------------------------+

- Benchmark Test

 * Test environments:
      - VM with Intel Xeon Platinum 8 core 2.50GHz, 16 GiB mem.
      - SMC sndbuf/DMB size 1MB.

 * Test object:
      - TCP: run on TCP loopback.
      - SMC lo: run on SMC loopback-ism.

1. ipc-benchmark (see [3])

 - ./<foo> -c 1000000 -s 100

                            TCP                  SMC-lo
Message
rate (msg/s)              84991                  151293(+78.01%)

2. sockperf

 - serv: <smc_run> sockperf sr --tcp
 - clnt: <smc_run> sockperf { tp | pp } --tcp --msg-size={ 64000 for tp | 14 for pp } -i 127.0.0.1 -t 30

                            TCP                  SMC-lo
Bandwidth(MBps)        5033.569                7987.732(+58.69%)
Latency(us)               5.986                   3.398(-43.23%)

3. nginx/wrk

 - serv: <smc_run> nginx
 - clnt: <smc_run> wrk -t 8 -c 1000 -d 30 http://127.0.0.1:80

                           TCP                   SMC-lo
Requests/s           187951.76                267107.90(+42.12%)

4. redis-benchmark

 - serv: <smc_run> redis-server
 - clnt: <smc_run> redis-benchmark -h 127.0.0.1 -q -t set,get -n 400000 -c 200 -d 1024

                           TCP                   SMC-lo
GET(Requests/s)       86132.64                118133.49(+37.15%)
SET(Requests/s)       87374.40                122887.86(+40.65%)

Change log:
v7->v6
- Patch #2: minor: remove unnecessary 'return' of inline smc_loopback_exit().
- Patch #10: minor: directly return 0 instead of 'rc' in smcd_cdc_msg_send().
- all: collect the Reviewed-by tags.

v6->RFC v5
Link: https://lore.kernel.org/netdev/20240414040304.54255-1-guwen@linux.alibaba.com/
- Patch #2: make the use of CONFIG_SMC_LO cleaner.
- Patch #5: mark some smcd_ops that loopback-ism doesn't support as
  optional and check for the support when they are called.
- Patch #7: keep loopback-ism at the beginning of the SMC-D device list.
- Some expression changes in commit logs and comments.

RFC v5->RFC v4:
Link: https://lore.kernel.org/netdev/20240324135522.108564-1-guwen@linux.alibaba.com/
- Patch #2: minor changes in description of config SMC_LO and comments.
- Patch #10: minor changes in comments and if(smc_ism_support_dmb_nocopy())
  check in smcd_cdc_msg_send().
- Patch #3: change smc_lo_generate_id() to smc_lo_generate_ids() and SMC_LO_CHID
  to SMC_LO_RESERVED_CHID.
- Patch #5: memcpy while holding the ldev->dmb_ht_lock.
- Some expression changes in commit logs.

RFC v4->v3:
Link: https://lore.kernel.org/netdev/20240317100545.96663-1-guwen@linux.alibaba.com/
- The merge window of v6.9 is open, so post this series as an RFC.
- Patch #6: since some information fed back by smc_nl_handle_smcd_dev() dose
  not apply to Emulated-ISM (including loopback-ism here), loopback-ism is
  not exposed through smc netlink for the time being. we may refactor this
  part when smc netlink interface is updated.

v3->v2:
Link: https://lore.kernel.org/netdev/20240312142743.41406-1-guwen@linux.alibaba.com/
- Patch #11: use tasklet_schedule(&conn->rx_tsklet) instead of smcd_cdc_rx_handler()
  to avoid possible recursive locking of conn->send_lock and use {read|write}_lock_bh()
  to acquire dmb_ht_lock.

v2->v1:
Link: https://lore.kernel.org/netdev/20240307095536.29648-1-guwen@linux.alibaba.com/
- All the patches: changed the term virtual-ISM to Emulated-ISM as defined by SMCv2.1.
- Patch #3: optimized the description of SMC_LO config. Avoid exposing loopback-ism
  to sysfs and remove all the knobs until future definition clear.
- Patch #3: try to make lockdep happy by using read_lock_bh() in smc_lo_move_data().
- Patch #6: defaultly use physical contiguous DMB buffers.
- Patch #11: defaultly enable DMB no-copy for loopback-ism and free the DMB in
  unregister_dmb or detach_dmb when dmb_node->refcnt reaches 0, instead of using
  wait_event to keep waiting in unregister_dmb.

v1->RFC:
Link: https://lore.kernel.org/netdev/20240111120036.109903-1-guwen@linux.alibaba.com/
- Patch #9: merge rx_bytes and tx_bytes as xfer_bytes statistics:
  /sys/devices/virtual/smc/loopback-ism/xfer_bytes
- Patch #10: add support_dmb_nocopy operation to check if SMC-D device supports
  merging sndbuf with peer DMB.
- Patch #13 & #14: introduce loopback-ism device control of DMB memory type and
  control of whether to merge sndbuf and DMB. They can be respectively set by:
  /sys/devices/virtual/smc/loopback-ism/dmb_type
  /sys/devices/virtual/smc/loopback-ism/dmb_copy
  The motivation for these two control is that a performance bottleneck was
  found when using vzalloced DMB and sndbuf is merged with DMB, and there are
  many CPUs and CONFIG_HARDENED_USERCOPY is set [4]. The bottleneck is caused
  by the lock contention in vmap_area_lock [5] which is involved in memcpy_from_msg()
  or memcpy_to_msg(). Currently, Uladzislau Rezki is working on mitigating the
  vmap lock contention [6]. It has significant effects, but using virtual memory
  still has additional overhead compared to using physical memory.
  So this new version provides controls of dmb_type and dmb_copy to suit
  different scenarios.
- Some minor changes and comments improvements.

RFC->old version([1]):
Link: https://lore.kernel.org/netdev/1702214654-32069-1-git-send-email-guwen@linux.alibaba.com/
- Patch #1: improve the loopback-ism dump, it shows as follows now:
  # smcd d
  FID  Type  PCI-ID        PCHID  InUse  #LGs  PNET-ID
  0000 0     loopback-ism  ffff   No        0
- Patch #3: introduce the smc_ism_set_v2_capable() helper and set
  smc_ism_v2_capable when ISMv2 or virtual ISM is registered,
  regardless of whether there is already a device in smcd device list.
- Patch #3: loopback-ism will be added into /sys/devices/virtual/smc/loopback-ism/.
- Patch #8: introduce the runtime switch /sys/devices/virtual/smc/loopback-ism/active
  to activate or deactivate the loopback-ism.
- Patch #9: introduce the statistics of loopback-ism by
  /sys/devices/virtual/smc/loopback-ism/{{tx|rx}_tytes|dmbs_cnt}.
- Some minor changes and comments improvements.

[1] https://lore.kernel.org/netdev/1695568613-125057-1-git-send-email-guwen@linux.alibaba.com/
[2] https://lore.kernel.org/netdev/20231219142616.80697-1-guwen@linux.alibaba.com/
[3] https://github.com/goldsborough/ipc-bench
[4] https://lore.kernel.org/all/3189e342-c38f-6076-b730-19a6efd732a5@linux.alibaba.com/
[5] https://lore.kernel.org/all/238e63cd-e0e8-4fbf-852f-bc4d5bc35d5a@linux.alibaba.com/
[6] https://lore.kernel.org/all/20240102184633.748113-1-urezki@gmail.com/
====================

Link: https://lore.kernel.org/r/20240428060738.60843-1-guwen@linux.alibaba.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

This implements operations related to merging sndbuf with peer DMB in
loopback-ism. The DMB won't be freed until no sndbuf is attached to it.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

If the local sndbuf shares the same physical memory with peer DMB,
the cursor update processing needs to be adapted to ensure that the
data to be consumed won't be overwritten.

So in this case, the fin_curs and sndbuf_space that were originally
updated after sending the CDC message should be modified to not be
update until the peer updates cons_curs.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

If the device used by SMC-D supports merging local sndbuf to peer DMB,
then create sndbuf descriptor and attach it to peer DMB once peer
token is obtained, and detach and free the sndbuf descriptor when the
connection is freed.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

In some scenarios using Emulated-ISM device, sndbuf can share the same
physical memory region with peer DMB to avoid data copy from one side
to the other. In such case the sndbuf is only a descriptor that
describes the shared memory and does not actually occupy memory, it's
more like a ghost buffer.

      +----------+                     +----------+
      | socket A |                     | socket B |
      +----------+                     +----------+
            |                               |
       +--------+                       +--------+
       | sndbuf |                       |  DMB   |
       |  desc  |                       |  desc  |
       +--------+                       +--------+
            |                               |
            |                          +----v-----+
            +-------------------------->  memory  |
                                       +----------+

So here introduces three new SMC-D device operations to check if this
feature is supported by device, and to {attach|detach} ghost sndbuf to
peer DMB. For now only loopback-ism supports this.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

After the loopback-ism device is ready, add it to the SMC-D device list
as an ISMv2 device, and always keep it at the beginning to ensure it is
preferred for providing a shortcut for data transfer within the same
kernel.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Since loopback-ism is not a PCI device, the PCI information fed back by
smc_nl_handle_smcd_dev() does not apply to loopback-ism. So currently
ignore loopback-ism when dumping SMC-D devices. The netlink function of
loopback-ism will be refactored when SMC netlink interface is updated.

Link: https://lore.kernel.org/r/caab067b-f5c3-490f-9259-262624c236b4@linux.ibm.com/Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Some operations are not supported by new introduced Emulated-ISM, so
mark them as optional and check if the device supports them when called.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

This implements DMB (un)registration and data move operations of
loopback-ism device.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

This implements operations related to IDs for the loopback-ism device.
loopback-ism uses an Extended GID that is a 128-bit GID instead of the
existing ISM 64-bit GID, and uses the CHID defined with the reserved
value 0xFFFF.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

This introduces a kind of Emulated-ISM device named loopback-ism for
SMCv2.1. The loopback-ism device is currently exclusive for SMC usage,
and aims to provide an SMC shortcut for sockets within the same kernel,
leading to improved intra-OS traffic performance. Configuration of this
feature is managed through the config SMC_LO.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Gerd Bayer <gbayer@linux.ibm.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

The struct 'ism_client' is specialized for s390 platform firmware ISM.
So replace it with 'void' to make SMCD DMB registration helper generic
for both Emulated-ISM and existing ISM.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows [1][2].

As the "ids" variable is a pointer to "struct sctp_assoc_ids" and this
structure ends in a flexible array:

struct sctp_assoc_ids {
	[...]
	sctp_assoc_t	gaids_assoc_id[];
};

the preferred way in the kernel is to use the struct_size() helper to
do the arithmetic instead of the calculation "size + size * count" in
the kmalloc() function.

Also, refactor the code adding the "ids_size" variable to avoid sizing
twice.

This way, the code is more readable and safer.

This code was detected with the help of Coccinelle, and audited and
modified manually.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
Link: https://github.com/KSPP/linux/issues/160 [2]
Signed-off-by: Erick Archer <erick.archer@outlook.com>
Acked-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/PAXPR02MB724871DB78375AB06B5171C88B152@PAXPR02MB7248.eurprd02.prod.outlook.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

Xuan Zhuo says:

====================
virtio-net: support device stats

https://github.com/oasis-tcs/virtio-spec/commit/42f389989823039724f95bbbd243291ab0064f82

The virtio net supports to get device stats.
====================

Link: https://lore.kernel.org/r/20240426033928.77778-1-xuanzhuo@linux.alibaba.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

To enhance functionality, we now support reporting statistics through
the netdev-generic netlink (netdev-genl) queue stats interface. However,
this does not extend to all statistics, so a new field, qstat_offset,
has been introduced. This field determines which statistics should be
reported via netdev-genl queue stats.

Given that queue stats are retrieved individually per queue, it's
necessary for the virtnet_get_hw_stats() function to be capable of
fetching statistics for a specific queue.

As the document https://docs.kernel.org/next/networking/statistics.html#notes-for-driver-authors

We should not duplicate the stats which get reported via the netlink API in
ethtool. If the stats are for queue stat, that will not be reported by
ethtool -S.

python3 ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml
    --dump qstats-get --json '{"scope": "queue"}'
[{'ifindex': 2,
  'queue-id': 0,
  'queue-type': 'rx',
  'rx-bytes': 157844011,
  'rx-csum-bad': 0,
  'rx-csum-none': 0,
  'rx-csum-unnecessary': 2195386,
  'rx-hw-drop-overruns': 0,
  'rx-hw-drop-ratelimits': 0,
  'rx-hw-drops': 12964,
  'rx-packets': 598929},
 {'ifindex': 2,
  'queue-id': 0,
  'queue-type': 'tx',
  'tx-bytes': 1938511,
  'tx-csum-none': 0,
  'tx-hw-drop-errors': 0,
  'tx-hw-drop-ratelimits': 0,
  'tx-hw-drops': 0,
  'tx-needs-csum': 61263,
  'tx-packets': 15515}]
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

These stats are commonly. Support reporting those via netdev-genl queue
stats.

name: rx-hw-drops
name: rx-hw-drop-overruns
name: rx-csum-unnecessary
name: rx-csum-none
name: rx-csum-bad
name: rx-hw-gro-packets
name: rx-hw-gro-bytes
name: rx-hw-gro-wire-packets
name: rx-hw-gro-wire-bytes
name: rx-hw-drop-ratelimits
name: tx-hw-drops
name: tx-hw-drop-errors
name: tx-csum-none
name: tx-needs-csum
name: tx-hw-gso-packets
name: tx-hw-gso-bytes
name: tx-hw-gso-wire-packets
name: tx-hw-gso-wire-bytes
name: tx-hw-drop-ratelimits
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Now, we just show the stats of every queue.

But for the user, the total values of every stat may are valuable.

NIC statistics:
     rx_packets: 373522
     rx_bytes: 85919736
     rx_drops: 0
     rx_xdp_packets: 0
     rx_xdp_tx: 0
     rx_xdp_redirects: 0
     rx_xdp_drops: 0
     rx_kicks: 11125
     rx_hw_notifications: 0
     rx_hw_packets: 1325870
     rx_hw_bytes: 263348963
     rx_hw_interrupts: 0
     rx_hw_drops: 1451
     rx_hw_drop_overruns: 0
     rx_hw_csum_valid: 1325870
     rx_hw_needs_csum: 1325870
     rx_hw_csum_none: 0
     rx_hw_csum_bad: 0
     rx_hw_ratelimit_packets: 0
     rx_hw_ratelimit_bytes: 0
     tx_packets: 10050
     tx_bytes: 1230176
     tx_xdp_tx: 0
     tx_xdp_tx_drops: 0
     tx_kicks: 10050
     tx_timeouts: 0
     tx_hw_notifications: 0
     tx_hw_packets: 32281
     tx_hw_bytes: 4315590
     tx_hw_interrupts: 0
     tx_hw_drops: 0
     tx_hw_drop_malformed: 0
     tx_hw_csum_none: 0
     tx_hw_needs_csum: 32281
     tx_hw_ratelimit_packets: 0
     tx_hw_ratelimit_bytes: 0
     rx0_packets: 373522
     rx0_bytes: 85919736
     rx0_drops: 0
     rx0_xdp_packets: 0
     rx0_xdp_tx: 0
     rx0_xdp_redirects: 0
     rx0_xdp_drops: 0
     rx0_kicks: 11125
     rx0_hw_notifications: 0
     rx0_hw_packets: 1325870
     rx0_hw_bytes: 263348963
     rx0_hw_interrupts: 0
     rx0_hw_drops: 1451
     rx0_hw_drop_overruns: 0
     rx0_hw_csum_valid: 1325870
     rx0_hw_needs_csum: 1325870
     rx0_hw_csum_none: 0
     rx0_hw_csum_bad: 0
     rx0_hw_ratelimit_packets: 0
     rx0_hw_ratelimit_bytes: 0
     tx0_packets: 10050
     tx0_bytes: 1230176
     tx0_xdp_tx: 0
     tx0_xdp_tx_drops: 0
     tx0_kicks: 10050
     tx0_timeouts: 0
     tx0_hw_notifications: 0
     tx0_hw_packets: 32281
     tx0_hw_bytes: 4315590
     tx0_hw_interrupts: 0
     tx0_hw_drops: 0
     tx0_hw_drop_malformed: 0
     tx0_hw_csum_none: 0
     tx0_hw_needs_csum: 32281
     tx0_hw_ratelimit_packets: 0
     tx0_hw_ratelimit_bytes: 0
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

In the last commit, we introduced some helpers for device stats.
And the drivers stats are realized by the open code.
This commit make the helpers to support driver stats.
Then we can have the unify helper for device and driver stats.
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

As the spec https://github.com/oasis-tcs/virtio-spec/commit/42f389989823039724f95bbbd243291ab0064f82

make virtio-net support getting the stats from the device by ethtool -S
<eth0>.

NIC statistics:
     rx0_packets: 582951
     rx0_bytes: 155307077
     rx0_drops: 0
     rx0_xdp_packets: 0
     rx0_xdp_tx: 0
     rx0_xdp_redirects: 0
     rx0_xdp_drops: 0
     rx0_kicks: 17007
     rx0_hw_packets: 2179409
     rx0_hw_bytes: 510015040
     rx0_hw_notifications: 0
     rx0_hw_interrupts: 0
     rx0_hw_needs_csum: 2179409
     rx0_hw_ratelimit_bytes: 0
     tx0_packets: 15361
     tx0_bytes: 1918970
     tx0_xdp_tx: 0
     tx0_xdp_tx_drops: 0
     tx0_kicks: 15361
     tx0_timeouts: 0
     tx0_hw_packets: 32272
     tx0_hw_bytes: 4311698
     tx0_hw_notifications: 0
     tx0_hw_interrupts: 0
     tx0_hw_ratelimit_bytes: 0

The follow stats are hidden, there are exported by the queue stat API
in the subsequent comment.

    VIRTNET_STATS_DESC_RX(basic, drops)
    VIRTNET_STATS_DESC_RX(basic, drop_overruns),
    VIRTNET_STATS_DESC_TX(basic, drops),
    VIRTNET_STATS_DESC_TX(basic, drop_malformed),
    VIRTNET_STATS_DESC_RX(csum, csum_valid),
    VIRTNET_STATS_DESC_RX(csum, csum_none),
    VIRTNET_STATS_DESC_RX(csum, csum_bad),
    VIRTNET_STATS_DESC_TX(csum, needs_csum),
    VIRTNET_STATS_DESC_TX(csum, csum_none),
    VIRTNET_STATS_DESC_RX(gso, gso_packets),
    VIRTNET_STATS_DESC_RX(gso, gso_bytes),
    VIRTNET_STATS_DESC_RX(gso, gso_packets_coalesced),
    VIRTNET_STATS_DESC_RX(gso, gso_bytes_coalesced),
    VIRTNET_STATS_DESC_TX(gso, gso_packets),
    VIRTNET_STATS_DESC_TX(gso, gso_bytes),
    VIRTNET_STATS_DESC_TX(gso, gso_segments),
    VIRTNET_STATS_DESC_TX(gso, gso_segments_bytes),
    VIRTNET_STATS_DESC_RX(speed, ratelimit_packets),
    VIRTNET_STATS_DESC_TX(speed, ratelimit_packets),
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>