This patch adds supports for mdio bus. A later path adds PHYLIB
support on the top of this.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Link: https://patch.msgid.link/20240623235507.108147-7-fujita.tomonori@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

This patch adds basic Rx handling. The Rx logic uses three major data
structures; two ring buffers with NIC and one database. One ring
buffer is used to send information to NIC about memory to be stored
packets to be received. The other is used to get information from NIC
about received packets. The database is used to keep the information
about DMA mapping. After a packet arrived, the db is used to pass the
packet to the network stack.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Hans-Frieder Vogt <hfdevel@gmx.net>
Link: https://patch.msgid.link/20240623235507.108147-6-fujita.tomonori@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

This patch adds device specific structures to initialize the hardware
with basic Tx handling. The original driver loads the embedded
firmware in the header file. This driver is implemented to use the
firmware APIs.

The Tx logic uses three major data structures; two ring buffers with
NIC and one database. One ring buffer is used to send information
about packets to be sent for NIC. The other is used to get information
from NIC about packet that are sent. The database is used to keep the
information about DMA mapping. After a packet is sent, the db is used
to free the resource used for the packet.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Link: https://patch.msgid.link/20240623235507.108147-5-fujita.tomonori@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

This adds several defines to handle registers in Tehuti Networks
TN40xx chips for later patches.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Hans-Frieder Vogt <hfdevel@gmx.net>
Link: https://patch.msgid.link/20240623235507.108147-4-fujita.tomonori@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

This just adds the scaffolding for an ethernet driver for Tehuti
Networks TN40xx chips.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20240623235507.108147-3-fujita.tomonori@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Add the Edimax Vendor ID (0x1432) for an ethernet driver for Tehuti
Networks TN40xx chips. This ID can be used for Realtek 8180 and Ralink
rt28xx wireless drivers.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20240623235507.108147-2-fujita.tomonori@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Update the mt7530 binding with some minor updates that make the document
easier to read.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://patch.msgid.link/20240624211858.1990601-1-chris.packham@alliedtelesis.co.nzSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Ziwei Xiao says:

====================
gve: Add flow steering support

To support flow steering in GVE driver, there are two adminq changes
need to be made in advance.

The first one is adding adminq mutex lock, which is to allow the
incoming flow steering operations to be able to temporarily drop the
rtnl_lock to reduce the latency for registering flow rules among
several NICs at the same time. This could be achieved by the future
changes to reduce the drivers' dependencies on the rtnl lock for
particular ethtool ops.

The second one is to add the extended adminq command so that we can
support larger adminq command such as configure_flow_rule command. In
that patch, there is a new added function called
gve_adminq_execute_extended_cmd with the attribute of __maybe_unused.
That attribute will be removed in the third patch of this series where
it will use the previously unused function.

And the other three patches are needed for the actual flow steering
feature support in driver.
====================

Link: https://patch.msgid.link/20240625001232.1476315-1-ziweixiao@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Implement the ethtool commands that can be used to configure and query
flow-steering rules.

A large part of this change consists of translating the ethtool
representation of 'ntuples' to our internal gve_flow_rule and vice-versa
in the new created gve_flow_rule.c

Considering the possible large amount of flow rules, the driver doesn't
store all the rules locally. When the user runs 'ethtool -n <nic>' to
check the registered rules, the driver will send adminq command to
query a limited amount of rules/rule ids(that filled in a 4096 bytes dma
memory) at a time as a cache for the ethtool queries. The adminq query
commands will be repeated for several times until the ethtool has
queried all the needed rules.
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240625001232.1476315-6-ziweixiao@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Add new adminq commands for the driver to configure and query flow rules
that are stored in the device. Flow steering rules are assigned with a
location that determines the relative order of the rules.

Flow rules can run up to an order of millions. In such cases, storing
a full copy of the rules in the driver to prepare for the ethtool query
is infeasible while querying them from the device is better. That needs
to be optimized too so that we don't send a lot of adminq commands. The
solution here is to store a limited number of rules/rule ids in the
driver in a cache. Use dma_pool to allocate 4k bytes which lets device
write at most 46 flow rules(4096/88) or 1024 rule ids(4096/4) at a time.

For configuring flow rules, there are 3 sub-commands:
- ADD which adds a rule at the location supplied
- DEL which deletes the rule at the location supplied
- RESET which clears all currently active rules in the device

For querying flow rules, there are also 3 sub-commands:
- QUERY_RULES corresponds to ETHTOOL_GRXCLSRULE. It fills the rules in
  the allocated cache after querying the device
- QUERY_RULES_IDS corresponds to ETHTOOL_GRXCLSRLALL. It fills the
  rule_ids in the allocated cache after querying the device
- QUERY_RULES_STATS corresponds to ETHTOOL_GRXCLSRLCNT. It queries the
  device's current flow rule number and the supported max flow rule
  limit
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240625001232.1476315-5-ziweixiao@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Add a new device option to signal to the driver that the device supports
flow steering. This device option also carries the maximum number of
flow steering rules that the device can store.
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240625001232.1476315-4-ziweixiao@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

The adminq command is limited to 64 bytes per entry and it's 56 bytes
for the command itself at maximum. To support larger commands, we need
to dma_alloc a separate memory to put the command in that memory and
send the dma memory address instead of the actual command.

Introduce an extended adminq command to wrap the real command with the
inner opcode and the allocated dma memory address specified. Once the
device receives it, it can get the real command from the given dma
memory address. As designed with the device, all the extended commands
will use inner opcode larger than 0xFF.
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240625001232.1476315-3-ziweixiao@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

We were depending on the rtnl_lock to make sure there is only one adminq
command running at a time. But some commands may take too long to hold
the rtnl_lock, such as the upcoming flow steering operations. For such
situations, it can temporarily drop the rtnl_lock, and replace it for
these operations with a new adminq lock, which can ensure the adminq
command execution to be thread-safe.
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240625001232.1476315-2-ziweixiao@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Heng Qi says:

====================
ethtool: provide the dim profile fine-tuning channel

The NetDIM library provides excellent acceleration for many modern
network cards. However, the default profiles of DIM limits its maximum
capabilities for different NICs, so providing a way which the NIC can
be custom configured is necessary.

Currently, the way is based on the commonly used "ethtool -C".

For example,
on the server side, the virtio-net NIC with rx dim enabled has 8
queues and runs nginx.
The client uses the following command to send traffic to the server:
  ./wrk http://server_ip:80 -c 64 -t 5 -d 30

Then adjust the default rx-profile for server dim to

  {.usec =   1, .pkts = 256, .comps = n/a,},
  {.usec =   8, .pkts = 256, .comps = n/a,},
  {.usec =  30, .pkts = 256, .comps = n/a,},
  {.usec =  64, .pkts = 256, .comps = n/a,},
  {.usec = 128, .pkts = 256, .comps = n/a,}

The server PPS is improved by 20%+.
====================

Link: https://patch.msgid.link/20240621101353.107425-1-hengqi@linux.alibaba.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Virtio-net has different types of back-end device implementations.
In order to effectively optimize the dim library's gains for different
device implementations, let's use the new interface params to
initialize and query dim results from a customized profile list.
Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240621101353.107425-6-hengqi@linux.alibaba.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

DIM-related mode and work have been collected in one same place,
so new interfaces are added to provide convenience.
Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240621101353.107425-5-hengqi@linux.alibaba.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

The NetDIM library, currently leveraged by an array of NICs, delivers
excellent acceleration benefits. Nevertheless, NICs vary significantly
in their dim profile list prerequisites.

Specifically, virtio-net backends may present diverse sw or hw device
implementation, making a one-size-fits-all parameter list impractical.
On Alibaba Cloud, the virtio DPU's performance under the default DIM
profile falls short of expectations, partly due to a mismatch in
parameter configuration.

I also noticed that ice/idpf/ena and other NICs have customized
profilelist or placed some restrictions on dim capabilities.

Motivated by this, I tried adding new params for "ethtool -C" that provides
a per-device control to modify and access a device's interrupt parameters.

Usage
========
The target NIC is named ethx.

Assume that ethx only declares support for rx profile setting
(with DIM_PROFILE_RX flag set in profile_flags) and supports modification
of usec and pkt fields.

1. Query the currently customized list of the device

$ ethtool -c ethx
...
rx-profile:
{.usec =   1, .pkts = 256, .comps = n/a,},
{.usec =   8, .pkts = 256, .comps = n/a,},
{.usec =  64, .pkts = 256, .comps = n/a,},
{.usec = 128, .pkts = 256, .comps = n/a,},
{.usec = 256, .pkts = 256, .comps = n/a,}
tx-profile:   n/a

2. Tune
$ ethtool -C ethx rx-profile 1,1,n_2,n,n_3,3,n_4,4,n_n,5,n
"n" means do not modify this field.
$ ethtool -c ethx
...
rx-profile:
{.usec =   1, .pkts =   1, .comps = n/a,},
{.usec =   2, .pkts = 256, .comps = n/a,},
{.usec =   3, .pkts =   3, .comps = n/a,},
{.usec =   4, .pkts =   4, .comps = n/a,},
{.usec = 256, .pkts =   5, .comps = n/a,}
tx-profile:   n/a

3. Hint
If the device does not support some type of customized dim profiles,
the corresponding "n/a" will display.

If the "n/a" field is being modified, -EOPNOTSUPP will be reported.
Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240621101353.107425-4-hengqi@linux.alibaba.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

DIMLIB's capabilities are supplied by the dim, net_dim, and
rdma_dim objects, and dim's interfaces solely act as a base for
net_dim and rdma_dim and are not explicitly used anywhere else.
rdma_dim is utilized by the infiniband driver, while net_dim
is for network devices, excluding the soc/fsl driver.

In this patch, net_dim relies on some NET's interfaces, thus
DIMLIB needs to explicitly depend on the NET Kconfig.

The soc/fsl driver uses the functions provided by net_dim, so
it also needs to depend on NET.
Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240621101353.107425-3-hengqi@linux.alibaba.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Useful macros will be used effectively elsewhere.
These will be utilized in subsequent patches.
Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240621101353.107425-2-hengqi@linux.alibaba.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Geert Uytterhoeven says:

====================
ravb: Add MII support for R-Car V4M

All EtherAVB instances on R-Car Gen3/Gen4 SoCs support the RGMII
interface.  In addition, the first two EtherAVB instances on R-Car V4M
also support the MII interface, but this is not yet supported by the
driver.  This patch series adds support for MII on R-Car Gen4, after the
customary cleanup.

The corresponding pin control support is available in [1].

Compile-tested only, as all AVB interfaces on the Gray Hawk Single
development board are connected to RGMII PHYs.
No regressions on R-Car V4H.

[1] "[PATCH/RFC] pinctrl: renesas: r8a779h0: Add AVB MII pins and groups"
    https://lore.kernel.org/4a0a12227f2145ef53b18bc08f45b19dcd745fc6.1718378739.git.geert+renesas@glider.be/

v1: https://lore.kernel.org/f0ef3e00aec461beb33869ab69ccb44a23d78f51.1718378166.git.geert+renesas@glider.be
====================

Link: https://patch.msgid.link/cover.1719234830.git.geert+renesas@glider.beSigned-off-by: Jakub Kicinski <kuba@kernel.org>

All EtherAVB instances on R-Car Gen3/Gen4 SoCs support the RGMII
interface.  In addition, the first two EtherAVB instances on R-Car V4M
also support the MII interface, but this is not yet supported by the
driver.

Add support for MII on R-Car Gen4 by adding an R-Car Gen4-specific EMAC
initialization function that selects the MII clock instead of the RGMII
clock when the PHY interface is MII.  Note that all implementations of
EtherAVB on R-Car Gen4 SoCs have the APSR register, but only MII-capable
instances are documented to have the MIISELECT bit, which has a
documented value of zero when reserved.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://patch.msgid.link/3a21d1d6680864aa85afff9260234c2b8054020a.1719234830.git.geert+renesas@glider.beSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Move ravb_gen2_hw_info before ravb_gen3_hw_info to match
ravb_match_table[] order.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://patch.msgid.link/a76febe3737e26365a784e9193da9363f22aa550.1719234830.git.geert+renesas@glider.beSigned-off-by: Jakub Kicinski <kuba@kernel.org>

This place is fetching the stats, u64_stats_update_begin()/end()
should not be used, and the fetcher of stats is in the same context
as the updater of the stats, so don't need any protection
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Link: https://lore.kernel.org/20240621094552.53469-1-lirongqing@baidu.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

It seems that there is no definition for config IP_GRE, and it is not a
dependency of other configs, so remove it.

linux$ find -name Kconfig | xargs grep "IP_GRE"
<-- nothing

There is a IPV6_GRE config defined in net/ipv6/Kconfig. It only depends
on NET_IPGRE_DEMUX but not IP_GRE.
Signed-off-by: Yujie Liu <yujie.liu@intel.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20240624055539.2092322-1-yujie.liu@intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

This fixes a sparse warning.

Fixes: d18d3f0a ("l2tp: replace hlist with simple list for per-tunnel session list")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202406220754.evK8Hrjw-lkp@intel.com/Signed-off-by: James Chapman <jchapman@katalix.com>
Link: https://patch.msgid.link/20240624082945.1925009-1-jchapman@katalix.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Introduce an additional validation to ensure that the PPE index
is modified exclusively for mtk_eth ingress devices.
This primarily addresses the issue related
to WED operation with multiple PPEs.

Fixes: dee4dd10 ("net: ethernet: mtk_eth_soc: ppe: add support for multiple PPEs")
Signed-off-by: Elad Yifee <eladwf@gmail.com>
Link: https://lore.kernel.org/r/20240623175113.24437-1-eladwf@gmail.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

Vineeth Karumanchi says:

====================
net: macb: WOL enhancements

- Add provisioning for queue tie-off and queue disable during suspend.
- Add support for ARP packet types to WoL.
- Advertise WoL attributes by default.
- Extend MACB supported WoL modes to the PHY supported WoL modes.
- Deprecate magic-packet property.

v6: https://lore.kernel.org/netdev/20240617070413.2291511-1-vineeth.karumanchi@amd.com/
v5: https://lore.kernel.org/netdev/20240611162827.887162-1-vineeth.karumanchi@amd.com/
v4: https://lore.kernel.org/lkml/20240610053936.622237-1-vineeth.karumanchi@amd.com/
v3: https://lore.kernel.org/netdev/20240605102457.4050539-1-vineeth.karumanchi@amd.com/
v2: https://lore.kernel.org/netdev/20240222153848.2374782-1-vineeth.karumanchi@amd.com/
v1: https://lore.kernel.org/lkml/20240130104845.3995341-1-vineeth.karumanchi@amd.com/#t
====================

Link: https://lore.kernel.org/r/20240621045735.3031357-1-vineeth.karumanchi@amd.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

WOL modes such as magic-packet should be an OS policy.
By default, advertise supported modes and use ethtool to activate
the required mode.
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Extend wake-on LAN support with an ARP packet.

Currently, if PHY supports WOL, ethtool ignores the modes supported
by MACB. This change extends the WOL modes with MACB supported modes.

Advertise wake-on LAN supported modes by default without relying on
dt node. By default, wake-on LAN will be in disabled state.
Using ethtool, users can enable/disable or choose packet types.

For wake-on LAN via ARP, ensure the IP address is assigned and
report an error otherwise.
Co-developed-by: Harini Katakam <harini.katakam@amd.com>
Signed-off-by: Harini Katakam <harini.katakam@amd.com>
Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Tested-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> # on SAMA7G5
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Enable queue disable for Versal devices.
Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

When GEM is used as a wake device, it is not mandatory for the RX DMA
to be active. The RX engine in IP only needs to receive and identify
a wake packet through an interrupt. The wake packet is of no further
significance; hence, it is not required to be copied into memory.
By disabling RX DMA during suspend, we can avoid unnecessary DMA
processing of any incoming traffic.

During suspend, perform either of the below operations:

- tie-off/dummy descriptor: Disable unused queues by connecting
  them to a looped descriptor chain without free slots.

- queue disable: The newer IP version allows disabling individual queues.
Co-developed-by: Harini Katakam <harini.katakam@amd.com>
Signed-off-by: Harini Katakam <harini.katakam@amd.com>
Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Tested-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> # on SAMA7G5
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Kuniyuki Iwashima says:

====================
af_unix: Remove spin_lock_nested() and convert to lock_cmp_fn.

This series removes spin_lock_nested() in AF_UNIX and instead
defines the locking orders as functions tied to each lock by
lockdep_set_lock_cmp_fn().

When the defined function returns a negative value, lockdep
considers it will not cause deadlock.  (See ->cmp_fn() in
check_deadlock() and check_prev_add().)

When we cannot define the total ordering, we return -1 for
the allowed ordering and otherwise 0 as undefined. [0]

[0]: https://lore.kernel.org/netdev/thzkgbuwuo3knevpipu4rzsh5qgmwhklihypdgziiruabvh46f@uwdkpcfxgloo/

Changes:
  v4:
    * Patch 4
      * Make unix_state_lock_cmp_fn() symmetric.

  v3: https://lore.kernel.org/netdev/20240614200715.93150-1-kuniyu@amazon.com/
    * Patch 3
      * Cache sk->sk_state
      * s/unix_state_lock()/unix_state_unlock()/
    * Patch 8
      * Add embryo -> listener locking order

  v2: https://lore.kernel.org/netdev/20240611222905.34695-1-kuniyu@amazon.com/
   * Patch 1 & 2
      * Use (((l) > (r)) - ((l) < (r))) for comparison

  v1: https://lore.kernel.org/netdev/20240610223501.73191-1-kuniyu@amazon.com/
====================

Link: https://lore.kernel.org/r/20240620205623.60139-1-kuniyu@amazon.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

When (AF_UNIX, SOCK_STREAM) socket connect()s to a listening socket,
the listener's sk_peer_pid/sk_peer_cred are copied to the client in
copy_peercred().

Then, two sk_peer_locks are held there; one is client's and another
is listener's.

However, the latter is not needed because we hold the listner's
unix_state_lock() there and unix_listen() cannot update the cred
concurrently.

Let's drop the unnecessary spin_lock() and use the bare spin_lock()
for the client to protect concurrent read by getsockopt(SO_PEERCRED).
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

When (AF_UNIX, SOCK_STREAM) socket connect()s to a listening socket,
the listener's sk_peer_pid/sk_peer_cred are copied to the client in
copy_peercred().

Then, the client's sk_peer_pid and sk_peer_cred are always NULL, so
we need not call put_pid() and put_cred() there.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

init_peercred() is called in 3 places:

  1. socketpair() : both sockets
  2. connect()    : child socket
  3. listen()     : listening socket

The first two need not hold sk_peer_lock because no one can
touch the socket.

Let's set cred/pid without holding lock for the two cases and
rename the old init_peercred() to update_peercred() to properly
reflect the use case.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

While GC is cleaning up cyclic references by SCM_RIGHTS,
unix_collect_skb() collects skb in the socket's recvq.

If the socket is TCP_LISTEN, we need to collect skb in the
embryo's queue.  Then, both the listener's recvq lock and
the embroy's one are held.

The locking is always done in the listener -> embryo order.

Let's define it as unix_recvq_lock_cmp_fn() instead of using
spin_lock_nested().

Note that the reverse order is defined for consistency.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Commit 1971d13f ("af_unix: Suppress false-positive lockdep splat for
spin_lock() in __unix_gc().") added U_LOCK_GC_LISTENER for the old GC,
but it's no longer needed for the new GC.

Let's remove U_LOCK_GC_LISTENER and unix_state_lock_nested() as there's
no user.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

sk_diag_dump_icons() acquires embryo's lock by unix_state_lock_nested()
to fetch its peer.

The embryo's ->peer is set to NULL only when its parent listener is
close()d.  Then, unix_release_sock() is called for each embryo after
unlinking skb by skb_dequeue().

In sk_diag_dump_icons(), we hold the parent's recvq lock, so we need
not acquire unix_state_lock_nested(), and peer is always non-NULL.

Let's remove unnecessary unix_state_lock_nested() and non-NULL test
for peer.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

sk_diag_dump_peer() and sk_diag_dump() call unix_state_lock() for
sock_i_ino() which reads SOCK_INODE(sk->sk_socket)->i_ino, but it's
protected by sk->sk_callback_lock.

Let's remove unnecessary unix_state_lock().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

While a SOCK_(STREAM|SEQPACKET) socket connect()s to another, we hold
two locks of them by unix_state_lock() and unix_state_lock_nested() in
unix_stream_connect().

Before unix_state_lock_nested(), the following is guaranteed by checking
sk->sk_state:

  1. The first socket is TCP_LISTEN
  2. The second socket is not the first one
  3. Simultaneous connect() must fail

So, the client state can be TCP_CLOSE or TCP_LISTEN or TCP_ESTABLISHED.

Let's define the expected states as unix_state_lock_cmp_fn() instead of
using unix_state_lock_nested().

Note that 2. is detected by debug_spin_lock_before() and 3. cannot be
expressed as lock_cmp_fn.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>