Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 238 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/v4l/open.rst b/Documentation/userspace-api/media/v4l/open.rst
new file mode 100644
index 000000000..18bfb9b81
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/open.rst
@@ -0,0 +1,238 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: V4L
+
+.. _open:
+
+***************************
+Opening and Closing Devices
+***************************
+
+.. _v4l2_hardware_control:
+
+Controlling a hardware peripheral via V4L2
+==========================================
+
+Hardware that is supported using the V4L2 uAPI often consists of multiple
+devices or peripherals, each of which have their own driver.
+
+The bridge driver exposes one or more V4L2 device nodes
+(see :ref:`v4l2_device_naming`).
+
+There are other drivers providing support for other components of
+the hardware, which may also expose device nodes, called V4L2 sub-devices.
+
+When such V4L2 sub-devices are exposed, they allow controlling those
+other hardware components - usually connected via a serial bus (like
+I²C, SMBus or SPI). Depending on the bridge driver, those sub-devices
+can be controlled indirectly via the bridge driver or explicitly via
+the :ref:`Media Controller <media_controller>` and via the
+:ref:`V4L2 sub-devices <subdev>`.
+
+The devices that require the use of the
+:ref:`Media Controller <media_controller>` are called **MC-centric**
+devices. The devices that are fully controlled via V4L2 device nodes
+are called **video-node-centric**.
+
+Userspace can check if a V4L2 hardware peripheral is MC-centric by
+calling :ref:`VIDIOC_QUERYCAP` and checking the
+:ref:`device_caps field <device-capabilities>`.
+
+If the device returns ``V4L2_CAP_IO_MC`` flag at ``device_caps``,
+then it is MC-centric, otherwise, it is video-node-centric.
+
+It is required for MC-centric drivers to identify the V4L2
+sub-devices and to configure the pipelines via the
+:ref:`media controller API <media_controller>` before using the peripheral.
+Also, the sub-devices' configuration shall be controlled via the
+:ref:`sub-device API <subdev>`.
+
+.. note::
+
+   A video-node-centric may still provide media-controller and
+   sub-device interfaces as well.
+
+  However, in that case the media-controller and the sub-device
+  interfaces are read-only and just provide information about the
+  device. The actual configuration is done via the video nodes.
+
+.. _v4l2_device_naming:
+
+V4L2 Device Node Naming
+=======================
+
+V4L2 drivers are implemented as kernel modules, loaded manually by the
+system administrator or automatically when a device is first discovered.
+The driver modules plug into the ``videodev`` kernel module. It provides
+helper functions and a common application interface specified in this
+document.
+
+Each driver thus loaded registers one or more device nodes with major
+number 81. Minor numbers are allocated dynamically unless the kernel
+is compiled with the kernel option CONFIG_VIDEO_FIXED_MINOR_RANGES.
+In that case minor numbers are allocated in ranges depending on the
+device node type.
+
+The device nodes supported by the Video4Linux subsystem are:
+
+======================== ====================================================
+Default device node name Usage
+======================== ====================================================
+``/dev/videoX``		 Video and metadata for capture/output devices
+``/dev/vbiX``		 Vertical blank data (i.e. closed captions, teletext)
+``/dev/radioX``		 Radio tuners and modulators
+``/dev/swradioX``	 Software Defined Radio tuners and modulators
+``/dev/v4l-touchX``	 Touch sensors
+``/dev/v4l-subdevX``	 Video sub-devices (used by sensors and other
+			 components of the hardware peripheral)\ [#]_
+======================== ====================================================
+
+Where ``X`` is a non-negative integer.
+
+.. note::
+
+   1. The actual device node name is system-dependent, as udev rules may apply.
+   2. There is no guarantee that ``X`` will remain the same for the same
+      device, as the number depends on the device driver's probe order.
+      If you need an unique name, udev default rules produce
+      ``/dev/v4l/by-id/`` and ``/dev/v4l/by-path/`` directories containing
+      links that can be used uniquely to identify a V4L2 device node::
+
+	$ tree /dev/v4l
+	/dev/v4l
+	├── by-id
+	│   └── usb-OmniVision._USB_Camera-B4.04.27.1-video-index0 -> ../../video0
+	└── by-path
+	    └── pci-0000:00:14.0-usb-0:2:1.0-video-index0 -> ../../video0
+
+.. [#] **V4L2 sub-device nodes** (e. g. ``/dev/v4l-subdevX``) use a different
+       set of system calls, as covered at :ref:`subdev`.
+
+Many drivers support "video_nr", "radio_nr" or "vbi_nr" module
+options to select specific video/radio/vbi node numbers. This allows the
+user to request that the device node is named e.g. /dev/video5 instead
+of leaving it to chance. When the driver supports multiple devices of
+the same type more than one device node number can be assigned,
+separated by commas:
+
+.. code-block:: none
+
+   # modprobe mydriver video_nr=0,1 radio_nr=0,1
+
+In ``/etc/modules.conf`` this may be written as:
+
+::
+
+    options mydriver video_nr=0,1 radio_nr=0,1
+
+When no device node number is given as module option the driver supplies
+a default.
+
+Normally udev will create the device nodes in /dev automatically for
+you. If udev is not installed, then you need to enable the
+CONFIG_VIDEO_FIXED_MINOR_RANGES kernel option in order to be able to
+correctly relate a minor number to a device node number. I.e., you need
+to be certain that minor number 5 maps to device node name video5. With
+this kernel option different device types have different minor number
+ranges. These ranges are listed in :ref:`devices`.
+
+The creation of character special files (with mknod) is a privileged
+operation and devices cannot be opened by major and minor number. That
+means applications cannot *reliably* scan for loaded or installed
+drivers. The user must enter a device name, or the application can try
+the conventional device names.
+
+.. _related:
+
+Related Devices
+===============
+
+Devices can support several functions. For example video capturing, VBI
+capturing and radio support.
+
+The V4L2 API creates different V4L2 device nodes for each of these functions.
+
+The V4L2 API was designed with the idea that one device node could
+support all functions. However, in practice this never worked: this
+'feature' was never used by applications and many drivers did not
+support it and if they did it was certainly never tested. In addition,
+switching a device node between different functions only works when
+using the streaming I/O API, not with the
+:c:func:`read()`/\ :c:func:`write()` API.
+
+Today each V4L2 device node supports just one function.
+
+Besides video input or output the hardware may also support audio
+sampling or playback. If so, these functions are implemented as ALSA PCM
+devices with optional ALSA audio mixer devices.
+
+One problem with all these devices is that the V4L2 API makes no
+provisions to find these related V4L2 device nodes. Some really complex
+hardware use the Media Controller (see :ref:`media_controller`) which can
+be used for this purpose. But several drivers do not use it, and while some
+code exists that uses sysfs to discover related V4L2 device nodes (see
+libmedia_dev in the
+`v4l-utils <http://git.linuxtv.org/cgit.cgi/v4l-utils.git/>`__ git
+repository), there is no library yet that can provide a single API
+towards both Media Controller-based devices and devices that do not use
+the Media Controller. If you want to work on this please write to the
+linux-media mailing list:
+`https://linuxtv.org/lists.php <https://linuxtv.org/lists.php>`__.
+
+Multiple Opens
+==============
+
+V4L2 devices can be opened more than once. [#f1]_ When this is supported
+by the driver, users can for example start a "panel" application to
+change controls like brightness or audio volume, while another
+application captures video and audio. In other words, panel applications
+are comparable to an ALSA audio mixer application. Just opening a V4L2
+device should not change the state of the device. [#f2]_
+
+Once an application has allocated the memory buffers needed for
+streaming data (by calling the :ref:`VIDIOC_REQBUFS`
+or :ref:`VIDIOC_CREATE_BUFS` ioctls, or
+implicitly by calling the :c:func:`read()` or
+:c:func:`write()` functions) that application (filehandle)
+becomes the owner of the device. It is no longer allowed to make changes
+that would affect the buffer sizes (e.g. by calling the
+:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl) and other applications are
+no longer allowed to allocate buffers or start or stop streaming. The
+EBUSY error code will be returned instead.
+
+Merely opening a V4L2 device does not grant exclusive access. [#f3]_
+Initiating data exchange however assigns the right to read or write the
+requested type of data, and to change related properties, to this file
+descriptor. Applications can request additional access privileges using
+the priority mechanism described in :ref:`app-pri`.
+
+Shared Data Streams
+===================
+
+V4L2 drivers should not support multiple applications reading or writing
+the same data stream on a device by copying buffers, time multiplexing
+or similar means. This is better handled by a proxy application in user
+space.
+
+Functions
+=========
+
+To open and close V4L2 devices applications use the
+:c:func:`open()` and :c:func:`close()` function,
+respectively. Devices are programmed using the
+:ref:`ioctl() <func-ioctl>` function as explained in the following
+sections.
+
+.. [#f1]
+   There are still some old and obscure drivers that have not been
+   updated to allow for multiple opens. This implies that for such
+   drivers :c:func:`open()` can return an ``EBUSY`` error code
+   when the device is already in use.
+
+.. [#f2]
+   Unfortunately, opening a radio device often switches the state of the
+   device to radio mode in many drivers. This behavior should be fixed
+   eventually as it violates the V4L2 specification.
+
+.. [#f3]
+   Drivers could recognize the ``O_EXCL`` open flag. Presently this is
+   not required, so applications cannot know if it really works.