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, 202 insertions, 0 deletions

diff --git a/Documentation/core-api/local_ops.rst b/Documentation/core-api/local_ops.rst
new file mode 100644
index 000000000..0b42ceaaf
--- /dev/null
+++ b/Documentation/core-api/local_ops.rst
@@ -0,0 +1,202 @@
+
+.. _local_ops:
+
+=================================================
+Semantics and Behavior of Local Atomic Operations
+=================================================
+
+:Author: Mathieu Desnoyers
+
+
+This document explains the purpose of the local atomic operations, how
+to implement them for any given architecture and shows how they can be used
+properly. It also stresses on the precautions that must be taken when reading
+those local variables across CPUs when the order of memory writes matters.
+
+.. note::
+
+    Note that ``local_t`` based operations are not recommended for general
+    kernel use. Please use the ``this_cpu`` operations instead unless there is
+    really a special purpose. Most uses of ``local_t`` in the kernel have been
+    replaced by ``this_cpu`` operations. ``this_cpu`` operations combine the
+    relocation with the ``local_t`` like semantics in a single instruction and
+    yield more compact and faster executing code.
+
+
+Purpose of local atomic operations
+==================================
+
+Local atomic operations are meant to provide fast and highly reentrant per CPU
+counters. They minimize the performance cost of standard atomic operations by
+removing the LOCK prefix and memory barriers normally required to synchronize
+across CPUs.
+
+Having fast per CPU atomic counters is interesting in many cases: it does not
+require disabling interrupts to protect from interrupt handlers and it permits
+coherent counters in NMI handlers. It is especially useful for tracing purposes
+and for various performance monitoring counters.
+
+Local atomic operations only guarantee variable modification atomicity wrt the
+CPU which owns the data. Therefore, care must taken to make sure that only one
+CPU writes to the ``local_t`` data. This is done by using per cpu data and
+making sure that we modify it from within a preemption safe context. It is
+however permitted to read ``local_t`` data from any CPU: it will then appear to
+be written out of order wrt other memory writes by the owner CPU.
+
+
+Implementation for a given architecture
+=======================================
+
+It can be done by slightly modifying the standard atomic operations: only
+their UP variant must be kept. It typically means removing LOCK prefix (on
+i386 and x86_64) and any SMP synchronization barrier. If the architecture does
+not have a different behavior between SMP and UP, including
+``asm-generic/local.h`` in your architecture's ``local.h`` is sufficient.
+
+The ``local_t`` type is defined as an opaque ``signed long`` by embedding an
+``atomic_long_t`` inside a structure. This is made so a cast from this type to
+a ``long`` fails. The definition looks like::
+
+    typedef struct { atomic_long_t a; } local_t;
+
+
+Rules to follow when using local atomic operations
+==================================================
+
+* Variables touched by local ops must be per cpu variables.
+* *Only* the CPU owner of these variables must write to them.
+* This CPU can use local ops from any context (process, irq, softirq, nmi, ...)
+  to update its ``local_t`` variables.
+* Preemption (or interrupts) must be disabled when using local ops in
+  process context to make sure the process won't be migrated to a
+  different CPU between getting the per-cpu variable and doing the
+  actual local op.
+* When using local ops in interrupt context, no special care must be
+  taken on a mainline kernel, since they will run on the local CPU with
+  preemption already disabled. I suggest, however, to explicitly
+  disable preemption anyway to make sure it will still work correctly on
+  -rt kernels.
+* Reading the local cpu variable will provide the current copy of the
+  variable.
+* Reads of these variables can be done from any CPU, because updates to
+  "``long``", aligned, variables are always atomic. Since no memory
+  synchronization is done by the writer CPU, an outdated copy of the
+  variable can be read when reading some *other* cpu's variables.
+
+
+How to use local atomic operations
+==================================
+
+::
+
+    #include <linux/percpu.h>
+    #include <asm/local.h>
+
+    static DEFINE_PER_CPU(local_t, counters) = LOCAL_INIT(0);
+
+
+Counting
+========
+
+Counting is done on all the bits of a signed long.
+
+In preemptible context, use ``get_cpu_var()`` and ``put_cpu_var()`` around
+local atomic operations: it makes sure that preemption is disabled around write
+access to the per cpu variable. For instance::
+
+    local_inc(&get_cpu_var(counters));
+    put_cpu_var(counters);
+
+If you are already in a preemption-safe context, you can use
+``this_cpu_ptr()`` instead::
+
+    local_inc(this_cpu_ptr(&counters));
+
+
+
+Reading the counters
+====================
+
+Those local counters can be read from foreign CPUs to sum the count. Note that
+the data seen by local_read across CPUs must be considered to be out of order
+relatively to other memory writes happening on the CPU that owns the data::
+
+    long sum = 0;
+    for_each_online_cpu(cpu)
+            sum += local_read(&per_cpu(counters, cpu));
+
+If you want to use a remote local_read to synchronize access to a resource
+between CPUs, explicit ``smp_wmb()`` and ``smp_rmb()`` memory barriers must be used
+respectively on the writer and the reader CPUs. It would be the case if you use
+the ``local_t`` variable as a counter of bytes written in a buffer: there should
+be a ``smp_wmb()`` between the buffer write and the counter increment and also a
+``smp_rmb()`` between the counter read and the buffer read.
+
+
+Here is a sample module which implements a basic per cpu counter using
+``local.h``::
+
+    /* test-local.c
+     *
+     * Sample module for local.h usage.
+     */
+
+
+    #include <asm/local.h>
+    #include <linux/module.h>
+    #include <linux/timer.h>
+
+    static DEFINE_PER_CPU(local_t, counters) = LOCAL_INIT(0);
+
+    static struct timer_list test_timer;
+
+    /* IPI called on each CPU. */
+    static void test_each(void *info)
+    {
+            /* Increment the counter from a non preemptible context */
+            printk("Increment on cpu %d\n", smp_processor_id());
+            local_inc(this_cpu_ptr(&counters));
+
+            /* This is what incrementing the variable would look like within a
+             * preemptible context (it disables preemption) :
+             *
+             * local_inc(&get_cpu_var(counters));
+             * put_cpu_var(counters);
+             */
+    }
+
+    static void do_test_timer(unsigned long data)
+    {
+            int cpu;
+
+            /* Increment the counters */
+            on_each_cpu(test_each, NULL, 1);
+            /* Read all the counters */
+            printk("Counters read from CPU %d\n", smp_processor_id());
+            for_each_online_cpu(cpu) {
+                    printk("Read : CPU %d, count %ld\n", cpu,
+                            local_read(&per_cpu(counters, cpu)));
+            }
+            mod_timer(&test_timer, jiffies + 1000);
+    }
+
+    static int __init test_init(void)
+    {
+            /* initialize the timer that will increment the counter */
+            timer_setup(&test_timer, do_test_timer, 0);
+            mod_timer(&test_timer, jiffies + 1);
+
+            return 0;
+    }
+
+    static void __exit test_exit(void)
+    {
+            timer_shutdown_sync(&test_timer);
+    }
+
+    module_init(test_init);
+    module_exit(test_exit);
+
+    MODULE_LICENSE("GPL");
+    MODULE_AUTHOR("Mathieu Desnoyers");
+    MODULE_DESCRIPTION("Local Atomic Ops");