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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/core-api/kernel-api.rst
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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(). ...
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+====================
+The Linux Kernel API
+====================
+
+
+List Management Functions
+=========================
+
+.. kernel-doc:: include/linux/list.h
+ :internal:
+
+Basic C Library Functions
+=========================
+
+When writing drivers, you cannot in general use routines which are from
+the C Library. Some of the functions have been found generally useful
+and they are listed below. The behaviour of these functions may vary
+slightly from those defined by ANSI, and these deviations are noted in
+the text.
+
+String Conversions
+------------------
+
+.. kernel-doc:: lib/vsprintf.c
+ :export:
+
+.. kernel-doc:: include/linux/kstrtox.h
+ :functions: kstrtol kstrtoul
+
+.. kernel-doc:: lib/kstrtox.c
+ :export:
+
+.. kernel-doc:: lib/string_helpers.c
+ :export:
+
+String Manipulation
+-------------------
+
+.. kernel-doc:: include/linux/fortify-string.h
+ :internal:
+
+.. kernel-doc:: lib/string.c
+ :export:
+
+.. kernel-doc:: include/linux/string.h
+ :internal:
+
+.. kernel-doc:: mm/util.c
+ :functions: kstrdup kstrdup_const kstrndup kmemdup kmemdup_nul memdup_user
+ vmemdup_user strndup_user memdup_user_nul
+
+Basic Kernel Library Functions
+==============================
+
+The Linux kernel provides more basic utility functions.
+
+Bit Operations
+--------------
+
+.. kernel-doc:: include/asm-generic/bitops/instrumented-atomic.h
+ :internal:
+
+.. kernel-doc:: include/asm-generic/bitops/instrumented-non-atomic.h
+ :internal:
+
+.. kernel-doc:: include/asm-generic/bitops/instrumented-lock.h
+ :internal:
+
+Bitmap Operations
+-----------------
+
+.. kernel-doc:: lib/bitmap.c
+ :doc: bitmap introduction
+
+.. kernel-doc:: include/linux/bitmap.h
+ :doc: declare bitmap
+
+.. kernel-doc:: include/linux/bitmap.h
+ :doc: bitmap overview
+
+.. kernel-doc:: include/linux/bitmap.h
+ :doc: bitmap bitops
+
+.. kernel-doc:: lib/bitmap.c
+ :export:
+
+.. kernel-doc:: lib/bitmap.c
+ :internal:
+
+.. kernel-doc:: include/linux/bitmap.h
+ :internal:
+
+Command-line Parsing
+--------------------
+
+.. kernel-doc:: lib/cmdline.c
+ :export:
+
+Sorting
+-------
+
+.. kernel-doc:: lib/sort.c
+ :export:
+
+.. kernel-doc:: lib/list_sort.c
+ :export:
+
+Text Searching
+--------------
+
+.. kernel-doc:: lib/textsearch.c
+ :doc: ts_intro
+
+.. kernel-doc:: lib/textsearch.c
+ :export:
+
+.. kernel-doc:: include/linux/textsearch.h
+ :functions: textsearch_find textsearch_next \
+ textsearch_get_pattern textsearch_get_pattern_len
+
+CRC and Math Functions in Linux
+===============================
+
+Arithmetic Overflow Checking
+----------------------------
+
+.. kernel-doc:: include/linux/overflow.h
+ :internal:
+
+CRC Functions
+-------------
+
+.. kernel-doc:: lib/crc4.c
+ :export:
+
+.. kernel-doc:: lib/crc7.c
+ :export:
+
+.. kernel-doc:: lib/crc8.c
+ :export:
+
+.. kernel-doc:: lib/crc16.c
+ :export:
+
+.. kernel-doc:: lib/crc32.c
+
+.. kernel-doc:: lib/crc-ccitt.c
+ :export:
+
+.. kernel-doc:: lib/crc-itu-t.c
+ :export:
+
+Base 2 log and power Functions
+------------------------------
+
+.. kernel-doc:: include/linux/log2.h
+ :internal:
+
+Integer power Functions
+-----------------------
+
+.. kernel-doc:: lib/math/int_pow.c
+ :export:
+
+.. kernel-doc:: lib/math/int_sqrt.c
+ :export:
+
+Division Functions
+------------------
+
+.. kernel-doc:: include/asm-generic/div64.h
+ :functions: do_div
+
+.. kernel-doc:: include/linux/math64.h
+ :internal:
+
+.. kernel-doc:: lib/math/gcd.c
+ :export:
+
+UUID/GUID
+---------
+
+.. kernel-doc:: lib/uuid.c
+ :export:
+
+Kernel IPC facilities
+=====================
+
+IPC utilities
+-------------
+
+.. kernel-doc:: ipc/util.c
+ :internal:
+
+FIFO Buffer
+===========
+
+kfifo interface
+---------------
+
+.. kernel-doc:: include/linux/kfifo.h
+ :internal:
+
+relay interface support
+=======================
+
+Relay interface support is designed to provide an efficient mechanism
+for tools and facilities to relay large amounts of data from kernel
+space to user space.
+
+relay interface
+---------------
+
+.. kernel-doc:: kernel/relay.c
+ :export:
+
+.. kernel-doc:: kernel/relay.c
+ :internal:
+
+Module Support
+==============
+
+Module Loading
+--------------
+
+.. kernel-doc:: kernel/kmod.c
+ :export:
+
+Inter Module support
+--------------------
+
+Refer to the files in kernel/module/ for more information.
+
+Hardware Interfaces
+===================
+
+DMA Channels
+------------
+
+.. kernel-doc:: kernel/dma.c
+ :export:
+
+Resources Management
+--------------------
+
+.. kernel-doc:: kernel/resource.c
+ :internal:
+
+.. kernel-doc:: kernel/resource.c
+ :export:
+
+MTRR Handling
+-------------
+
+.. kernel-doc:: arch/x86/kernel/cpu/mtrr/mtrr.c
+ :export:
+
+Security Framework
+==================
+
+.. kernel-doc:: security/security.c
+ :internal:
+
+.. kernel-doc:: security/inode.c
+ :export:
+
+Audit Interfaces
+================
+
+.. kernel-doc:: kernel/audit.c
+ :export:
+
+.. kernel-doc:: kernel/auditsc.c
+ :internal:
+
+.. kernel-doc:: kernel/auditfilter.c
+ :internal:
+
+Accounting Framework
+====================
+
+.. kernel-doc:: kernel/acct.c
+ :internal:
+
+Block Devices
+=============
+
+.. kernel-doc:: include/linux/bio.h
+.. kernel-doc:: block/blk-core.c
+ :export:
+
+.. kernel-doc:: block/blk-core.c
+ :internal:
+
+.. kernel-doc:: block/blk-map.c
+ :export:
+
+.. kernel-doc:: block/blk-sysfs.c
+ :internal:
+
+.. kernel-doc:: block/blk-settings.c
+ :export:
+
+.. kernel-doc:: block/blk-flush.c
+ :export:
+
+.. kernel-doc:: block/blk-lib.c
+ :export:
+
+.. kernel-doc:: block/blk-integrity.c
+ :export:
+
+.. kernel-doc:: kernel/trace/blktrace.c
+ :internal:
+
+.. kernel-doc:: block/genhd.c
+ :internal:
+
+.. kernel-doc:: block/genhd.c
+ :export:
+
+.. kernel-doc:: block/bdev.c
+ :export:
+
+Char devices
+============
+
+.. kernel-doc:: fs/char_dev.c
+ :export:
+
+Clock Framework
+===============
+
+The clock framework defines programming interfaces to support software
+management of the system clock tree. This framework is widely used with
+System-On-Chip (SOC) platforms to support power management and various
+devices which may need custom clock rates. Note that these "clocks"
+don't relate to timekeeping or real time clocks (RTCs), each of which
+have separate frameworks. These :c:type:`struct clk <clk>`
+instances may be used to manage for example a 96 MHz signal that is used
+to shift bits into and out of peripherals or busses, or otherwise
+trigger synchronous state machine transitions in system hardware.
+
+Power management is supported by explicit software clock gating: unused
+clocks are disabled, so the system doesn't waste power changing the
+state of transistors that aren't in active use. On some systems this may
+be backed by hardware clock gating, where clocks are gated without being
+disabled in software. Sections of chips that are powered but not clocked
+may be able to retain their last state. This low power state is often
+called a *retention mode*. This mode still incurs leakage currents,
+especially with finer circuit geometries, but for CMOS circuits power is
+mostly used by clocked state changes.
+
+Power-aware drivers only enable their clocks when the device they manage
+is in active use. Also, system sleep states often differ according to
+which clock domains are active: while a "standby" state may allow wakeup
+from several active domains, a "mem" (suspend-to-RAM) state may require
+a more wholesale shutdown of clocks derived from higher speed PLLs and
+oscillators, limiting the number of possible wakeup event sources. A
+driver's suspend method may need to be aware of system-specific clock
+constraints on the target sleep state.
+
+Some platforms support programmable clock generators. These can be used
+by external chips of various kinds, such as other CPUs, multimedia
+codecs, and devices with strict requirements for interface clocking.
+
+.. kernel-doc:: include/linux/clk.h
+ :internal:
+
+Synchronization Primitives
+==========================
+
+Read-Copy Update (RCU)
+----------------------
+
+.. kernel-doc:: include/linux/rcupdate.h
+
+.. kernel-doc:: kernel/rcu/tree.c
+
+.. kernel-doc:: kernel/rcu/tree_exp.h
+
+.. kernel-doc:: kernel/rcu/update.c
+
+.. kernel-doc:: include/linux/srcu.h
+
+.. kernel-doc:: kernel/rcu/srcutree.c
+
+.. kernel-doc:: include/linux/rculist_bl.h
+
+.. kernel-doc:: include/linux/rculist.h
+
+.. kernel-doc:: include/linux/rculist_nulls.h
+
+.. kernel-doc:: include/linux/rcu_sync.h
+
+.. kernel-doc:: kernel/rcu/sync.c