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, 226 insertions, 0 deletions

diff --git a/Documentation/maintainer/rebasing-and-merging.rst b/Documentation/maintainer/rebasing-and-merging.rst
new file mode 100644
index 000000000..09f988e7f
--- /dev/null
+++ b/Documentation/maintainer/rebasing-and-merging.rst
@@ -0,0 +1,226 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====================
+Rebasing and merging
+====================
+
+Maintaining a subsystem, as a general rule, requires a familiarity with the
+Git source-code management system.  Git is a powerful tool with a lot of
+features; as is often the case with such tools, there are right and wrong
+ways to use those features.  This document looks in particular at the use
+of rebasing and merging.  Maintainers often get in trouble when they use
+those tools incorrectly, but avoiding problems is not actually all that
+hard.
+
+One thing to be aware of in general is that, unlike many other projects,
+the kernel community is not scared by seeing merge commits in its
+development history.  Indeed, given the scale of the project, avoiding
+merges would be nearly impossible.  Some problems encountered by
+maintainers result from a desire to avoid merges, while others come from
+merging a little too often.
+
+Rebasing
+========
+
+"Rebasing" is the process of changing the history of a series of commits
+within a repository.  There are two different types of operations that are
+referred to as rebasing since both are done with the ``git rebase``
+command, but there are significant differences between them:
+
+ - Changing the parent (starting) commit upon which a series of patches is
+   built.  For example, a rebase operation could take a patch set built on
+   the previous kernel release and base it, instead, on the current
+   release.  We'll call this operation "reparenting" in the discussion
+   below.
+
+ - Changing the history of a set of patches by fixing (or deleting) broken
+   commits, adding patches, adding tags to commit changelogs, or changing
+   the order in which commits are applied.  In the following text, this
+   type of operation will be referred to as "history modification"
+
+The term "rebasing" will be used to refer to both of the above operations.
+Used properly, rebasing can yield a cleaner and clearer development
+history; used improperly, it can obscure that history and introduce bugs.
+
+There are a few rules of thumb that can help developers to avoid the worst
+perils of rebasing:
+
+ - History that has been exposed to the world beyond your private system
+   should usually not be changed.  Others may have pulled a copy of your
+   tree and built on it; modifying your tree will create pain for them.  If
+   work is in need of rebasing, that is usually a sign that it is not yet
+   ready to be committed to a public repository.
+
+   That said, there are always exceptions.  Some trees (linux-next being
+   a significant example) are frequently rebased by their nature, and
+   developers know not to base work on them.  Developers will sometimes
+   expose an unstable branch for others to test with or for automated
+   testing services.  If you do expose a branch that may be unstable in
+   this way, be sure that prospective users know not to base work on it.
+
+ - Do not rebase a branch that contains history created by others.  If you
+   have pulled changes from another developer's repository, you are now a
+   custodian of their history.  You should not change it.  With few
+   exceptions, for example, a broken commit in a tree like this should be
+   explicitly reverted rather than disappeared via history modification.
+
+ - Do not reparent a tree without a good reason to do so.  Just being on a
+   newer base or avoiding a merge with an upstream repository is not
+   generally a good reason.
+
+ - If you must reparent a repository, do not pick some random kernel commit
+   as the new base.  The kernel is often in a relatively unstable state
+   between release points; basing development on one of those points
+   increases the chances of running into surprising bugs.  When a patch
+   series must move to a new base, pick a stable point (such as one of
+   the -rc releases) to move to.
+
+ - Realize that reparenting a patch series (or making significant history
+   modifications) changes the environment in which it was developed and,
+   likely, invalidates much of the testing that was done.  A reparented
+   patch series should, as a general rule, be treated like new code and
+   retested from the beginning.
+
+A frequent cause of merge-window trouble is when Linus is presented with a
+patch series that has clearly been reparented, often to a random commit,
+shortly before the pull request was sent.  The chances of such a series
+having been adequately tested are relatively low - as are the chances of
+the pull request being acted upon.
+
+If, instead, rebasing is limited to private trees, commits are based on a
+well-known starting point, and they are well tested, the potential for
+trouble is low.
+
+Merging
+=======
+
+Merging is a common operation in the kernel development process; the 5.1
+development cycle included 1,126 merge commits - nearly 9% of the total.
+Kernel work is accumulated in over 100 different subsystem trees, each of
+which may contain multiple topic branches; each branch is usually developed
+independently of the others.  So naturally, at least one merge will be
+required before any given branch finds its way into an upstream repository.
+
+Many projects require that branches in pull requests be based on the
+current trunk so that no merge commits appear in the history.  The kernel
+is not such a project; any rebasing of branches to avoid merges will, most
+likely, lead to trouble.
+
+Subsystem maintainers find themselves having to do two types of merges:
+from lower-level subsystem trees and from others, either sibling trees or
+the mainline.  The best practices to follow differ in those two situations.
+
+Merging from lower-level trees
+------------------------------
+
+Larger subsystems tend to have multiple levels of maintainers, with the
+lower-level maintainers sending pull requests to the higher levels.  Acting
+on such a pull request will almost certainly generate a merge commit; that
+is as it should be.  In fact, subsystem maintainers may want to use
+the --no-ff flag to force the addition of a merge commit in the rare cases
+where one would not normally be created so that the reasons for the merge
+can be recorded.  The changelog for the merge should, for any kind of
+merge, say *why* the merge is being done.  For a lower-level tree, "why" is
+usually a summary of the changes that will come with that pull.
+
+Maintainers at all levels should be using signed tags on their pull
+requests, and upstream maintainers should verify the tags when pulling
+branches.  Failure to do so threatens the security of the development
+process as a whole.
+
+As per the rules outlined above, once you have merged somebody else's
+history into your tree, you cannot rebase that branch, even if you
+otherwise would be able to.
+
+Merging from sibling or upstream trees
+--------------------------------------
+
+While merges from downstream are common and unremarkable, merges from other
+trees tend to be a red flag when it comes time to push a branch upstream.
+Such merges need to be carefully thought about and well justified, or
+there's a good chance that a subsequent pull request will be rejected.
+
+It is natural to want to merge the master branch into a repository; this
+type of merge is often called a "back merge".  Back merges can help to make
+sure that there are no conflicts with parallel development and generally
+gives a warm, fuzzy feeling of being up-to-date.  But this temptation
+should be avoided almost all of the time.
+
+Why is that?  Back merges will muddy the development history of your own
+branch.  They will significantly increase your chances of encountering bugs
+from elsewhere in the community and make it hard to ensure that the work
+you are managing is stable and ready for upstream.  Frequent merges can
+also obscure problems with the development process in your tree; they can
+hide interactions with other trees that should not be happening (often) in
+a well-managed branch.
+
+That said, back merges are occasionally required; when that happens, be
+sure to document *why* it was required in the commit message.  As always,
+merge to a well-known stable point, rather than to some random commit.
+Even then, you should not back merge a tree above your immediate upstream
+tree; if a higher-level back merge is really required, the upstream tree
+should do it first.
+
+One of the most frequent causes of merge-related trouble is when a
+maintainer merges with the upstream in order to resolve merge conflicts
+before sending a pull request.  Again, this temptation is easy enough to
+understand, but it should absolutely be avoided.  This is especially true
+for the final pull request: Linus is adamant that he would much rather see
+merge conflicts than unnecessary back merges.  Seeing the conflicts lets
+him know where potential problem areas are.  He does a lot of merges (382
+in the 5.1 development cycle) and has gotten quite good at conflict
+resolution - often better than the developers involved.
+
+So what should a maintainer do when there is a conflict between their
+subsystem branch and the mainline?  The most important step is to warn
+Linus in the pull request that the conflict will happen; if nothing else,
+that demonstrates an awareness of how your branch fits into the whole.  For
+especially difficult conflicts, create and push a *separate* branch to show
+how you would resolve things.  Mention that branch in your pull request,
+but the pull request itself should be for the unmerged branch.
+
+Even in the absence of known conflicts, doing a test merge before sending a
+pull request is a good idea.  It may alert you to problems that you somehow
+didn't see from linux-next and helps to understand exactly what you are
+asking upstream to do.
+
+Another reason for doing merges of upstream or another subsystem tree is to
+resolve dependencies.  These dependency issues do happen at times, and
+sometimes a cross-merge with another tree is the best way to resolve them;
+as always, in such situations, the merge commit should explain why the
+merge has been done.  Take a moment to do it right; people will read those
+changelogs.
+
+Often, though, dependency issues indicate that a change of approach is
+needed.  Merging another subsystem tree to resolve a dependency risks
+bringing in other bugs and should almost never be done.  If that subsystem
+tree fails to be pulled upstream, whatever problems it had will block the
+merging of your tree as well.  Preferable alternatives include agreeing
+with the maintainer to carry both sets of changes in one of the trees or
+creating a topic branch dedicated to the prerequisite commits that can be
+merged into both trees.  If the dependency is related to major
+infrastructural changes, the right solution might be to hold the dependent
+commits for one development cycle so that those changes have time to
+stabilize in the mainline.
+
+Finally
+=======
+
+It is relatively common to merge with the mainline toward the beginning of
+the development cycle in order to pick up changes and fixes done elsewhere
+in the tree.  As always, such a merge should pick a well-known release
+point rather than some random spot.  If your upstream-bound branch has
+emptied entirely into the mainline during the merge window, you can pull it
+forward with a command like::
+
+  git merge v5.2-rc1^0
+
+The "^0" will cause Git to do a fast-forward merge (which should be
+possible in this situation), thus avoiding the addition of a spurious merge
+commit.
+
+The guidelines laid out above are just that: guidelines.  There will always
+be situations that call out for a different solution, and these guidelines
+should not prevent developers from doing the right thing when the need
+arises.  But one should always think about whether the need has truly
+arisen and be prepared to explain why something abnormal needs to be done.