Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from David Miller:

 1) Disable RISCV BPF JIT builds when !MMU, from Björn Töpel.

 2) nf_tables leaves dangling pointer after free, fix from Eric Dumazet.

 3) Out of boundary write in __xsk_rcv_memcpy(), fix from Li RongQing.

 4) Adjust icmp6 message source address selection when routes have a
    preferred source address set, from Tim Stallard.

 5) Be sure to validate HSR protocol version when creating new links,
    from Taehee Yoo.

 6) CAP_NET_ADMIN should be sufficient to manage l2tp tunnels even in
    non-initial namespaces, from Michael Weiß.

 7) Missing release firmware call in mlx5, from Eran Ben Elisha.

 8) Fix variable type in macsec_changelink(), caught by KASAN. Fix from
    Taehee Yoo.

 9) Fix pause frame negotiation in marvell phy driver, from Clemens
    Gruber.

10) Record RX queue early enough in tun packet paths such that XDP
    programs will see the correct RX queue index, from Gilberto Bertin.

11) Fix double unlock in mptcp, from Florian Westphal.

12) Fix offset overflow in ARM bpf JIT, from Luke Nelson.

13) marvell10g needs to soft reset PHY when coming out of low power
    mode, from Russell King.

14) Fix MTU setting regression in stmmac for some chip types, from
    Florian Fainelli.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (101 commits)
  amd-xgbe: Use __napi_schedule() in BH context
  mISDN: make dmril and dmrim static
  net: stmmac: dwmac-sunxi: Provide TX and RX fifo sizes
  net: dsa: mt7530: fix tagged frames pass-through in VLAN-unaware mode
  tipc: fix incorrect increasing of link window
  Documentation: Fix tcp_challenge_ack_limit default value
  net: tulip: make early_486_chipsets static
  dt-bindings: net: ethernet-phy: add desciption for ethernet-phy-id1234.d400
  ipv6: remove redundant assignment to variable err
  net/rds: Use ERR_PTR for rds_message_alloc_sgs()
  net: mscc: ocelot: fix untagged packet drops when enslaving to vlan aware bridge
  selftests/bpf: Check for correct program attach/detach in xdp_attach test
  libbpf: Fix type of old_fd in bpf_xdp_set_link_opts
  libbpf: Always specify expected_attach_type on program load if supported
  xsk: Add missing check on user supplied headroom size
  mac80211: fix channel switch trigger from unknown mesh peer
  mac80211: fix race in ieee80211_register_hw()
  net: marvell10g: soft-reset the PHY when coming out of low power
  net: marvell10g: report firmware version
  net/cxgb4: Check the return from t4_query_params properly
  ...

1 files changed, 176 insertions, 0 deletions

diff --git a/Documentation/networking/net_dim.rst b/Documentation/networking/net_dim.rst
new file mode 100644
index 000000000000..3bed9fd95336
--- /dev/null
+++ b/Documentation/networking/net_dim.rst
@@ -0,0 +1,176 @@
+======================================================
+Net DIM - Generic Network Dynamic Interrupt Moderation
+======================================================
+
+:Author: Tal Gilboa <talgi@mellanox.com>
+
+.. contents:: :depth: 2
+
+Assumptions
+===========
+
+This document assumes the reader has basic knowledge in network drivers
+and in general interrupt moderation.
+
+
+Introduction
+============
+
+Dynamic Interrupt Moderation (DIM) (in networking) refers to changing the
+interrupt moderation configuration of a channel in order to optimize packet
+processing. The mechanism includes an algorithm which decides if and how to
+change moderation parameters for a channel, usually by performing an analysis on
+runtime data sampled from the system. Net DIM is such a mechanism. In each
+iteration of the algorithm, it analyses a given sample of the data, compares it
+to the previous sample and if required, it can decide to change some of the
+interrupt moderation configuration fields. The data sample is composed of data
+bandwidth, the number of packets and the number of events. The time between
+samples is also measured. Net DIM compares the current and the previous data and
+returns an adjusted interrupt moderation configuration object. In some cases,
+the algorithm might decide not to change anything. The configuration fields are
+the minimum duration (microseconds) allowed between events and the maximum
+number of wanted packets per event. The Net DIM algorithm ascribes importance to
+increase bandwidth over reducing interrupt rate.
+
+
+Net DIM Algorithm
+=================
+
+Each iteration of the Net DIM algorithm follows these steps:
+
+#. Calculates new data sample.
+#. Compares it to previous sample.
+#. Makes a decision - suggests interrupt moderation configuration fields.
+#. Applies a schedule work function, which applies suggested configuration.
+
+The first two steps are straightforward, both the new and the previous data are
+supplied by the driver registered to Net DIM. The previous data is the new data
+supplied to the previous iteration. The comparison step checks the difference
+between the new and previous data and decides on the result of the last step.
+A step would result as "better" if bandwidth increases and as "worse" if
+bandwidth reduces. If there is no change in bandwidth, the packet rate is
+compared in a similar fashion - increase == "better" and decrease == "worse".
+In case there is no change in the packet rate as well, the interrupt rate is
+compared. Here the algorithm tries to optimize for lower interrupt rate so an
+increase in the interrupt rate is considered "worse" and a decrease is
+considered "better". Step #2 has an optimization for avoiding false results: it
+only considers a difference between samples as valid if it is greater than a
+certain percentage. Also, since Net DIM does not measure anything by itself, it
+assumes the data provided by the driver is valid.
+
+Step #3 decides on the suggested configuration based on the result from step #2
+and the internal state of the algorithm. The states reflect the "direction" of
+the algorithm: is it going left (reducing moderation), right (increasing
+moderation) or standing still. Another optimization is that if a decision
+to stay still is made multiple times, the interval between iterations of the
+algorithm would increase in order to reduce calculation overhead. Also, after
+"parking" on one of the most left or most right decisions, the algorithm may
+decide to verify this decision by taking a step in the other direction. This is
+done in order to avoid getting stuck in a "deep sleep" scenario. Once a
+decision is made, an interrupt moderation configuration is selected from
+the predefined profiles.
+
+The last step is to notify the registered driver that it should apply the
+suggested configuration. This is done by scheduling a work function, defined by
+the Net DIM API and provided by the registered driver.
+
+As you can see, Net DIM itself does not actively interact with the system. It
+would have trouble making the correct decisions if the wrong data is supplied to
+it and it would be useless if the work function would not apply the suggested
+configuration. This does, however, allow the registered driver some room for
+manoeuvre as it may provide partial data or ignore the algorithm suggestion
+under some conditions.
+
+
+Registering a Network Device to DIM
+===================================
+
+Net DIM API exposes the main function net_dim().
+This function is the entry point to the Net
+DIM algorithm and has to be called every time the driver would like to check if
+it should change interrupt moderation parameters. The driver should provide two
+data structures: :c:type:`struct dim <dim>` and
+:c:type:`struct dim_sample <dim_sample>`. :c:type:`struct dim <dim>`
+describes the state of DIM for a specific object (RX queue, TX queue,
+other queues, etc.). This includes the current selected profile, previous data
+samples, the callback function provided by the driver and more.
+:c:type:`struct dim_sample <dim_sample>` describes a data sample,
+which will be compared to the data sample stored in :c:type:`struct dim <dim>`
+in order to decide on the algorithm's next
+step. The sample should include bytes, packets and interrupts, measured by
+the driver.
+
+In order to use Net DIM from a networking driver, the driver needs to call the
+main net_dim() function. The recommended method is to call net_dim() on each
+interrupt. Since Net DIM has a built-in moderation and it might decide to skip
+iterations under certain conditions, there is no need to moderate the net_dim()
+calls as well. As mentioned above, the driver needs to provide an object of type
+:c:type:`struct dim <dim>` to the net_dim() function call. It is advised for
+each entity using Net DIM to hold a :c:type:`struct dim <dim>` as part of its
+data structure and use it as the main Net DIM API object.
+The :c:type:`struct dim_sample <dim_sample>` should hold the latest
+bytes, packets and interrupts count. No need to perform any calculations, just
+include the raw data.
+
+The net_dim() call itself does not return anything. Instead Net DIM relies on
+the driver to provide a callback function, which is called when the algorithm
+decides to make a change in the interrupt moderation parameters. This callback
+will be scheduled and run in a separate thread in order not to add overhead to
+the data flow. After the work is done, Net DIM algorithm needs to be set to
+the proper state in order to move to the next iteration.
+
+
+Example
+=======
+
+The following code demonstrates how to register a driver to Net DIM. The actual
+usage is not complete but it should make the outline of the usage clear.
+
+.. code-block:: c
+
+  #include <linux/dim.h>
+
+  /* Callback for net DIM to schedule on a decision to change moderation */
+  void my_driver_do_dim_work(struct work_struct *work)
+  {
+	/* Get struct dim from struct work_struct */
+	struct dim *dim = container_of(work, struct dim,
+				       work);
+	/* Do interrupt moderation related stuff */
+	...
+
+	/* Signal net DIM work is done and it should move to next iteration */
+	dim->state = DIM_START_MEASURE;
+  }
+
+  /* My driver's interrupt handler */
+  int my_driver_handle_interrupt(struct my_driver_entity *my_entity, ...)
+  {
+	...
+	/* A struct to hold current measured data */
+	struct dim_sample dim_sample;
+	...
+	/* Initiate data sample struct with current data */
+	dim_update_sample(my_entity->events,
+		          my_entity->packets,
+		          my_entity->bytes,
+		          &dim_sample);
+	/* Call net DIM */
+	net_dim(&my_entity->dim, dim_sample);
+	...
+  }
+
+  /* My entity's initialization function (my_entity was already allocated) */
+  int my_driver_init_my_entity(struct my_driver_entity *my_entity, ...)
+  {
+	...
+	/* Initiate struct work_struct with my driver's callback function */
+	INIT_WORK(&my_entity->dim.work, my_driver_do_dim_work);
+	...
+  }
+
+Dynamic Interrupt Moderation (DIM) library API
+==============================================
+
+.. kernel-doc:: include/linux/dim.h
+    :internal: