Merge tag 'net-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "We have a few fixes for long standing issues, in particular Eric's fix
  to not underestimate the skb sizes, and my fix for brokenness of
  register_netdevice() error path. They may uncover other bugs so we
  will keep an eye on them. Also included are Willem's fixes for
  kmap(_atomic).

  Looking at the "current release" fixes, it seems we are about one rc
  behind a normal cycle. We've previously seen an uptick of "people had
  run their test suites" / "humans actually tried to use new features"
  fixes between rc2 and rc3.

  Summary:

  Current release - regressions:

   - fix feature enforcement to allow NETIF_F_HW_TLS_TX if IP_CSUM &&
     IPV6_CSUM

   - dcb: accept RTM_GETDCB messages carrying set-like DCB commands if
     user is admin for backward-compatibility

   - selftests/tls: fix selftests build after adding ChaCha20-Poly1305

  Current release - always broken:

   - ppp: fix refcount underflow on channel unbridge

   - bnxt_en: clear DEFRAG flag in firmware message when retry flashing

   - smc: fix out of bound access in the new netlink interface

  Previous releases - regressions:

   - fix use-after-free with UDP GRO by frags

   - mptcp: better msk-level shutdown

   - rndis_host: set proper input size for OID_GEN_PHYSICAL_MEDIUM
     request

   - i40e: xsk: fix potential NULL pointer dereferencing

  Previous releases - always broken:

   - skb frag: kmap_atomic fixes

   - avoid 32 x truesize under-estimation for tiny skbs

   - fix issues around register_netdevice() failures

   - udp: prevent reuseport_select_sock from reading uninitialized socks

   - dsa: unbind all switches from tree when DSA master unbinds

   - dsa: clear devlink port type before unregistering slave netdevs

   - can: isotp: isotp_getname(): fix kernel information leak

   - mlxsw: core: Thermal control fixes

   - ipv6: validate GSO SKB against MTU before finish IPv6 processing

   - stmmac: use __napi_schedule() for PREEMPT_RT

   - net: mvpp2: remove Pause and Asym_Pause support

  Misc:

   - remove from MAINTAINERS folks who had been inactive for >5yrs"

* tag 'net-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (58 commits)
  mptcp: fix locking in mptcp_disconnect()
  net: Allow NETIF_F_HW_TLS_TX if IP_CSUM && IPV6_CSUM
  MAINTAINERS: dccp: move Gerrit Renker to CREDITS
  MAINTAINERS: ipvs: move Wensong Zhang to CREDITS
  MAINTAINERS: tls: move Aviad to CREDITS
  MAINTAINERS: ena: remove Zorik Machulsky from reviewers
  MAINTAINERS: vrf: move Shrijeet to CREDITS
  MAINTAINERS: net: move Alexey Kuznetsov to CREDITS
  MAINTAINERS: altx: move Jay Cliburn to CREDITS
  net: avoid 32 x truesize under-estimation for tiny skbs
  nt: usb: USB_RTL8153_ECM should not default to y
  net: stmmac: fix taprio configuration when base_time is in the past
  net: stmmac: fix taprio schedule configuration
  net: tip: fix a couple kernel-doc markups
  net: sit: unregister_netdevice on newlink's error path
  net: stmmac: Fixed mtu channged by cache aligned
  cxgb4/chtls: Fix tid stuck due to wrong update of qid
  i40e: fix potential NULL pointer dereferencing
  net: stmmac: use __napi_schedule() for PREEMPT_RT
  can: mcp251xfd: mcp251xfd_handle_rxif_one(): fix wrong NULL pointer check
  ...

4 files changed, 173 insertions, 9 deletions

diff --git a/Documentation/devicetree/bindings/net/renesas,etheravb.yaml b/Documentation/devicetree/bindings/net/renesas,etheravb.yaml
index 244befb6402a..de9dd574a2f9 100644
--- a/Documentation/devicetree/bindings/net/renesas,etheravb.yaml
+++ b/Documentation/devicetree/bindings/net/renesas,etheravb.yaml
@@ -163,6 +163,7 @@ allOf:
             enum:
               - renesas,etheravb-r8a774a1
               - renesas,etheravb-r8a774b1
+              - renesas,etheravb-r8a774e1
               - renesas,etheravb-r8a7795
               - renesas,etheravb-r8a7796
               - renesas,etheravb-r8a77961
diff --git a/Documentation/devicetree/bindings/net/snps,dwmac.yaml b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
index b2f6083f556a..dfbf5fe4547a 100644
--- a/Documentation/devicetree/bindings/net/snps,dwmac.yaml
+++ b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
@@ -161,7 +161,8 @@ properties:
             * snps,route-dcbcp, DCB Control Packets
             * snps,route-up, Untagged Packets
             * snps,route-multi-broad, Multicast & Broadcast Packets
-          * snps,priority, RX queue priority (Range 0x0 to 0xF)
+          * snps,priority, bitmask of the tagged frames priorities assigned to
+            the queue
 
   snps,mtl-tx-config:
     $ref: /schemas/types.yaml#/definitions/phandle
@@ -188,7 +189,10 @@ properties:
             * snps,idle_slope, unlock on WoL
             * snps,high_credit, max write outstanding req. limit
             * snps,low_credit, max read outstanding req. limit
-          * snps,priority, TX queue priority (Range 0x0 to 0xF)
+          * snps,priority, bitmask of the priorities assigned to the queue.
+            When a PFC frame is received with priorities matching the bitmask,
+            the queue is blocked from transmitting for the pause time specified
+            in the PFC frame.
 
   snps,reset-gpio:
     deprecated: true
diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst
index e65665c5ab50..17bdcb746dcf 100644
--- a/Documentation/networking/netdevices.rst
+++ b/Documentation/networking/netdevices.rst
@@ -10,18 +10,177 @@ Introduction
 The following is a random collection of documentation regarding
 network devices.
 
-struct net_device allocation rules
-==================================
+struct net_device lifetime rules
+================================
 Network device structures need to persist even after module is unloaded and
 must be allocated with alloc_netdev_mqs() and friends.
 If device has registered successfully, it will be freed on last use
-by free_netdev(). This is required to handle the pathologic case cleanly
-(example: rmmod mydriver </sys/class/net/myeth/mtu )
+by free_netdev(). This is required to handle the pathological case cleanly
+(example: ``rmmod mydriver </sys/class/net/myeth/mtu``)
 
-alloc_netdev_mqs()/alloc_netdev() reserve extra space for driver
+alloc_netdev_mqs() / alloc_netdev() reserve extra space for driver
 private data which gets freed when the network device is freed. If
 separately allocated data is attached to the network device
-(netdev_priv(dev)) then it is up to the module exit handler to free that.
+(netdev_priv()) then it is up to the module exit handler to free that.
+
+There are two groups of APIs for registering struct net_device.
+First group can be used in normal contexts where ``rtnl_lock`` is not already
+held: register_netdev(), unregister_netdev().
+Second group can be used when ``rtnl_lock`` is already held:
+register_netdevice(), unregister_netdevice(), free_netdevice().
+
+Simple drivers
+--------------
+
+Most drivers (especially device drivers) handle lifetime of struct net_device
+in context where ``rtnl_lock`` is not held (e.g. driver probe and remove paths).
+
+In that case the struct net_device registration is done using
+the register_netdev(), and unregister_netdev() functions:
+
+.. code-block:: c
+
+  int probe()
+  {
+    struct my_device_priv *priv;
+    int err;
+
+    dev = alloc_netdev_mqs(...);
+    if (!dev)
+      return -ENOMEM;
+    priv = netdev_priv(dev);
+
+    /* ... do all device setup before calling register_netdev() ...
+     */
+
+    err = register_netdev(dev);
+    if (err)
+      goto err_undo;
+
+    /* net_device is visible to the user! */
+
+  err_undo:
+    /* ... undo the device setup ... */
+    free_netdev(dev);
+    return err;
+  }
+
+  void remove()
+  {
+    unregister_netdev(dev);
+    free_netdev(dev);
+  }
+
+Note that after calling register_netdev() the device is visible in the system.
+Users can open it and start sending / receiving traffic immediately,
+or run any other callback, so all initialization must be done prior to
+registration.
+
+unregister_netdev() closes the device and waits for all users to be done
+with it. The memory of struct net_device itself may still be referenced
+by sysfs but all operations on that device will fail.
+
+free_netdev() can be called after unregister_netdev() returns on when
+register_netdev() failed.
+
+Device management under RTNL
+----------------------------
+
+Registering struct net_device while in context which already holds
+the ``rtnl_lock`` requires extra care. In those scenarios most drivers
+will want to make use of struct net_device's ``needs_free_netdev``
+and ``priv_destructor`` members for freeing of state.
+
+Example flow of netdev handling under ``rtnl_lock``:
+
+.. code-block:: c
+
+  static void my_setup(struct net_device *dev)
+  {
+    dev->needs_free_netdev = true;
+  }
+
+  static void my_destructor(struct net_device *dev)
+  {
+    some_obj_destroy(priv->obj);
+    some_uninit(priv);
+  }
+
+  int create_link()
+  {
+    struct my_device_priv *priv;
+    int err;
+
+    ASSERT_RTNL();
+
+    dev = alloc_netdev(sizeof(*priv), "net%d", NET_NAME_UNKNOWN, my_setup);
+    if (!dev)
+      return -ENOMEM;
+    priv = netdev_priv(dev);
+
+    /* Implicit constructor */
+    err = some_init(priv);
+    if (err)
+      goto err_free_dev;
+
+    priv->obj = some_obj_create();
+    if (!priv->obj) {
+      err = -ENOMEM;
+      goto err_some_uninit;
+    }
+    /* End of constructor, set the destructor: */
+    dev->priv_destructor = my_destructor;
+
+    err = register_netdevice(dev);
+    if (err)
+      /* register_netdevice() calls destructor on failure */
+      goto err_free_dev;
+
+    /* If anything fails now unregister_netdevice() (or unregister_netdev())
+     * will take care of calling my_destructor and free_netdev().
+     */
+
+    return 0;
+
+  err_some_uninit:
+    some_uninit(priv);
+  err_free_dev:
+    free_netdev(dev);
+    return err;
+  }
+
+If struct net_device.priv_destructor is set it will be called by the core
+some time after unregister_netdevice(), it will also be called if
+register_netdevice() fails. The callback may be invoked with or without
+``rtnl_lock`` held.
+
+There is no explicit constructor callback, driver "constructs" the private
+netdev state after allocating it and before registration.
+
+Setting struct net_device.needs_free_netdev makes core call free_netdevice()
+automatically after unregister_netdevice() when all references to the device
+are gone. It only takes effect after a successful call to register_netdevice()
+so if register_netdevice() fails driver is responsible for calling
+free_netdev().
+
+free_netdev() is safe to call on error paths right after unregister_netdevice()
+or when register_netdevice() fails. Parts of netdev (de)registration process
+happen after ``rtnl_lock`` is released, therefore in those cases free_netdev()
+will defer some of the processing until ``rtnl_lock`` is released.
+
+Devices spawned from struct rtnl_link_ops should never free the
+struct net_device directly.
+
+.ndo_init and .ndo_uninit
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+``.ndo_init`` and ``.ndo_uninit`` callbacks are called during net_device
+registration and de-registration, under ``rtnl_lock``. Drivers can use
+those e.g. when parts of their init process need to run under ``rtnl_lock``.
+
+``.ndo_init`` runs before device is visible in the system, ``.ndo_uninit``
+runs during de-registering after device is closed but other subsystems
+may still have outstanding references to the netdevice.
 
 MTU
 ===
diff --git a/Documentation/networking/tls-offload.rst b/Documentation/networking/tls-offload.rst
index 0f55c6d540f9..9af3334d9ad0 100644
--- a/Documentation/networking/tls-offload.rst
+++ b/Documentation/networking/tls-offload.rst
@@ -530,7 +530,7 @@ TLS device feature flags only control adding of new TLS connection
 offloads, old connections will remain active after flags are cleared.
 
 TLS encryption cannot be offloaded to devices without checksum calculation
-offload. Hence, TLS TX device feature flag requires NETIF_F_HW_CSUM being set.
+offload. Hence, TLS TX device feature flag requires TX csum offload being set.
 Disabling the latter implies clearing the former. Disabling TX checksum offload
 should not affect old connections, and drivers should make sure checksum
 calculation does not break for them.