It has been reported that since
commit 05212ba8 ("r8169: set RxConfig after tx/rx is enabled for RTL8169sb/8110sb devices")
at least RTL_GIGA_MAC_VER_38 NICs work erratically after a resume from
suspend.
The problem has been traced to a missing RX_MULTI_EN bit in the RxConfig
register.
We already set this bit for RTL_GIGA_MAC_VER_35 NICs of the same 8168F
chip family so let's do it also for its other siblings: RTL_GIGA_MAC_VER_36
and RTL_GIGA_MAC_VER_38.

Curiously, the NIC seems to work fine after a system boot without having
this bit set as long as the system isn't suspended and resumed.

Fixes: 05212ba8 ("r8169: set RxConfig after tx/rx is enabled for RTL8169sb/8110sb devices")
Reported-by: NChris Clayton <chris2553@googlemail.com>
Signed-off-by: NMaciej S. Szmigiero <mail@maciej.szmigiero.name>
Reviewed-by: NHeiner Kallweit <hkallweit1@gmail.com>
Tested-by: NChris Clayton <chris2553@googlemail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 63ae7949 ("net: socionext: Use descriptor info instead of MMIO reads on Rx")
removed constant mmio reads from the driver and started using a descriptor
field to check if packet should be processed.
This lead the napi rx handler being constantly called while no packets
needed processing and ksoftirq getting 100% cpu usage. Issue one mmio read
to clear the irq correcty after processing packets
Signed-off-by: NIlias Apalodimas <ilias.apalodimas@linaro.org>
Reported-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

During boot, mlx4_core sets the driverinit configuration parameters and
updates the devlink module on the initial values calling
devlink_param_driverinit_value_set().
If devlink_param_driverinit_value_set() returns an error mlx4_core
reports kernel module warning.

This caused false alarm during boot in case kernel was compiled with
CONFIG_NET_DEVLINK off.
Fix by removing warning reported in case
devlink_param_driverinit_value_set() fails.

This actually makes the function mlx4_devlink_set_init_value()
redundant to using directly devlink_param_driverinit_value_set() and so
removed.

It fixes the following kernel trace:

 mlx4_core 0000:00:06.0: devlink set parameter 0 value failed (err = -95)
 mlx4_core 0000:00:06.0: devlink set parameter 1 value failed (err = -95)
 mlx4_core 0000:00:06.0: devlink set parameter 4 value failed (err = -95)
 mlx4_core 0000:00:06.0: devlink set parameter 5 value failed (err = -95)
 mlx4_core 0000:00:06.0: devlink set parameter 3 value failed (err = -95)

Fixes: bd1b51dc ("mlx4: Add mlx4 initial parameters table and register it")
Signed-off-by: NMoshe Shemesh <moshe@mellanox.com>
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When booting kernel with LOCKDEP option, below warning info was found:

WARNING: possible recursive locking detected
4.19.0-rc7+ #14 Not tainted
--------------------------------------------
swapper/0/1 is trying to acquire lock:
00000000dcfc0fc8 (&(&list->lock)->rlock#4){+...}, at: spin_lock_bh
include/linux/spinlock.h:334 [inline]
00000000dcfc0fc8 (&(&list->lock)->rlock#4){+...}, at:
tipc_link_reset+0x125/0xdf0 net/tipc/link.c:850

but task is already holding lock:
00000000cbb9b036 (&(&list->lock)->rlock#4){+...}, at: spin_lock_bh
include/linux/spinlock.h:334 [inline]
00000000cbb9b036 (&(&list->lock)->rlock#4){+...}, at:
tipc_link_reset+0xfa/0xdf0 net/tipc/link.c:849

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&list->lock)->rlock#4);
  lock(&(&list->lock)->rlock#4);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by swapper/0/1:
 #0: 00000000f7539d34 (pernet_ops_rwsem){+.+.}, at:
register_pernet_subsys+0x19/0x40 net/core/net_namespace.c:1051
 #1: 00000000cbb9b036 (&(&list->lock)->rlock#4){+...}, at:
spin_lock_bh include/linux/spinlock.h:334 [inline]
 #1: 00000000cbb9b036 (&(&list->lock)->rlock#4){+...}, at:
tipc_link_reset+0xfa/0xdf0 net/tipc/link.c:849

stack backtrace:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7+ #14
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1af/0x295 lib/dump_stack.c:113
 print_deadlock_bug kernel/locking/lockdep.c:1759 [inline]
 check_deadlock kernel/locking/lockdep.c:1803 [inline]
 validate_chain kernel/locking/lockdep.c:2399 [inline]
 __lock_acquire+0xf1e/0x3c60 kernel/locking/lockdep.c:3411
 lock_acquire+0x1db/0x520 kernel/locking/lockdep.c:3900
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168
 spin_lock_bh include/linux/spinlock.h:334 [inline]
 tipc_link_reset+0x125/0xdf0 net/tipc/link.c:850
 tipc_link_bc_create+0xb5/0x1f0 net/tipc/link.c:526
 tipc_bcast_init+0x59b/0xab0 net/tipc/bcast.c:521
 tipc_init_net+0x472/0x610 net/tipc/core.c:82
 ops_init+0xf7/0x520 net/core/net_namespace.c:129
 __register_pernet_operations net/core/net_namespace.c:940 [inline]
 register_pernet_operations+0x453/0xac0 net/core/net_namespace.c:1011
 register_pernet_subsys+0x28/0x40 net/core/net_namespace.c:1052
 tipc_init+0x83/0x104 net/tipc/core.c:140
 do_one_initcall+0x109/0x70a init/main.c:885
 do_initcall_level init/main.c:953 [inline]
 do_initcalls init/main.c:961 [inline]
 do_basic_setup init/main.c:979 [inline]
 kernel_init_freeable+0x4bd/0x57f init/main.c:1144
 kernel_init+0x13/0x180 init/main.c:1063
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413

The reason why the noise above was complained by LOCKDEP is because we
nested to hold l->wakeupq.lock and l->inputq->lock in tipc_link_reset
function. In fact it's unnecessary to move skb buffer from l->wakeupq
queue to l->inputq queue while holding the two locks at the same time.
Instead, we can move skb buffers in l->wakeupq queue to a temporary
list first and then move the buffers of the temporary list to l->inputq
queue, which is also safe for us.

Fixes: 3f32d0be ("tipc: lock wakeup & inputq at tipc_link_reset()")
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Acked-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Paolo Abeni says:

====================
net: explicitly requires bash when needed.

Some test scripts require bash-only features but use the default shell.
This may cause random failures if the default shell is not bash.
Instead of doing a potentially complex rewrite of such scripts, these patches
require the bash interpreter, where needed.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The udpgso_bench.sh script requires several bash-only features. This
may cause random failures if the default shell is not bash.
Address the above explicitly requiring bash as the script interpreter

Fixes: 3a687bef ("selftests: udp gso benchmark")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

the script rtnetlink.sh requires a bash-only features (sleep with sub-second
precision). This may cause random test failure if the default shell is not
bash.
Address the above explicitly requiring bash as the script interpreter.

Fixes: 33b01b7b ("selftests: add rtnetlink test script")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Added support for Gemalto's Cinterion ALASxx WWAN interfaces
by adding QMI_FIXED_INTF with Cinterion's VID and PID.
Signed-off-by: NGiacinto Cifelli <gciofono@gmail.com>
Acked-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In tipc_sk_filter_rcv(), when we detect protocol messages with error we
call tipc_sk_conn_proto_rcv() and let it reset the connection and notify
the socket by calling sk->sk_state_change().

However, tipc_sk_filter_rcv() may have been called from the function
tipc_backlog_rcv(), in which case the socket lock is held and the socket
already awake. This means that the sk_state_change() call is ignored and
the error notification lost. Now the receive queue will remain empty and
the socket sleeps forever.

In this commit, we convert the protocol message into a connection abort
message and enqueue it into the socket's receive queue. By this addition
to the above state change we cover all conditions.
Acked-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NParthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the patch referred to below we added link tolerance as an additional
criteria for declaring broadcast transmission "stale" and resetting the
affected links.

However, the 'tolerance' field of the broadcast link is never set, and
remains at zero. This renders the whole commit without the intended
improving effect, but luckily also with no negative effect.

In this commit we add the missing initialization.

Fixes: a4dc70d4 ("tipc: extend link reset criteria for stale packet retransmission")
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sabrina Dubroca says:

====================
net: ipv4: fixes for PMTU when link MTU changes

The first patch adapts the changes that commit e9fa1495 ("ipv6:
Reflect MTU changes on PMTU of exceptions for MTU-less routes") did in
IPv6 to IPv4: lower PMTU when the first hop's MTU drops below it, and
raise PMTU when the first hop was limiting PMTU discovery and its MTU
is increased.

The second patch fixes bugs introduced in commit d52e5a7e ("ipv4:
lock mtu in fnhe when received PMTU < net.ipv4.route.min_pmtu") that
only appear once the first patch is applied.

Selftests for these cases were introduced in net-next commit
e44e428f ("selftests: pmtu: add basic IPv4 and IPv6 PMTU tests")

v2: add cover letter, and fix a few small things in patch 1
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When an MTU update with PMTU smaller than net.ipv4.route.min_pmtu is
received, we must clamp its value. However, we can receive a PMTU
exception with PMTU < old_mtu < ip_rt_min_pmtu, which would lead to an
increase in PMTU.

To fix this, take the smallest of the old MTU and ip_rt_min_pmtu.

Before this patch, in case of an update, the exception's MTU would
always change. Now, an exception can have only its lock flag updated,
but not the MTU, so we need to add a check on locking to the following
"is this exception getting updated, or close to expiring?" test.

Fixes: d52e5a7e ("ipv4: lock mtu in fnhe when received PMTU < net.ipv4.route.min_pmtu")
Signed-off-by: NSabrina Dubroca <sd@queasysnail.net>
Reviewed-by: NStefano Brivio <sbrivio@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit 5aad1de5 ("ipv4: use separate genid for next hop
exceptions"), exceptions get deprecated separately from cached
routes. In particular, administrative changes don't clear PMTU anymore.

As Stefano described in commit e9fa1495 ("ipv6: Reflect MTU changes
on PMTU of exceptions for MTU-less routes"), the PMTU discovered before
the local MTU change can become stale:
 - if the local MTU is now lower than the PMTU, that PMTU is now
   incorrect
 - if the local MTU was the lowest value in the path, and is increased,
   we might discover a higher PMTU

Similarly to what commit e9fa1495 did for IPv6, update PMTU in those
cases.

If the exception was locked, the discovered PMTU was smaller than the
minimal accepted PMTU. In that case, if the new local MTU is smaller
than the current PMTU, let PMTU discovery figure out if locking of the
exception is still needed.

To do this, we need to know the old link MTU in the NETDEV_CHANGEMTU
notifier. By the time the notifier is called, dev->mtu has been
changed. This patch adds the old MTU as additional information in the
notifier structure, and a new call_netdevice_notifiers_u32() function.

Fixes: 5aad1de5 ("ipv4: use separate genid for next hop exceptions")
Signed-off-by: NSabrina Dubroca <sd@queasysnail.net>
Reviewed-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The fib6_info_alloc() function allocates percpu memory to hold per CPU
pointers to rt6_info, but this memory is never freed. Fix it.

Fixes: a64efe14 ("net/ipv6: introduce fib6_info struct and helpers")
Signed-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

David Howells says:

====================
rxrpc: Fix packet reception code

Here are a set of patches that prepares for and fix problems in rxrpc's
package reception code.  There serious problems are:

 (A) There's a window between binding the socket and setting the data_ready
     hook in which packets can find their way into the UDP socket's receive
     queues.

 (B) The skb_recv_udp() will return an error (and clear the error state) if
     there was an error on the Tx side.  rxrpc doesn't handle this.

 (C) The rxrpc data_ready handler doesn't fully drain the UDP receive
     queue.

 (D) The rxrpc data_ready handler assumes it is called in a non-reentrant
 state.

The second patch fixes (A) - (C); the third patch renders (B) and (C)
non-issues by using the recap_rcv hook instead of data_ready - and the
final patch fixes (D).  That last is the most complex.

The preparatory patches are:

 (1) Fix some places that are doing things in the wrong net namespace.

 (2) Stop taking the rcu read lock as it's held by the IP input routine in
     the call chain.

 (3) Only end the Tx phase if *we* rotated the final packet out of the Tx
     buffer.

 (4) Don't assume that the call state won't change after dropping the
     call_state lock.

 (5) Only take receive window and MTU suze parameters from an ACK packet if
     it's the latest ACK packet.

 (6) Record connection-level abort information correctly.

 (7) Fix a trace line.

And then there are three main patches - note that these are mixed in with
the preparatory patches somewhat:

 (1) Fix the setup window (A), skb_recv_udp() error check (B) and packet
     drainage (C).

 (2) Switch to using the encap_rcv instead of data_ready to cut out the
     effects of the UDP read queues and get the packets delivered directly.

 (3) Add more locking into the various packet input paths to defend against
     re-entrance (D).
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In rds_send_mprds_hash(), if the calculated hash value is non-zero and
the MPRDS connections are not yet up, it will wait.  But it should not
wait if the send is non-blocking.  In this case, it should just use the
base c_path for sending the message.
Signed-off-by: NKa-Cheong Poon <ka-cheong.poon@oracle.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot managed to crash in skb_checksum_help() [1] :

        BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb));

Root cause is the following check in skb_partial_csum_set()

	if (unlikely(start > skb_headlen(skb)) ||
	    unlikely((int)start + off > skb_headlen(skb) - 2))
		return false;

If skb_headlen(skb) is 1, then (skb_headlen(skb) - 2) becomes 0xffffffff
and the check fails to detect that ((int)start + off) is off the limit,
since the compare is unsigned.

When we fix that, then the first condition (start > skb_headlen(skb))
becomes obsolete.

Then we should also check that (skb_headroom(skb) + start) wont
overflow 16bit field.

[1]
kernel BUG at net/core/dev.c:2880!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 7330 Comm: syz-executor4 Not tainted 4.19.0-rc6+ #253
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:skb_checksum_help+0x9e3/0xbb0 net/core/dev.c:2880
Code: 85 00 ff ff ff 48 c1 e8 03 42 80 3c 28 00 0f 84 09 fb ff ff 48 8b bd 00 ff ff ff e8 97 a8 b9 fb e9 f8 fa ff ff e8 2d 09 76 fb <0f> 0b 48 8b bd 28 ff ff ff e8 1f a8 b9 fb e9 b1 f6 ff ff 48 89 cf
RSP: 0018:ffff8801d83a6f60 EFLAGS: 00010293
RAX: ffff8801b9834380 RBX: ffff8801b9f8d8c0 RCX: ffffffff8608c6d7
RDX: 0000000000000000 RSI: ffffffff8608cc63 RDI: 0000000000000006
RBP: ffff8801d83a7068 R08: ffff8801b9834380 R09: 0000000000000000
R10: ffff8801d83a76d8 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000010001 R14: 000000000000ffff R15: 00000000000000a8
FS:  00007f1a66db5700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7d77f091b0 CR3: 00000001ba252000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_csum_hwoffload_help+0x8f/0xe0 net/core/dev.c:3269
 validate_xmit_skb+0xa2a/0xf30 net/core/dev.c:3312
 __dev_queue_xmit+0xc2f/0x3950 net/core/dev.c:3797
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
 packet_snd net/packet/af_packet.c:2928 [inline]
 packet_sendmsg+0x422d/0x64c0 net/packet/af_packet.c:2953

Fixes: 5ff8dda3 ("net: Ensure partial checksum offset is inside the skb head")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Moshe Shemesh says:

====================
devlink param type string fixes

This patchset fixes devlink param infrastructure for string param type.

The devlink param infrastructure doesn't handle copying the string data
correctly.  The first two patches fix it and the third patch adds helper
function to safely copy string value without exceeding
DEVLINK_PARAM_MAX_STRING_VALUE.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Devlink string param buffer is allocated at the size of
DEVLINK_PARAM_MAX_STRING_VALUE. Add helper function which makes sure
this size is not exceeded.
Renamed DEVLINK_PARAM_MAX_STRING_VALUE to
__DEVLINK_PARAM_MAX_STRING_VALUE to emphasize that it should be used by
devlink only. The driver should use the helper function instead to
verify it doesn't exceed the allowed length.
Signed-off-by: NMoshe Shemesh <moshe@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Driverinit configuration mode value is held by devlink to enable the
driver fetch the value after reload command. In case the param type is
string devlink should copy the value from driver string buffer to
devlink string buffer on devlink_param_driverinit_value_set() and
vice-versa on devlink_param_driverinit_value_get().

Fixes: ec01aeb1 ("devlink: Add support for get/set driverinit value")
Signed-off-by: NMoshe Shemesh <moshe@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case devlink param type is string, it needs to copy the string value
it got from the input to devlink_param_value.

Fixes: e3b7ca18 ("devlink: Add param set command")
Signed-off-by: NMoshe Shemesh <moshe@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Arthur Kiyanovski says:

====================
minor bug fixes for ENA Ethernet driver

Arthur Kiyanovski (4):
  net: ena: fix warning in rmmod caused by double iounmap
  net: ena: fix rare bug when failed restart/resume is followed by
    driver removal
  net: ena: fix NULL dereference due to untimely napi initialization
  net: ena: fix auto casting to boolean
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Eliminate potential auto casting compilation error.

Fixes: 1738cd3e ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: NArthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

napi poll functions should be initialized before running request_irq(),
to handle a rare condition where there is a pending interrupt, causing
the ISR to fire immediately while the poll function wasn't set yet,
causing a NULL dereference.

Fixes: 1738cd3e ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: NArthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In a rare scenario when ena_device_restore() fails, followed by device
remove, an FLR will not be issued. In this case, the device will keep
sending asynchronous AENQ keep-alive events, even after driver removal,
leading to memory corruption.

Fixes: 8c5c7abd ("net: ena: add power management ops to the ENA driver")
Signed-off-by: NArthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Memory mapped with devm_ioremap is automatically freed when the driver
is disconnected from the device. Therefore there is no need to
explicitly call devm_iounmap.

Fixes: 0857d92f ("net: ena: add missing unmap bars on device removal")
Fixes: 411838e7 ("net: ena: fix rare kernel crash when bar memory remap fails")
Signed-off-by: NArthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The rxrpc_input_packet() function and its call tree was built around the
assumption that data_ready() handler called from UDP to inform a kernel
service that there is data to be had was non-reentrant.  This means that
certain locking could be dispensed with.

This, however, turns out not to be the case with a multi-queue network card
that can deliver packets to multiple cpus simultaneously.  Each of those
cpus can be in the rxrpc_input_packet() function at the same time.

Fix by adding or changing some structure members:

 (1) Add peer->rtt_input_lock to serialise access to the RTT buffer.

 (2) Make conn->service_id into a 32-bit variable so that it can be
     cmpxchg'd on all arches.

 (3) Add call->input_lock to serialise access to the Rx/Tx state.  Note
     that although the Rx and Tx states are (almost) entirely separate,
     there's no point completing the separation and having separate locks
     since it's a bi-phasal RPC protocol rather than a bi-direction
     streaming protocol.  Data transmission and data reception do not take
     place simultaneously on any particular call.

and making the following functional changes:

 (1) In rxrpc_input_data(), hold call->input_lock around the core to
     prevent simultaneous producing of packets into the Rx ring and
     updating of tracking state for a particular call.

 (2) In rxrpc_input_ping_response(), only read call->ping_serial once, and
     check it before checking RXRPC_CALL_PINGING as that's a cheaper test.
     The bit test and bit clear can then be combined.  No further locking
     is needed here.

 (3) In rxrpc_input_ack(), take call->input_lock after we've parsed much of
     the ACK packet.  The superseded ACK check is then done both before and
     after the lock is taken.

     The handing of ackinfo data is split, parsing before the lock is taken
     and processing with it held.  This is keyed on rxMTU being non-zero.

     Congestion management is also done within the locked section.

 (4) In rxrpc_input_ackall(), take call->input_lock around the Tx window
     rotation.  The ACKALL packet carries no information and is only really
     useful after all packets have been transmitted since it's imprecise.

 (5) In rxrpc_input_implicit_end_call(), we use rx->incoming_lock to
     prevent calls being simultaneously implicitly ended on two cpus and
     also to prevent any races with incoming call setup.

 (6) In rxrpc_input_packet(), use cmpxchg() to effect the service upgrade
     on a connection.  It is only permitted to happen once for a
     connection.

 (7) In rxrpc_new_incoming_call(), we have to recheck the routing inside
     rx->incoming_lock to see if someone else set up the call, connection
     or peer whilst we were getting there.  We can't trust the values from
     the earlier routing check unless we pin refs on them - which we want
     to avoid.

     Further, we need to allow for an incoming call to have its state
     changed on another CPU between us making it live and us adjusting it
     because the conn is now in the RXRPC_CONN_SERVICE state.

 (8) In rxrpc_peer_add_rtt(), take peer->rtt_input_lock around the access
     to the RTT buffer.  Don't need to lock around setting peer->rtt.

For reference, the inventory of state-accessing or state-altering functions
used by the packet input procedure is:

> rxrpc_input_packet()
  * PACKET CHECKING

  * ROUTING
    > rxrpc_post_packet_to_local()
    > rxrpc_find_connection_rcu() - uses RCU
      > rxrpc_lookup_peer_rcu() - uses RCU
      > rxrpc_find_service_conn_rcu() - uses RCU
      > idr_find() - uses RCU

  * CONNECTION-LEVEL PROCESSING
    - Service upgrade
      - Can only happen once per conn
      ! Changed to use cmpxchg
    > rxrpc_post_packet_to_conn()
    - Setting conn->hi_serial
      - Probably safe not using locks
      - Maybe use cmpxchg

  * CALL-LEVEL PROCESSING
    > Old-call checking
      > rxrpc_input_implicit_end_call()
        > rxrpc_call_completed()
	> rxrpc_queue_call()
	! Need to take rx->incoming_lock
	> __rxrpc_disconnect_call()
	> rxrpc_notify_socket()
    > rxrpc_new_incoming_call()
      - Uses rx->incoming_lock for the entire process
        - Might be able to drop this earlier in favour of the call lock
      > rxrpc_incoming_call()
      	! Conflicts with rxrpc_input_implicit_end_call()
    > rxrpc_send_ping()
      - Don't need locks to check rtt state
      > rxrpc_propose_ACK

  * PACKET DISTRIBUTION
    > rxrpc_input_call_packet()
      > rxrpc_input_data()
	* QUEUE DATA PACKET ON CALL
	> rxrpc_reduce_call_timer()
	  - Uses timer_reduce()
	! Needs call->input_lock()
	> rxrpc_receiving_reply()
	  ! Needs locking around ack state
	  > rxrpc_rotate_tx_window()
	  > rxrpc_end_tx_phase()
	> rxrpc_proto_abort()
	> rxrpc_input_dup_data()
	- Fills the Rx buffer
	- rxrpc_propose_ACK()
	- rxrpc_notify_socket()

      > rxrpc_input_ack()
	* APPLY ACK PACKET TO CALL AND DISCARD PACKET
	> rxrpc_input_ping_response()
	  - Probably doesn't need any extra locking
	  ! Need READ_ONCE() on call->ping_serial
	  > rxrpc_input_check_for_lost_ack()
	    - Takes call->lock to consult Tx buffer
	  > rxrpc_peer_add_rtt()
	    ! Needs to take a lock (peer->rtt_input_lock)
	    ! Could perhaps manage with cmpxchg() and xadd() instead
	> rxrpc_input_requested_ack
	  - Consults Tx buffer
	    ! Probably needs a lock
	  > rxrpc_peer_add_rtt()
	> rxrpc_propose_ack()
	> rxrpc_input_ackinfo()
	  - Changes call->tx_winsize
	    ! Use cmpxchg to handle change
	    ! Should perhaps track serial number
	  - Uses peer->lock to record MTU specification changes
	> rxrpc_proto_abort()
	! Need to take call->input_lock
	> rxrpc_rotate_tx_window()
	> rxrpc_end_tx_phase()
	> rxrpc_input_soft_acks()
	- Consults the Tx buffer
	> rxrpc_congestion_management()
	  - Modifies the Tx annotations
	  ! Needs call->input_lock()
	  > rxrpc_queue_call()

      > rxrpc_input_abort()
	* APPLY ABORT PACKET TO CALL AND DISCARD PACKET
	> rxrpc_set_call_completion()
	> rxrpc_notify_socket()

      > rxrpc_input_ackall()
	* APPLY ACKALL PACKET TO CALL AND DISCARD PACKET
	! Need to take call->input_lock
	> rxrpc_rotate_tx_window()
	> rxrpc_end_tx_phase()

    > rxrpc_reject_packet()

There are some functions used by the above that queue the packet, after
which the procedure is terminated:

 - rxrpc_post_packet_to_local()
   - local->event_queue is an sk_buff_head
   - local->processor is a work_struct
 - rxrpc_post_packet_to_conn()
   - conn->rx_queue is an sk_buff_head
   - conn->processor is a work_struct
 - rxrpc_reject_packet()
   - local->reject_queue is an sk_buff_head
   - local->processor is a work_struct

And some that offload processing to process context:

 - rxrpc_notify_socket()
   - Uses RCU lock
   - Uses call->notify_lock to call call->notify_rx
   - Uses call->recvmsg_lock to queue recvmsg side
 - rxrpc_queue_call()
   - call->processor is a work_struct
 - rxrpc_propose_ACK()
   - Uses call->lock to wrap __rxrpc_propose_ACK()

And a bunch that complete a call, all of which use call->state_lock to
protect the call state:

 - rxrpc_call_completed()
 - rxrpc_set_call_completion()
 - rxrpc_abort_call()
 - rxrpc_proto_abort()
   - Also uses rxrpc_queue_call()

Fixes: 17926a79 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix the rxrpc_tx_packet trace line by storing the where parameter.

Fixes: 4764c0da ("rxrpc: Trace packet transmission")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix connection-level abort handling to cache the abort and error codes
properly so that a new incoming call can be properly aborted if it races
with the parent connection being aborted by another CPU.

The abort_code and error parameters can then be dropped from
rxrpc_abort_calls().

Fixes: f5c17aae ("rxrpc: Calls should only have one terminal state")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Move the out-of-order and duplicate ACK packet check to before the call to
rxrpc_input_ackinfo() so that the receive window size and MTU size are only
checked in the latest ACK packet and don't regress.

Fixes: 248f219c ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Carry the call state out of the locked section in rxrpc_rotate_tx_window()
rather than sampling it afterwards.  This is only used to select tracepoint
data, but could have changed by the time we do the tracepoint.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

We should only call the function to end a call's Tx phase if we rotated the
marked-last packet out of the transmission buffer.

Make rxrpc_rotate_tx_window() return an indication of whether it just
rotated the packet marked as the last out of the transmit buffer, carrying
the information out of the locked section in that function.

We can then check the return value instead of examining RXRPC_CALL_TX_LAST.

Fixes: 70790dbe ("rxrpc: Pass the last Tx packet marker in the annotation buffer")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

We don't need to take the RCU read lock in the rxrpc packet receive
function because it's held further up the stack in the IP input routine
around the UDP receive routines.

Fix this by dropping the RCU read lock calls from rxrpc_input_packet().
This simplifies the code.

Fixes: 70790dbe ("rxrpc: Pass the last Tx packet marker in the annotation buffer")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Use the UDP encap_rcv hook to cut the bit out of the rxrpc packet reception
in which a packet is placed onto the UDP receive queue and then immediately
removed again by rxrpc.  Going via the queue in this manner seems like it
should be unnecessary.

This does, however, require the invention of a value to place in encap_type
as that's one of the conditions to switch packets out to the encap_rcv
hook.  Possibly the value doesn't actually matter for anything other than
sockopts on the UDP socket, which aren't accessible outside of rxrpc
anyway.

This seems to cut a bit of time out of the time elapsed between each
sk_buff being timestamped and turning up in rxrpc (the final number in the
following trace excerpts).  I measured this by making the rxrpc_rx_packet
trace point print the time elapsed between the skb being timestamped and
the current time (in ns), e.g.:

	... 424.278721: rxrpc_rx_packet: ...  ACK 25026

So doing a 512MiB DIO read from my test server, with an unmodified kernel:

	N       min     max     sum		mean    stddev
	27605   2626    7581    7.83992e+07     2840.04 181.029

and with the patch applied:

	N       min     max     sum		mean    stddev
	27547   1895    12165   6.77461e+07     2459.29 255.02
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Eugene Syromiatnikov says:

====================
net/smc: userspace breakage fixes

These two patches correct some userspace-affecting issues introduced
during 4.19 development cycle, specifically:
 * New structure "struct smcd_diag_dmbinfo" has been defined in a way
   that would lead to different layout of the structure on most 32-bit
   ABIs in comparison with layout on 64-bit ABIs;
 * One of the commits renamed an UAPI-exposed field name.

Changes since v1:
 * Managed not to forget to add --cover-letter.
 * Commit ID format in commit message has been changed in accordance
   with Sergei Shtylyov's recommendations.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit c601171d ("net/smc: provide smc mode in smc_diag.c") changed
the name of diag_fallback field of struct smc_diag_msg structure
to diag_mode.  However, this structure is a part of UAPI, and this change
breaks user space applications that use it ([1], for example).  Since
the new name is more suitable, convert the field to a union that provides
access to the data via both the new and the old name.

[1] https://gitlab.com/strace/strace/blob/v4.24/netlink_smc_diag.c#L165

Fixes: c601171d ("net/smc: provide smc mode in smc_diag.c")
Signed-off-by: NEugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 4b1b7d3b ("net/smc: add SMC-D diag support") introduced
new UAPI-exposed structure, struct smcd_diag_dmbinfo.  However,
it's not usable by compat binaries, as it has different layout there.
Probably, the most straightforward fix that will avoid similar issues
in the future is to use __aligned_u64 for 64-bit fields.

Fixes: 4b1b7d3b ("net/smc: add SMC-D diag support")
Signed-off-by: NEugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

cls_u32.c misuses refcounts for struct tc_u_hnode - it counts references
via ->hlist and via ->tp_root together.  u32_destroy() drops the former
and, in case when there had been links, leaves the sucker on the list.
As the result, there's nothing to protect it from getting freed once links
are dropped.
That also makes the "is it busy" check incapable of catching the root
hnode - it *is* busy (there's a reference from tp), but we don't see it as
something separate.  "Is it our root?" check partially covers that, but
the problem exists for others' roots as well.

AFAICS, the minimal fix preserving the existing behaviour (where it doesn't
include oopsen, that is) would be this:
        * count tp->root and tp_c->hlist as separate references.  I.e.
have u32_init() set refcount to 2, not 1.
	* in u32_destroy() we always drop the former;
in u32_destroy_hnode() - the latter.

	That way we have *all* references contributing to refcount.  List
removal happens in u32_destroy_hnode() (called only when ->refcnt is 1)
an in u32_destroy() in case of tc_u_common going away, along with
everything reachable from it.  IOW, that way we know that
u32_destroy_key() won't free something still on the list (or pointed to by
someone's ->root).

Reproducer:

tc qdisc add dev eth0 ingress
tc filter add dev eth0 parent ffff: protocol ip prio 100 handle 1: \
u32 divisor 1
tc filter add dev eth0 parent ffff: protocol ip prio 200 handle 2: \
u32 divisor 1
tc filter add dev eth0 parent ffff: protocol ip prio 100 \
handle 1:0:11 u32 ht 1: link 801: offset at 0 mask 0f00 shift 6 \
plus 0 eat match ip protocol 6 ff
tc filter delete dev eth0 parent ffff: protocol ip prio 200
tc filter change dev eth0 parent ffff: protocol ip prio 100 \
handle 1:0:11 u32 ht 1: link 0: offset at 0 mask 0f00 shift 6 plus 0 \
eat match ip protocol 6 ff
tc filter delete dev eth0 parent ffff: protocol ip prio 100
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 2276f58a ("udp: use a separate rx queue for packet reception")
turned static inline __skb_recv_udp() from being a trivial helper around
__skb_recv_datagram() into a UDP specific implementaion, making it
EXPORT_SYMBOL_GPL() at the same time.

There are external modules that got broken by __skb_recv_udp() not being
visible to them. Let's unbreak them by making __skb_recv_udp EXPORT_SYMBOL().

Rationale (one of those) why this is actually "technically correct" thing
to do: __skb_recv_udp() used to be an inline wrapper around
__skb_recv_datagram(), which itself (still, and correctly so, I believe)
is EXPORT_SYMBOL().

Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Eric Dumazet <edumazet@google.com>
Fixes: 2276f58a ("udp: use a separate rx queue for packet reception")
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dave writes:
  "Networking fixes:

  1) Fix truncation of 32-bit right shift in bpf, from Jann Horn.

  2) Fix memory leak in wireless wext compat, from Stefan Seyfried.

  3) Use after free in cfg80211's reg_process_hint(), from Yu Zhao.

  4) Need to cancel pending work when unbinding in smsc75xx otherwise
     we oops, also from Yu Zhao.

  5) Don't allow enslaving a team device to itself, from Ido Schimmel.

  6) Fix backwards compat with older userspace for rtnetlink FDB dumps.
     From Mauricio Faria.

  7) Add validation of tc policy netlink attributes, from David Ahern.

  8) Fix RCU locking in rawv6_send_hdrinc(), from Wei Wang."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (26 commits)
  net: mvpp2: Extract the correct ethtype from the skb for tx csum offload
  ipv6: take rcu lock in rawv6_send_hdrinc()
  net: sched: Add policy validation for tc attributes
  rtnetlink: fix rtnl_fdb_dump() for ndmsg header
  yam: fix a missing-check bug
  net: bpfilter: Fix type cast and pointer warnings
  net: cxgb3_main: fix a missing-check bug
  bpf: 32-bit RSH verification must truncate input before the ALU op
  net: phy: phylink: fix SFP interface autodetection
  be2net: don't flip hw_features when VXLANs are added/deleted
  net/packet: fix packet drop as of virtio gso
  net: dsa: b53: Keep CPU port as tagged in all VLANs
  openvswitch: load NAT helper
  bnxt_en: get the reduced max_irqs by the ones used by RDMA
  bnxt_en: free hwrm resources, if driver probe fails.
  bnxt_en: Fix enables field in HWRM_QUEUE_COS2BW_CFG request
  bnxt_en: Fix VNIC reservations on the PF.
  team: Forbid enslaving team device to itself
  net/usb: cancel pending work when unbinding smsc75xx
  mlxsw: spectrum: Delete RIF when VLAN device is removed
  ...