net: qualcomm: rmnet: add tx packets aggregation

Add tx packets aggregation.

Bidirectional TCP throughput tests through iperf with low-cat
Thread-x based modems revelead performance issues both in tx
and rx.

The Windows driver does not show this issue: inspecting USB
packets revealed that the only notable change is the driver
enabling tx packets aggregation.

Tx packets aggregation is by default disabled and can be enabled
by increasing the value of ETHTOOL_A_COALESCE_TX_MAX_AGGR_FRAMES.

The maximum aggregated size is by default set to a reasonably low
value in order to support the majority of modems.

This implementation is based on patches available in Code Aurora
repositories (msm kernel) whose main authors are

Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Sean Tranchetti <stranche@codeaurora.org>

Signed-off-by: Daniele Palmas <dnlplm@gmail.com>
Reviewed-by: Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: qualcomm: rmnet: Update rmnet device MTU based on real device

Packets sent by rmnet to the real device have variable MAP header
lengths based on the data format configured. This patch adds checks
to ensure that the real device MTU is sufficient to transmit the MAP
packet comprising of the MAP header and the IP packet. This check
is enforced when rmnet devices are created and updated and during
MTU updates of both the rmnet and real device.

Additionally, rmnet devices now have a default MTU configured which
accounts for the real device MTU and the headroom based on the data
format.

Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Tested-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: rmnet: print error message when command fails

When rmnet netlink command fails, it doesn't print any error message.
So, users couldn't know the exact reason.
In order to tell the exact reason to the user, the extack error message
is used in this patch.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: rmnet: fix bridge mode bugs

In order to attach a bridge interface to the rmnet interface,
"master" operation is used.
(e.g. ip link set dummy1 master rmnet0)
But, in the rmnet_add_bridge(), which is a callback of ->ndo_add_slave()
doesn't register lower interface.
So, ->ndo_del_slave() doesn't work.
There are other problems too.
1. It couldn't detect circular upper/lower interface relationship.
2. It couldn't prevent stack overflow because of too deep depth
of upper/lower interface
3. It doesn't check the number of lower interfaces.
4. Panics because of several reasons.

The root problem of these issues is actually the same.
So, in this patch, these all problems will be fixed.

Test commands:
modprobe rmnet
ip link add dummy0 type dummy
ip link add rmnet0 link dummy0 type rmnet mux_id 1
ip link add dummy1 master rmnet0 type dummy
ip link add dummy2 master rmnet0 type dummy
ip link del rmnet0
ip link del dummy2
ip link del dummy1

Splat looks like:
[ 41.867595][ T1164] general protection fault, probably for non-canonical address 0xdffffc0000000101I
[ 41.869993][ T1164] KASAN: null-ptr-deref in range [0x0000000000000808-0x000000000000080f]
[ 41.872950][ T1164] CPU: 0 PID: 1164 Comm: ip Not tainted 5.6.0-rc1+ #447
[ 41.873915][ T1164] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 41.875161][ T1164] RIP: 0010:rmnet_unregister_bridge.isra.6+0x71/0xf0 [rmnet]
[ 41.876178][ T1164] Code: 48 89 ef 48 89 c6 5b 5d e9 fc fe ff ff e8 f7 f3 ff ff 48 8d b8 08 08 00 00 48 ba 00 7
[ 41.878925][ T1164] RSP: 0018:ffff8880c4d0f188 EFLAGS: 00010202
[ 41.879774][ T1164] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000101
[ 41.887689][ T1164] RDX: dffffc0000000000 RSI: ffffffffb8cf64f0 RDI: 0000000000000808
[ 41.888727][ T1164] RBP: ffff8880c40e4000 R08: ffffed101b3c0e3c R09: 0000000000000001
[ 41.889749][ T1164] R10: 0000000000000001 R11: ffffed101b3c0e3b R12: 1ffff110189a1e3c
[ 41.890783][ T1164] R13: ffff8880c4d0f200 R14: ffffffffb8d56160 R15: ffff8880ccc2c000
[ 41.891794][ T1164] FS: 00007f4300edc0c0(0000) GS:ffff8880d9c00000(0000) knlGS:0000000000000000
[ 41.892953][ T1164] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 41.893800][ T1164] CR2: 00007f43003bc8c0 CR3: 00000000ca53e001 CR4: 00000000000606f0
[ 41.894824][ T1164] Call Trace:
[ 41.895274][ T1164] ? rcu_is_watching+0x2c/0x80
[ 41.895895][ T1164] rmnet_config_notify_cb+0x1f7/0x590 [rmnet]
[ 41.896687][ T1164] ? rmnet_unregister_bridge.isra.6+0xf0/0xf0 [rmnet]
[ 41.897611][ T1164] ? rmnet_unregister_bridge.isra.6+0xf0/0xf0 [rmnet]
[ 41.898508][ T1164] ? __module_text_address+0x13/0x140
[ 41.899162][ T1164] notifier_call_chain+0x90/0x160
[ 41.899814][ T1164] rollback_registered_many+0x660/0xcf0
[ 41.900544][ T1164] ? netif_set_real_num_tx_queues+0x780/0x780
[ 41.901316][ T1164] ? __lock_acquire+0xdfe/0x3de0
[ 41.901958][ T1164] ? memset+0x1f/0x40
[ 41.902468][ T1164] ? __nla_validate_parse+0x98/0x1ab0
[ 41.903166][ T1164] unregister_netdevice_many.part.133+0x13/0x1b0
[ 41.903988][ T1164] rtnl_delete_link+0xbc/0x100
[ ... ]

Fixes: 60d58f971c10 ("net: qualcomm: rmnet: Implement bridge mode")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 284

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 and
only version 2 as published by the free software foundation this
program is distributed in the hope that it will be useful but
without any warranty without even the implied warranty of
merchantability or fitness for a particular purpose see the gnu
general public license for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 294 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141900.825281744@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net: qualcomm: rmnet: Convert the muxed endpoint to hlist

Rather than using a static array, use a hlist to store the muxed
endpoints and use the mux id to query the rmnet_device.
This is useful as usually very few mux ids are used.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Dan Williams <dcbw@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: qualcomm: rmnet: Remove duplicate setting of rmnet private info

The end point is set twice in the local_ep as well as the mux_id and
the real_dev in the rmnet private structure. Remove the local_ep.
While these elements are equivalent, rmnet_endpoint will be
used only as part of the rmnet_port for muxed scenarios in VND mode.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: qualcomm: rmnet: Rename real_dev_info to port

Make it similar to drivers like ipvlan / macvlan so it is easier to read.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Dan Williams <dcbw@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: qualcomm: rmnet: Implement ndo_get_iflink

This makes it easier to find out the parent dev.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Dan Williams <dcbw@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: qualcomm: rmnet: Refactor the new rmnet dev creation

Data format can be directly set from rmnet_newlink() since the
rmnet real dev info is already available.

Since __rmnet_get_real_dev_info() is no longer used in rmnet_config.c
after removal of those functions, move content to
rmnet_get_real_dev_info().

__rmnet_set_endpoint_config() is collapsed into
rmnet_set_endpoint_config() since only mux_id was being set additionally
within it. Remove an unnecessary mux_id check.

Set the mux_id for the rmnet_dev within rmnet_vnd_newlink() itself.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Dan Williams <dcbw@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers: net: ethernet: qualcomm: rmnet: Initial implementation

RmNet driver provides a transport agnostic MAP (multiplexing and
aggregation protocol) support in embedded module. Module provides
virtual network devices which can be attached to any IP-mode
physical device. This will be used to provide all MAP functionality
on future hardware in a single consistent location.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>