net: sched: take reference to psample group in flow_action infra

With recent patch set that removed rtnl lock dependency from cls hardware
offload API rtnl lock is only taken when reading action data and can be
released after action-specific data is parsed into intermediate
representation. However, sample action psample group is passed by pointer
without obtaining reference to it first, which makes it possible to
concurrently overwrite the action and deallocate object pointed by
psample_group pointer after rtnl lock is released but before driver
finished using the pointer.

To prevent such race condition, obtain reference to psample group while it
is used by flow_action infra. Extend psample API with function
psample_group_take() that increments psample group reference counter.
Extend struct tc_action_ops with new get_psample_group() API. Implement the
API for action sample using psample_group_take() and already existing
psample_group_put() as a destructor. Use it in tc_setup_flow_action() to
take reference to psample group pointed to by entry->sample.psample_group
and release it in tc_cleanup_flow_action().

Disable bh when taking psample_groups_lock. The lock is now taken while
holding action tcf_lock that is used by data path and requires bh to be
disabled, so doing the same for psample_groups_lock is necessary to
preserve SOFTIRQ-irq-safety.

Fixes: 918190f50eb6 ("net: sched: flower: don't take rtnl lock for cls hw offloads API")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: sample: allow accessing psample_group with rtnl

Recently implemented support for sample action in flow_offload infra leads
to following rcu usage warning:

[ 1938.234856] =============================
[ 1938.234858] WARNING: suspicious RCU usage
[ 1938.234863] 5.3.0-rc1+ #574 Not tainted
[ 1938.234866] -----------------------------
[ 1938.234869] include/net/tc_act/tc_sample.h:47 suspicious rcu_dereference_check() usage!
[ 1938.234872]
other info that might help us debug this:

[ 1938.234875]
rcu_scheduler_active = 2, debug_locks = 1
[ 1938.234879] 1 lock held by tc/19540:
[ 1938.234881] #0: 00000000b03cb918 (rtnl_mutex){+.+.}, at: tc_new_tfilter+0x47c/0x970
[ 1938.234900]
stack backtrace:
[ 1938.234905] CPU: 2 PID: 19540 Comm: tc Not tainted 5.3.0-rc1+ #574
[ 1938.234908] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b 03/30/2017
[ 1938.234911] Call Trace:
[ 1938.234922] dump_stack+0x85/0xc0
[ 1938.234930] tc_setup_flow_action+0xed5/0x2040
[ 1938.234944] fl_hw_replace_filter+0x11f/0x2e0 [cls_flower]
[ 1938.234965] fl_change+0xd24/0x1b30 [cls_flower]
[ 1938.234990] tc_new_tfilter+0x3e0/0x970
[ 1938.235021] ? tc_del_tfilter+0x720/0x720
[ 1938.235028] rtnetlink_rcv_msg+0x389/0x4b0
[ 1938.235038] ? netlink_deliver_tap+0x95/0x400
[ 1938.235044] ? rtnl_dellink+0x2d0/0x2d0
[ 1938.235053] netlink_rcv_skb+0x49/0x110
[ 1938.235063] netlink_unicast+0x171/0x200
[ 1938.235073] netlink_sendmsg+0x224/0x3f0
[ 1938.235091] sock_sendmsg+0x5e/0x60
[ 1938.235097] ___sys_sendmsg+0x2ae/0x330
[ 1938.235111] ? __handle_mm_fault+0x12cd/0x19e0
[ 1938.235125] ? __handle_mm_fault+0x12cd/0x19e0
[ 1938.235138] ? find_held_lock+0x2b/0x80
[ 1938.235147] ? do_user_addr_fault+0x22d/0x490
[ 1938.235160] __sys_sendmsg+0x59/0xa0
[ 1938.235178] do_syscall_64+0x5c/0xb0
[ 1938.235187] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1938.235192] RIP: 0033:0x7ff9a4d597b8
[ 1938.235197] Code: 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 65 8f 0c 00 8b 00 85 c0 75 17 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83
ec 28 89 54
[ 1938.235200] RSP: 002b:00007ffcfe381c48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 1938.235205] RAX: ffffffffffffffda RBX: 000000005d4497f9 RCX: 00007ff9a4d597b8
[ 1938.235208] RDX: 0000000000000000 RSI: 00007ffcfe381cb0 RDI: 0000000000000003
[ 1938.235211] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000006
[ 1938.235214] R10: 0000000000404ec2 R11: 0000000000000246 R12: 0000000000000001
[ 1938.235217] R13: 0000000000480640 R14: 0000000000000012 R15: 0000000000000001

Change tcf_sample_psample_group() helper to allow using it from both rtnl
and rcu protected contexts.

Fixes: a7a7be6087b0 ("net/sched: add sample action to the hardware intermediate representation")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Change TCA_ACT_* to TCA_ID_* to match that of TCA_ID_POLICE

Modify the kernel users of the TCA_ACT_* macros to use TCA_ID_*. For
example, use TCA_ID_GACT instead of TCA_ACT_GACT. This will align with
TCA_ID_POLICE and also differentiates these identifier, used in struct
tc_action_ops type field, from other macros starting with TCA_ACT_.

To make things clearer, we name the enum defining the TCA_ID_*
identifiers and also change the "type" field of struct tc_action to
id.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

act_sample: get rid of tcf_sample_cleanup_rcu()

Similar to commit d7fb60b9cafb ("net_sched: get rid of tcfa_rcu"),
TC actions don't need to respect RCU grace period, because it
is either just detached from tc filter (standalone case) or
it is removed together with tc filter (bound case) in which case
RCU grace period is already respected at filter layer.

Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/sched: Introduce sample tc action

This action allows the user to sample traffic matched by tc classifier.
The sampling consists of choosing packets randomly and sampling them using
the psample module. The user can configure the psample group number, the
sampling rate and the packet's truncation (to save kernel-user traffic).

Example:
To sample ingress traffic from interface eth1, one may use the commands:

tc qdisc add dev eth1 handle ffff: ingress

tc filter add dev eth1 parent ffff: \
matchall action sample rate 12 group 4

Where the first command adds an ingress qdisc and the second starts
sampling randomly with an average of one sampled packet per 12 packets on
dev eth1 to psample group 4.

Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>