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>

include/trace/define_trace.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Trace files that want to automate creation of all tracepoints defined
  * in their file should include this file. The following are macros that the

include/trace/events/9p.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM 9p
 

include/trace/events/alarmtimer.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM alarmtimer
 

include/trace/events/asoc.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM asoc
 

include/trace/events/bcache.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM bcache
 

include/trace/events/block.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM block
 

include/trace/events/bpf.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM bpf
 

include/trace/events/btrfs.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM btrfs
 

include/trace/events/cgroup.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM cgroup
 

include/trace/events/cma.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM cma
 

include/trace/events/compaction.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM compaction
 

include/trace/events/context_tracking.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM context_tracking
 

include/trace/events/cpuhp.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM cpuhp
 

include/trace/events/devlink.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #if IS_ENABLED(CONFIG_NET_DEVLINK)
 
 #undef TRACE_SYSTEM

include/trace/events/dma_fence.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM dma_fence
 

include/trace/events/ext4.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM ext4
 

include/trace/events/f2fs.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM f2fs
 

include/trace/events/fib.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM fib
 

include/trace/events/fib6.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM fib6
 

include/trace/events/filelock.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Events for filesystem locks
  *

include/trace/events/filemap.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM filemap
 

include/trace/events/fs_dax.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM fs_dax
 

include/trace/events/fsi.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM fsi

include/trace/events/fsi_master_gpio.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM fsi_master_gpio

include/trace/events/gpio.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM gpio
 

include/trace/events/hswadsp.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM hswadsp
 

include/trace/events/huge_memory.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM huge_memory
 

include/trace/events/intel-sst.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM intel-sst
 

include/trace/events/intel_ish.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM intel_ish
 

include/trace/events/iommu.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * iommu trace points
  *

include/trace/events/ipi.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM ipi
 

include/trace/events/irq.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM irq
 

include/trace/events/jbd2.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM jbd2
 

include/trace/events/kmem.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM kmem
 

include/trace/events/kvm.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #if !defined(_TRACE_KVM_MAIN_H) || defined(TRACE_HEADER_MULTI_READ)
 #define _TRACE_KVM_MAIN_H
 

include/trace/events/libata.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM libata
 

include/trace/events/lock.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM lock
 

include/trace/events/mce.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM mce
 

include/trace/events/mdio.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM mdio
 

include/trace/events/migrate.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM migrate
 

include/trace/events/mmc.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM mmc
 

include/trace/events/mmflags.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #include <linux/node.h>
 #include <linux/mmzone.h>
 #include <linux/compaction.h>

include/trace/events/module.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Because linux/module.h has tracepoints in the header, and ftrace.h
  * used to include this file, define_trace.h includes linux/module.h

include/trace/events/napi.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM napi
 

include/trace/events/net.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM net
 

include/trace/events/nilfs2.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM nilfs2
 

include/trace/events/nmi.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM nmi
 

include/trace/events/oom.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM oom
 

include/trace/events/page_isolation.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM page_isolation
 

include/trace/events/page_ref.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM page_ref
 

include/trace/events/pagemap.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM pagemap
 

include/trace/events/percpu.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM percpu
 

include/trace/events/power.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM power
 

include/trace/events/power_cpu_migrate.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM power
 

include/trace/events/printk.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM printk
 

include/trace/events/random.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM random
 

include/trace/events/rcu.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM rcu
 

include/trace/events/regulator.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM regulator
 

include/trace/events/rpm.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM rpm

include/trace/events/sched.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM sched
 

include/trace/events/scsi.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM scsi
 

include/trace/events/signal.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM signal
 

include/trace/events/skb.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM skb
 

include/trace/events/sock.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM sock
 

include/trace/events/spi.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM spi
 

include/trace/events/spmi.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM spmi
 

include/trace/events/sunrpc.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM sunrpc
 

include/trace/events/sunvnet.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM sunvnet
 

include/trace/events/swiotlb.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM swiotlb
 

include/trace/events/syscalls.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM raw_syscalls
 #undef TRACE_INCLUDE_FILE

include/trace/events/target.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM target
 

include/trace/events/task.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM task
 

include/trace/events/thermal.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM thermal
 

include/trace/events/thermal_power_allocator.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM thermal_power_allocator
 

include/trace/events/thp.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM thp
 

include/trace/events/timer.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM timer
 

include/trace/events/tlb.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM tlb
 

include/trace/events/udp.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM udp
 

include/trace/events/v4l2.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM v4l2
 

include/trace/events/vb2.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM vb2
 

include/trace/events/vmscan.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM vmscan
 

include/trace/events/vsock_virtio_transport_common.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM vsock
 

include/trace/events/wbt.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM wbt
 

include/trace/events/workqueue.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM workqueue
 

include/trace/events/writeback.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM writeback
 

include/trace/events/xdp.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM xdp
 

include/trace/events/xen.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM xen
 

include/trace/perf.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 
 #undef TRACE_SYSTEM_VAR
 

include/trace/syscall.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _TRACE_SYSCALL_H
 #define _TRACE_SYSCALL_H
 

include/trace/trace_events.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Stage 1 of the trace events.
  *