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>

16 files changed, 16 insertions, 0 deletions

diff --git a/drivers/pnp/Makefile b/drivers/pnp/Makefile
index bfba893cb321..71d532f18219 100644
--- a/drivers/pnp/Makefile
+++ b/drivers/pnp/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for the Linux Plug-and-Play Support.
 #
diff --git a/drivers/pnp/base.h b/drivers/pnp/base.h
index 3151fd164614..cdcfa39cf167 100644
--- a/drivers/pnp/base.h
+++ b/drivers/pnp/base.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (C) 2008 Hewlett-Packard Development Company, L.P.
  *	Bjorn Helgaas <bjorn.helgaas@hp.com>
diff --git a/drivers/pnp/card.c b/drivers/pnp/card.c
index 31ad9fc3f701..c2464ee08e4a 100644
--- a/drivers/pnp/card.c
+++ b/drivers/pnp/card.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * card.c - contains functions for managing groups of PnP devices
  *
diff --git a/drivers/pnp/core.c b/drivers/pnp/core.c
index b54620e53830..3bf18d718975 100644
--- a/drivers/pnp/core.c
+++ b/drivers/pnp/core.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * core.c - contains all core device and protocol registration functions
  *
diff --git a/drivers/pnp/driver.c b/drivers/pnp/driver.c
index 63452f20e3e9..93a30a8f88d1 100644
--- a/drivers/pnp/driver.c
+++ b/drivers/pnp/driver.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * driver.c - device id matching, driver model, etc.
  *
diff --git a/drivers/pnp/interface.c b/drivers/pnp/interface.c
index 5c5b3d47b5f6..187e4a1175b0 100644
--- a/drivers/pnp/interface.c
+++ b/drivers/pnp/interface.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * interface.c - contains everything related to the user interface
  *
diff --git a/drivers/pnp/isapnp/compat.c b/drivers/pnp/isapnp/compat.c
index 10bdcc4d4f7b..6c845b628316 100644
--- a/drivers/pnp/isapnp/compat.c
+++ b/drivers/pnp/isapnp/compat.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * compat.c - A series of functions to make it easier to convert drivers that use
  *            the old isapnp APIs. If possible use the new APIs instead.
diff --git a/drivers/pnp/manager.c b/drivers/pnp/manager.c
index 7ad3295752ef..144055593ec8 100644
--- a/drivers/pnp/manager.c
+++ b/drivers/pnp/manager.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * manager.c - Resource Management, Conflict Resolution, Activation and Disabling of Devices
  *
diff --git a/drivers/pnp/pnpacpi/pnpacpi.h b/drivers/pnp/pnpacpi/pnpacpi.h
index 051ef9699777..4489cd6dbc84 100644
--- a/drivers/pnp/pnpacpi/pnpacpi.h
+++ b/drivers/pnp/pnpacpi/pnpacpi.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef ACPI_PNP_H
 #define ACPI_PNP_H
 
diff --git a/drivers/pnp/pnpbios/bioscalls.c b/drivers/pnp/pnpbios/bioscalls.c
index ff563db025b3..ba5cfc3dbe11 100644
--- a/drivers/pnp/pnpbios/bioscalls.c
+++ b/drivers/pnp/pnpbios/bioscalls.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * bioscalls.c - the lowlevel layer of the PnPBIOS driver
  */
diff --git a/drivers/pnp/pnpbios/proc.c b/drivers/pnp/pnpbios/proc.c
index 5ee6b2a5f8d5..7d4aca7948dd 100644
--- a/drivers/pnp/pnpbios/proc.c
+++ b/drivers/pnp/pnpbios/proc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * /proc/bus/pnp interface for Plug and Play devices
  *
diff --git a/drivers/pnp/pnpbios/rsparser.c b/drivers/pnp/pnpbios/rsparser.c
index cca2f9f9f3e3..2f31b212b1a5 100644
--- a/drivers/pnp/pnpbios/rsparser.c
+++ b/drivers/pnp/pnpbios/rsparser.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * rsparser.c - parses and encodes pnpbios resource data streams
  */
diff --git a/drivers/pnp/quirks.c b/drivers/pnp/quirks.c
index d28e3ab9479c..f054cdddfef8 100644
--- a/drivers/pnp/quirks.c
+++ b/drivers/pnp/quirks.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *  This file contains quirk handling code for PnP devices
  *  Some devices do not report all their resources, and need to have extra
diff --git a/drivers/pnp/resource.c b/drivers/pnp/resource.c
index f980ff7166e9..70d4ba95735a 100644
--- a/drivers/pnp/resource.c
+++ b/drivers/pnp/resource.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * resource.c - Contains functions for registering and analyzing resource information
  *
diff --git a/drivers/pnp/support.c b/drivers/pnp/support.c
index f5beb24d036a..e4f53d31191d 100644
--- a/drivers/pnp/support.c
+++ b/drivers/pnp/support.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * support.c - standard functions for the use of pnp protocol drivers
  *
diff --git a/drivers/pnp/system.c b/drivers/pnp/system.c
index 49c1720df59a..6950503741eb 100644
--- a/drivers/pnp/system.c
+++ b/drivers/pnp/system.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * system.c - a driver for reserving pnp system resources
  *