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>
diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
index 1fb1189..c587e3c 100644
--- a/fs/nfs/Makefile
+++ b/fs/nfs/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for the Linux nfs filesystem routines.
 #
diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
index a69ef4e..95f74bd 100644
--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2014-2016 Christoph Hellwig.
  */
diff --git a/fs/nfs/blocklayout/extent_tree.c b/fs/nfs/blocklayout/extent_tree.c
index c85fbfd..7a57ff2 100644
--- a/fs/nfs/blocklayout/extent_tree.c
+++ b/fs/nfs/blocklayout/extent_tree.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2014-2016 Christoph Hellwig.
  */
diff --git a/fs/nfs/cache_lib.c b/fs/nfs/cache_lib.c
index 2ae676f..b60627b 100644
--- a/fs/nfs/cache_lib.c
+++ b/fs/nfs/cache_lib.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/cache_lib.c
  *
diff --git a/fs/nfs/cache_lib.h b/fs/nfs/cache_lib.h
index 4116d2c..4e6236a 100644
--- a/fs/nfs/cache_lib.h
+++ b/fs/nfs/cache_lib.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Helper routines for the NFS client caches
  *
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 2cddf7f..cd9d992 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/callback.c
  *
diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
index 3dc54d7..a20a0bc 100644
--- a/fs/nfs/callback.h
+++ b/fs/nfs/callback.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * linux/fs/nfs/callback.h
  *
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 14358de..19151f6 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/callback_proc.c
  *
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 681dd64..123c069 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/callback_xdr.c
  *
diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h
index e9d5557..ddaf264 100644
--- a/fs/nfs/delegation.h
+++ b/fs/nfs/delegation.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * linux/fs/nfs/delegation.h
  *
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index d25f10f..060c658 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/dns_resolve.c
  *
diff --git a/fs/nfs/dns_resolve.h b/fs/nfs/dns_resolve.h
index 2e4f596..576ff4b 100644
--- a/fs/nfs/dns_resolve.h
+++ b/fs/nfs/dns_resolve.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Resolve DNS hostnames into valid ip addresses
  */
diff --git a/fs/nfs/export.c b/fs/nfs/export.c
index 249cb96..83fd09f 100644
--- a/fs/nfs/export.c
+++ b/fs/nfs/export.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2015, Primary Data, Inc. All rights reserved.
  *
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h
index 98b34c9..679cb08 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * NFSv4 flexfile layout driver data structures.
  *
diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
index f32c58b..d62279d 100644
--- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c
+++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Device operations for the pnfs nfs4 file layout driver.
  *
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 5bdf952..f9a4a55 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * NFS internal definitions
  */
diff --git a/fs/nfs/io.c b/fs/nfs/io.c
index 1fc5d1c..20fef85 100644
--- a/fs/nfs/io.c
+++ b/fs/nfs/io.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2016 Trond Myklebust
  *
diff --git a/fs/nfs/iostat.h b/fs/nfs/iostat.h
index 0cb806f..2ddaab1 100644
--- a/fs/nfs/iostat.h
+++ b/fs/nfs/iostat.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  *  linux/fs/nfs/iostat.h
  *
diff --git a/fs/nfs/mount_clnt.c b/fs/nfs/mount_clnt.c
index 60bad88..d979ff4 100644
--- a/fs/nfs/mount_clnt.c
+++ b/fs/nfs/mount_clnt.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * In-kernel MOUNT protocol client
  *
diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h
index 5fbd2bd..fc9978c 100644
--- a/fs/nfs/netns.h
+++ b/fs/nfs/netns.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * NFS-private data for each "struct net".  Accessed with net_generic().
  */
diff --git a/fs/nfs/nfs.h b/fs/nfs/nfs.h
index 43679df..5ba0061 100644
--- a/fs/nfs/nfs.h
+++ b/fs/nfs/nfs.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (c) 2012 Netapp, Inc. All rights reserved.
  *
diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
index fe68dab..85e4b4a 100644
--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/nfs2xdr.c
  *
diff --git a/fs/nfs/nfs3_fs.h b/fs/nfs/nfs3_fs.h
index e134d65..f82e11c 100644
--- a/fs/nfs/nfs3_fs.h
+++ b/fs/nfs/nfs3_fs.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (C) 2014 Anna Schumaker.
  *
diff --git a/fs/nfs/nfs3acl.c b/fs/nfs/nfs3acl.c
index 720d92f5..7173a4e 100644
--- a/fs/nfs/nfs3acl.c
+++ b/fs/nfs/nfs3acl.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <linux/fs.h>
 #include <linux/gfp.h>
 #include <linux/nfs.h>
diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index d1e87ec..bc673fb 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *  linux/fs/nfs/nfs3proc.c
  *
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index e82c9e5..6cd33bd 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/nfs3xdr.c
  *
diff --git a/fs/nfs/nfs42.h b/fs/nfs/nfs42.h
index b6cd153..19ec38f8 100644
--- a/fs/nfs/nfs42.h
+++ b/fs/nfs/nfs42.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (c) 2014 Anna Schumaker <Anna.Schumaker@Netapp.com>
  */
diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index 6c2db51..9c37444 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2014 Anna Schumaker <Anna.Schumaker@Netapp.com>
  */
diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
index 5ee1b0f..5966e1e 100644
--- a/fs/nfs/nfs42xdr.c
+++ b/fs/nfs/nfs42xdr.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2014 Anna Schumaker <Anna.Schumaker@Netapp.com>
  */
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index ac4f10b..dcfcf7f 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * linux/fs/nfs/nfs4_fs.h
  *
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 0efba77..626d138 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *  linux/fs/nfs/file.c
  *
diff --git a/fs/nfs/nfs4getroot.c b/fs/nfs/nfs4getroot.c
index ac840601..1a69479 100644
--- a/fs/nfs/nfs4getroot.c
+++ b/fs/nfs/nfs4getroot.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 7d531da..8c3f327 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/nfs4namespace.c
  *
diff --git a/fs/nfs/nfs4session.h b/fs/nfs/nfs4session.h
index dfae488..3c550f2 100644
--- a/fs/nfs/nfs4session.h
+++ b/fs/nfs/nfs4session.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * fs/nfs/nfs4session.h
  *
diff --git a/fs/nfs/nfs4sysctl.c b/fs/nfs/nfs4sysctl.c
index 8693d77..0d91d84 100644
--- a/fs/nfs/nfs4sysctl.c
+++ b/fs/nfs/nfs4sysctl.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/nfs4sysctl.c
  *
diff --git a/fs/nfs/nfs4trace.c b/fs/nfs/nfs4trace.c
index 2850bce..e9fb3e5 100644
--- a/fs/nfs/nfs4trace.c
+++ b/fs/nfs/nfs4trace.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2013 Trond Myklebust <Trond.Myklebust@netapp.com>
  */
diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h
index be1da19..e7c6275 100644
--- a/fs/nfs/nfs4trace.h
+++ b/fs/nfs/nfs4trace.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (c) 2013 Trond Myklebust <Trond.Myklebust@netapp.com>
  */
diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 89a15db..effaa424 100644
--- a/fs/nfs/nfsroot.c
+++ b/fs/nfs/nfsroot.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *  Copyright (C) 1995, 1996  Gero Kuhlmann <gero@gkminix.han.de>
  *
diff --git a/fs/nfs/nfstrace.c b/fs/nfs/nfstrace.c
index c74f7af..b60d5fb 100644
--- a/fs/nfs/nfstrace.c
+++ b/fs/nfs/nfstrace.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2013 Trond Myklebust <Trond.Myklebust@netapp.com>
  */
diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
index 5517110..093290c 100644
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (c) 2013 Trond Myklebust <Trond.Myklebust@netapp.com>
  */
diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index 7962e49..f7fd919 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *  linux/fs/nfs/proc.c
  *
diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c
index 5a1d0de..06eb44b 100644
--- a/fs/nfs/symlink.c
+++ b/fs/nfs/symlink.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *  linux/fs/nfs/symlink.c
  *
diff --git a/fs/nfs/sysctl.c b/fs/nfs/sysctl.c
index bb6ed81..7aea195 100644
--- a/fs/nfs/sysctl.c
+++ b/fs/nfs/sysctl.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/fs/nfs/sysctl.c
  *
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index e3949d9..630b4a3 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *  linux/fs/nfs/unlink.c
  *