v4.19.13 snapshot.
diff --git a/scripts/documentation-file-ref-check b/scripts/documentation-file-ref-check
new file mode 100755
index 0000000..ad9db68
--- /dev/null
+++ b/scripts/documentation-file-ref-check
@@ -0,0 +1,164 @@
+#!/usr/bin/env perl
+# SPDX-License-Identifier: GPL-2.0
+#
+# Treewide grep for references to files under Documentation, and report
+# non-existing files in stderr.
+
+use warnings;
+use strict;
+use Getopt::Long qw(:config no_auto_abbrev);
+
+my $scriptname = $0;
+$scriptname =~ s,.*/([^/]+/),$1,;
+
+# Parse arguments
+my $help = 0;
+my $fix = 0;
+
+GetOptions(
+ 'fix' => \$fix,
+ 'h|help|usage' => \$help,
+);
+
+if ($help != 0) {
+ print "$scriptname [--help] [--fix]\n";
+ exit -1;
+}
+
+# Step 1: find broken references
+print "Finding broken references. This may take a while... " if ($fix);
+
+my %broken_ref;
+
+open IN, "git grep 'Documentation/'|"
+ or die "Failed to run git grep";
+while (<IN>) {
+ next if (!m/^([^:]+):(.*)/);
+
+ my $f = $1;
+ my $ln = $2;
+
+ # Makefiles and scripts contain nasty expressions to parse docs
+ next if ($f =~ m/Makefile/ || $f =~ m/\.sh$/);
+
+ # Skip this script
+ next if ($f eq $scriptname);
+
+ if ($ln =~ m,\b(\S*)(Documentation/[A-Za-z0-9\_\.\,\~/\*\[\]\?+-]*)(.*),) {
+ my $prefix = $1;
+ my $ref = $2;
+ my $base = $2;
+ my $extra = $3;
+
+ # some file references are like:
+ # /usr/src/linux/Documentation/DMA-{API,mapping}.txt
+ # For now, ignore them
+ next if ($extra =~ m/^{/);
+
+ # Remove footnotes at the end like:
+ # Documentation/devicetree/dt-object-internal.txt[1]
+ $ref =~ s/(txt|rst)\[\d+]$/$1/;
+
+ # Remove ending ']' without any '['
+ $ref =~ s/\].*// if (!($ref =~ m/\[/));
+
+ # Remove puntuation marks at the end
+ $ref =~ s/[\,\.]+$//;
+
+ my $fulref = "$prefix$ref";
+
+ $fulref =~ s/^(\<file|ref)://;
+ $fulref =~ s/^[\'\`]+//;
+ $fulref =~ s,^\$\(.*\)/,,;
+ $base =~ s,.*/,,;
+
+ # Remove URL false-positives
+ next if ($fulref =~ m/^http/);
+
+ # Remove sched-pelt false-positive
+ next if ($fulref =~ m,^Documentation/scheduler/sched-pelt$,);
+
+ # Discard some build examples from Documentation/target/tcm_mod_builder.txt
+ next if ($fulref =~ m,mnt/sdb/lio-core-2.6.git/Documentation/target,);
+
+ # Check if exists, evaluating wildcards
+ next if (grep -e, glob("$ref $fulref"));
+
+ # Accept relative Documentation patches for tools/
+ if ($f =~ m/tools/) {
+ my $path = $f;
+ $path =~ s,(.*)/.*,$1,;
+ next if (grep -e, glob("$path/$ref $path/$fulref"));
+ }
+
+ if ($fix) {
+ if (!($ref =~ m/(scripts|Kconfig|Kbuild)/)) {
+ $broken_ref{$ref}++;
+ }
+ } else {
+ print STDERR "$f: $fulref\n";
+ }
+ }
+}
+
+exit 0 if (!$fix);
+
+# Step 2: Seek for file name alternatives
+print "Auto-fixing broken references. Please double-check the results\n";
+
+foreach my $ref (keys %broken_ref) {
+ my $new =$ref;
+
+ # get just the basename
+ $new =~ s,.*/,,;
+
+ my $f="";
+
+ # usual reason for breakage: DT file moved around
+ if ($ref =~ /devicetree/) {
+ my $search = $new;
+ $search =~ s,^.*/,,;
+ $f = qx(find Documentation/devicetree/ -iname "*$search*") if ($search);
+ if (!$f) {
+ # Manufacturer name may have changed
+ $search =~ s/^.*,//;
+ $f = qx(find Documentation/devicetree/ -iname "*$search*") if ($search);
+ }
+ }
+
+ # usual reason for breakage: file renamed to .rst
+ if (!$f) {
+ $new =~ s/\.txt$/.rst/;
+ $f=qx(find . -iname $new) if ($new);
+ }
+
+ # usual reason for breakage: use dash or underline
+ if (!$f) {
+ $new =~ s/[-_]/[-_]/g;
+ $f=qx(find . -iname $new) if ($new);
+ }
+
+ # Wild guess: seek for the same name on another place
+ if (!$f) {
+ $f = qx(find . -iname $new) if ($new);
+ }
+
+ my @find = split /\s+/, $f;
+
+ if (!$f) {
+ print STDERR "ERROR: Didn't find a replacement for $ref\n";
+ } elsif (scalar(@find) > 1) {
+ print STDERR "WARNING: Won't auto-replace, as found multiple files close to $ref:\n";
+ foreach my $j (@find) {
+ $j =~ s,^./,,;
+ print STDERR " $j\n";
+ }
+ } else {
+ $f = $find[0];
+ $f =~ s,^./,,;
+ print "INFO: Replacing $ref to $f\n";
+ foreach my $j (qx(git grep -l $ref)) {
+ qx(sed "s\@$ref\@$f\@g" -i $j);
+ }
+ }
+}