checkpatch: use a list of "link" tags

The following commit will allow the use of a similar "link" tag.

Because there is a possibility that other similar tags will be added in
the future and to reduce the number of places where the code will be
modified to allow this new tag, a list with all these "link" tags is now
used.

Two variables are created from it: one to search for such tags and one to
print all tags in a warning message.

Link: https://lkml.kernel.org/r/20230314-doc-checkpatch-closes-tag-v4-3-d26d1fa66f9f@tessares.net
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Suggested-by: Joe Perches <joe@perches.com>
Acked-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kai Wasserbäch <kai@dev.carbon-project.org>
Cc: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

scripts/checkpatch.pl

@@ -620,6 +620,22 @@ our $signature_tags = qr{(?xi:
 	Cc:
 )};
 
+our @link_tags = qw(Link);
+
+#Create a search and print patterns for all these strings to be used directly below
+our $link_tags_search = "";
+our $link_tags_print = "";
+foreach my $entry (@link_tags) {
+	if ($link_tags_search ne "") {
+		$link_tags_search .= '|';
+		$link_tags_print .= ' or ';
+	}
+	$entry .= ':';
+	$link_tags_search .= $entry;
+	$link_tags_print .= "'$entry'";
+}
+$link_tags_search = "(?:${link_tags_search})";
+
 our $tracing_logging_tags = qr{(?xi:
 	[=-]*> |
 	<[=-]* |
@@ -3250,8 +3266,8 @@ sub process {
 					# file delta changes
 		      $line =~ /^\s*(?:[\w\.\-\+]*\/)++[\w\.\-\+]+:/ ||
 					# filename then :
-		      $line =~ /^\s*(?:Fixes:|Link:|$signature_tags)/i ||
-					# A Fixes: or Link: line or signature tag line
+		      $line =~ /^\s*(?:Fixes:|$link_tags_search|$signature_tags)/i ||
+					# A Fixes:, link or signature tag line
 		      $commit_log_possible_stack_dump)) {
 			WARN("COMMIT_LOG_LONG_LINE",
 			     "Possible unwrapped commit description (prefer a maximum 75 chars per line)\n" . $herecurr);
@@ -3266,13 +3282,13 @@ sub process {
 
 # Check for odd tags before a URI/URL
 		if ($in_commit_log &&
-		    $line =~ /^\s*(\w+):\s*http/ && $1 ne 'Link') {
+		    $line =~ /^\s*(\w+:)\s*http/ && $1 !~ /^$link_tags_search$/) {
 			if ($1 =~ /^v(?:ersion)?\d+/i) {
 				WARN("COMMIT_LOG_VERSIONING",
 				     "Patch version information should be after the --- line\n" . $herecurr);
 			} else {
 				WARN("COMMIT_LOG_USE_LINK",
-				     "Unknown link reference '$1:', use 'Link:' instead\n" . $herecurr);
+				     "Unknown link reference '$1', use $link_tags_print instead\n" . $herecurr);
 			}
 		}