[PATCH v2] checkpatch: fix multiple const * types

[Antonio Borneo]

Commit 1574a29f8e76 ("checkpatch: allow multiple const * types")
claims to support repetition of pattern "const *", but it actually
allows only one extra instance.
Check the following lines
	int a(char const * const x[]);
	int b(char const * const *x);
	int c(char const * const * const x[]);
	int d(char const * const * const *x);
with command
	./scripts/checkpatch.pl --show-types -f filename
to find that only the first line passes the test, while a warning
is triggered by the other 3 lines:
	WARNING:FUNCTION_ARGUMENTS: function definition argument
	'char const * const' should also have an identifier name
The reason is that the pattern match halts at the second asterisk
in the line, thus the remaining text starting with asterisk fails
to match a valid name for a variable.

Fixed by replacing "?" (Match 1 or 0 times) with "{0,4}" (Match
no more than 4 times) in the regular expression.
Fix also the similar test for types in unusual order.

Signed-off-by: Antonio Borneo <borneo.antonio@xxxxxxxxx>
Fixes: 1574a29f8e76 ("checkpatch: allow multiple const * types")
---
v1->v2
	use a max match {0,4} instead of *, to limit the memory
	used by perl

 scripts/checkpatch.pl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index a09333fd7cef..916a3fbd4d47 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -802,12 +802,12 @@ sub build_types {
 		  }x;
 	$Type	= qr{
 			$NonptrType
-			(?:(?:\s|\*|\[\])+\s*const|(?:\s|\*\s*(?:const\s*)?|\[\])+|(?:\s*\[\s*\])+)?
+			(?:(?:\s|\*|\[\])+\s*const|(?:\s|\*\s*(?:const\s*)?|\[\])+|(?:\s*\[\s*\])+){0,4}
 			(?:\s+$Inline|\s+$Modifier)*
 		  }x;
 	$TypeMisordered	= qr{
 			$NonptrTypeMisordered
-			(?:(?:\s|\*|\[\])+\s*const|(?:\s|\*\s*(?:const\s*)?|\[\])+|(?:\s*\[\s*\])+)?
+			(?:(?:\s|\*|\[\])+\s*const|(?:\s|\*\s*(?:const\s*)?|\[\])+|(?:\s*\[\s*\])+){0,4}
 			(?:\s+$Inline|\s+$Modifier)*
 		  }x;
 	$Declare	= qr{(?:$Storage\s+(?:$Inline\s+)?)?$Type};
-- 
2.21.0