Message-ID: <1431974526.2870.36.camel@perches.com>
Subject: Re: [PATCH] checkpatch: types found in one source file do not
 affect processing of others
From: Joe Perches <joe@perches.com>
To: Alex Dowad <alexinbeijing@gmail.com>
Cc: Andy Whitcroft <apw@canonical.com>,
        open list <linux-kernel@vger.kernel.org>
Date: Mon, 18 May 2015 11:42:06 -0700
In-Reply-To: <1431956009-16076-1-git-send-email-alexinbeijing@gmail.com>
References: <1431956009-16076-1-git-send-email-alexinbeijing@gmail.com>
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On Mon, 2015-05-18 at 15:33 +0200, Alex Dowad wrote:
> checkpatch uses various cues in its input files to discover the names of
> user-defined types. It then uses that information when processing expressions,
> to discover more style issues.
> 
> Unfortunately, in rare cases, this means that checkpatch may give different
> results if you run it on several files at the same time, or one by one! The
> reason is that it may identify a type (or something that looks like a type)
> in one file, and then carry this information over when processing a different
> file.
> 
> As an example, drivers/staging/media/bcm2048/radio-bcm2048.c contains this
> line (in a macro):
> 
>   size value;
> 
> Then drivers/staging/media/davinci_vpfe/vpfe_video.c has this line:
> 
>   while (size * *nbuffers > vpfe_dev->video_limit)
> 
> If checkpatch processes these 2 files together, the (spurious) "size" type
> detected in the first file will cause it to flag the second file for
> improper use of the pointer dereference operator!
> 
> Therefore, keep user-defined types in a separate array from built-in ones,
> and reset the array of user-defined types at the beginning of each new
> source file.
> 
> Signed-off-by: Alex Dowad <alexinbeijing@gmail.com>
> ---
> 
> Dear patch checkers,
> 
> I am not a Perl programmer -- please let me know if there is a better way to
> accomplish what I am trying to do here.
> 
> Your feedback will be appreciated,
> Alex Dowad
> 
>  scripts/checkpatch.pl | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)

I suggest this:
---
 scripts/checkpatch.pl | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 89b1df4..174d711 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -418,6 +418,7 @@ our @typeList = (
 	qr{${Ident}_handler_fn},
 	@typeListMisordered,
 );
+our @typeListFile = ();
 our @typeListWithAttr = (
 	@typeList,
 	qr{struct\s+$InitAttribute\s+$Ident},
@@ -427,6 +428,7 @@ our @typeListWithAttr = (
 our @modifierList = (
 	qr{fastcall},
 );
+our @modifierListFile = ();
 
 our @mode_permission_funcs = (
 	["module_param", 3],
@@ -510,8 +512,8 @@ if ($codespell) {
 $misspellings = join("|", sort keys %spelling_fix) if keys %spelling_fix;
 
 sub build_types {
-	my $mods = "(?x:  \n" . join("|\n  ", @modifierList) . "\n)";
-	my $all = "(?x:  \n" . join("|\n  ", @typeList) . "\n)";
+	my $mods = "(?x:  \n" . join("|\n  ", (@modifierList, @modifierListFile)) . "\n)";
+	my $all = "(?x:  \n" . join("|\n  ", (@typeList, @typeListFile)) . "\n)";
 	my $Misordered = "(?x:  \n" . join("|\n  ", @typeListMisordered) . "\n)";
 	my $allWithAttr = "(?x:  \n" . join("|\n  ", @typeListWithAttr) . "\n)";
 	$Modifier	= qr{(?:$Attribute|$Sparse|$mods)};
@@ -746,6 +748,9 @@ for my $filename (@ARGV) {
 	@fixed_inserted = ();
 	@fixed_deleted = ();
 	$fixlinenr = -1;
+	@modifierListFile = ();
+	@typeListFile = ();
+	build_types();
 }
 
 exit($exit);
@@ -1610,13 +1615,13 @@ sub possible {
 			for my $modifier (split(' ', $possible)) {
 				if ($modifier !~ $notPermitted) {
 					warn "MODIFIER: $modifier ($possible) ($line)\n" if ($dbg_possible);
-					push(@modifierList, $modifier);
+					push(@modifierListFile, $modifier);
 				}
 			}
 
 		} else {
 			warn "POSSIBLE: $possible ($line)\n" if ($dbg_possible);
-			push(@typeList, $possible);
+			push(@typeListFile, $possible);
 		}
 		build_types();
 	} else {


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