Message-ID: <1431994945.2870.114.camel@perches.com>
Subject: [PATCH V2] checkpatch: Make types found in a source file/patch local
From: Joe Perches <joe@perches.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Dowad <alexinbeijing@gmail.com>, Andy Whitcroft <apw@canonical.com>,
        LKML <linux-kernel@vger.kernel.org>
Date: Mon, 18 May 2015 17:22:25 -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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From: Alex Dowad <alexinbeijing@gmail.com>

checkpatch uses various cues in its input patches and files to discover the
names of user-defined types and modifiers. It then uses that information when
processing expressions to discover potential style issues.

Unfortunately, in rare cases, this means that checkpatch may give different
results if you run it on several input files in one execution, 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.

For example, drivers/staging/media/bcm2048/radio-bcm2048.c contains this
line (in a macro):

	size value;

and drivers/staging/media/davinci_vpfe/vpfe_video.c has this line:

	while (size * *nbuffers > vpfe_dev->video_limit)

If checkpatch processes these 2 files in a single command like:
	./scripts/checkpatch.pl -f $file1 $file2
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.

To fix this, store types and modifiers found in a file in separate arrays
from built-in ones, and reset the arrays of types and modifiers found
in files at the beginning of each new source file.

Signed-off-by: Alex Dowad <alexinbeijing@gmail.com>
Signed-off-by: Joe Perches <joe@perches.com>
---

I kept Alex's Signed-off-line as he found the issue, wrote the original
changelog and patch.  I did some perl neatening and added the modifier block.

 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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