checkpatch: improve MACRO_ARG_PRECEDENCE test

It is possible for a multiple line macro definition to have a false positive
report when an argument is used on a line after a continuation \.

This line might have a leading '+' as the initial character that could be
confused by checkpatch as an operator.

Avoid the leading character on multiple line macro definitions.

Link: http://lkml.kernel.org/r/60229d13399f9b6509db5a32e30d4c16951a60cd.1473836073.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 19 insertions, 1 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index ea1a7adce406..0ef3d837f2aa 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4833,13 +4833,31 @@ sub process {
                                 }
 
                         }
+
+                        # Make $define_stmt single line, comment-free, etc
+                        my @stmt_array = split('\n', $define_stmt);
+                        my $first = 1;
+                        $define_stmt = "";
+                        foreach my $l (@stmt_array) {
+                                $l =~ s/\\$//;
+                                if ($first) {
+                                        $define_stmt = $l;
+                                        $first = 0;
+                                } elsif ($l =~ /^[\+ ]/) {
+                                        $define_stmt .= substr($l, 1);
+                                }
+                        }
+                        $define_stmt =~ s/$;//g;
+                        $define_stmt =~ s/\s+/ /g;
+                        $define_stmt = trim($define_stmt);
+
 # check if any macro arguments are reused (ignore '...' and 'type')
                         foreach my $arg (@def_args) {
                                 next if ($arg =~ /\.\.\./);
                                 next if ($arg =~ /^type$/i);
                                 my $tmp = $define_stmt;
                                 $tmp =~ s/\b(typeof|__typeof__|__builtin\w+|typecheck\s*\(\s*$Type\s*,|\#+)\s*\(*\s*$arg\s*\)*\b//g;
-                                $tmp =~ s/\#\s*$arg\b//g;
+                                $tmp =~ s/\#+\s*$arg\b//g;
                                 $tmp =~ s/\b$arg\s*\#\#//g;
                                 my $use_cnt = $tmp =~ s/\b$arg\b//g;
                                 if ($use_cnt > 1) {