checkpatch: improve tests for multiple line function definitions

Add a block that identifies multiple line function definitions.

Save the function name into $context_function to improve the embedded
function name test.

Look for misplaced open brace on the function definition.
Emit an OPEN_BRACE error when the function definition is similar to

     void foo(int arg1,
              int arg2) {

Miscellanea:

o Remove the $realfile test in function declaration w/o named arguments test
o Comment the function declaration w/o named arguments test

Link: http://lkml.kernel.org/r/de620ed6ebab75fdfa323741ada2134a0f545892.1496835238.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: David Kershner <david.kershner@unisys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 25 insertions, 1 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index e9618ca31251..a103f4fc30a2 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -5899,7 +5899,8 @@ sub process {
                              "externs should be avoided in .c files\n" .  $herecurr);
                 }
 
-                if ($realfile =~ /\.[ch]$/ && defined $stat &&
+# check for function declarations that have arguments without identifier names
+                if (defined $stat &&
                     $stat =~ /^.\s*(?:extern\s+)?$Type\s*$Ident\s*\(\s*([^{]+)\s*\)\s*;/s &&
                     $1 ne "void") {
                         my $args = trim($1);
@@ -5912,6 +5913,29 @@ sub process {
                         }
                 }
 
+# check for function definitions
+                if ($^V && $^V ge 5.10.0 &&
+                    defined $stat &&
+                    $stat =~ /^.\s*(?:$Storage\s+)?$Type\s*($Ident)\s*$balanced_parens\s*{/s) {
+                        $context_function = $1;
+
+# check for multiline function definition with misplaced open brace
+                        my $ok = 0;
+                        my $cnt = statement_rawlines($stat);
+                        my $herectx = $here . "\n";
+                        for (my $n = 0; $n < $cnt; $n++) {
+                                my $rl = raw_line($linenr, $n);
+                                $herectx .=  $rl . "\n";
+                                $ok = 1 if ($rl =~ /^[ \+]\{/);
+                                $ok = 1 if ($rl =~ /\{/ && $n == 0);
+                                last if $rl =~ /^[ \+].*\{/;
+                        }
+                        if (!$ok) {
+                                ERROR("OPEN_BRACE",
+                                      "open brace '{' following function definitions go on the next line\n" . $herectx);
+                        }
+                }
+
 # checks for new __setup's
                 if ($rawline =~ /\b__setup\("([^"]*)"/) {
                         my $name = $1;