checkpatch: improve blank line after declaration test

Avoid multiple false positives by ignoring attributes.

Various attributes like volatile and ____cacheline_aligned_in_smp cause
checkpatch to emit invalid "Missing a blank line after declarations"
messages.

Use copies of $sline and $prevline, remove $Attribute and $Sparse, and use
the existing tests to avoid these false positives.

Miscellanea:

o Add volatile to $Attribute

This also reduces checkpatch runtime a bit by moving the indentation
comparison test to the start of the block to avoid multiple unnecessary
regex tests.

Link: https://lkml.kernel.org/r/9015fd00742bf4e5b824ad6d7fd7189530958548.camel@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>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index ca42017..bc80695 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -382,6 +382,7 @@ our $InitAttribute = qr{$InitAttributeData|$InitAttributeConst|$InitAttributeIni
 # We need \b after 'init' otherwise 'initconst' will cause a false positive in a check
 our $Attribute = qr{
                        const|
+                       volatile|
                        __percpu|
                        __nocast|
                        __safe|
@@ -3776,43 +3777,48 @@ sub process {
                }
 
 # check for missing blank lines after declarations
-               if ($sline =~ /^\+\s+\S/ &&                     #Not at char 1
-                       # actual declarations
-                   ($prevline =~ /^\+\s+$Declare\s*$Ident\s*[=,;:\[]/ ||
+# (declarations must have the same indentation and not be at the start of line)
+               if (($prevline =~ /\+(\s+)\S/) && $sline =~ /^\+$1\S/) {
+                       # use temporaries
+                       my $sl = $sline;
+                       my $pl = $prevline;
+                       # remove $Attribute/$Sparse uses to simplify comparisons
+                       $sl =~ s/\b(?:$Attribute|$Sparse)\b//g;
+                       $pl =~ s/\b(?:$Attribute|$Sparse)\b//g;
+                       if (($pl =~ /^\+\s+$Declare\s*$Ident\s*[=,;:\[]/ ||
                        # function pointer declarations
-                    $prevline =~ /^\+\s+$Declare\s*\(\s*\*\s*$Ident\s*\)\s*[=,;:\[\(]/ ||
+                            $pl =~ /^\+\s+$Declare\s*\(\s*\*\s*$Ident\s*\)\s*[=,;:\[\(]/ ||
                        # foo bar; where foo is some local typedef or #define
-                    $prevline =~ /^\+\s+$Ident(?:\s+|\s*\*\s*)$Ident\s*[=,;\[]/ ||
+                            $pl =~ /^\+\s+$Ident(?:\s+|\s*\*\s*)$Ident\s*[=,;\[]/ ||
                        # known declaration macros
-                    $prevline =~ /^\+\s+$declaration_macros/) &&
+                            $pl =~ /^\+\s+$declaration_macros/) &&
                        # for "else if" which can look like "$Ident $Ident"
-                   !($prevline =~ /^\+\s+$c90_Keywords\b/ ||
+                           !($pl =~ /^\+\s+$c90_Keywords\b/ ||
                        # other possible extensions of declaration lines
-                     $prevline =~ /(?:$Compare|$Assignment|$Operators)\s*$/ ||
+                             $pl =~ /(?:$Compare|$Assignment|$Operators)\s*$/ ||
                        # not starting a section or a macro "\" extended line
-                     $prevline =~ /(?:\{\s*|\\)$/) &&
+                             $pl =~ /(?:\{\s*|\\)$/) &&
                        # looks like a declaration
-                   !($sline =~ /^\+\s+$Declare\s*$Ident\s*[=,;:\[]/ ||
+                           !($sl =~ /^\+\s+$Declare\s*$Ident\s*[=,;:\[]/ ||
                        # function pointer declarations
-                     $sline =~ /^\+\s+$Declare\s*\(\s*\*\s*$Ident\s*\)\s*[=,;:\[\(]/ ||
+                             $sl =~ /^\+\s+$Declare\s*\(\s*\*\s*$Ident\s*\)\s*[=,;:\[\(]/ ||
                        # foo bar; where foo is some local typedef or #define
-                     $sline =~ /^\+\s+$Ident(?:\s+|\s*\*\s*)$Ident\s*[=,;\[]/ ||
+                             $sl =~ /^\+\s+$Ident(?:\s+|\s*\*\s*)$Ident\s*[=,;\[]/ ||
                        # known declaration macros
-                     $sline =~ /^\+\s+$declaration_macros/ ||
+                             $sl =~ /^\+\s+$declaration_macros/ ||
                        # start of struct or union or enum
-                     $sline =~ /^\+\s+(?:static\s+)?(?:const\s+)?(?:union|struct|enum|typedef)\b/ ||
+                             $sl =~ /^\+\s+(?:static\s+)?(?:const\s+)?(?:union|struct|enum|typedef)\b/ ||
                        # start or end of block or continuation of declaration
-                     $sline =~ /^\+\s+(?:$|[\{\}\.\#\"\?\:\(\[])/ ||
+                             $sl =~ /^\+\s+(?:$|[\{\}\.\#\"\?\:\(\[])/ ||
                        # bitfield continuation
-                     $sline =~ /^\+\s+$Ident\s*:\s*\d+\s*[,;]/ ||
+                             $sl =~ /^\+\s+$Ident\s*:\s*\d+\s*[,;]/ ||
                        # other possible extensions of declaration lines
-                     $sline =~ /^\+\s+\(?\s*(?:$Compare|$Assignment|$Operators)/) &&
-                       # indentation of previous and current line are the same
-                   (($prevline =~ /\+(\s+)\S/) && $sline =~ /^\+$1\S/)) {
-                       if (WARN("LINE_SPACING",
-                                "Missing a blank line after declarations\n" . $hereprev) &&
-                           $fix) {
-                               fix_insert_line($fixlinenr, "\+");
+                             $sl =~ /^\+\s+\(?\s*(?:$Compare|$Assignment|$Operators)/)) {
+                               if (WARN("LINE_SPACING",
+                                        "Missing a blank line after declarations\n" . $hereprev) &&
+                                   $fix) {
+                                       fix_insert_line($fixlinenr, "\+");
+                               }
                        }
                }