scripts/checkpatch.pl | 70 ++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 56 insertions(+), 14 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index fdacd759078e..dd344ac77cb8 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2114,6 +2114,29 @@ sub pos_last_openparen {
 	return length(expand_tabs(substr($line, 0, $last_openparen))) + 1;
 }
 
+sub get_decl {
+	my ($line) = @_;
+
+	# typical declarations
+	if ($line =~ /^\+\s+($Declare\s*$Ident)\s*[=,;:\[]/) {
+		return $1;
+	}
+	# function pointer declarations
+	if ($line =~ /^\+\s+($Declare\s*\(\s*\*\s*$Ident\s*\))\s*[=,;:\[\(]/) {
+		return $1;
+	}
+	# foo bar; where foo is some local typedef or #define
+	if ($line =~ /^\+\s+($Ident(?:\s+|\s*\*\s*)$Ident)\s*[=,;\[]/) {
+		return $1;
+	}
+	# known declaration macros
+	if ($line =~ /^\+\s+$(declaration_macros)/) {
+		return $1;
+	}
+
+	return undef;
+}
+
 sub process {
 	my $filename = shift;
 
@@ -3063,9 +3086,7 @@ sub process {
 			$last_blank_line = $linenr;
 		}
 
-# check for missing blank lines after declarations
-		if ($sline =~ /^\+\s+\S/ &&			#Not at char 1
-			# actual declarations
+		my $prev_decl =
 		    ($prevline =~ /^\+\s+$Declare\s*$Ident\s*[=,;:\[]/ ||
 			# function pointer declarations
 		     $prevline =~ /^\+\s+$Declare\s*\(\s*\*\s*$Ident\s*\)\s*[=,;:\[\(]/ ||
@@ -3078,25 +3099,30 @@ sub process {
 			# other possible extensions of declaration lines
 		      $prevline =~ /(?:$Compare|$Assignment|$Operators)\s*$/ ||
 			# not starting a section or a macro "\" extended line
-		      $prevline =~ /(?:\{\s*|\\)$/) &&
-			# looks like a declaration
-		    !($sline =~ /^\+\s+$Declare\s*$Ident\s*[=,;:\[]/ ||
+		      $prevline =~ /(?:\{\s*|\\)$/);
+		my $sline_decl =
+		    $sline =~ /^\+\s+$Declare\s*$Ident\s*[=,;:\[]/ ||
 			# function pointer declarations
-		      $sline =~ /^\+\s+$Declare\s*\(\s*\*\s*$Ident\s*\)\s*[=,;:\[\(]/ ||
+		    $sline =~ /^\+\s+$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*[=,;\[]/ ||
+		    $sline =~ /^\+\s+$Ident(?:\s+|\s*\*\s*)$Ident\s*[=,;\[]/ ||
 			# known declaration macros
-		      $sline =~ /^\+\s+$declaration_macros/ ||
+		    $sline =~ /^\+\s+$declaration_macros/ ||
 			# start of struct or union or enum
-		      $sline =~ /^\+\s+(?:union|struct|enum|typedef)\b/ ||
+		    $sline =~ /^\+\s+(?:union|struct|enum|typedef)\b/ ||
 			# start or end of block or continuation of declaration
-		      $sline =~ /^\+\s+(?:$|[\{\}\.\#\"\?\:\(\[])/ ||
+		    $sline =~ /^\+\s+(?:$|[\{\}\.\#\"\?\:\(\[])/ ||
 			# bitfield continuation
-		      $sline =~ /^\+\s+$Ident\s*:\s*\d+\s*[,;]/ ||
+		    $sline =~ /^\+\s+$Ident\s*:\s*\d+\s*[,;]/ ||
 			# other possible extensions of declaration lines
-		      $sline =~ /^\+\s+\(?\s*(?:$Compare|$Assignment|$Operators)/) &&
+		    $sline =~ /^\+\s+\(?\s*(?:$Compare|$Assignment|$Operators)/;
+
+# check for missing blank lines after declarations
+		if ($sline =~ /^\+\s+\S/ &&			#Not at char 1
+			# actual declarations
+		    $prev_decl && !$sline_decl &&
 			# indentation of previous and current line are the same
-		    (($prevline =~ /\+(\s+)\S/) && $sline =~ /^\+$1\S/)) {
+		    ($prevline =~ /\+(\s+)\S/ && $sline =~ /^\+$1\S/)) {
 			if (WARN("LINE_SPACING",
 				 "Missing a blank line after declarations\n" . $hereprev) &&
 			    $fix) {
@@ -3104,6 +3130,22 @@ sub process {
 			}
 		}
 
+# check for reverse christmas tree declarations in net/ and drivers/net/
+		if ($realfile =~ m@^(?:drivers/net/|net/)@ &&
+		    $sline =~ /^\+\s+\S/ &&			#Not at char 1
+			# actual declarations
+		    $prev_decl && $sline_decl &&
+			# indentation of previous and current line are the same
+		    (($prevline =~ /\+(\s+)\S/) && $sline =~ /^\+$1\S/)) {
+			my $p = get_decl($prevline);
+			my $l = get_decl($sline);
+			if (defined($p) && defined($l) && length($p) < length($l) &&
+			    CHK("REVERSE_XMAS_TREE",
+				"Prefer ordering declarations longest to shortest\n" . $hereprev) &&
+			    $fix) {
+			}
+		}
+
 # check for spaces at the beginning of a line.
 # Exceptions:
 #  1) within comments