diff --git a/build-aux/check-spacing.pl b/build-aux/check-spacing.pl
index 75bcfd9a5c..cdd991bd6e 100755
--- a/build-aux/check-spacing.pl
+++ b/build-aux/check-spacing.pl
@@ -96,6 +96,111 @@ sub KillComments {
     return;
 }
 
+#
+# CheckWhiteSpaces:
+# $_[0]: $data(in)
+# $_[1]: $location(in), which format is file-path:line-num:line-code
+#
+# Check whitespaces according to code spec of libvirt.
+#
+sub CheckWhiteSpaces {
+    my $ret = 0;
+    my ($data, $location) = @_;
+
+    # We need to match things like
+    #
+    #  int foo (int bar, bool wizz);
+    #  foo (bar, wizz);
+    #
+    # but not match things like:
+    #
+    #  typedef int (*foo)(bar wizz)
+    #
+    # we can't do this (efficiently) without
+    # missing things like
+    #
+    #  foo (*bar, wizz);
+    #
+    # We also don't want to spoil the $data so it can be used
+    # later on.
+
+    # For temporary modifications
+    my $tmpdata = $$data;
+    while ($tmpdata =~ /(\w+)\s\((?!\*)/) {
+        my $kw = $1;
+
+        # Allow space after keywords only
+        if ($kw =~ /^(?:if|for|while|switch|return)$/) {
+            $tmpdata =~ s/(?:$kw\s\()/XXX(/;
+        } else {
+            print "Whitespace after non-keyword:\n$$location";
+            $ret = 1;
+            last;
+        }
+    }
+
+    # Require whitespace immediately after keywords
+    if ($$data =~ /\b(?:if|for|while|switch|return)\(/) {
+        print "No whitespace after keyword:\n$$location";
+        $ret = 1;
+    }
+
+    # Forbid whitespace between )( of a function typedef
+    if ($$data =~ /\(\*\w+\)\s+\(/) {
+        print "Whitespace between ')' and '(':\n$$location";
+        $ret = 1;
+    }
+
+    # Forbid whitespace following ( or prior to )
+    # but allow whitespace before ) on a single line
+    # (optionally followed by a semicolon)
+    if (($$data =~ /\s\)/ && not $$data =~ /^\s+\);?$/) ||
+        $$data =~ /\((?!$)\s/) {
+        print "Whitespace after '(' or before ')':\n$$location";
+        $ret = 1;
+    }
+
+    # Forbid whitespace before ";" or ",". Things like below are allowed:
+    #
+    # 1) The expression is empty for "for" loop. E.g.
+    #   for (i = 0; ; i++)
+    #
+    # 2) An empty statement. E.g.
+    #   while (write(statuswrite, &status, 1) == -1 &&
+    #          errno == EINTR)
+    #       ;
+    #
+    if ($$data =~ /\s[;,]/) {
+        unless ($$data =~ /\S; ; / ||
+                $$data =~ /^\s+;/) {
+            print "Whitespace before semicolon or comma:\n$$location";
+            $ret = 1;
+        }
+    }
+
+    # Require EOL, macro line continuation, or whitespace after ";".
+    # Allow "for (;;)" as an exception.
+    if ($$data =~ /;[^	 \\\n;)]/) {
+        print "Invalid character after semicolon:\n$$location";
+        $ret = 1;
+    }
+
+    # Require EOL, space, or enum/struct end after comma.
+    if ($$data =~ /,[^ \\\n)}]/) {
+        print "Invalid character after comma:\n$$location";
+        $ret = 1;
+    }
+
+    # Require spaces around assignment '=', compounds and '=='
+    if ($$data =~ /[^ ]\b[!<>&|\-+*\/%\^=]?=/ ||
+        $$data =~ /=[^= \\\n]/) {
+        print "Spacing around '=' or '==':\n$$location";
+        $ret = 1;
+    }
+
+    return $ret;
+}
+
 my $ret = 0;
 
 foreach my $file (@ARGV) {
@@ -111,8 +216,6 @@ foreach my $file (@ARGV) {
     while (defined (my $line = <FILE>)) {
         my $data = $line;
         my $location = "$file:$.:\n$line";
-        # For temporary modifications
-        my $tmpdata;
 
         # Kill any quoted , ; = or "
         $data =~ s/'[";,=]'/'X'/g;
@@ -129,102 +232,7 @@ foreach my $file (@ARGV) {
 
         KillComments(\$data, \$incomment);
 
-        # We need to match things like
-        #
-        #  int foo (int bar, bool wizz);
-        #  foo (bar, wizz);
-        #
-        # but not match things like:
-        #
-        #  typedef int (*foo)(bar wizz)
-        #
-        # we can't do this (efficiently) without
-        # missing things like
-        #
-        #  foo (*bar, wizz);
-        #
-        # We also don't want to spoil the $data so it can be used
-        # later on.
-        $tmpdata = $data;
-        while ($tmpdata =~ /(\w+)\s\((?!\*)/) {
-            my $kw = $1;
-
-            # Allow space after keywords only
-            if ($kw =~ /^(?:if|for|while|switch|return)$/) {
-                $tmpdata =~ s/(?:$kw\s\()/XXX(/;
-            } else {
-                print "Whitespace after non-keyword:\n";
-                print "$file:$.: $line";
-                $ret = 1;
-                last;
-            }
-        }
-
-        # Require whitespace immediately after keywords
-        if ($data =~ /\b(?:if|for|while|switch|return)\(/) {
-            print "No whitespace after keyword:\n";
-            print "$file:$.: $line";
-            $ret = 1;
-        }
-
-        # Forbid whitespace between )( of a function typedef
-        if ($data =~ /\(\*\w+\)\s+\(/) {
-            print "Whitespace between ')' and '(':\n";
-            print "$file:$.: $line";
-            $ret = 1;
-        }
-
-        # Forbid whitespace following ( or prior to )
-        # but allow whitespace before ) on a single line
-        # (optionally followed by a semicolon)
-        if (($data =~ /\s\)/ && not $data =~ /^\s+\);?$/) ||
-            $data =~ /\((?!$)\s/) {
-            print "Whitespace after '(' or before ')':\n";
-            print "$file:$.: $line";
-            $ret = 1;
-        }
-
-        # Forbid whitespace before ";" or ",". Things like below are allowed:
-        #
-        # 1) The expression is empty for "for" loop. E.g.
-        #   for (i = 0; ; i++)
-        #
-        # 2) An empty statement. E.g.
-        #   while (write(statuswrite, &status, 1) == -1 &&
-        #          errno == EINTR)
-        #       ;
-        #
-        if ($data =~ /\s[;,]/) {
-            unless ($data =~ /\S; ; / ||
-                    $data =~ /^\s+;/) {
-                print "Whitespace before semicolon or comma:\n";
-                print "$file:$.: $line";
-                $ret = 1;
-            }
-        }
-
-        # Require EOL, macro line continuation, or whitespace after ";".
-        # Allow "for (;;)" as an exception.
-        if ($data =~ /;[^	 \\\n;)]/) {
-            print "Invalid character after semicolon:\n";
-            print "$file:$.: $line";
-            $ret = 1;
-        }
-
-        # Require EOL, space, or enum/struct end after comma.
-        if ($data =~ /,[^ \\\n)}]/) {
-            print "Invalid character after comma:\n";
-            print "$file:$.: $line";
-            $ret = 1;
-        }
-
-        # Require spaces around assignment '=', compounds and '=='
-        if ($data =~ /[^ ]\b[!<>&|\-+*\/%\^=]?=/ ||
-            $data =~ /=[^= \\\n]/) {
-            print "Spacing around '=' or '==':\n";
-            print "$file:$.: $line";
-            $ret = 1;
-        }
+        $ret = 1 if CheckWhiteSpaces(\$data, \$location);
 
         # One line conditional statements with one line bodies should
         # not use curly brackets.