[PATCH 2/3] checkpatch: check for __smp outside barrier.h

["Michael S. Tsirkin" <mst@redhat.com>]

Introduction of __smp barriers cleans up a bunch of duplicate code, but
it gives people an additional handle onto a "new" set of barriers - just
because they're prefixed with __* unfortunately doesn't stop anyone from
using it (as happened with other arch stuff before.)

Add a checkpatch test so it will trigger a warning.

Reported-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 scripts/checkpatch.pl | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 0245bbe..e3f9ad9 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -5130,6 +5130,17 @@ sub process {
 			}
 		}
 
+		my @underscore_smp_barriers = map {"__" . $_} @smp_barriers;
+		my $underscore_all_barriers = join('|', @underscore_smp_barriers);
+
+		if ($realfile !~ m@^include/asm-generic/@ &&
+		    $realfile !~ m@/barrier\.h$@ &&
+		    $line =~ m/\b($underscore_all_barriers)\(/ &&
+		    $line !~ m/^.\s*\#\s*define\s+($underscore_all_barriers)\(/) {
+			WARN("MEMORY_BARRIER",
+			     "__smp memory barriers shouldn't be used outside barrier.h and asm-generic\n" . $herecurr);
+		}
+
 # check for waitqueue_active without a comment.
 		if ($line =~ /\bwaitqueue_active\s*\(/) {
 			if (!ctx_has_comment($first_line, $linenr)) {
-- 
MST