checkpatch.pl: add missing memory barriers

SMP-only barriers were missing in checkpatch.pl

Refactor code slightly to make adding more variants easier.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Julian Calaby <julian.calaby@gmail.com>
Acked-by: Joe Perches <joe@perches.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

scripts/checkpatch.pl

@@ -5116,7 +5116,27 @@ sub process {
 			}
 		}
 # check for memory barriers without a comment.
-		if ($line =~ /\b(mb|rmb|wmb|read_barrier_depends|smp_mb|smp_rmb|smp_wmb|smp_read_barrier_depends)\(/) {
+
+		my $barriers = qr{
+			mb|
+			rmb|
+			wmb|
+			read_barrier_depends
+		}x;
+		my $barrier_stems = qr{
+			mb__before_atomic|
+			mb__after_atomic|
+			store_release|
+			load_acquire|
+			store_mb|
+			(?:$barriers)
+		}x;
+		my $all_barriers = qr{
+			(?:$barriers)|
+			smp_(?:$barrier_stems)
+		}x;
+
+		if ($line =~ /\b(?:$all_barriers)\s*\(/) {
 			if (!ctx_has_comment($first_line, $linenr)) {
 				WARN("MEMORY_BARRIER",
 				     "memory barrier without comment\n" . $herecurr);