checkpatch: check for __smp outside barrier.h

mstsirkin · mstsirkin · commit f4073b0f6e11 · 2016-01-12T20:47:07.000+02:00
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 &lt;linux@arm.linux.org.uk&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Acked-by: Julian Calaby &lt;julian.calaby@gmail.com&gt;
Acked-by: Joe Perches &lt;joe@perches.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
@@ -5143,6 +5143,16 @@ sub process {
 			}
 		}
 
+		my $underscore_smp_barriers = qr{__smp_(?:$barrier_stems)}x;
+
+		if ($realfile !~ m@^include/asm-generic/@ &&
+		    $realfile !~ m@/barrier\.h$@ &&
+		    $line =~ m/\b(?:$underscore_smp_barriers)\s*\(/ &&
+		    $line !~ m/^.\s*\#\s*define\s+(?:$underscore_smp_barriers)\s*\(/) {
+			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)) {
