[S390] cio: Make CIO_* macros safe if dbfs are not available.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/cio_debug.h b/drivers/s390/cio/cio_debug.h
index f88844a..c9bf898 100644
--- a/drivers/s390/cio/cio_debug.h
+++ b/drivers/s390/cio/cio_debug.h
@@ -23,6 +23,8 @@
static inline void
CIO_HEX_EVENT(int level, void *data, int length)
{
+ if (unlikely(!cio_debug_trace_id))
+ return;
while (length > 0) {
debug_event(cio_debug_trace_id, level, data, length);
length -= cio_debug_trace_id->buf_size;