[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>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/s390/cio/cio_debug.h b/drivers/s390/cio/cio_debug.h
index f88844adae1b..c9bf8989930f 100644
--- a/drivers/s390/cio/cio_debug.h
+++ b/drivers/s390/cio/cio_debug.h
@@ -23,6 +23,8 @@ extern debug_info_t *cio_debug_crw_id;
 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;