[S390] cio: Make ccw_dev_id_is_equal() more robust.

Using memcmp to compare ccw_dev_id implies that the whole structure (incl.
padding) has always been completely initialized to sane values. Comparing
the structures field by field doesn't make such assumptions.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/asm-s390/cio.h b/include/asm-s390/cio.h
index cabd5bb74b5a..d92785030980 100644
--- a/include/asm-s390/cio.h
+++ b/include/asm-s390/cio.h
@@ -278,7 +278,10 @@ struct ccw_dev_id {
 static inline int ccw_dev_id_is_equal(struct ccw_dev_id *dev_id1,
                                       struct ccw_dev_id *dev_id2)
 {
-        return !memcmp(dev_id1, dev_id2, sizeof(struct ccw_dev_id));
+        if ((dev_id1->ssid == dev_id2->ssid) &&
+            (dev_id1->devno == dev_id2->devno))
+                return 1;
+        return 0;
 }
 
 extern int diag210(struct diag210 *addr);