From df699cc16ea5ef93a917676dcdd4376e02860ad5 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Tue, 27 Jul 2021 09:45:13 -0400
Subject: [PATCH] dm writecache: report invalid return from writecache_map
 helpers

If some "writecache_map_*" function returns invalid state, it is a bug.
So, we should report it and not fail silently.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm-writecache.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 64d7a798244a..e89868cf7d98 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -1545,10 +1545,13 @@ done:
 		return DM_MAPIO_SUBMITTED;
 
 	case WC_MAP_ERROR:
-	default:
 		wc_unlock(wc);
 		bio_io_error(bio);
 		return DM_MAPIO_SUBMITTED;
+
+	default:
+		BUG();
+		return -1;
 	}
 }