dm writecache: report invalid return from writecache_map helpers

Mikulas Patocka · snitm · commit df699cc16ea5 · 2021-08-10T13:27:48.000-04:00
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 &lt;mpatocka@redhat.com&gt;
Signed-off-by: Mike Snitzer &lt;snitzer@redhat.com&gt;
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
@@ -1545,10 +1545,13 @@ static int writecache_map(struct dm_target *ti, struct bio *bio)
 		return DM_MAPIO_SUBMITTED;
 
 	case WC_MAP_ERROR:
-	default:
 		wc_unlock(wc);
 		bio_io_error(bio);
 		return DM_MAPIO_SUBMITTED;
+
+	default:
+		BUG();
+		return -1;
 	}
 }
 

Original file line number	Diff line number	Diff line change
`@@ -1545,10 +1545,13 @@ static int writecache_map(struct dm_target ti, struct bio bio)`
`1545`	`1545`	`return DM_MAPIO_SUBMITTED;`
`1546`	`1546`
`1547`	`1547`	`case WC_MAP_ERROR:`
`1548`		`- default:`
`1549`	`1548`	`wc_unlock(wc);`
`1550`	`1549`	`bio_io_error(bio);`
`1551`	`1550`	`return DM_MAPIO_SUBMITTED;`
	`1551`	`+`
	`1552`	`+ default:`
	`1553`	`+ BUG();`
	`1554`	`+ return -1;`
`1552`	`1555`	`}`
`1553`	`1556`	`}`
`1554`	`1557`