block: ensure correct integrity capability propagation in stacked devices

queue_limits_stack_integrity() incorrectly sets
BLK_INTEGRITY_DEVICE_CAPABLE for a DM device even when none of its
underlying devices support integrity. This happens because the flag is
inherited unconditionally. Ensure that integrity capabilities are
correctly propagated only when the underlying devices actually support
integrity.

Reported-by: M Nikhil <[email protected]>
Link: https://lore.kernel.org/linux-block/[email protected]/
Fixes: c6e56cf ("block: move integrity information into queue_limits")
Signed-off-by: Anuj Gupta <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: Anuj Gupta

block/blk-settings.c

@@ -864,36 +864,28 @@ bool queue_limits_stack_integrity(struct queue_limits *t,
 	if (!IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY))
 		return true;
 
-	if (!ti->tuple_size) {
-		/* inherit the settings from the first underlying device */
-		if (!(ti->flags & BLK_INTEGRITY_STACKED)) {
-			ti->flags = BLK_INTEGRITY_DEVICE_CAPABLE |
-				(bi->flags & BLK_INTEGRITY_REF_TAG);
-			ti->csum_type = bi->csum_type;
-			ti->tuple_size = bi->tuple_size;
-			ti->pi_offset = bi->pi_offset;
-			ti->interval_exp = bi->interval_exp;
-			ti->tag_size = bi->tag_size;
-			goto done;
-		}
-		if (!bi->tuple_size)
-			goto done;
+	if (ti->flags & BLK_INTEGRITY_STACKED) {
+		if (ti->tuple_size != bi->tuple_size)
+			goto incompatible;
+		if (ti->interval_exp != bi->interval_exp)
+			goto incompatible;
+		if (ti->tag_size != bi->tag_size)
+			goto incompatible;
+		if (ti->csum_type != bi->csum_type)
+			goto incompatible;
+		if ((ti->flags & BLK_INTEGRITY_REF_TAG) !=
+		    (bi->flags & BLK_INTEGRITY_REF_TAG))
+			goto incompatible;
+	} else {
+		ti->flags = BLK_INTEGRITY_STACKED;
+		ti->flags |= (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) |
+			     (bi->flags & BLK_INTEGRITY_REF_TAG);
+		ti->csum_type = bi->csum_type;
+		ti->tuple_size = bi->tuple_size;
+		ti->pi_offset = bi->pi_offset;
+		ti->interval_exp = bi->interval_exp;
+		ti->tag_size = bi->tag_size;
 	}
-
-	if (ti->tuple_size != bi->tuple_size)
-		goto incompatible;
-	if (ti->interval_exp != bi->interval_exp)
-		goto incompatible;
-	if (ti->tag_size != bi->tag_size)
-		goto incompatible;
-	if (ti->csum_type != bi->csum_type)
-		goto incompatible;
-	if ((ti->flags & BLK_INTEGRITY_REF_TAG) !=
-	    (bi->flags & BLK_INTEGRITY_REF_TAG))
-		goto incompatible;
-
-done:
-	ti->flags |= BLK_INTEGRITY_STACKED;
 	return true;
 
 incompatible: