[PATCH v3 1/2] block: ensure correct integrity capability propagation in stacked devices

[Anuj Gupta]

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 <nikh1092 at linux.ibm.com>
Link: https://lore.kernel.org/linux-block/f6130475-3ccd-45d2-abde-3ccceada0f0a@linux.ibm.com/
Fixes: c6e56cf6b2e7 ("block: move integrity information into queue_limits")
Signed-off-by: Anuj Gupta <anuj20.g at samsung.com>
---
 block/blk-settings.c | 50 +++++++++++++++++++-------------------------
 1 file changed, 21 insertions(+), 29 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index c44dadc35e1e..d0469a812734 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -859,36 +859,28 @@ 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:
-- 
2.25.1