[PATCH v1 1/3] block: Fix incorrect integrity sysfs reporting for DM devices

[Anuj Gupta <anuj20.g@samsung.com>]

The integrity stacking logic in device-mapper currently does not
explicitly mark the device with BLK_INTEGRITY_NOGENERATE and
BLK_INTEGRITY_NOVERIFY when the underlying device(s) do not support
integrity. This can lead to incorrect sysfs reporting of integrity
attributes.

Additionally, 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
blindly inherited from the first base device, even if it lacks integrity
support.

This patch ensures:
1. BLK_INTEGRITY_NOGENERATE and BLK_INTEGRITY_NOVERIFY are set correctly:
   - When the underlying device does not support integrity.
   - When integrity stacking fails due to incompatible profiles.
2. device_is_integrity_capable is correctly propagated to reflect the
actual capability of the stacked device.

Reported-by: M Nikhil <nikhilm@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@samsung.com>
---
 block/blk-settings.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index c44dadc35e1e..c32517c8bc2e 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -861,7 +861,8 @@ bool queue_limits_stack_integrity(struct queue_limits *t,
 
 	if (!ti->tuple_size) {
 		/* inherit the settings from the first underlying device */
-		if (!(ti->flags & BLK_INTEGRITY_STACKED)) {
+		if (!(ti->flags & BLK_INTEGRITY_STACKED) &&
+		    (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE)) {
 			ti->flags = BLK_INTEGRITY_DEVICE_CAPABLE |
 				(bi->flags & BLK_INTEGRITY_REF_TAG);
 			ti->csum_type = bi->csum_type;
@@ -871,8 +872,11 @@ bool queue_limits_stack_integrity(struct queue_limits *t,
 			ti->tag_size = bi->tag_size;
 			goto done;
 		}
-		if (!bi->tuple_size)
+		if (!bi->tuple_size) {
+			ti->flags |= BLK_INTEGRITY_NOGENERATE |
+				     BLK_INTEGRITY_NOVERIFY;
 			goto done;
+		}
 	}
 
 	if (ti->tuple_size != bi->tuple_size)
@@ -893,6 +897,7 @@ bool queue_limits_stack_integrity(struct queue_limits *t,
 
 incompatible:
 	memset(ti, 0, sizeof(*ti));
+	ti->flags |= BLK_INTEGRITY_NOGENERATE | BLK_INTEGRITY_NOVERIFY;
 	return false;
 }
 EXPORT_SYMBOL_GPL(queue_limits_stack_integrity);
-- 
2.25.1