block: Make blk-integrity preclude hardware inline encryption

Whenever a device supports blk-integrity, make the kernel pretend that
the device doesn't support inline encryption (essentially by setting the
keyslot manager in the request queue to NULL).

There's no hardware currently that supports both integrity and inline
encryption. However, it seems possible that there will be such hardware
in the near future (like the NVMe key per I/O support that might support
both inline encryption and PI).

But properly integrating both features is not trivial, and without
real hardware that implements both, it is difficult to tell if it will
be done correctly by the majority of hardware that support both.
So it seems best not to support both features together right now, and
to decide what to do at probe time.

Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 7 insertions, 0 deletions

diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index ff1070edbb40..c03705cbb9c9 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -409,6 +409,13 @@ void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template
 	bi->tag_size = template->tag_size;
 
 	disk->queue->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+	if (disk->queue->ksm) {
+		pr_warn("blk-integrity: Integrity and hardware inline encryption are not supported together. Disabling hardware inline encryption.\n");
+		blk_ksm_unregister(disk->queue);
+	}
+#endif
 }
 EXPORT_SYMBOL(blk_integrity_register);