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Date:   Fri,  4 Jun 2021 19:58:58 +0000
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Subject: [PATCH v3 08/10] dm: handle error from blk_ksm_register()
From:   Satya Tangirala <satyat@google.com>
To:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Jens Axboe <axboe@kernel.dk>, Eric Biggers <ebiggers@google.com>,
        Satya Tangirala <satyat@google.com>
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Precedence: bulk

Handle any error from blk_ksm_register() in the callers. Previously,
the callers ignored the return value because blk_ksm_register() wouldn't
fail as long as the request_queue didn't have integrity support too, but
as this is no longer the case, it's safer for the callers to just handle
the return value appropriately.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 drivers/md/dm-table.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 29cbfc3e3c4b..e44f304b5c1a 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1354,7 +1354,21 @@ static void dm_update_keyslot_manager(struct request_queue *q,
 
 	/* Make the ksm less restrictive */
 	if (!q->ksm) {
-		blk_ksm_register(t->ksm, q);
+		/*
+		 * This WARN_ON should never trigger since t->ksm isn't be
+		 * "empty" (i.e. will support at least 1 crypto capability), the
+		 * request queue doesn't support integrity (since
+		 * dm_table_construct_keyslot_manager() checks that), and
+		 * it also satisfies all the block layer constraints
+		 * "sufficiently" (as in the constraints of the DM device's
+		 * request queue won't preclude any of the intersection of the
+		 * supported capabilities of the underlying devices, since if
+		 * some capability were precluded by the DM device's request
+		 * queue's constraints, that capability would also have been
+		 * precluded by one of the child device's request queues)
+		 */
+		if (WARN_ON(!blk_ksm_register(t->ksm, q)))
+			dm_destroy_keyslot_manager(t->ksm);
 	} else {
 		blk_ksm_update_capabilities(q->ksm, t->ksm);
 		dm_destroy_keyslot_manager(t->ksm);
-- 
2.32.0.rc1.229.g3e70b5a671-goog