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From:   Satya Tangirala <satyaprateek2357@gmail.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 <satyaprateek2357@gmail.com>,
        Satya Tangirala <satyat@google.com>
Subject: [PATCH v4 6/9] mmc: handle error from blk_ksm_register()
Date:   Tue,  6 Jul 2021 22:29:40 -0700
Message-Id: <20210707052943.3960-7-satyaprateek2357@gmail.com>
In-Reply-To: <20210707052943.3960-1-satyaprateek2357@gmail.com>
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From: Satya Tangirala <satyat@google.com>

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/mmc/core/crypto.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/crypto.c b/drivers/mmc/core/crypto.c
index 419a368f8402..c87be58a5548 100644
--- a/drivers/mmc/core/crypto.c
+++ b/drivers/mmc/core/crypto.c
@@ -21,8 +21,17 @@ void mmc_crypto_set_initial_state(struct mmc_host *host)
 
 void mmc_crypto_setup_queue(struct request_queue *q, struct mmc_host *host)
 {
-	if (host->caps2 & MMC_CAP2_CRYPTO)
-		blk_ksm_register(&host->ksm, q);
+	if (host->caps2 & MMC_CAP2_CRYPTO) {
+		/*
+		 * This WARN_ON should never trigger since &host->ksm won't be
+		 * "empty" (i.e. will support at least 1 crypto capability), an
+		 * MMC device's request queue doesn't support integrity, and all MMC
+		 * devices that currently support inline encryption also satisfy all the
+		 * block layer constraints (i.e. support SG gaps, don't have chunk
+		 * sectors, have a sufficiently large supported max_segments per bio)
+		 */
+		WARN_ON(!blk_ksm_register(&host->ksm, q));
+	}
 }
 EXPORT_SYMBOL_GPL(mmc_crypto_setup_queue);
 
-- 
2.25.1