Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
IronPort-SDR: XnjCdqp9hV2W37s1lbN523WxVYG2WHZtyuqimhtWZMZ2JiOLhlGrcEqPjvx25YymKk1JPORBfO
 vN1sElhLSZuMZ1juJu6p9SPatoONNjBbNffWkatqjd+C1l0aXCZImkjQZ3C31UycqdNvZ55IEF
 FQh9dJIKAHL5+CF7JQqAF7ODzaBGboeV0wtDwPiPeZd2+YgageIu26FnCFJLva2qWpz1Q11A/S
 Byxojt1lOfRE/JVKnXrzXH56xPLsKmY3Im//vbaL5kOPtfdovCSJwiXgyWV0lYPbDfRLFQz9L6
 uIM=
IronPort-SDR: ZW3RNp6tbr2w+5fsT76ggG7COcc145PRIPzF5WseehGyhVilZmEtX6Y6k9fWRZL73jCU7yDjGL
 jr1nUgQ03ImqxEkKlyIbA4+ofGFD6n1gaOwQhjqo8ZEDLhd9jj0vegwRijyHnOfUYdUpNGmPi7
 haD3GSFcQA/PycoDSQA1YXQn4EjbIjf0nl2D4V4vwO3eN5aMPqLETKs2mcWTahpDGYCWBsjLTv
 ZgYhWSDK/9fu/TOQtgm36fgwK+kddF9/lAtCFjMf3oPzaSBLM/Foda4CGFx/ojvb3EjSPuJcTP
 E6vGyE4U82ZlDUqkwzLWJs8C
IronPort-SDR: 6L/qkuUpRLpq5j7Us88MNbIeaasBDhxW4R5pOXqumpUPDYK6dV8wJa1xdir7E7Jb+O35z2TsQi
 6bcJzzfyCjpS8ijVqPGz4NuUBXaRwJFfhSSi30ssUsGKVYVy0J8qYysmc09mS/zoHhWE72/BB8
 7P2FGFC1O9hmghq4d1cV2JzCSeeq91R90q960+Eh7I1Fsj8HTsZdFP+uIUqqtF0wg3mAIP5NYN
 +Cm6IR3zFOBh7JzFDrY30QMLVIEHF6t7yfccekYFy0aEZ3G45+vibgztnnqxpHXfW5v1ZumIK6
 rvs=
WDCIronportException: Internal
From:   Avri Altman <avri.altman@wdc.com>
To:     Ulf Hansson <ulf.hansson@linaro.org>, linux-mmc@vger.kernel.org,
        Adrian Hunter <adrian.hunter@intel.com>
Cc:     linux-kernel@vger.kernel.org, Avri Altman <avri.altman@wdc.com>,
        Brendan Peter <bpeter@lytx.com>
Subject: [PATCH v3 1/2] mmc: block: Issue flush only if allowed
Date:   Tue, 20 Apr 2021 08:53:05 +0300
Message-Id: <20210420055306.4858-2-avri.altman@wdc.com>
In-Reply-To: <20210420055306.4858-1-avri.altman@wdc.com>
References: <20210420055306.4858-1-avri.altman@wdc.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The cache may be flushed to the nonvolatile storage by writing to
FLUSH_CACHE byte (EXT_CSD byte [32]). When in command queueing mode, the
cache may be flushed by issuing a CMDQ_TASK_ DEV_MGMT (CMD48) with a
FLUSH_CACHE op-code.  Either way, verify that The cache function is
turned ON before doing so.

fixes: 1e8e55b67030 (mmc: block: Add CQE support)

Reported-by: Brendan Peter <bpeter@lytx.com>
Tested-by: Brendan Peter <bpeter@lytx.com>
Signed-off-by: Avri Altman <avri.altman@wdc.com>
---
 drivers/mmc/core/block.c   | 7 +++++++
 drivers/mmc/core/mmc.c     | 2 +-
 drivers/mmc/core/mmc_ops.h | 5 +++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 8bfd4d95b386..5b6501fc9fb7 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1476,6 +1476,11 @@ static int mmc_blk_cqe_issue_flush(struct mmc_queue *mq, struct request *req)
 	struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
 	struct mmc_request *mrq = mmc_blk_cqe_prep_dcmd(mqrq, req);
 
+	if (mmc_card_mmc(mq->card) && !mmc_flush_allowed(mq->card)) {
+		blk_mq_end_request(req, BLK_STS_OK);
+		return -EPERM;
+	}
+
 	mrq->cmd->opcode = MMC_SWITCH;
 	mrq->cmd->arg = (MMC_SWITCH_MODE_WRITE_BYTE << 24) |
 			(EXT_CSD_FLUSH_CACHE << 16) |
@@ -2226,6 +2231,8 @@ enum mmc_issued mmc_blk_mq_issue_rq(struct mmc_queue *mq, struct request *req)
 		switch (req_op(req)) {
 		case REQ_OP_FLUSH:
 			ret = mmc_blk_cqe_issue_flush(mq, req);
+			if (ret == -EPERM)
+				return MMC_REQ_FINISHED;
 			break;
 		case REQ_OP_READ:
 		case REQ_OP_WRITE:
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 9ad4aa537867..e3da62ffcb5e 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -2037,7 +2037,7 @@ static int _mmc_flush_cache(struct mmc_card *card)
 {
 	int err = 0;
 
-	if (card->ext_csd.cache_size > 0 && card->ext_csd.cache_ctrl & 1) {
+	if (mmc_flush_allowed(card)) {
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 				 EXT_CSD_FLUSH_CACHE, 1,
 				 CACHE_FLUSH_TIMEOUT_MS);
diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h
index 5782fdf4e8e9..2682bf66708a 100644
--- a/drivers/mmc/core/mmc_ops.h
+++ b/drivers/mmc/core/mmc_ops.h
@@ -19,6 +19,11 @@ enum mmc_busy_cmd {
 struct mmc_host;
 struct mmc_card;
 
+static inline bool mmc_flush_allowed(struct mmc_card *card)
+{
+	return card->ext_csd.cache_size > 0 && card->ext_csd.cache_ctrl & 1;
+}
+
 int mmc_select_card(struct mmc_card *card);
 int mmc_deselect_cards(struct mmc_host *host);
 int mmc_set_dsr(struct mmc_host *host);
-- 
2.25.1