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From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Asutosh Das <asutoshd@codeaurora.org>,
        Avri Altman <avri.altman@wdc.com>,
        Bean Huo <beanhuo@micron.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Can Guo <cang@codeaurora.org>
Cc:     Jaegeuk Kim <jaegeuk@kernel.org>
Subject: [PATCH] scsi: ufs: add a quirk to disable FUA support
Date:   Tue, 31 May 2022 13:10:53 -0700
Message-Id: <20220531201053.3300018-1-jaegeuk@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

UFS stack shows very low performance of FUA comparing to write and cache_flush.
Let's add a quirk to adjust it.

E.g., average latency according to the chunk size of write

Write(us/KB)	4	64	256	1024	2048
FUA		873.792	754.604	995.624	1011.67	1067.99
CACHE_FLUSH	824.703	712.98	800.307	1019.5	1037.37

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 drivers/scsi/ufs/ufshcd.c | 3 +++
 drivers/scsi/ufs/ufshcd.h | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 3f9caafa91bf..811f3467879c 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5035,6 +5035,9 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
 	 */
 	sdev->silence_suspend = 1;
 
+	if (hba->quirks & UFSHCD_QUIRK_BROKEN_FUA)
+		sdev->broken_fua = 1;
+
 	ufshcd_crypto_register(hba, q);
 
 	return 0;
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 94f545be183a..6c480c6741d6 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -602,6 +602,11 @@ enum ufshcd_quirks {
 	 * support physical host configuration.
 	 */
 	UFSHCD_QUIRK_SKIP_PH_CONFIGURATION		= 1 << 16,
+
+	/*
+	 * This quirk disables FUA support.
+	 */
+	UFSHCD_QUIRK_BROKEN_FUA				= 1 << 17,
 };
 
 enum ufshcd_caps {
-- 
2.36.1.255.ge46751e96f-goog