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From: Jaegeuk Kim <jaegeuk@kernel.org>
To: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
	kernel-team@android.com
Cc: cang@codeaurora.org, alim.akhtar@samsung.com,
	avri.altman@wdc.com, bvanassche@acm.org,
	martin.petersen@oracle.com, stanley.chu@mediatek.com,
	Jaegeuk Kim <jaegeuk@google.com>
Subject: [PATCH v5 2/7] scsi: ufs: atomic update for clkgating_enable
Date: Tue, 17 Nov 2020 08:58:34 -0800	[thread overview]
Message-ID: <20201117165839.1643377-3-jaegeuk@kernel.org> (raw)
In-Reply-To: <20201117165839.1643377-1-jaegeuk@kernel.org>

From: Jaegeuk Kim <jaegeuk@google.com>

When giving a stress test which enables/disables clkgating, we hit device
timeout sometimes. This patch avoids subtle racy condition to address it.

Note that, this requires a patch to address the device stuck by REQ_CLKS_OFF in
__ufshcd_release().

The fix is "scsi: ufs: avoid to call REQ_CLKS_OFF to CLKS_OFF".

Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
---
 drivers/scsi/ufs/ufshcd.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index cc8d5f0c3fdc..6c9269bffcbd 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1808,19 +1808,19 @@ static ssize_t ufshcd_clkgate_enable_store(struct device *dev,
 		return -EINVAL;
 
 	value = !!value;
+
+	spin_lock_irqsave(hba->host->host_lock, flags);
 	if (value == hba->clk_gating.is_enabled)
 		goto out;
 
-	if (value) {
-		ufshcd_release(hba);
-	} else {
-		spin_lock_irqsave(hba->host->host_lock, flags);
+	if (value)
+		__ufshcd_release(hba);
+	else
 		hba->clk_gating.active_reqs++;
-		spin_unlock_irqrestore(hba->host->host_lock, flags);
-	}
 
 	hba->clk_gating.is_enabled = value;
 out:
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	return count;
 }
 
-- 
2.29.2.299.gdc1121823c-goog


  parent reply	other threads:[~2020-11-17 16:58 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-17 16:58 [PATCH v5 0/5] scsi: ufs: add some fixes Jaegeuk Kim
2020-11-17 16:58 ` [PATCH v5 1/7] scsi: ufs: avoid to call REQ_CLKS_OFF to CLKS_OFF Jaegeuk Kim
2020-11-18  3:54   ` Can Guo
2020-11-17 16:58 ` Jaegeuk Kim [this message]
2020-11-18  3:54   ` [PATCH v5 2/7] scsi: ufs: atomic update for clkgating_enable Can Guo
2020-11-17 16:58 ` [PATCH v5 3/7] scsi: ufs: clear UAC for FFU and RPMB LUNs Jaegeuk Kim
2020-11-17 16:58 ` [PATCH v5 4/7] scsi: ufs: use WQ_HIGHPRI for gating work Jaegeuk Kim
2020-11-17 16:58 ` [PATCH v5 5/7] scsi: add more contexts in the ufs tracepoints Jaegeuk Kim
2020-11-17 16:58 ` [PATCH v5 6/7] scsi: ufs: fix clkgating on/off correctly Jaegeuk Kim
2020-11-17 16:58 ` [PATCH v5 7/7] scsi: ufs: show lba and length for unmap commands Jaegeuk Kim
2020-11-18  1:11   ` Can Guo
2020-11-20  3:01 ` [PATCH v5 0/5] scsi: ufs: add some fixes Martin K. Petersen
2020-11-24  3:58 ` Martin K. Petersen

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