From: Jaegeuk Kim <jaegeuk@google.com>
Date: Tue, 17 Nov 2020 16:58:34 +0000 (-0800)
Subject: scsi: ufs: Atomic update for clkgating_enable
X-Git-Tag: v5.15~2044^2~161
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b664511297644eac34038df877b3ad7bcaa81913;p=platform%2Fkernel%2Flinux-starfive.git

scsi: ufs: Atomic update for clkgating_enable

While running a stress test which enables/disables clkgating, we
occasionally hit device timeout. This patch avoids a subtle race condition
to address it.

Link: https://lore.kernel.org/r/20201117165839.1643377-3-jaegeuk@kernel.org
Reviewed-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 9f53f639..3287402 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1818,19 +1818,19 @@ 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;
 }