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From: Stanley Chu <stanley.chu@mediatek.com>
To: <linux-scsi@vger.kernel.org>, <martin.petersen@oracle.com>,
	<avri.altman@wdc.com>, <alim.akhtar@samsung.com>,
	<jejb@linux.ibm.com>, <bvanassche@acm.org>
Cc: <beanhuo@micron.com>, <asutoshd@codeaurora.org>,
	<cang@codeaurora.org>, <matthias.bgg@gmail.com>,
	<linux-mediatek@lists.infradead.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <kuohong.wang@mediatek.com>,
	<peter.wang@mediatek.com>, <chun-hung.wu@mediatek.com>,
	<andy.teng@mediatek.com>, <chaotian.jing@mediatek.com>,
	<cc.chou@mediatek.com>, Stanley Chu <stanley.chu@mediatek.com>
Subject: [PATCH v3] scsi: ufs: Fix possible infinite loop in ufshcd_hold
Date: Sun, 9 Aug 2020 13:07:34 +0800	[thread overview]
Message-ID: <20200809050734.18740-1-stanley.chu@mediatek.com> (raw)

In ufshcd_suspend(), after clk-gating is suspended and link is set
as Hibern8 state, ufshcd_hold() is still possibly invoked before
ufshcd_suspend() returns. For example, MediaTek's suspend vops may
issue UIC commands which would call ufshcd_hold() during the command
issuing flow.

Now if UFSHCD_CAP_HIBERN8_WITH_CLK_GATING capability is enabled,
then ufshcd_hold() may enter infinite loops because there is no
clk-ungating work scheduled or pending. In this case, ufshcd_hold()
shall just bypass, and keep the link as Hibern8 state.

Co-Developed-by: Andy Teng <andy.teng@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
---
Changes since v2:
    - Rebase to the latest Martin's queue branch
    - Add missing Reviewed tag since Avri's letter is not showing up in LKML and Patchwork
---
 drivers/scsi/ufs/ufshcd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 307622284239..b4f948027b3e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1561,6 +1561,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
 int ufshcd_hold(struct ufs_hba *hba, bool async)
 {
 	int rc = 0;
+	bool flush_result;
 	unsigned long flags;
 
 	if (!ufshcd_is_clkgating_allowed(hba))
@@ -1592,7 +1593,9 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
 				break;
 			}
 			spin_unlock_irqrestore(hba->host->host_lock, flags);
-			flush_work(&hba->clk_gating.ungate_work);
+			flush_result = flush_work(&hba->clk_gating.ungate_work);
+			if (hba->clk_gating.is_suspended && !flush_result)
+				goto out;
 			spin_lock_irqsave(hba->host->host_lock, flags);
 			goto start;
 		}
-- 
2.18.0

WARNING: multiple messages have this Message-ID (diff)
From: Stanley Chu <stanley.chu@mediatek.com>
To: <linux-scsi@vger.kernel.org>, <martin.petersen@oracle.com>,
	<avri.altman@wdc.com>, <alim.akhtar@samsung.com>,
	<jejb@linux.ibm.com>, <bvanassche@acm.org>
Cc: Stanley Chu <stanley.chu@mediatek.com>,
	andy.teng@mediatek.com, cc.chou@mediatek.com,
	chun-hung.wu@mediatek.com, kuohong.wang@mediatek.com,
	linux-kernel@vger.kernel.org, cang@codeaurora.org,
	linux-mediatek@lists.infradead.org, peter.wang@mediatek.com,
	matthias.bgg@gmail.com, beanhuo@micron.com,
	chaotian.jing@mediatek.com, linux-arm-kernel@lists.infradead.org,
	asutoshd@codeaurora.org
Subject: [PATCH v3] scsi: ufs: Fix possible infinite loop in ufshcd_hold
Date: Sun, 9 Aug 2020 13:07:34 +0800	[thread overview]
Message-ID: <20200809050734.18740-1-stanley.chu@mediatek.com> (raw)

In ufshcd_suspend(), after clk-gating is suspended and link is set
as Hibern8 state, ufshcd_hold() is still possibly invoked before
ufshcd_suspend() returns. For example, MediaTek's suspend vops may
issue UIC commands which would call ufshcd_hold() during the command
issuing flow.

Now if UFSHCD_CAP_HIBERN8_WITH_CLK_GATING capability is enabled,
then ufshcd_hold() may enter infinite loops because there is no
clk-ungating work scheduled or pending. In this case, ufshcd_hold()
shall just bypass, and keep the link as Hibern8 state.

Co-Developed-by: Andy Teng <andy.teng@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
---
Changes since v2:
    - Rebase to the latest Martin's queue branch
    - Add missing Reviewed tag since Avri's letter is not showing up in LKML and Patchwork
---
 drivers/scsi/ufs/ufshcd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 307622284239..b4f948027b3e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1561,6 +1561,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
 int ufshcd_hold(struct ufs_hba *hba, bool async)
 {
 	int rc = 0;
+	bool flush_result;
 	unsigned long flags;
 
 	if (!ufshcd_is_clkgating_allowed(hba))
@@ -1592,7 +1593,9 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
 				break;
 			}
 			spin_unlock_irqrestore(hba->host->host_lock, flags);
-			flush_work(&hba->clk_gating.ungate_work);
+			flush_result = flush_work(&hba->clk_gating.ungate_work);
+			if (hba->clk_gating.is_suspended && !flush_result)
+				goto out;
 			spin_lock_irqsave(hba->host->host_lock, flags);
 			goto start;
 		}
-- 
2.18.0
_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

WARNING: multiple messages have this Message-ID (diff)
From: Stanley Chu <stanley.chu@mediatek.com>
To: <linux-scsi@vger.kernel.org>, <martin.petersen@oracle.com>,
	<avri.altman@wdc.com>, <alim.akhtar@samsung.com>,
	<jejb@linux.ibm.com>, <bvanassche@acm.org>
Cc: Stanley Chu <stanley.chu@mediatek.com>,
	andy.teng@mediatek.com, cc.chou@mediatek.com,
	chun-hung.wu@mediatek.com, kuohong.wang@mediatek.com,
	linux-kernel@vger.kernel.org, cang@codeaurora.org,
	linux-mediatek@lists.infradead.org, peter.wang@mediatek.com,
	matthias.bgg@gmail.com, beanhuo@micron.com,
	chaotian.jing@mediatek.com, linux-arm-kernel@lists.infradead.org,
	asutoshd@codeaurora.org
Subject: [PATCH v3] scsi: ufs: Fix possible infinite loop in ufshcd_hold
Date: Sun, 9 Aug 2020 13:07:34 +0800	[thread overview]
Message-ID: <20200809050734.18740-1-stanley.chu@mediatek.com> (raw)

In ufshcd_suspend(), after clk-gating is suspended and link is set
as Hibern8 state, ufshcd_hold() is still possibly invoked before
ufshcd_suspend() returns. For example, MediaTek's suspend vops may
issue UIC commands which would call ufshcd_hold() during the command
issuing flow.

Now if UFSHCD_CAP_HIBERN8_WITH_CLK_GATING capability is enabled,
then ufshcd_hold() may enter infinite loops because there is no
clk-ungating work scheduled or pending. In this case, ufshcd_hold()
shall just bypass, and keep the link as Hibern8 state.

Co-Developed-by: Andy Teng <andy.teng@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
---
Changes since v2:
    - Rebase to the latest Martin's queue branch
    - Add missing Reviewed tag since Avri's letter is not showing up in LKML and Patchwork
---
 drivers/scsi/ufs/ufshcd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 307622284239..b4f948027b3e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1561,6 +1561,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
 int ufshcd_hold(struct ufs_hba *hba, bool async)
 {
 	int rc = 0;
+	bool flush_result;
 	unsigned long flags;
 
 	if (!ufshcd_is_clkgating_allowed(hba))
@@ -1592,7 +1593,9 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
 				break;
 			}
 			spin_unlock_irqrestore(hba->host->host_lock, flags);
-			flush_work(&hba->clk_gating.ungate_work);
+			flush_result = flush_work(&hba->clk_gating.ungate_work);
+			if (hba->clk_gating.is_suspended && !flush_result)
+				goto out;
 			spin_lock_irqsave(hba->host->host_lock, flags);
 			goto start;
 		}
-- 
2.18.0
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply	other threads:[~2020-08-09  5:08 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-09  5:07 Stanley Chu [this message]
2020-08-09  5:07 ` [PATCH v3] scsi: ufs: Fix possible infinite loop in ufshcd_hold Stanley Chu
2020-08-09  5:07 ` Stanley Chu
2020-08-18  3:12 ` Martin K. Petersen
2020-08-18  3:12   ` Martin K. Petersen
2020-08-18  3:12   ` Martin K. Petersen

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