[v3] scsi: ufs: Fix possible infinite loop in ufshcd_hold
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Message ID 20200809050734.18740-1-stanley.chu@mediatek.com
State Accepted
Commit 93b6c5db06028a3b55122bbb74d0715dd8ca4ae0
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Series
  • [v3] scsi: ufs: Fix possible infinite loop in ufshcd_hold
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Commit Message

Stanley Chu Aug. 9, 2020, 5:07 a.m. UTC
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(-)

Comments

Martin K. Petersen Aug. 18, 2020, 3:12 a.m. UTC | #1
On Sun, 9 Aug 2020 13:07:34 +0800, Stanley Chu wrote:

> 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.

Applied to 5.9/scsi-fixes, thanks!

[1/1] scsi: ufs: Fix possible infinite loop in ufshcd_hold
      https://git.kernel.org/mkp/scsi/c/93b6c5db0602

Patch
diff mbox series

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;
 		}