| From 5269ff2c50e8b0429fc5afb99f47123102ea97f2 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Sun, 9 Aug 2020 13:07:34 +0800 |
| Subject: scsi: ufs: Fix possible infinite loop in ufshcd_hold |
| |
| From: Stanley Chu <stanley.chu@mediatek.com> |
| |
| [ Upstream commit 93b6c5db06028a3b55122bbb74d0715dd8ca4ae0 ] |
| |
| 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. |
| |
| Link: https://lore.kernel.org/r/20200809050734.18740-1-stanley.chu@mediatek.com |
| Reviewed-by: Avri Altman <avri.altman@wdc.com> |
| Co-developed-by: Andy Teng <andy.teng@mediatek.com> |
| Signed-off-by: Andy Teng <andy.teng@mediatek.com> |
| Signed-off-by: Stanley Chu <stanley.chu@mediatek.com> |
| Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| 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 a7f520581cb0f..9916c574e8b80 100644 |
| --- a/drivers/scsi/ufs/ufshcd.c |
| +++ b/drivers/scsi/ufs/ufshcd.c |
| @@ -659,6 +659,7 @@ unblock_reqs: |
| int ufshcd_hold(struct ufs_hba *hba, bool async) |
| { |
| int rc = 0; |
| + bool flush_result; |
| unsigned long flags; |
| |
| if (!ufshcd_is_clkgating_allowed(hba)) |
| @@ -690,7 +691,9 @@ start: |
| 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; |
| } |
| -- |
| 2.25.1 |
| |