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scsi: ufs: Fix possible infinite loop in ufshcd_hold

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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>
This commit is contained in:
Stanley Chu 2020-08-09 13:07:34 +08:00 committed by Martin K. Petersen
parent fa39ab5184
commit 93b6c5db06
1 changed files with 4 additions and 1 deletions
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5
drivers/scsi/ufs/ufshcd.c
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@ -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;
}