Re: [PATCH 1/2] scsi: ufs: Protect some contexts from unexpected clock scaling

[Bean Huo <huobean@gmail.com>]

Hi Can

On Wed, 2020-12-09 at 05:35 -0800, Can Guo wrote:
> 
>  
> @@ -1160,6 +1166,7 @@ static void
> ufshcd_clock_scaling_unprepare(struct ufs_hba *hba)
>  {
>  	up_write(&hba->clk_scaling_lock);
>  	ufshcd_scsi_unblock_requests(hba);
> +	ufshcd_release(hba);
>  }
>  
>  /**
> @@ -1175,12 +1182,9 @@ static int ufshcd_devfreq_scale(struct ufs_hba
> *hba, bool scale_up)
>  {
>  	int ret = 0;
>  
> -	/* let's not get into low power until clock scaling is
> completed */
> -	ufshcd_hold(hba, false);
> -
>  	ret = ufshcd_clock_scaling_prepare(hba);
>  	if (ret)
> -		goto out;
> +		return ret;
>  
>  	/* scale down the gear before scaling down clocks */
>  	if (!scale_up) {
> @@ -1212,8 +1216,6 @@ static int ufshcd_devfreq_scale(struct ufs_hba
> *hba, bool scale_up)
>  
>  out_unprepare:
>  	ufshcd_clock_scaling_unprepare(hba);
> -out:
> -	ufshcd_release(hba);
>  	return ret;
>  }

I didn't understand why moving ufshcd_hold/ufshcd_release into
ufshcd_clock_scaling_prepare()/ufshcd_clock_scaling_unprepare().


>  
> @@ -1294,15 +1296,8 @@ static int ufshcd_devfreq_target(struct device
> *dev,
>  	}
>  	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
>  
> -	pm_runtime_get_noresume(hba->dev);
> -	if (!pm_runtime_active(hba->dev)) {
> -		pm_runtime_put_noidle(hba->dev);
> -		ret = -EAGAIN;
> -		goto out;
> -	}
>  	start = ktime_get();
>  	ret = ufshcd_devfreq_scale(hba, scale_up);
> -	pm_runtime_put(hba->dev);
>  

which branch are you working on?  I didn't see this part codes in the
branch 5.11/scsi-queue and 5.11/scsi-staging.

Bean