Re: [PATCH v3 1/9] scsi: ufs: Differentiate status between hba pm ops and wl pm ops

[Can Guo <cang@codeaurora.org>]

Hi Bart,

On 2021-06-17 01:50, Bart Van Assche wrote:
> On 6/9/21 9:43 PM, Can Guo wrote:
>> @@ -8784,7 +8786,7 @@ static int __ufshcd_wl_suspend(struct ufs_hba 
>> *hba, enum ufs_pm_op pm_op)
>>  	enum ufs_dev_pwr_mode req_dev_pwr_mode;
>>  	enum uic_link_state req_link_state;
>> 
>> -	hba->pm_op_in_progress = true;
>> +	hba->wl_pm_op_in_progress = true;
>>  	if (pm_op != UFS_SHUTDOWN_PM) {
>>  		pm_lvl = pm_op == UFS_RUNTIME_PM ?
>>  			 hba->rpm_lvl : hba->spm_lvl;
>> @@ -8919,7 +8921,7 @@ static int __ufshcd_wl_suspend(struct ufs_hba 
>> *hba, enum ufs_pm_op pm_op)
>>  		hba->clk_gating.is_suspended = false;
>>  		ufshcd_release(hba);
>>  	}
>> -	hba->pm_op_in_progress = false;
>> +	hba->wl_pm_op_in_progress = false;
>>  	return ret;
>>  }
> 
> Are the __ufshcd_wl_suspend() calls serialized in any way? If not, will
> the value of wl_pm_op_in_progress be incorrect if multiple kernel
> threads run __ufshcd_wl_suspend() concurrently and one of the
> __ufshcd_wl_suspend() instances returns earlier than the other?
> 

Sorry for getting back late on this... I was stuck by some urgent 
issues.

Yes, __ufshcd_wl_suspend() calls are serilized, because it is called by
either runtime suspend or system suspend, and runtime suspend and system
suspend are serialized - Rafael J. Wysocki has put a lot of efforts on 
it,
see also 1e2ef05bb8cf8 ("PM: Limit race conditions between runtime PM 
and
system sleep (v2)")).

> Thanks,
> 
> Bart.