linux-kernel - RE:(2) [PATCH v5 3/6] scsi: ufs: wb: Add explicit flush sysfs attribute

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Message-ID: <20220801052718epcms2p11e9e1677abbc0e573cddff4e641e212f@epcms2p1>
Date:   Mon, 01 Aug 2022 14:27:18 +0900
From:   Jinyoung CHOI <j-young.choi@...sung.com>
To:     Bart Van Assche <bvanassche@....org>,
        ALIM AKHTAR <alim.akhtar@...sung.com>,
        "avri.altman@....com" <avri.altman@....com>,
        "jejb@...ux.ibm.com" <jejb@...ux.ibm.com>,
        "martin.petersen@...cle.com" <martin.petersen@...cle.com>,
        "beanhuo@...ron.com" <beanhuo@...ron.com>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE:(2) [PATCH v5 3/6] scsi: ufs: wb: Add explicit flush sysfs
 attribute

>On 7/28/22 21:56, Jinyoung CHOI wrote:
>> diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
>> index 6b248abb1bd7..7e9e1db55d60 100644
>> --- a/Documentation/ABI/testing/sysfs-driver-ufs
>> +++ b/Documentation/ABI/testing/sysfs-driver-ufs
>> @@ -1417,6 +1417,16 @@ Description:	This node is used to set or display whether UFS WriteBooster is
>>   		platform that doesn't support UFSHCD_CAP_CLK_SCALING, we can
>>   		disable/enable WriteBooster through this sysfs node.
>>   
>> +What:		/sys/bus/platform/drivers/ufshcd/*/wb_buf_flush_en
>> +What:		/sys/bus/platform/devices/*.ufs/wb_buf_flush_en
>> +Date:		July 2022
>> +Contact:	Jinyoung Choi <j-young.choi@...sung.com>
>> +Description:	This node is used to set or display whether WriteBooster
>                      ^^^^
>
>Please change "node" into "attribute" (here and below). Sysfs files are 
>called attributes.
>

The wb_on description is also written as node.
This will also be changed to other commit.


>> +		buffer flusing is enabled. The data written in the WriteBooster
>                        ^^^^^^^
>                        flushing?
>> +		Buffer can be flushed by an explicit host command or
>> +		implicitly while in hibernate (HIBERN8) state.
>
>The above sentence is misleading because it suggests that setting this 
>attribute causes the WB buffer to be flushed in its entirety. That is 
>not correct - what this attribute controls is whether or not the UFS 
>device is allowed to start with flushing the WB buffer.
>

It seems to have been written so briefly.
Because each device manufacturer may have different flush policies,
So, I did not describe the amount. This is the same as the ufs spec.
I will add more explanation.
And, I don't fully understand your comment (That is not correct ~)
If you explain it more, I will consider it.


>> +	if (!ufshcd_is_wb_allowed(hba) ||
>> +	    (hba->quirks & UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL)) {
>> +		dev_warn(dev, "It is not allowed to configure WB buf flush!\n");
>
>flush -> flushing
>

OK, I will fix it.


>> +	ufshcd_rpm_get_sync(hba);
>> +	res = ufshcd_wb_toggle_buf_flush(hba, wb_buf_flush_en);
>> +	ufshcd_rpm_put_sync(hba);
>> +out:
>> +	up(&hba->host_sem);
>> +	return res < 0 ? res : count;
>> +}
>
>Please leave a blank line above goto labels as requested by the kernel 
>coding style guide.
>
>Thanks,
>
>Bart.

OK, I will fix it.
wb_on_store() will also be modified with this. (other commit)

Kind Regards,
Jinyoung