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Subject: Re: [PATCH v3 4/6] scsi: ufshpb: Change sysfs node hpb_stats/rb_*
 prefix to start with rcmd_*
From:   Bean Huo <huobean@gmail.com>
To:     Avri Altman <Avri.Altman@wdc.com>,
        "alim.akhtar@samsung.com" <alim.akhtar@samsung.com>,
        "jejb@linux.ibm.com" <jejb@linux.ibm.com>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        "stanley.chu@mediatek.com" <stanley.chu@mediatek.com>,
        "beanhuo@micron.com" <beanhuo@micron.com>,
        "bvanassche@acm.org" <bvanassche@acm.org>,
        "tomas.winkler@intel.com" <tomas.winkler@intel.com>,
        "daejun7.park@samsung.com" <daejun7.park@samsung.com>,
        "keosung.park@samsung.com" <keosung.park@samsung.com>,
        "peter.wang@mediatek.com" <peter.wang@mediatek.com>,
        "powen.kao@mediatek.com" <powen.kao@mediatek.com>
Cc:     "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Date:   Tue, 26 Apr 2022 23:44:14 +0200
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On Mon, 2022-04-25 at 06:19 +0000, Avri Altman wrote:
> > From: Bean Huo <beanhuo@micron.com>
> >=20
> > According to the documentation of the sysfs nodes rb_noti_cnt,
> > rb_active_cnt
> > and rb_inactive_cnt, they are all related to HPB recommendation in
> > UPIU
> > response packet. I don't know what 'rb' refers to, I think 'rcmd'
> > (recommendation) should be the correct abbreviation.
> rb stands for READ-BUFFER
>=20
Thanks. right. probably it is HPB READ BUFFER.  I think based on the
documentation,rcmd much makes sense, there is region inactive
recommendation, it is no need to issue HPB read buffer.

> >=20
> > Change the sysfs documentation about these sysfs nodes to highlight
> > what
> > they mean under different HPB control modes.
> >=20
> > Signed-off-by: Bean Huo <beanhuo@micron.com>
> I don't think it is allowed to change the kernel's ABI.
>=20

I don't know where this limitation is stated, I see a lot of ABI change
patches on the mailing list. Also, I didn't change its original
meaning, I added a new node meaning to make it clearer. According to
the documentation on these nodes, they should be used in HPB host
control mode, right? Otherwise, we should add a new note for HPB host
control mode. Considering we already have these nodes, we don't need to
change the HPB host control mode code just by changing the ABI to have
the HPB host control mode reuse them. Here are my thoughts on change.
Please consider my changes again.


Kind regards,
Bean


> Thanks,
> Avri