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From:   Arthur Simchaev <Arthur.Simchaev@wdc.com>
To:     Greg KH <gregkh@linuxfoundation.org>,
        Bart Van Assche <bvanassche@acm.org>
CC:     "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "alim.akhtar@samsung.com" <alim.akhtar@samsung.com>,
        Bean Huo <beanhuo@micron.com>
Subject: RE: [PATCH] scsi: ufs: sysfs: add is_ascii_output entry
Thread-Topic: [PATCH] scsi: ufs: sysfs: add is_ascii_output entry
Thread-Index: AQHW/5sHTsWV8bv5R0C33pPiphtkYqpSTqiAgAUgsQCAAEppMA==
Date:   Sun, 14 Feb 2021 14:21:01 +0000
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Done.

Regards
Arthur

> -----Original Message-----
> From: Greg KH <gregkh@linuxfoundation.org>
> Sent: Sunday, February 14, 2021 11:54 AM
> To: Bart Van Assche <bvanassche@acm.org>
> Cc: Arthur Simchaev <Arthur.Simchaev@wdc.com>; James E . J . Bottomley
> <jejb@linux.vnet.ibm.com>; Martin K . Petersen
> <martin.petersen@oracle.com>; linux-scsi@vger.kernel.org; linux-
> kernel@vger.kernel.org; alim.akhtar@samsung.com; Bean Huo
> <beanhuo@micron.com>; Arthur Simchaev <Arthur.Simchaev@wdc.com>
> Subject: Re: [PATCH] scsi: ufs: sysfs: add is_ascii_output entry
>=20
> CAUTION: This email originated from outside of Western Digital. Do not cl=
ick
> on links or open attachments unless you recognize the sender and know tha=
t
> the content is safe.
>=20
>=20
> On Wed, Feb 10, 2021 at 07:35:25PM -0800, Bart Van Assche wrote:
> > On 2/10/21 2:53 AM, Arthur Simchaev wrote:
> > > +static bool is_ascii_output =3D true;
> >
> > [ ... ]
> >
> > >  static const char *ufschd_uic_link_state_to_string(
> > >                     enum uic_link_state state)
> > >  {
> > > @@ -693,7 +695,15 @@ static ssize_t _name##_show(struct device *dev,
> \
> > >                                   SD_ASCII_STD);                    \
> > >     if (ret < 0)                                                    \
> > >             goto out;                                               \
> > > -   ret =3D sysfs_emit(buf, "%s\n", desc_buf);                       =
 \
> > > +   if (is_ascii_output) {                                          \
> > > +           ret =3D sysfs_emit(buf, "%s\n", desc_buf);               =
 \
> > > +   } else {                                                        \
> > > +           int i;                                                  \
> > > +                                                                   \
> > > +           for (i =3D 0; i < desc_buf[0]; i++)                      =
 \
> > > +                   hex_byte_pack(buf + i * 2, desc_buf[i]);        \
> > > +           ret =3D sysfs_emit(buf, "%s\n", buf);                    =
 \
> > > +   }                                                               \
> > >  out:                                                                =
       \
> > >     pm_runtime_put_sync(hba->dev);                                  \
> > >     kfree(desc_buf);                                                \
> >
> > Please do not introduce a mode variable but instead introduce a new
> > attribute such that there is one attribute for the unicode output and
> > one attribute for the ASCII output. Mode variables are troublesome when
> > e.g. two scripts try to set the mode attribute concurrently.
>=20
> Agreed, just make a new sysfs file, please never change the output of an
> existing sysfs file, that way will guarantee confusion in userspace.
>=20
> thanks,
>=20
> greg k-h