Re: [PATCH v2 1/2] scsi: ufs: core: Add support to notify userspace of UniPro QoS events

[Can Guo]

Hi Bart,

On 2/26/2026 2:48 AM, Bart Van Assche wrote:
> On 2/24/26 6:29 PM, Can Guo wrote:
> > +What: /sys/bus/platform/drivers/ufshcd/*/dme_qos_notification
> > +What: /sys/bus/platform/devices/*.ufs/dme_qos_notification
> > +Date:        February 2026
> > +Contact:    Can Guo <can.guo@xxxxxxxxxxxxxxxx>
> > +Description:
> > +        This attribute shows and clears the DME    Quality of Service
> > +        notification from UFSHCI UECDME.
> > +
> > +        The attribute is read/write.
>
> The above text is incomplete. It should explain that
> dme_qos_notification is a bitfield, what the meaning of the bits in this
> bitfield are, when this bitfield is updated, that the only value that
> can be written into this bitfield is 0 and also what the effect of
> writing 0 into this bitfield is.
Done.
> > diff --git a/drivers/ufs/core/ufshcd-priv.h 
> > b/drivers/ufs/core/ufshcd-priv.h
> > index 7d6d19361af9..14e8cb145f43 100644
> > --- a/drivers/ufs/core/ufshcd-priv.h
> > +++ b/drivers/ufs/core/ufshcd-priv.h
> > @@ -446,4 +446,10 @@ static inline void ufs_rpmb_remove(struct 
> > ufs_hba *hba)
> >   }
> >   #endif
> >   +static inline void sysfs_notify_dirent_safe(struct kernfs_node *sd)
> > +{
> > +    if (sd)
> > +        sysfs_notify_dirent(sd);
> > +}
>
> This function is very short and is not used outside
> drivers/ufs/core/ufshcd.c. Is it really needed to introduce this 
> function? If this function is preserved, please consider moving it into
> drivers/ufs/core/ufshcd.c.
Done.
> > @@ -11044,6 +11051,8 @@ int ufshcd_init(struct ufs_hba *hba, void 
> __iomem *mmio_base, unsigned int irq)
> >           goto out_disable;
> >
> >       ufs_sysfs_add_nodes(hba->dev);
> > +    hba->dme_qos_sysfs_handle = sysfs_get_dirent(hba->dev->kobj.sd,
> > +                             "dme_qos_notification");
> >       async_schedule(ufshcd_async_scan, hba);
> >
> >       device_enable_async_suspend(dev);
>
> Where is the sysfs_put() call that corresponds to the above 
> sysfs_get_dirent() call?
Good catch, I missed it.. Will add it in next version.
> > + * @dme_qos_notification: UFS host controller DME QoS notification
>
> Please explain also here that this is a bitfield and where the meaning
> of the bits in this bitfield are defined.
Done.
> Thanks,
>
> Bart.