Re: [PATCH v3 1/1] scsi: ufs: core: Add support to notify userspace of UniPro QoS events

[Can Guo]

On 3/4/2026 5:12 PM, Peter Wang (王信友) wrote:
> On Sun, 2026-03-01 at 04:51 -0800, Can Guo wrote:
> > @@ -1768,3 +1768,26 @@ Description:
> >                 ====================   ===========================
> > 
> >                 The attribute is read only.
> > +
> > +What:         
> > /sys/bus/platform/drivers/ufshcd/*/dme_qos_notification
> > +What:          /sys/bus/platform/devices/*.ufs/dme_qos_notification
> > +Date:          February 2026
>
> March 2026
Good catch
> > @@ -9097,6 +9106,12 @@ static int ufshcd_post_device_init(struct
> > ufs_hba *hba)
> > 
> >         /* UFS device is also active now */
> >         ufshcd_set_ufs_dev_active(hba);
> > +
> > +       /* Indicate that DME QoS Monitor has been reset */
> > +       atomic_set(&hba->dme_qos_notification, 0x1);
> > 
>
> Reset value should be 0?
Bit[0] is used to communicate to userspace that DME QOS has been reset,
see also the bit assignments explained in the patch.
> > @@ -1116,6 +1121,10 @@ struct ufs_hba {
> >         int critical_health_count;
> >         atomic_t dev_lvl_exception_count;
> >         u64 dev_lvl_exception_id;
> > +
> > +       atomic_t dme_qos_notification;
> > +       struct kernfs_node *dme_qos_sysfs_handle;
>
> Why is dme_qos_sysfs_handle necessary?
> Wouldn't it be sufficient to use
> sysfs_notify(&hba->dev->kobj, NULL, "dme_qos_notification");
> without checking whether dme_qos_sysfs_handle is NULL?
sysfs_notify() cannot be used under atomic context, i.e., IRQ context.

Thanks,
Can Guo.
> Thanks
> Peter
>
> ************* MEDIATEK Confidentiality Notice
>   ********************
> The information contained in this e-mail message (including any
> attachments) may be confidential, proprietary, privileged, or otherwise
> exempt from disclosure under applicable laws. It is intended to be
> conveyed only to the designated recipient(s). Any use, dissemination,
> distribution, printing, retaining or copying of this e-mail (including its
> attachments) by unintended recipient(s) is strictly prohibited and may
> be unlawful. If you are not an intended recipient of this e-mail, or believe
>   
> that you have received this e-mail in error, please notify the sender
> immediately (by replying to this e-mail), delete any and all copies of
> this e-mail (including any attachments) from your system, and do not
> disclose the content of this e-mail to any other person. Thank you!