Re: [PATCH 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs

[Can Guo]

On 2021-01-05 04:05, Bean Huo wrote:
> On Sat, 2021-01-02 at 05:59 -0800, Can Guo wrote:
> > + * @shutting_down: flag to check if shutdown has been invoked
>
> I am not much sure if this flag is need, since once PM going in
> shutdown path, what will be returnded by pm_runtime_get_sync()?
>
> If pm_runtime_get_sync() will fail, just check its return.

That depends. During/after shutdown, for UFS's case only,
pm_runtime_get_sync(hba->dev) will most likely return 0,
because it is already RUNTIME_ACTIVE, pm_runtime_get_sync()
will directly return 0... meaning you cannot count on it.

Check Stanley's change -
https://lore.kernel.org/patchwork/patch/1341389/

Can Guo.

> Hi Rafael
> would you please help us confirm this?
>
> thanks,
> Bean
>
>
> > + * @host_sem: semaphore used to serialize concurrent contexts
> >   * @eh_wq: Workqueue that eh_work works on
> >   * @eh_work: Worker to handle UFS errors that require s/w attention
> >   * @eeh_work: Worker to handle exception events
> > @@ -751,7 +753,8 @@ struct ufs_hba {
> >         u32 intr_mask;
> >         u16 ee_ctrl_mask;
> >         bool is_powered;
> > -       struct semaphore eh_sem;
> > +       bool shutting_down;
> > +       struct semaphore host_sem;