On 10/27, Can Guo wrote:
> On 2020-10-27 11:33, Jaegeuk Kim wrote:
> > On 10/27, Can Guo wrote:
> > > On 2020-10-27 03:51, Jaegeuk Kim wrote:
> > > > From: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> > > >
> > > > When giving a stress test which enables/disables clkgating, we hit
> > > > device
> > > > timeout sometimes. This patch avoids subtle racy condition to address
> > > > it.
> > > >
> > > > Note that, this requires a patch to address the device stuck by
> > > > REQ_CLKS_OFF in
> > > > __ufshcd_release().
> > > >
> > > > The fix is "scsi: ufs: avoid to call REQ_CLKS_OFF to CLKS_OFF".
> > >
> > > Why don't you just squash the fix into this one?
> >
> > I'm seeing this patch just revealed that problem.
>
> That scenario (back to back calling of ufshcd_release()) only happens
> when you stress the clkgate_enable sysfs node, so let's keep the fix
> as one to make things simple. What do you think?
If we don't have this patch, do you think this issue won't happen at all?
>
> Thanks,
>
> Can Guo.
>
> >
> > >
> > > Thanks,
> > >
> > > Can Guo.
> > >
> > > >
> > > > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> > > > ---
> > > > drivers/scsi/ufs/ufshcd.c | 12 ++++++------
> > > > 1 file changed, 6 insertions(+), 6 deletions(-)
> > > >
> > > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > > > index cc8d5f0c3fdc..6c9269bffcbd 100644
> > > > --- a/drivers/scsi/ufs/ufshcd.c
> > > > +++ b/drivers/scsi/ufs/ufshcd.c
> > > > @@ -1808,19 +1808,19 @@ static ssize_t
> > > > ufshcd_clkgate_enable_store(struct device *dev,
> > > > return -EINVAL;
> > > >
> > > > value = !!value;
> > > > +
> > > > + spin_lock_irqsave(hba->host->host_lock, flags);
> > > > if (value == hba->clk_gating.is_enabled)
> > > > goto out;
> > > >
> > > > - if (value) {
> > > > - ufshcd_release(hba);
> > > > - } else {
> > > > - spin_lock_irqsave(hba->host->host_lock, flags);
> > > > + if (value)
> > > > + __ufshcd_release(hba);
> > > > + else
> > > > hba->clk_gating.active_reqs++;
> > > > - spin_unlock_irqrestore(hba->host->host_lock, flags);
> > > > - }
> > > >
> > > > hba->clk_gating.is_enabled = value;
> > > > out:
> > > > + spin_unlock_irqrestore(hba->host->host_lock, flags);
> > > > return count;
> > > > }
