Re: [PATCH v2 1/5] scsi: ufs: atomic update for clkgating_enable

jaegeuk
2020-10-21T04:41:33Z

On 10/21, Can Guo wrote:
> On 2020-10-21 03:52, Jaegeuk Kim wrote:
> > From: Jaegeuk Kim <jaegeuk@google.com>
> >
> > When giving a stress test which enables/disables clkgating, we hit
> > device
> > timeout sometimes. This patch avoids subtle racy condition to address
> > it.
> >
> > Cc: Alim Akhtar <alim.akhtar@samsung.com>
> > Cc: Avri Altman <avri.altman@wdc.com>
> > Cc: Can Guo <cang@codeaurora.org>
> > Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
>
> Reviewed-by: Can Guo <cang@codeaurora.org>
>
> Next time can you have a cover letter in case of multiple patches?

Ah, it seems I had to cc you here as well.

https://lore.kernel.org/linux-scsi/20201020195258.2005605-1-jaegeuk@kernel.org/T/#mb4e43f3bd03a6b7bc136bea21ac805041c1417a2

>
> Thanks,
>
> Can Guo.
>
> > ---
> > 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 b8f573a02713..7344353a9167 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -1807,19 +1807,19 @@ 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;
> > }