2020-10-21 09:57:07

by Jaegeuk Kim

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

From: Jaegeuk Kim <[email protected]>

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 <[email protected]>
Cc: Avri Altman <[email protected]>
Cc: Can Guo <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
---
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;
}

--
2.29.0.rc1.297.gfa9743e501-goog

2020-10-21 12:02:33

by Can Guo

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

On 2020-10-21 03:52, Jaegeuk Kim wrote:
> From: Jaegeuk Kim <[email protected]>
>
> 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 <[email protected]>
> Cc: Avri Altman <[email protected]>
> Cc: Can Guo <[email protected]>
> Signed-off-by: Jaegeuk Kim <[email protected]>

Reviewed-by: Can Guo <[email protected]>

Next time can you have a cover letter in case of multiple patches?

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;
> }

2020-10-21 12:26:43

by Jaegeuk Kim

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

On 10/21, Can Guo wrote:
> On 2020-10-21 03:52, Jaegeuk Kim wrote:
> > From: Jaegeuk Kim <[email protected]>
> >
> > 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 <[email protected]>
> > Cc: Avri Altman <[email protected]>
> > Cc: Can Guo <[email protected]>
> > Signed-off-by: Jaegeuk Kim <[email protected]>
>
> Reviewed-by: Can Guo <[email protected]>
>
> 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/[email protected]/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;
> > }