[PATCH] scsi: ufs: fix no clkgating due to tag being alive

[PATCH] scsi: ufs: fix no clkgating due to tag being alive

[Jaegeuk Kim]

The below call stack prevents clk_gating at every IO completion.
We can remove the condition, ufshcd_any_tag_in_use(), since clkgating_work
will check it again.

ufshcd_complete_requests(struct ufs_hba *hba)
  ufshcd_transfer_req_compl()
    __ufshcd_transfer_req_compl()
      __ufshcd_release(hba)
        if (ufshcd_any_tag_in_use() == 1)
           return;
  ufshcd_tmc_handler(hba);
    blk_mq_tagset_busy_iter();

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@kernel.org>
---
 drivers/scsi/ufs/ufshcd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 1d157ff58d81..22fecb9a4ec2 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1727,7 +1727,7 @@ static void __ufshcd_release(struct ufs_hba *hba)
 
 	if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended
 		|| hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL
-		|| ufshcd_any_tag_in_use(hba) || hba->outstanding_tasks
+		|| hba->outstanding_tasks
 		|| hba->active_uic_cmd || hba->uic_async_done
 		|| ufshcd_eh_in_progress(hba))
 		return;
-- 
2.29.0.rc1.297.gfa9743e501-goog

Re: [PATCH v2] scsi: ufs: fix clkgating on/off correctly

[jaegeuk]

The below call stack prevents clk_gating at every IO completion.
We can remove the condition, ufshcd_any_tag_in_use(), since clkgating_work
will check it again.

ufshcd_complete_requests(struct ufs_hba *hba)
  ufshcd_transfer_req_compl()
    __ufshcd_transfer_req_compl()
      __ufshcd_release(hba)
        if (ufshcd_any_tag_in_use() == 1)
           return;
  ufshcd_tmc_handler(hba);
    blk_mq_tagset_busy_iter();

In addition, we have to avoid gate_work, if it was disabled.

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@kernel.org>
---

Change log from v1:
 - change the patch subject
 - fix clkgate.is_enable to work

 drivers/scsi/ufs/ufshcd.c | 5 +++--
 drivers/scsi/ufs/ufshcd.h | 5 +++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index a2db8182663d..75e8a76f20c7 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1729,9 +1729,10 @@ static void __ufshcd_release(struct ufs_hba *hba)
 
 	if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended
 		|| hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL
-		|| ufshcd_any_tag_in_use(hba) || hba->outstanding_tasks
+		|| hba->outstanding_tasks
 		|| hba->active_uic_cmd || hba->uic_async_done
-		|| ufshcd_eh_in_progress(hba))
+		|| ufshcd_eh_in_progress(hba)
+		|| ufshcd_is_clkgating_enabled(hba))
 		return;
 
 	hba->clk_gating.state = REQ_CLKS_OFF;
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 8344d8cb3678..09e59cb86e69 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -814,6 +814,11 @@ static inline bool ufshcd_is_auto_hibern8_supported(struct ufs_hba *hba)
 		!(hba->quirks & UFSHCD_QUIRK_BROKEN_AUTO_HIBERN8);
 }
 
+static inline bool ufshcd_is_clkgating_enabled(struct ufs_hba *hba)
+{
+	return hba->clk_gating.is_enabled;
+}
+
 static inline bool ufshcd_is_auto_hibern8_enabled(struct ufs_hba *hba)
 {
 	return FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK, hba->ahit) ? true : false;
-- 
2.29.0.rc1.297.gfa9743e501-goog

Re: [PATCH v2] scsi: ufs: fix clkgating on/off correctly

[Can Guo]

On 2020-10-17 05:18, jaegeuk@kernel.org wrote:
> The below call stack prevents clk_gating at every IO completion.
> We can remove the condition, ufshcd_any_tag_in_use(), since 
> clkgating_work
> will check it again.

Thanks for fixing it, actually we have noticed this for a while.
It used to work well, please add a Fixes tag or mention the commit
which breaks clk gating functionality - the commit which introduces
func ufshcd_any_tag_in_use().

Regards,

Can Guo.

> 
> ufshcd_complete_requests(struct ufs_hba *hba)
>   ufshcd_transfer_req_compl()
>     __ufshcd_transfer_req_compl()
>       __ufshcd_release(hba)
>         if (ufshcd_any_tag_in_use() == 1)
>            return;
>   ufshcd_tmc_handler(hba);
>     blk_mq_tagset_busy_iter();
> 
> In addition, we have to avoid gate_work, if it was disabled.
> 
> 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@kernel.org>
> ---
> 
> Change log from v1:
>  - change the patch subject
>  - fix clkgate.is_enable to work
> 
>  drivers/scsi/ufs/ufshcd.c | 5 +++--
>  drivers/scsi/ufs/ufshcd.h | 5 +++++
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index a2db8182663d..75e8a76f20c7 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1729,9 +1729,10 @@ static void __ufshcd_release(struct ufs_hba 
> *hba)
> 
>  	if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended
>  		|| hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL
> -		|| ufshcd_any_tag_in_use(hba) || hba->outstanding_tasks
> +		|| hba->outstanding_tasks
>  		|| hba->active_uic_cmd || hba->uic_async_done
> -		|| ufshcd_eh_in_progress(hba))
> +		|| ufshcd_eh_in_progress(hba)
> +		|| ufshcd_is_clkgating_enabled(hba))
>  		return;
> 
>  	hba->clk_gating.state = REQ_CLKS_OFF;
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 8344d8cb3678..09e59cb86e69 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -814,6 +814,11 @@ static inline bool
> ufshcd_is_auto_hibern8_supported(struct ufs_hba *hba)
>  		!(hba->quirks & UFSHCD_QUIRK_BROKEN_AUTO_HIBERN8);
>  }
> 
> +static inline bool ufshcd_is_clkgating_enabled(struct ufs_hba *hba)
> +{
> +	return hba->clk_gating.is_enabled;
> +}
> +
>  static inline bool ufshcd_is_auto_hibern8_enabled(struct ufs_hba *hba)
>  {
>  	return FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK, hba->ahit) ? true : 
> false;

Re: [PATCH v2] scsi: ufs: fix clkgating on/off correctly

[Can Guo]

On 2020-10-17 05:18, jaegeuk@kernel.org wrote:
> The below call stack prevents clk_gating at every IO completion.
> We can remove the condition, ufshcd_any_tag_in_use(), since 
> clkgating_work
> will check it again.
> 
> ufshcd_complete_requests(struct ufs_hba *hba)
>   ufshcd_transfer_req_compl()
>     __ufshcd_transfer_req_compl()
>       __ufshcd_release(hba)
>         if (ufshcd_any_tag_in_use() == 1)
>            return;
>   ufshcd_tmc_handler(hba);
>     blk_mq_tagset_busy_iter();
> 
> In addition, we have to avoid gate_work, if it was disabled.
> 
> 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@kernel.org>
> ---
> 
> Change log from v1:
>  - change the patch subject
>  - fix clkgate.is_enable to work
> 
>  drivers/scsi/ufs/ufshcd.c | 5 +++--
>  drivers/scsi/ufs/ufshcd.h | 5 +++++
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index a2db8182663d..75e8a76f20c7 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1729,9 +1729,10 @@ static void __ufshcd_release(struct ufs_hba 
> *hba)
> 
>  	if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended
>  		|| hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL
> -		|| ufshcd_any_tag_in_use(hba) || hba->outstanding_tasks
> +		|| hba->outstanding_tasks
>  		|| hba->active_uic_cmd || hba->uic_async_done
> -		|| ufshcd_eh_in_progress(hba))
> +		|| ufshcd_eh_in_progress(hba)
> +		|| ufshcd_is_clkgating_enabled(hba))

I guess you want it to be "!ufshcd_is_clkgating_enabled(hba)" - if
clk gating is enabled, we should let gating happen but not bail, right?

That said, I don't think we need to check whether clk gating is enabled 
or
not here, since ufshcd_clkgating_store() manipulates 
clk_gating->active_reqs
in an atomic way. If someone disables clk gating -> 
clk_gating->active_reqs++,
this check becomes TURE on the very first condition.

So the very fisrt patch looks better to me.

Thanks,

Can Guo.

>  		return;
> 
>  	hba->clk_gating.state = REQ_CLKS_OFF;
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 8344d8cb3678..09e59cb86e69 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -814,6 +814,11 @@ static inline bool
> ufshcd_is_auto_hibern8_supported(struct ufs_hba *hba)
>  		!(hba->quirks & UFSHCD_QUIRK_BROKEN_AUTO_HIBERN8);
>  }
> 
> +static inline bool ufshcd_is_clkgating_enabled(struct ufs_hba *hba)
> +{
> +	return hba->clk_gating.is_enabled;
> +}
> +
>  static inline bool ufshcd_is_auto_hibern8_enabled(struct ufs_hba *hba)
>  {
>  	return FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK, hba->ahit) ? true : 
> false;

Re: [PATCH v2] scsi: ufs: fix clkgating on/off correctly

[jaegeuk]

On 10/20, Can Guo wrote:
> On 2020-10-17 05:18, jaegeuk@kernel.org wrote:
> > The below call stack prevents clk_gating at every IO completion.
> > We can remove the condition, ufshcd_any_tag_in_use(), since
> > clkgating_work
> > will check it again.
> > 
> > ufshcd_complete_requests(struct ufs_hba *hba)
> >   ufshcd_transfer_req_compl()
> >     __ufshcd_transfer_req_compl()
> >       __ufshcd_release(hba)
> >         if (ufshcd_any_tag_in_use() == 1)
> >            return;
> >   ufshcd_tmc_handler(hba);
> >     blk_mq_tagset_busy_iter();
> > 
> > In addition, we have to avoid gate_work, if it was disabled.
> > 
> > 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@kernel.org>
> > ---
> > 
> > Change log from v1:
> >  - change the patch subject
> >  - fix clkgate.is_enable to work
> > 
> >  drivers/scsi/ufs/ufshcd.c | 5 +++--
> >  drivers/scsi/ufs/ufshcd.h | 5 +++++
> >  2 files changed, 8 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index a2db8182663d..75e8a76f20c7 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -1729,9 +1729,10 @@ static void __ufshcd_release(struct ufs_hba *hba)
> > 
> >  	if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended
> >  		|| hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL
> > -		|| ufshcd_any_tag_in_use(hba) || hba->outstanding_tasks
> > +		|| hba->outstanding_tasks
> >  		|| hba->active_uic_cmd || hba->uic_async_done
> > -		|| ufshcd_eh_in_progress(hba))
> > +		|| ufshcd_eh_in_progress(hba)
> > +		|| ufshcd_is_clkgating_enabled(hba))
> 
> I guess you want it to be "!ufshcd_is_clkgating_enabled(hba)" - if
> clk gating is enabled, we should let gating happen but not bail, right?
> 
> That said, I don't think we need to check whether clk gating is enabled or
> not here, since ufshcd_clkgating_store() manipulates clk_gating->active_reqs
> in an atomic way. If someone disables clk gating ->
> clk_gating->active_reqs++,
> this check becomes TURE on the very first condition.

Yeah, I found the above and and was testing it locally. Anyway, it seems you're
right. Let me give it a try back again.

Thanks,

> 
> So the very fisrt patch looks better to me.
> 
> Thanks,
> 
> Can Guo.
> 
> >  		return;
> > 
> >  	hba->clk_gating.state = REQ_CLKS_OFF;
> > diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> > index 8344d8cb3678..09e59cb86e69 100644
> > --- a/drivers/scsi/ufs/ufshcd.h
> > +++ b/drivers/scsi/ufs/ufshcd.h
> > @@ -814,6 +814,11 @@ static inline bool
> > ufshcd_is_auto_hibern8_supported(struct ufs_hba *hba)
> >  		!(hba->quirks & UFSHCD_QUIRK_BROKEN_AUTO_HIBERN8);
> >  }
> > 
> > +static inline bool ufshcd_is_clkgating_enabled(struct ufs_hba *hba)
> > +{
> > +	return hba->clk_gating.is_enabled;
> > +}
> > +
> >  static inline bool ufshcd_is_auto_hibern8_enabled(struct ufs_hba *hba)
> >  {
> >  	return FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK, hba->ahit) ? true :
> > false;