None of the callers of arm_smmu_cmdq_batch_submit() cares about the batch
after a submission. So, it'll be certainly safe to nuke the cmds->num, at
least upon a successful one. This will ease a bit a wrapper function, for
the new arm_smmu_invs structure.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 2a8b46b948f05..cccf8f52ee0d5 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -974,11 +974,17 @@ static void arm_smmu_cmdq_batch_add(struct arm_smmu_device *smmu,
 	cmds->num++;
 }
 
+/* Clears cmds->num after a successful submission */
 static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu,
 				      struct arm_smmu_cmdq_batch *cmds)
 {
-	return arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmdq, cmds->cmds,
-					   cmds->num, true);
+	int ret;
+
+	ret = arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmdq, cmds->cmds,
+					  cmds->num, true);
+	if (!ret)
+		cmds->num = 0;
+	return ret;
 }
 
 static void arm_smmu_page_response(struct device *dev, struct iopf_fault *unused,
-- 
2.43.0

On Mon, Sep 08, 2025 at 04:26:55PM -0700, Nicolin Chen wrote:
> None of the callers of arm_smmu_cmdq_batch_submit() cares about the batch
> after a submission. So, it'll be certainly safe to nuke the cmds->num, at
> least upon a successful one. This will ease a bit a wrapper function, for
> the new arm_smmu_invs structure.

This was added when arm_smmu_cmdq_batch_submit() was needed by a
new arm_smmu_invs helper that used it at a few places. But after
a few rounds of rework, I found that there is only one call now.

I will drop this patch.

Thanks
Nicolin

On 9/9/25 09:26, Nicolin Chen wrote:
> None of the callers of arm_smmu_cmdq_batch_submit() cares about the batch
> after a submission. So, it'll be certainly safe to nuke the cmds->num, at
> least upon a successful one. This will ease a bit a wrapper function, for
> the new arm_smmu_invs structure.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 2a8b46b948f05..cccf8f52ee0d5 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -974,11 +974,17 @@ static void arm_smmu_cmdq_batch_add(struct arm_smmu_device *smmu,
>  	cmds->num++;
>  }
>  
> +/* Clears cmds->num after a successful submission */
>  static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu,
>  				      struct arm_smmu_cmdq_batch *cmds)
>  {

Nit: arm_smmu_cmdq_batch_submit_clear()?

> -	return arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmdq, cmds->cmds,
> -					   cmds->num, true);
> +	int ret;
> +
> +	ret = arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmdq, cmds->cmds,
> +					  cmds->num, true);
> +	if (!ret)
> +		cmds->num = 0;
> +	return ret;
>  }
>  
>  static void arm_smmu_page_response(struct device *dev, struct iopf_fault *unused,

Acked-by: Balbir Singh <balbirs@nvidia.com>

Balbir

On Tue, Sep 09, 2025 at 01:16:11PM +1000, Balbir Singh wrote:
> On 9/9/25 09:26, Nicolin Chen wrote:
> > None of the callers of arm_smmu_cmdq_batch_submit() cares about the batch
> > after a submission. So, it'll be certainly safe to nuke the cmds->num, at
> > least upon a successful one. This will ease a bit a wrapper function, for
> > the new arm_smmu_invs structure.
> > 
> > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> > ---
> >  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 10 ++++++++--
> >  1 file changed, 8 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > index 2a8b46b948f05..cccf8f52ee0d5 100644
> > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > @@ -974,11 +974,17 @@ static void arm_smmu_cmdq_batch_add(struct arm_smmu_device *smmu,
> >  	cmds->num++;
> >  }
> >  
> > +/* Clears cmds->num after a successful submission */
> >  static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu,
> >  				      struct arm_smmu_cmdq_batch *cmds)
> >  {
> 
> Nit: arm_smmu_cmdq_batch_submit_clear()?

Probably not. There is no particular point in highlighting it in
the function name, as there is no use case wanting an uncleared
version.

Thanks
Nicolin

On 9/9/25 15:42, Nicolin Chen wrote:
> On Tue, Sep 09, 2025 at 01:16:11PM +1000, Balbir Singh wrote:
>> On 9/9/25 09:26, Nicolin Chen wrote:
>>> None of the callers of arm_smmu_cmdq_batch_submit() cares about the batch
>>> after a submission. So, it'll be certainly safe to nuke the cmds->num, at
>>> least upon a successful one. This will ease a bit a wrapper function, for
>>> the new arm_smmu_invs structure.
>>>
>>> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
>>> ---
>>>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 10 ++++++++--
>>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>>> index 2a8b46b948f05..cccf8f52ee0d5 100644
>>> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>>> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>>> @@ -974,11 +974,17 @@ static void arm_smmu_cmdq_batch_add(struct arm_smmu_device *smmu,
>>>  	cmds->num++;
>>>  }
>>>  
>>> +/* Clears cmds->num after a successful submission */
>>>  static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu,
>>>  				      struct arm_smmu_cmdq_batch *cmds)
>>>  {
>>
>> Nit: arm_smmu_cmdq_batch_submit_clear()?
> 
> Probably not. There is no particular point in highlighting it in
> the function name, as there is no use case wanting an uncleared
> version.

I did not suggest we need an uncleared version, I suggested the change
in name to highlight that the function has a side-effect of clearing
the cmds->num

Thanks,
Balbir

On Wed, Sep 10, 2025 at 08:49:52AM +1000, Balbir Singh wrote:
> On 9/9/25 15:42, Nicolin Chen wrote:
> > On Tue, Sep 09, 2025 at 01:16:11PM +1000, Balbir Singh wrote:
> >> On 9/9/25 09:26, Nicolin Chen wrote:
> >>> None of the callers of arm_smmu_cmdq_batch_submit() cares about the batch
> >>> after a submission. So, it'll be certainly safe to nuke the cmds->num, at
> >>> least upon a successful one. This will ease a bit a wrapper function, for
> >>> the new arm_smmu_invs structure.
> >>>
> >>> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> >>> ---
> >>>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 10 ++++++++--
> >>>  1 file changed, 8 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> >>> index 2a8b46b948f05..cccf8f52ee0d5 100644
> >>> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> >>> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> >>> @@ -974,11 +974,17 @@ static void arm_smmu_cmdq_batch_add(struct arm_smmu_device *smmu,
> >>>  	cmds->num++;
> >>>  }
> >>>  
> >>> +/* Clears cmds->num after a successful submission */
> >>>  static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu,
> >>>  				      struct arm_smmu_cmdq_batch *cmds)
> >>>  {
> >>
> >> Nit: arm_smmu_cmdq_batch_submit_clear()?
> > 
> > Probably not. There is no particular point in highlighting it in
> > the function name, as there is no use case wanting an uncleared
> > version.
> 
> I did not suggest we need an uncleared version, I suggested the change
> in name to highlight that the function has a side-effect of clearing
> the cmds->num

No caller cares about the "side effect"...

Nicolin