Mailing List Archive: [PATCH v4 09/11] xen/arm: smmuv3: Use fallthrough pseudo-keyword

[PATCH v4 09/11] xen/arm: smmuv3: Use fallthrough pseudo-keyword

Jan 8, 2021, 6:46 AM

Post #1 of 6 (14 views)

Merge the patch from linux to use fallthrough pseudo-keyword.

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
---
Changes in V4:
- This patch is introduce in this verison.
---
xen/drivers/passthrough/arm/smmu-v3.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
index 5ce14850b4..f5f8b4c981 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -932,7 +932,6 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
*/
return;
case CMDQ_ERR_CERROR_ILL_IDX:
- /* Fallthrough */
default:
break;
}
@@ -2488,7 +2487,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
case IDR0_STALL_MODEL_FORCE:
smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
- /* Fallthrough */
+ fallthrough;
case IDR0_STALL_MODEL_STALL:
smmu->features |= ARM_SMMU_FEAT_STALLS;
}
@@ -2505,7 +2504,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
switch (FIELD_GET(IDR0_TTF, reg)) {
case IDR0_TTF_AARCH32_64:
smmu->ias = 40;
- /* Fallthrough */
+ fallthrough;
case IDR0_TTF_AARCH64:
break;
default:
@@ -2589,7 +2588,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
default:
dev_info(smmu->dev,
"unknown output address size. Truncating to 48-bit\n");
- /* Fallthrough */
+ fallthrough;
case IDR5_OAS_48_BIT:
smmu->oas = 48;
}
--
2.17.1

Re: [PATCH v4 09/11] xen/arm: smmuv3: Use fallthrough pseudo-keyword [ In reply to ]

sstabellini at kernel

Jan 8, 2021, 5:44 PM

Post #2 of 6 (13 views)

Permalink

On Fri, 8 Jan 2021, Rahul Singh wrote:
> Merge the patch from linux to use fallthrough pseudo-keyword.
>
> Replace the existing /* fall through */ comments and its variants with
> the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
> fall-through markings when it is the case.
>
> Signed-off-by: Rahul Singh <rahul.singh@arm.com>
> ---
> Changes in V4:
> - This patch is introduce in this verison.
> ---
> xen/drivers/passthrough/arm/smmu-v3.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
> index 5ce14850b4..f5f8b4c981 100644
> --- a/xen/drivers/passthrough/arm/smmu-v3.c
> +++ b/xen/drivers/passthrough/arm/smmu-v3.c
> @@ -932,7 +932,6 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
> */
> return;
> case CMDQ_ERR_CERROR_ILL_IDX:
> - /* Fallthrough */

The fallthrough keyword is unnecessary here because of default, right?

> default:
> break;
> }
> @@ -2488,7 +2487,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
> case IDR0_STALL_MODEL_FORCE:
> smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
> - /* Fallthrough */
> + fallthrough;
> case IDR0_STALL_MODEL_STALL:
> smmu->features |= ARM_SMMU_FEAT_STALLS;
> }
> @@ -2505,7 +2504,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> switch (FIELD_GET(IDR0_TTF, reg)) {
> case IDR0_TTF_AARCH32_64:
> smmu->ias = 40;
> - /* Fallthrough */
> + fallthrough;
> case IDR0_TTF_AARCH64:
> break;
> default:
> @@ -2589,7 +2588,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> default:
> dev_info(smmu->dev,
> "unknown output address size. Truncating to 48-bit\n");
> - /* Fallthrough */
> + fallthrough;
> case IDR5_OAS_48_BIT:
> smmu->oas = 48;
> }
> --
> 2.17.1
>

Re: [PATCH v4 09/11] xen/arm: smmuv3: Use fallthrough pseudo-keyword [ In reply to ]

Rahul.Singh at arm

Jan 9, 2021, 10:57 AM

Post #3 of 6 (13 views)

Permalink

Hello Stefano,

Thanks for reviewing the series.

> On 9 Jan 2021, at 1:44 am, Stefano Stabellini <sstabellini@kernel.org> wrote:
>
> On Fri, 8 Jan 2021, Rahul Singh wrote:
>> Merge the patch from linux to use fallthrough pseudo-keyword.
>>
>> Replace the existing /* fall through */ comments and its variants with
>> the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
>> fall-through markings when it is the case.
>>
>> Signed-off-by: Rahul Singh <rahul.singh@arm.com>
>> ---
>> Changes in V4:
>> - This patch is introduce in this verison.
>> ---
>> xen/drivers/passthrough/arm/smmu-v3.c | 7 +++----
>> 1 file changed, 3 insertions(+), 4 deletions(-)
>>
>> diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
>> index 5ce14850b4..f5f8b4c981 100644
>> --- a/xen/drivers/passthrough/arm/smmu-v3.c
>> +++ b/xen/drivers/passthrough/arm/smmu-v3.c
>> @@ -932,7 +932,6 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
>> */
>> return;
>> case CMDQ_ERR_CERROR_ILL_IDX:
>> - /* Fallthrough */
>
> The fallthrough keyword is unnecessary here because of default, right?

Yes you are right fallthrough keyword is unnecessary here because "-Wimplicit-fallthrough” will not through the warning when a case label falls through to a case that breaks or returns.Therefore there is no need to have the fallthrough keyword here.

Regards,
Rahul

>
>
>> default:
>> break;
>> }
>> @@ -2488,7 +2487,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
>> switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
>> case IDR0_STALL_MODEL_FORCE:
>> smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
>> - /* Fallthrough */
>> + fallthrough;
>> case IDR0_STALL_MODEL_STALL:
>> smmu->features |= ARM_SMMU_FEAT_STALLS;
>> }
>> @@ -2505,7 +2504,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
>> switch (FIELD_GET(IDR0_TTF, reg)) {
>> case IDR0_TTF_AARCH32_64:
>> smmu->ias = 40;
>> - /* Fallthrough */
>> + fallthrough;
>> case IDR0_TTF_AARCH64:
>> break;
>> default:
>> @@ -2589,7 +2588,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
>> default:
>> dev_info(smmu->dev,
>> "unknown output address size. Truncating to 48-bit\n");
>> - /* Fallthrough */
>> + fallthrough;
>> case IDR5_OAS_48_BIT:
>> smmu->oas = 48;
>> }
>> --
>> 2.17.1

Re: [PATCH v4 09/11] xen/arm: smmuv3: Use fallthrough pseudo-keyword [ In reply to ]

Bertrand.Marquis at arm

Jan 12, 2021, 3:34 AM

Post #4 of 6 (13 views)

Permalink

> On 8 Jan 2021, at 14:46, Rahul Singh <Rahul.Singh@arm.com> wrote:
>
> Merge the patch from linux to use fallthrough pseudo-keyword.
>
> Replace the existing /* fall through */ comments and its variants with
> the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
> fall-through markings when it is the case.
>
> Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>

Maybe the fallthrough could be removed by the commiter ?

Cheers
Bertrand

> ---
> Changes in V4:
> - This patch is introduce in this verison.
> ---
> xen/drivers/passthrough/arm/smmu-v3.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
> index 5ce14850b4..f5f8b4c981 100644
> --- a/xen/drivers/passthrough/arm/smmu-v3.c
> +++ b/xen/drivers/passthrough/arm/smmu-v3.c
> @@ -932,7 +932,6 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
> */
> return;
> case CMDQ_ERR_CERROR_ILL_IDX:
> - /* Fallthrough */
> default:
> break;
> }
> @@ -2488,7 +2487,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
> case IDR0_STALL_MODEL_FORCE:
> smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
> - /* Fallthrough */
> + fallthrough;
> case IDR0_STALL_MODEL_STALL:
> smmu->features |= ARM_SMMU_FEAT_STALLS;
> }
> @@ -2505,7 +2504,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> switch (FIELD_GET(IDR0_TTF, reg)) {
> case IDR0_TTF_AARCH32_64:
> smmu->ias = 40;
> - /* Fallthrough */
> + fallthrough;
> case IDR0_TTF_AARCH64:
> break;
> default:
> @@ -2589,7 +2588,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> default:
> dev_info(smmu->dev,
> "unknown output address size. Truncating to 48-bit\n");
> - /* Fallthrough */
> + fallthrough;
> case IDR5_OAS_48_BIT:
> smmu->oas = 48;
> }
> --
> 2.17.1
>

Re: [PATCH v4 09/11] xen/arm: smmuv3: Use fallthrough pseudo-keyword [ In reply to ]

julien at xen

Jan 15, 2021, 4:18 AM

Post #5 of 6 (13 views)

Permalink

Hi Rahul,

On 08/01/2021 14:46, Rahul Singh wrote:
> Merge the patch from linux to use fallthrough pseudo-keyword.

Please add more information about the patch you are backporting. Is it a
clean backport?

>
> Replace the existing /* fall through */ comments and its variants with
> the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
> fall-through markings when it is the case.
>
> Signed-off-by: Rahul Singh <rahul.singh@arm.com>
> ---
> Changes in V4:
> - This patch is introduce in this verison.
> ---
> xen/drivers/passthrough/arm/smmu-v3.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
> index 5ce14850b4..f5f8b4c981 100644
> --- a/xen/drivers/passthrough/arm/smmu-v3.c
> +++ b/xen/drivers/passthrough/arm/smmu-v3.c
> @@ -932,7 +932,6 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
> */
> return;
> case CMDQ_ERR_CERROR_ILL_IDX:
> - /* Fallthrough */
> default:
> break;
> }
> @@ -2488,7 +2487,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
> case IDR0_STALL_MODEL_FORCE:
> smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
> - /* Fallthrough */
> + fallthrough;
> case IDR0_STALL_MODEL_STALL:
> smmu->features |= ARM_SMMU_FEAT_STALLS;
> }
> @@ -2505,7 +2504,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> switch (FIELD_GET(IDR0_TTF, reg)) {
> case IDR0_TTF_AARCH32_64:
> smmu->ias = 40;
> - /* Fallthrough */
> + fallthrough;
> case IDR0_TTF_AARCH64:
> break;
> default:
> @@ -2589,7 +2588,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> default:
> dev_info(smmu->dev,
> "unknown output address size. Truncating to 48-bit\n");
> - /* Fallthrough */
> + fallthrough;
> case IDR5_OAS_48_BIT:
> smmu->oas = 48;
> }
>

--
Julien Grall

Re: [PATCH v4 09/11] xen/arm: smmuv3: Use fallthrough pseudo-keyword [ In reply to ]

Rahul.Singh at arm

Jan 18, 2021, 7:33 AM

Post #6 of 6 (11 views)

Permalink

Hello Julien,

> On 15 Jan 2021, at 12:18 pm, Julien Grall <julien@xen.org> wrote:
>
> Hi Rahul,
>
> On 08/01/2021 14:46, Rahul Singh wrote:
>> Merge the patch from linux to use fallthrough pseudo-keyword.
>
> Please add more information about the patch you are backporting. Is it a clean backport?

Ok . I will add more information about the patch. Yes I think we can say it is clean backport.

Patch merged is :
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c?h=v5.9.10&id=df561f6688fef775baa341a0f5d960becd248b11

Regards,
Rahul

>
>> Replace the existing /* fall through */ comments and its variants with
>> the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
>> fall-through markings when it is the case.
>> Signed-off-by: Rahul Singh <rahul.singh@arm.com>
>> ---
>> Changes in V4:
>> - This patch is introduce in this verison.
>> ---
>> xen/drivers/passthrough/arm/smmu-v3.c | 7 +++----
>> 1 file changed, 3 insertions(+), 4 deletions(-)
>> diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
>> index 5ce14850b4..f5f8b4c981 100644
>> --- a/xen/drivers/passthrough/arm/smmu-v3.c
>> +++ b/xen/drivers/passthrough/arm/smmu-v3.c
>> @@ -932,7 +932,6 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
>> */
>> return;
>> case CMDQ_ERR_CERROR_ILL_IDX:
>> - /* Fallthrough */
>> default:
>> break;
>> }
>> @@ -2488,7 +2487,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
>> switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
>> case IDR0_STALL_MODEL_FORCE:
>> smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
>> - /* Fallthrough */
>> + fallthrough;
>> case IDR0_STALL_MODEL_STALL:
>> smmu->features |= ARM_SMMU_FEAT_STALLS;
>> }
>> @@ -2505,7 +2504,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
>> switch (FIELD_GET(IDR0_TTF, reg)) {
>> case IDR0_TTF_AARCH32_64:
>> smmu->ias = 40;
>> - /* Fallthrough */
>> + fallthrough;
>> case IDR0_TTF_AARCH64:
>> break;
>> default:
>> @@ -2589,7 +2588,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
>> default:
>> dev_info(smmu->dev,
>> "unknown output address size. Truncating to 48-bit\n");
>> - /* Fallthrough */
>> + fallthrough;
>> case IDR5_OAS_48_BIT:
>> smmu->oas = 48;
>> }
>
> --
> Julien Grall