Re: [PATCH mlx5-next 1/5] vfio/mlx5: Reorganize the VF is migratable code

[Yishai Hadas <yishaih@nvidia.com>]

On 04/05/2022 23:13, Alex Williamson wrote:
> On Wed, 27 Apr 2022 12:31:16 +0300
> Yishai Hadas <yishaih@nvidia.com> wrote:
>
>> Reorganize the VF is migratable code to be in a separate function, next
>> patches from the series may use this.
>>
>> Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
>> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
>> ---
>>   drivers/vfio/pci/mlx5/cmd.c  | 18 ++++++++++++++++++
>>   drivers/vfio/pci/mlx5/cmd.h  |  1 +
>>   drivers/vfio/pci/mlx5/main.c | 22 +++++++---------------
>>   3 files changed, 26 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
>> index 5c9f9218cc1d..d608b8167f58 100644
>> --- a/drivers/vfio/pci/mlx5/cmd.c
>> +++ b/drivers/vfio/pci/mlx5/cmd.c
>> @@ -71,6 +71,24 @@ int mlx5vf_cmd_query_vhca_migration_state(struct pci_dev *pdev, u16 vhca_id,
>>   	return ret;
>>   }
>>   
>> +bool mlx5vf_cmd_is_migratable(struct pci_dev *pdev)
>> +{
>> +	struct mlx5_core_dev *mdev = mlx5_vf_get_core_dev(pdev);
>> +	bool migratable = false;
>> +
>> +	if (!mdev)
>> +		return false;
>> +
>> +	if (!MLX5_CAP_GEN(mdev, migration))
>> +		goto end;
>> +
>> +	migratable = true;
>> +
>> +end:
>> +	mlx5_vf_put_core_dev(mdev);
>> +	return migratable;
>> +}
> This goto seems unnecessary, couldn't it instead be written:
>
> {
> 	struct mlx5_core_dev *mdev = mlx5_vf_get_core_dev(pdev);
> 	boot migratable = true;
>
> 	if (!mdev)
> 		return false;
>
> 	if (!MLX5_CAP_GEN(mdev, migration))
> 		migratable = false;
>
> 	mlx5_vf_put_core_mdev(mdev);
> 	return migratable;
> }
>
> Thanks,
> Alex


V1 will handle that as part of some refactoring and combing this patch 
and patch #3 based on your notes there.

Thanks.

>
>> +
>>   int mlx5vf_cmd_get_vhca_id(struct pci_dev *pdev, u16 function_id, u16 *vhca_id)
>>   {
>>   	struct mlx5_core_dev *mdev = mlx5_vf_get_core_dev(pdev);
>> diff --git a/drivers/vfio/pci/mlx5/cmd.h b/drivers/vfio/pci/mlx5/cmd.h
>> index 1392a11a9cc0..2da6a1c0ec5c 100644
>> --- a/drivers/vfio/pci/mlx5/cmd.h
>> +++ b/drivers/vfio/pci/mlx5/cmd.h
>> @@ -29,6 +29,7 @@ int mlx5vf_cmd_resume_vhca(struct pci_dev *pdev, u16 vhca_id, u16 op_mod);
>>   int mlx5vf_cmd_query_vhca_migration_state(struct pci_dev *pdev, u16 vhca_id,
>>   					  size_t *state_size);
>>   int mlx5vf_cmd_get_vhca_id(struct pci_dev *pdev, u16 function_id, u16 *vhca_id);
>> +bool mlx5vf_cmd_is_migratable(struct pci_dev *pdev);
>>   int mlx5vf_cmd_save_vhca_state(struct pci_dev *pdev, u16 vhca_id,
>>   			       struct mlx5_vf_migration_file *migf);
>>   int mlx5vf_cmd_load_vhca_state(struct pci_dev *pdev, u16 vhca_id,
>> diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
>> index bbec5d288fee..2578f61eaeae 100644
>> --- a/drivers/vfio/pci/mlx5/main.c
>> +++ b/drivers/vfio/pci/mlx5/main.c
>> @@ -597,21 +597,13 @@ static int mlx5vf_pci_probe(struct pci_dev *pdev,
>>   		return -ENOMEM;
>>   	vfio_pci_core_init_device(&mvdev->core_device, pdev, &mlx5vf_pci_ops);
>>   
>> -	if (pdev->is_virtfn) {
>> -		struct mlx5_core_dev *mdev =
>> -			mlx5_vf_get_core_dev(pdev);
>> -
>> -		if (mdev) {
>> -			if (MLX5_CAP_GEN(mdev, migration)) {
>> -				mvdev->migrate_cap = 1;
>> -				mvdev->core_device.vdev.migration_flags =
>> -					VFIO_MIGRATION_STOP_COPY |
>> -					VFIO_MIGRATION_P2P;
>> -				mutex_init(&mvdev->state_mutex);
>> -				spin_lock_init(&mvdev->reset_lock);
>> -			}
>> -			mlx5_vf_put_core_dev(mdev);
>> -		}
>> +	if (pdev->is_virtfn && mlx5vf_cmd_is_migratable(pdev)) {
>> +		mvdev->migrate_cap = 1;
>> +		mvdev->core_device.vdev.migration_flags =
>> +			VFIO_MIGRATION_STOP_COPY |
>> +			VFIO_MIGRATION_P2P;
>> +		mutex_init(&mvdev->state_mutex);
>> +		spin_lock_init(&mvdev->reset_lock);
>>   	}
>>   
>>   	ret = vfio_pci_core_register_device(&mvdev->core_device);