Re: [PATCH v4 02/11] mm: Change CONFIG option for mm->pasid field

Lu Baolu
2022-02-08T02:41:43Z

On 2/8/22 7:02 AM, Fenghua Yu wrote:
> This currently depends on CONFIG_IOMMU_SUPPORT. But it is only
> needed when CONFIG_IOMMU_SVA option is enabled.
>
> Change the CONFIG guards around definition and initialization
> of mm->pasid field.
>
> Suggested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> Reviewed-by: Tony Luck <tony.luck@intel.com>
> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> v4:
> - Add "Reviewed-by: Thomas Gleixner <tglx@linutronix.de>" (Thomas).
>
> v2:
> - Change condition to more accurate CONFIG_IOMMU_SVA (Jacob and Tony)
>
> include/linux/mm_types.h | 2 +-
> kernel/fork.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 5140e5feb486..c5cbfd7915ad 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -631,7 +631,7 @@ struct mm_struct {
> #endif
> struct work_struct async_put_work;
>
> -#ifdef CONFIG_IOMMU_SUPPORT
> +#ifdef CONFIG_IOMMU_SVA
> u32 pasid;
> #endif
> } __randomize_layout;
> diff --git a/kernel/fork.c b/kernel/fork.c
> index d75a528f7b21..6ee7551d3bd2 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -1021,7 +1021,7 @@ static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
>
> static void mm_init_pasid(struct mm_struct *mm)
> {
> -#ifdef CONFIG_IOMMU_SUPPORT
> +#ifdef CONFIG_IOMMU_SVA
> mm->pasid = INIT_PASID;
> #endif
> }

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>

Best regards,
baolu