Re: [PATCH kernel v3 1/4] powerpc/iommu: Pass mm_struct to init/cleanup helpers

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, Oct 20, 2016 at 02:03:47PM +1100, Alexey Kardashevskiy wrote:
> We are going to get rid of @current references in mmu_context_boos3s64.c
> and cache mm_struct in the VFIO container. Since mm_context_t does not
> have reference counting, we will be using mm_struct which does have
> the reference counter.
> 
> This changes mm_iommu_init/mm_iommu_cleanup to receive mm_struct rather
> than mm_context_t (which is embedded into mm).
> 
> This should not cause any behavioral change.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  arch/powerpc/include/asm/mmu_context.h | 4 ++--
>  arch/powerpc/kernel/setup-common.c     | 2 +-
>  arch/powerpc/mm/mmu_context_book3s64.c | 4 ++--
>  arch/powerpc/mm/mmu_context_iommu.c    | 9 +++++----
>  4 files changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
> index 5c45114..424844b 100644
> --- a/arch/powerpc/include/asm/mmu_context.h
> +++ b/arch/powerpc/include/asm/mmu_context.h
> @@ -23,8 +23,8 @@ extern bool mm_iommu_preregistered(void);
>  extern long mm_iommu_get(unsigned long ua, unsigned long entries,
>  		struct mm_iommu_table_group_mem_t **pmem);
>  extern long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem);
> -extern void mm_iommu_init(mm_context_t *ctx);
> -extern void mm_iommu_cleanup(mm_context_t *ctx);
> +extern void mm_iommu_init(struct mm_struct *mm);
> +extern void mm_iommu_cleanup(struct mm_struct *mm);
>  extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua,
>  		unsigned long size);
>  extern struct mm_iommu_table_group_mem_t *mm_iommu_find(unsigned long ua,
> diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
> index 270ee30..f516ac5 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -915,7 +915,7 @@ void __init setup_arch(char **cmdline_p)
>  	init_mm.context.pte_frag = NULL;
>  #endif
>  #ifdef CONFIG_SPAPR_TCE_IOMMU
> -	mm_iommu_init(&init_mm.context);
> +	mm_iommu_init(&init_mm);
>  #endif
>  	irqstack_early_init();
>  	exc_lvl_early_init();
> diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
> index b114f8b..ad82735 100644
> --- a/arch/powerpc/mm/mmu_context_book3s64.c
> +++ b/arch/powerpc/mm/mmu_context_book3s64.c
> @@ -115,7 +115,7 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
>  	mm->context.pte_frag = NULL;
>  #endif
>  #ifdef CONFIG_SPAPR_TCE_IOMMU
> -	mm_iommu_init(&mm->context);
> +	mm_iommu_init(mm);
>  #endif
>  	return 0;
>  }
> @@ -160,7 +160,7 @@ static inline void destroy_pagetable_page(struct mm_struct *mm)
>  void destroy_context(struct mm_struct *mm)
>  {
>  #ifdef CONFIG_SPAPR_TCE_IOMMU
> -	mm_iommu_cleanup(&mm->context);
> +	mm_iommu_cleanup(mm);
>  #endif
>  
>  #ifdef CONFIG_PPC_ICSWX
> diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c
> index e0f1c33..ad2e575 100644
> --- a/arch/powerpc/mm/mmu_context_iommu.c
> +++ b/arch/powerpc/mm/mmu_context_iommu.c
> @@ -373,16 +373,17 @@ void mm_iommu_mapped_dec(struct mm_iommu_table_group_mem_t *mem)
>  }
>  EXPORT_SYMBOL_GPL(mm_iommu_mapped_dec);
>  
> -void mm_iommu_init(mm_context_t *ctx)
> +void mm_iommu_init(struct mm_struct *mm)
>  {
> -	INIT_LIST_HEAD_RCU(&ctx->iommu_group_mem_list);
> +	INIT_LIST_HEAD_RCU(&mm->context.iommu_group_mem_list);
>  }
>  
> -void mm_iommu_cleanup(mm_context_t *ctx)
> +void mm_iommu_cleanup(struct mm_struct *mm)
>  {
>  	struct mm_iommu_table_group_mem_t *mem, *tmp;
>  
> -	list_for_each_entry_safe(mem, tmp, &ctx->iommu_group_mem_list, next) {
> +	list_for_each_entry_safe(mem, tmp, &mm->context.iommu_group_mem_list,
> +			next) {
>  		list_del_rcu(&mem->next);
>  		mm_iommu_do_free(mem);
>  	}

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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