Subject: Re: [PATCH kernel 1/4] powerpc/mm/iommu: Rename mm_iommu_get

From: David Gibson <[email-masked]>
Date: Wed, 17 Oct 2018 11:44:34 +1100

On Mon, Oct 15, 2018 at 08:24:13PM +1100, Alexey Kardashevskiy wrote:
> Normally mm_iommu_get() is supposed to add a reference and
> mm_iommu_put() to remove it. However historically mm_iommu_find() does
> the referencing and mm_iommu_get() is doing allocation and referencing.
> 
> This is step 1 towards simpler mm_iommu_get().
> 
> This renames:
> - mm_iommu_get to mm_iommu_new;
> - mm_iommu_find to mm_iommu_get.
> 
> This should cause no behavioural change.
> 
> Signed-off-by: Alexey Kardashevskiy <[email-masked]>

Erm.. as far as I can tell, mm_iommu_find() doesn't adjust any
reference counts, so renaming it to mm_iommu_get() doesn't really make
sense.

> ---
>  arch/powerpc/include/asm/mmu_context.h | 4 ++--
>  arch/powerpc/mm/mmu_context_iommu.c    | 8 ++++----
>  drivers/vfio/vfio_iommu_spapr_tce.c    | 6 +++---
>  3 files changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
> index b694d6a..59d4941 100644
> --- a/arch/powerpc/include/asm/mmu_context.h
> +++ b/arch/powerpc/include/asm/mmu_context.h
> @@ -21,7 +21,7 @@ struct mm_iommu_table_group_mem_t;
>  
>  extern int isolate_lru_page(struct page *page);	/* from internal.h */
>  extern bool mm_iommu_preregistered(struct mm_struct *mm);
> -extern long mm_iommu_get(struct mm_struct *mm,
> +extern long mm_iommu_new(struct mm_struct *mm,
>  		unsigned long ua, unsigned long entries,
>  		struct mm_iommu_table_group_mem_t **pmem);
>  extern long mm_iommu_put(struct mm_struct *mm,
> @@ -32,7 +32,7 @@ extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
>  		unsigned long ua, unsigned long size);
>  extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(
>  		struct mm_struct *mm, unsigned long ua, unsigned long size);
> -extern struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
> +extern struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm,
>  		unsigned long ua, unsigned long entries);
>  extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
>  		unsigned long ua, unsigned int pageshift, unsigned long *hpa);
> diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c
> index 56c2234..8eeb99d 100644
> --- a/arch/powerpc/mm/mmu_context_iommu.c
> +++ b/arch/powerpc/mm/mmu_context_iommu.c
> @@ -126,7 +126,7 @@ static int mm_iommu_move_page_from_cma(struct page *page)
>  	return 0;
>  }
>  
> -long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries,
> +long mm_iommu_new(struct mm_struct *mm, unsigned long ua, unsigned long entries,
>  		struct mm_iommu_table_group_mem_t **pmem)
>  {
>  	struct mm_iommu_table_group_mem_t *mem;
> @@ -252,7 +252,7 @@ long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries,
>  
>  	return ret;
>  }
> -EXPORT_SYMBOL_GPL(mm_iommu_get);
> +EXPORT_SYMBOL_GPL(mm_iommu_new);
>  
>  static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem)
>  {
> @@ -368,7 +368,7 @@ struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(struct mm_struct *mm,
>  	return ret;
>  }
>  
> -struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
> +struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm,
>  		unsigned long ua, unsigned long entries)
>  {
>  	struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
> @@ -382,7 +382,7 @@ struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
>  
>  	return ret;
>  }
> -EXPORT_SYMBOL_GPL(mm_iommu_find);
> +EXPORT_SYMBOL_GPL(mm_iommu_get);
>  
>  long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
>  		unsigned long ua, unsigned int pageshift, unsigned long *hpa)
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> index ad63725..1701798 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -156,7 +156,7 @@ static long tce_iommu_unregister_pages(struct tce_container *container,
>  	if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK))
>  		return -EINVAL;
>  
> -	mem = mm_iommu_find(container->mm, vaddr, size >> PAGE_SHIFT);
> +	mem = mm_iommu_get(container->mm, vaddr, size >> PAGE_SHIFT);
>  	if (!mem)
>  		return -ENOENT;
>  
> @@ -185,7 +185,7 @@ static long tce_iommu_register_pages(struct tce_container *container,
>  			((vaddr + size) < vaddr))
>  		return -EINVAL;
>  
> -	mem = mm_iommu_find(container->mm, vaddr, entries);
> +	mem = mm_iommu_get(container->mm, vaddr, entries);
>  	if (mem) {
>  		list_for_each_entry(tcemem, &container->prereg_list, next) {
>  			if (tcemem->mem == mem)
> @@ -193,7 +193,7 @@ static long tce_iommu_register_pages(struct tce_container *container,
>  		}
>  	}
>  
> -	ret = mm_iommu_get(container->mm, vaddr, entries, &mem);
> +	ret = mm_iommu_new(container->mm, vaddr, entries, &mem);
>  	if (ret)
>  		return ret;
>  

-- 
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