Re: [PATCH v2 1/5] mm: move vma_policy() and anon_vma_name() decls to mm_types.h

[Vlastimil Babka]

On 10/9/23 22:53, Lorenzo Stoakes wrote:
> The vma_policy() define is a helper specifically for a VMA field so it
> makes sense to host it in the memory management types header.
> 
> The anon_vma_name(), anon_vma_name_alloc() and anon_vma_name_free()
> functions are a little out of place in mm_inline.h as they define external
> functions, and so it makes sense to locate them in mm_types.h.
> 
> The purpose of these relocations is to make it possible to abstract static
> inline wrappers which invoke both of these helpers.
> 
> Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>

Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
>  include/linux/mempolicy.h |  4 ----
>  include/linux/mm_inline.h | 20 +-------------------
>  include/linux/mm_types.h  | 27 +++++++++++++++++++++++++++
>  3 files changed, 28 insertions(+), 23 deletions(-)
> 
> diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
> index 3c208d4f0ee9..2801d5b0a4e9 100644
> --- a/include/linux/mempolicy.h
> +++ b/include/linux/mempolicy.h
> @@ -89,8 +89,6 @@ static inline struct mempolicy *mpol_dup(struct mempolicy *pol)
>  	return pol;
>  }
>  
> -#define vma_policy(vma) ((vma)->vm_policy)
> -
>  static inline void mpol_get(struct mempolicy *pol)
>  {
>  	if (pol)
> @@ -222,8 +220,6 @@ static inline struct mempolicy *get_vma_policy(struct vm_area_struct *vma,
>  	return NULL;
>  }
>  
> -#define vma_policy(vma) NULL
> -
>  static inline int
>  vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
>  {
> diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
> index 8148b30a9df1..9ae7def16cb2 100644
> --- a/include/linux/mm_inline.h
> +++ b/include/linux/mm_inline.h
> @@ -4,6 +4,7 @@
>  
>  #include <linux/atomic.h>
>  #include <linux/huge_mm.h>
> +#include <linux/mm_types.h>
>  #include <linux/swap.h>
>  #include <linux/string.h>
>  #include <linux/userfaultfd_k.h>
> @@ -352,15 +353,6 @@ void lruvec_del_folio(struct lruvec *lruvec, struct folio *folio)
>  }
>  
>  #ifdef CONFIG_ANON_VMA_NAME
> -/*
> - * mmap_lock should be read-locked when calling anon_vma_name(). Caller should
> - * either keep holding the lock while using the returned pointer or it should
> - * raise anon_vma_name refcount before releasing the lock.
> - */
> -extern struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma);
> -extern struct anon_vma_name *anon_vma_name_alloc(const char *name);
> -extern void anon_vma_name_free(struct kref *kref);
> -
>  /* mmap_lock should be read-locked */
>  static inline void anon_vma_name_get(struct anon_vma_name *anon_name)
>  {
> @@ -415,16 +407,6 @@ static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,
>  }
>  
>  #else /* CONFIG_ANON_VMA_NAME */
> -static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)
> -{
> -	return NULL;
> -}
> -
> -static inline struct anon_vma_name *anon_vma_name_alloc(const char *name)
> -{
> -	return NULL;
> -}
> -
>  static inline void anon_vma_name_get(struct anon_vma_name *anon_name) {}
>  static inline void anon_vma_name_put(struct anon_vma_name *anon_name) {}
>  static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma,
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 36c5b43999e6..21eb56145f57 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -546,6 +546,27 @@ struct anon_vma_name {
>  	char name[];
>  };
>  
> +#ifdef CONFIG_ANON_VMA_NAME
> +/*
> + * mmap_lock should be read-locked when calling anon_vma_name(). Caller should
> + * either keep holding the lock while using the returned pointer or it should
> + * raise anon_vma_name refcount before releasing the lock.
> + */
> +struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma);
> +struct anon_vma_name *anon_vma_name_alloc(const char *name);
> +void anon_vma_name_free(struct kref *kref);
> +#else /* CONFIG_ANON_VMA_NAME */
> +static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)
> +{
> +	return NULL;
> +}
> +
> +static inline struct anon_vma_name *anon_vma_name_alloc(const char *name)
> +{
> +	return NULL;
> +}
> +#endif
> +
>  struct vma_lock {
>  	struct rw_semaphore lock;
>  };
> @@ -662,6 +683,12 @@ struct vm_area_struct {
>  	struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
>  } __randomize_layout;
>  
> +#ifdef CONFIG_NUMA
> +#define vma_policy(vma) ((vma)->vm_policy)
> +#else
> +#define vma_policy(vma) NULL
> +#endif
> +
>  #ifdef CONFIG_SCHED_MM_CID
>  struct mm_cid {
>  	u64 time;