Re: [PATCH] drm: Promote drm_mm alignment to u64

[Christian König <deathsimple@xxxxxxxxxxx>]

Am 27.11.2016 um 20:05 schrieb Chris Wilson:
> In places (e.g. i915.ko), the alignment is exported to userspace as u64
> and there now exists hardware for which we can indeed utilize a u64
> alignment. As such, we need to keep 64bit integers throughout when
> handling alignment.
>
> Testcase: igt/drm_mm/align64
> Testcase: igt/gem_exec_alignment
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>

Reviewed-by: Christian König <christian.koenig@xxxxxxx>.

And yeah, we have a couple of use cases aligning something to a 4GB 
boundary in a large address space as well.

Regards,
Christian.

> ---
>   drivers/gpu/drm/drm_mm.c | 37 +++++++++++++++++--------------------
>   include/drm/drm_mm.h     | 16 ++++++++--------
>   2 files changed, 25 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
> index 025dcd8cadcb..b5b0b667677d 100644
> --- a/drivers/gpu/drm/drm_mm.c
> +++ b/drivers/gpu/drm/drm_mm.c
> @@ -93,12 +93,12 @@
>   
>   static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
>   						u64 size,
> -						unsigned alignment,
> +						u64 alignment,
>   						unsigned long color,
>   						enum drm_mm_search_flags flags);
>   static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
>   						u64 size,
> -						unsigned alignment,
> +						u64 alignment,
>   						unsigned long color,
>   						u64 start,
>   						u64 end,
> @@ -227,7 +227,7 @@ static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node,
>   
>   static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
>   				 struct drm_mm_node *node,
> -				 u64 size, unsigned alignment,
> +				 u64 size, u64 alignment,
>   				 unsigned long color,
>   				 enum drm_mm_allocator_flags flags)
>   {
> @@ -246,10 +246,9 @@ static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
>   		adj_start = adj_end - size;
>   
>   	if (alignment) {
> -		u64 tmp = adj_start;
> -		unsigned rem;
> +		u64 rem;
>   
> -		rem = do_div(tmp, alignment);
> +		div64_u64_rem(adj_start, alignment, &rem);
>   		if (rem) {
>   			if (flags & DRM_MM_CREATE_TOP)
>   				adj_start -= rem;
> @@ -377,7 +376,7 @@ EXPORT_SYMBOL(drm_mm_reserve_node);
>    * 0 on success, -ENOSPC if there's no suitable hole.
>    */
>   int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,
> -			       u64 size, unsigned alignment,
> +			       u64 size, u64 alignment,
>   			       unsigned long color,
>   			       enum drm_mm_search_flags sflags,
>   			       enum drm_mm_allocator_flags aflags)
> @@ -399,7 +398,7 @@ EXPORT_SYMBOL(drm_mm_insert_node_generic);
>   
>   static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
>   				       struct drm_mm_node *node,
> -				       u64 size, unsigned alignment,
> +				       u64 size, u64 alignment,
>   				       unsigned long color,
>   				       u64 start, u64 end,
>   				       enum drm_mm_allocator_flags flags)
> @@ -424,10 +423,9 @@ static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
>   		adj_start = adj_end - size;
>   
>   	if (alignment) {
> -		u64 tmp = adj_start;
> -		unsigned rem;
> +		u64 rem;
>   
> -		rem = do_div(tmp, alignment);
> +		div64_u64_rem(adj_start, alignment, &rem);
>   		if (rem) {
>   			if (flags & DRM_MM_CREATE_TOP)
>   				adj_start -= rem;
> @@ -483,7 +481,7 @@ static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
>    * 0 on success, -ENOSPC if there's no suitable hole.
>    */
>   int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node,
> -					u64 size, unsigned alignment,
> +					u64 size, u64 alignment,
>   					unsigned long color,
>   					u64 start, u64 end,
>   					enum drm_mm_search_flags sflags,
> @@ -550,16 +548,15 @@ void drm_mm_remove_node(struct drm_mm_node *node)
>   }
>   EXPORT_SYMBOL(drm_mm_remove_node);
>   
> -static int check_free_hole(u64 start, u64 end, u64 size, unsigned alignment)
> +static int check_free_hole(u64 start, u64 end, u64 size, u64 alignment)
>   {
>   	if (end - start < size)
>   		return 0;
>   
>   	if (alignment) {
> -		u64 tmp = start;
> -		unsigned rem;
> +		u64 rem;
>   
> -		rem = do_div(tmp, alignment);
> +		div64_u64_rem(start, alignment, &rem);
>   		if (rem)
>   			start += alignment - rem;
>   	}
> @@ -569,7 +566,7 @@ static int check_free_hole(u64 start, u64 end, u64 size, unsigned alignment)
>   
>   static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
>   						      u64 size,
> -						      unsigned alignment,
> +						      u64 alignment,
>   						      unsigned long color,
>   						      enum drm_mm_search_flags flags)
>   {
> @@ -611,7 +608,7 @@ static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
>   
>   static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
>   							u64 size,
> -							unsigned alignment,
> +							u64 alignment,
>   							unsigned long color,
>   							u64 start,
>   							u64 end,
> @@ -729,7 +726,7 @@ EXPORT_SYMBOL(drm_mm_replace_node);
>    */
>   void drm_mm_init_scan(struct drm_mm *mm,
>   		      u64 size,
> -		      unsigned alignment,
> +		      u64 alignment,
>   		      unsigned long color)
>   {
>   	mm->scan_color = color;
> @@ -762,7 +759,7 @@ EXPORT_SYMBOL(drm_mm_init_scan);
>    */
>   void drm_mm_init_scan_with_range(struct drm_mm *mm,
>   				 u64 size,
> -				 unsigned alignment,
> +				 u64 alignment,
>   				 unsigned long color,
>   				 u64 start,
>   				 u64 end)
> diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
> index dff4c507d2c2..dc9710c31a45 100644
> --- a/include/drm/drm_mm.h
> +++ b/include/drm/drm_mm.h
> @@ -92,12 +92,12 @@ struct drm_mm {
>   	struct rb_root interval_tree;
>   
>   	unsigned int scan_check_range : 1;
> -	unsigned scan_alignment;
> +	unsigned int scanned_blocks;
>   	unsigned long scan_color;
> +	u64 scan_alignment;
>   	u64 scan_size;
>   	u64 scan_hit_start;
>   	u64 scan_hit_end;
> -	unsigned scanned_blocks;
>   	u64 scan_start;
>   	u64 scan_end;
>   	struct drm_mm_node *prev_scanned_node;
> @@ -229,7 +229,7 @@ int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node);
>   int drm_mm_insert_node_generic(struct drm_mm *mm,
>   			       struct drm_mm_node *node,
>   			       u64 size,
> -			       unsigned alignment,
> +			       u64 alignment,
>   			       unsigned long color,
>   			       enum drm_mm_search_flags sflags,
>   			       enum drm_mm_allocator_flags aflags);
> @@ -252,7 +252,7 @@ int drm_mm_insert_node_generic(struct drm_mm *mm,
>   static inline int drm_mm_insert_node(struct drm_mm *mm,
>   				     struct drm_mm_node *node,
>   				     u64 size,
> -				     unsigned alignment,
> +				     u64 alignment,
>   				     enum drm_mm_search_flags flags)
>   {
>   	return drm_mm_insert_node_generic(mm, node, size, alignment, 0, flags,
> @@ -262,7 +262,7 @@ static inline int drm_mm_insert_node(struct drm_mm *mm,
>   int drm_mm_insert_node_in_range_generic(struct drm_mm *mm,
>   					struct drm_mm_node *node,
>   					u64 size,
> -					unsigned alignment,
> +					u64 alignment,
>   					unsigned long color,
>   					u64 start,
>   					u64 end,
> @@ -289,7 +289,7 @@ int drm_mm_insert_node_in_range_generic(struct drm_mm *mm,
>   static inline int drm_mm_insert_node_in_range(struct drm_mm *mm,
>   					      struct drm_mm_node *node,
>   					      u64 size,
> -					      unsigned alignment,
> +					      u64 alignment,
>   					      u64 start,
>   					      u64 end,
>   					      enum drm_mm_search_flags flags)
> @@ -331,11 +331,11 @@ __drm_mm_interval_first(struct drm_mm *mm, u64 start, u64 last);
>   
>   void drm_mm_init_scan(struct drm_mm *mm,
>   		      u64 size,
> -		      unsigned alignment,
> +		      u64 alignment,
>   		      unsigned long color);
>   void drm_mm_init_scan_with_range(struct drm_mm *mm,
>   				 u64 size,
> -				 unsigned alignment,
> +				 u64 alignment,
>   				 unsigned long color,
>   				 u64 start,
>   				 u64 end);


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