[Intel-gfx] [PATCH 3/4] drm/i915: handle walking compact dma scatter lists

Imre Deak imre.deak at intel.com
Sat Feb 9 14:59:04 PST 2013


On Sat, 2013-02-09 at 23:51 +0100, Daniel Vetter wrote:
> On Sat, Feb 09, 2013 at 05:27:35PM +0200, Imre Deak wrote:
> > So far the assumption was that each dma scatter list entry contains only
> > a single page. This might not hold in the future, when we'll introduce
> > compact scatter lists, so prepare for this everywhere in the i915 code
> > where we walk such a list.
> > 
> > We'll fix the place _creating_ these lists separately in the next patch
> > to help the reviewing/bisectability.
> > 
> > Reference: http://www.spinics.net/lists/dri-devel/msg33917.html
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> 
> Since we now have such a nice macro to loop over sg pages ... Care to also
> convert the two existing (correct loops) in i915_gem_gtt.c and intel-gtt.c
> in a follow-up patch?

Ok, will do.

--Imre

> -Daniel
> 
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h        |   17 ++++++-----------
> >  drivers/gpu/drm/i915/i915_gem.c        |   22 ++++++----------------
> >  drivers/gpu/drm/i915/i915_gem_dmabuf.c |   13 +++++++------
> >  drivers/gpu/drm/i915/i915_gem_tiling.c |   18 ++++++++++--------
> >  4 files changed, 29 insertions(+), 41 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index 08c5def..0462428 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -1531,17 +1531,12 @@ void i915_gem_lastclose(struct drm_device *dev);
> >  int __must_check i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
> >  static inline struct page *i915_gem_object_get_page(struct drm_i915_gem_object *obj, int n)
> >  {
> > -	struct scatterlist *sg = obj->pages->sgl;
> > -	int nents = obj->pages->nents;
> > -	while (nents > SG_MAX_SINGLE_ALLOC) {
> > -		if (n < SG_MAX_SINGLE_ALLOC - 1)
> > -			break;
> > -
> > -		sg = sg_chain_ptr(sg + SG_MAX_SINGLE_ALLOC - 1);
> > -		n -= SG_MAX_SINGLE_ALLOC - 1;
> > -		nents -= SG_MAX_SINGLE_ALLOC - 1;
> > -	}
> > -	return sg_page(sg+n);
> > +	struct drm_sg_iter sg_iter;
> > +
> > +	drm_for_each_sg_page(&sg_iter, obj->pages->sgl, n << PAGE_SHIFT)
> > +		return sg_iter.page;
> > +
> > +	return NULL;
> >  }
> >  static inline void i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
> >  {
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index d746177..4a199e0 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -411,8 +411,7 @@ i915_gem_shmem_pread(struct drm_device *dev,
> >  	int obj_do_bit17_swizzling, page_do_bit17_swizzling;
> >  	int prefaulted = 0;
> >  	int needs_clflush = 0;
> > -	struct scatterlist *sg;
> > -	int i;
> > +	struct drm_sg_iter sg_iter;
> >  
> >  	user_data = (char __user *) (uintptr_t) args->data_ptr;
> >  	remain = args->size;
> > @@ -441,11 +440,8 @@ i915_gem_shmem_pread(struct drm_device *dev,
> >  
> >  	offset = args->offset;
> >  
> > -	for_each_sg(obj->pages->sgl, sg, obj->pages->nents, i) {
> > -		struct page *page;
> > -
> > -		if (i < offset >> PAGE_SHIFT)
> > -			continue;
> > +	drm_for_each_sg_page(&sg_iter, obj->pages->sgl, offset) {
> > +		struct page *page = sg_iter.page;
> >  
> >  		if (remain <= 0)
> >  			break;
> > @@ -460,7 +456,6 @@ i915_gem_shmem_pread(struct drm_device *dev,
> >  		if ((shmem_page_offset + page_length) > PAGE_SIZE)
> >  			page_length = PAGE_SIZE - shmem_page_offset;
> >  
> > -		page = sg_page(sg);
> >  		page_do_bit17_swizzling = obj_do_bit17_swizzling &&
> >  			(page_to_phys(page) & (1 << 17)) != 0;
> >  
> > @@ -732,8 +727,7 @@ i915_gem_shmem_pwrite(struct drm_device *dev,
> >  	int hit_slowpath = 0;
> >  	int needs_clflush_after = 0;
> >  	int needs_clflush_before = 0;
> > -	int i;
> > -	struct scatterlist *sg;
> > +	struct drm_sg_iter sg_iter;
> >  
> >  	user_data = (char __user *) (uintptr_t) args->data_ptr;
> >  	remain = args->size;
> > @@ -768,13 +762,10 @@ i915_gem_shmem_pwrite(struct drm_device *dev,
> >  	offset = args->offset;
> >  	obj->dirty = 1;
> >  
> > -	for_each_sg(obj->pages->sgl, sg, obj->pages->nents, i) {
> > -		struct page *page;
> > +	drm_for_each_sg_page(&sg_iter, obj->pages->sgl, offset) {
> > +		struct page *page = sg_iter.page;
> >  		int partial_cacheline_write;
> >  
> > -		if (i < offset >> PAGE_SHIFT)
> > -			continue;
> > -
> >  		if (remain <= 0)
> >  			break;
> >  
> > @@ -796,7 +787,6 @@ i915_gem_shmem_pwrite(struct drm_device *dev,
> >  			((shmem_page_offset | page_length)
> >  				& (boot_cpu_data.x86_clflush_size - 1));
> >  
> > -		page = sg_page(sg);
> >  		page_do_bit17_swizzling = obj_do_bit17_swizzling &&
> >  			(page_to_phys(page) & (1 << 17)) != 0;
> >  
> > diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> > index 6a5af68..ac98792 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> > @@ -62,7 +62,7 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme
> >  	src = obj->pages->sgl;
> >  	dst = st->sgl;
> >  	for (i = 0; i < obj->pages->nents; i++) {
> > -		sg_set_page(dst, sg_page(src), PAGE_SIZE, 0);
> > +		sg_set_page(dst, sg_page(src), src->length, 0);
> >  		dst = sg_next(dst);
> >  		src = sg_next(src);
> >  	}
> > @@ -105,7 +105,7 @@ static void *i915_gem_dmabuf_vmap(struct dma_buf *dma_buf)
> >  {
> >  	struct drm_i915_gem_object *obj = dma_buf->priv;
> >  	struct drm_device *dev = obj->base.dev;
> > -	struct scatterlist *sg;
> > +	struct drm_sg_iter sg_iter;
> >  	struct page **pages;
> >  	int ret, i;
> >  
> > @@ -124,14 +124,15 @@ static void *i915_gem_dmabuf_vmap(struct dma_buf *dma_buf)
> >  
> >  	ret = -ENOMEM;
> >  
> > -	pages = drm_malloc_ab(obj->pages->nents, sizeof(struct page *));
> > +	pages = drm_malloc_ab(obj->base.size >> PAGE_SHIFT, sizeof(*pages));
> >  	if (pages == NULL)
> >  		goto error;
> >  
> > -	for_each_sg(obj->pages->sgl, sg, obj->pages->nents, i)
> > -		pages[i] = sg_page(sg);
> > +	i = 0;
> > +	drm_for_each_sg_page(&sg_iter, obj->pages->sgl, 0);
> > +		pages[i++] = sg_iter.page;
> >  
> > -	obj->dma_buf_vmapping = vmap(pages, obj->pages->nents, 0, PAGE_KERNEL);
> > +	obj->dma_buf_vmapping = vmap(pages, i, 0, PAGE_KERNEL);
> >  	drm_free_large(pages);
> >  
> >  	if (!obj->dma_buf_vmapping)
> > diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
> > index abcba2f..834ed70 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_tiling.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
> > @@ -473,28 +473,29 @@ i915_gem_swizzle_page(struct page *page)
> >  void
> >  i915_gem_object_do_bit_17_swizzle(struct drm_i915_gem_object *obj)
> >  {
> > -	struct scatterlist *sg;
> > -	int page_count = obj->base.size >> PAGE_SHIFT;
> > +	struct drm_sg_iter sg_iter;
> >  	int i;
> >  
> >  	if (obj->bit_17 == NULL)
> >  		return;
> >  
> > -	for_each_sg(obj->pages->sgl, sg, page_count, i) {
> > -		struct page *page = sg_page(sg);
> > +	i = 0;
> > +	drm_for_each_sg_page(&sg_iter, obj->pages->sgl, 0) {
> > +		struct page *page = sg_iter.page;
> >  		char new_bit_17 = page_to_phys(page) >> 17;
> >  		if ((new_bit_17 & 0x1) !=
> >  		    (test_bit(i, obj->bit_17) != 0)) {
> >  			i915_gem_swizzle_page(page);
> >  			set_page_dirty(page);
> >  		}
> > +		i++;
> >  	}
> >  }
> >  
> >  void
> >  i915_gem_object_save_bit_17_swizzle(struct drm_i915_gem_object *obj)
> >  {
> > -	struct scatterlist *sg;
> > +	struct drm_sg_iter sg_iter;
> >  	int page_count = obj->base.size >> PAGE_SHIFT;
> >  	int i;
> >  
> > @@ -508,11 +509,12 @@ i915_gem_object_save_bit_17_swizzle(struct drm_i915_gem_object *obj)
> >  		}
> >  	}
> >  
> > -	for_each_sg(obj->pages->sgl, sg, page_count, i) {
> > -		struct page *page = sg_page(sg);
> > -		if (page_to_phys(page) & (1 << 17))
> > +	i = 0;
> > +	drm_for_each_sg_page(&sg_iter, obj->pages->sgl, 0) {
> > +		if (page_to_phys(sg_iter.page) & (1 << 17))
> >  			__set_bit(i, obj->bit_17);
> >  		else
> >  			__clear_bit(i, obj->bit_17);
> > +		i++;
> >  	}
> >  }
> > -- 
> > 1.7.10.4
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 




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