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Gerd Hoffmann

2020-Aug-18 07:48 UTC

[Nouveau] [PATCH 1/2] drm: allow limiting the scatter list size.

Add max_segment argument to drm_prime_pages_to_sg().  When set pass it
through to the __sg_alloc_table_from_pages() call, otherwise use
SCATTERLIST_MAX_SEGMENT.

Also add max_segment field to gem objects and pass it to
drm_prime_pages_to_sg() calls in drivers and helpers.

Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
---
 include/drm/drm_gem.h                       |  8 ++++++++
 include/drm/drm_prime.h                     |  3 ++-
 drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c |  3 ++-
 drivers/gpu/drm/drm_gem_shmem_helper.c      |  3 ++-
 drivers/gpu/drm/drm_prime.c                 | 10 +++++++---
 drivers/gpu/drm/etnaviv/etnaviv_gem.c       |  3 ++-
 drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c |  3 ++-
 drivers/gpu/drm/msm/msm_gem.c               |  3 ++-
 drivers/gpu/drm/msm/msm_gem_prime.c         |  3 ++-
 drivers/gpu/drm/nouveau/nouveau_prime.c     |  3 ++-
 drivers/gpu/drm/radeon/radeon_prime.c       |  3 ++-
 drivers/gpu/drm/rockchip/rockchip_drm_gem.c |  6 ++++--
 drivers/gpu/drm/tegra/gem.c                 |  3 ++-
 drivers/gpu/drm/vgem/vgem_drv.c             |  3 ++-
 drivers/gpu/drm/xen/xen_drm_front_gem.c     |  3 ++-
 15 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 337a48321705..dea5e92e745b 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -241,6 +241,14 @@ struct drm_gem_object {
 	 */
 	size_t size;
 
+	/**
+	 * @max_segment:
+	 *
+	 * Max size for scatter list segments.  When unset the default
+	 * (SCATTERLIST_MAX_SEGMENT) is used.
+	 */
+	size_t max_segment;
+
 	/**
 	 * @name:
 	 *
diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h
index 9af7422b44cf..2c3689435cb4 100644
--- a/include/drm/drm_prime.h
+++ b/include/drm/drm_prime.h
@@ -88,7 +88,8 @@ void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void
*vaddr);
 int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
 int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma);
 
-struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int
nr_pages);
+struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int
nr_pages,
+				       size_t max_segment);
 struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
 				     int flags);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
index 519ce4427fce..5e8a9760b33f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
@@ -303,7 +303,8 @@ static struct sg_table *amdgpu_dma_buf_map(struct
dma_buf_attachment *attach,
 	switch (bo->tbo.mem.mem_type) {
 	case TTM_PL_TT:
 		sgt = drm_prime_pages_to_sg(bo->tbo.ttm->pages,
-					    bo->tbo.num_pages);
+					    bo->tbo.num_pages,
+					    obj->max_segment);
 		if (IS_ERR(sgt))
 			return sgt;
 
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c
b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 4b7cfbac4daa..cfb979d808fd 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -656,7 +656,8 @@ struct sg_table *drm_gem_shmem_get_sg_table(struct
drm_gem_object *obj)
 
 	WARN_ON(shmem->base.import_attach);
 
-	return drm_prime_pages_to_sg(shmem->pages, obj->size >>
PAGE_SHIFT);
+	return drm_prime_pages_to_sg(shmem->pages, obj->size >>
PAGE_SHIFT,
+				     obj->max_segment);
 }
 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
 
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 1693aa7c14b5..27c783fd6633 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -802,7 +802,8 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = 
{
  *
  * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
  */
-struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int
nr_pages)
+struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int
nr_pages,
+				       size_t max_segment)
 {
 	struct sg_table *sg = NULL;
 	int ret;
@@ -813,8 +814,11 @@ struct sg_table *drm_prime_pages_to_sg(struct page **pages,
unsigned int nr_page
 		goto out;
 	}
 
-	ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
-				nr_pages << PAGE_SHIFT, GFP_KERNEL);
+	if (max_segment == 0 || max_segment > SCATTERLIST_MAX_SEGMENT)
+		max_segment = SCATTERLIST_MAX_SEGMENT;
+	ret = __sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
+					  nr_pages << PAGE_SHIFT,
+					  max_segment, GFP_KERNEL);
 	if (ret)
 		goto out;
 
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
index f06e19e7be04..e5b6e7996f80 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
@@ -103,7 +103,8 @@ struct page **etnaviv_gem_get_pages(struct
etnaviv_gem_object *etnaviv_obj)
 		int npages = etnaviv_obj->base.size >> PAGE_SHIFT;
 		struct sg_table *sgt;
 
-		sgt = drm_prime_pages_to_sg(etnaviv_obj->pages, npages);
+		sgt = drm_prime_pages_to_sg(etnaviv_obj->pages, npages,
+					    etnaviv_obj->base.max_segment);
 		if (IS_ERR(sgt)) {
 			dev_err(dev->dev, "failed to allocate sgt: %ld\n",
 				PTR_ERR(sgt));
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
index 6d9e5c3c4dd5..f327676450bd 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
@@ -19,7 +19,8 @@ struct sg_table *etnaviv_gem_prime_get_sg_table(struct
drm_gem_object *obj)
 	if (WARN_ON(!etnaviv_obj->pages))  /* should have already pinned! */
 		return ERR_PTR(-EINVAL);
 
-	return drm_prime_pages_to_sg(etnaviv_obj->pages, npages);
+	return drm_prime_pages_to_sg(etnaviv_obj->pages, npages,
+				     obj->max_segment);
 }
 
 void *etnaviv_gem_prime_vmap(struct drm_gem_object *obj)
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index b2f49152b4d4..f805419bb84a 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -126,7 +126,8 @@ static struct page **get_pages(struct drm_gem_object *obj)
 
 		msm_obj->pages = p;
 
-		msm_obj->sgt = drm_prime_pages_to_sg(p, npages);
+		msm_obj->sgt = drm_prime_pages_to_sg(p, npages,
+						     obj->max_segment);
 		if (IS_ERR(msm_obj->sgt)) {
 			void *ptr = ERR_CAST(msm_obj->sgt);
 
diff --git a/drivers/gpu/drm/msm/msm_gem_prime.c
b/drivers/gpu/drm/msm/msm_gem_prime.c
index d7c8948427fe..a5a412564c7f 100644
--- a/drivers/gpu/drm/msm/msm_gem_prime.c
+++ b/drivers/gpu/drm/msm/msm_gem_prime.c
@@ -19,7 +19,8 @@ struct sg_table *msm_gem_prime_get_sg_table(struct
drm_gem_object *obj)
 	if (WARN_ON(!msm_obj->pages))  /* should have already pinned! */
 		return NULL;
 
-	return drm_prime_pages_to_sg(msm_obj->pages, npages);
+	return drm_prime_pages_to_sg(msm_obj->pages, npages,
+				     obj->max_segment);
 }
 
 void *msm_gem_prime_vmap(struct drm_gem_object *obj)
diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c
b/drivers/gpu/drm/nouveau/nouveau_prime.c
index bae6a3eccee0..56a2e916d51a 100644
--- a/drivers/gpu/drm/nouveau/nouveau_prime.c
+++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
@@ -32,7 +32,8 @@ struct sg_table *nouveau_gem_prime_get_sg_table(struct
drm_gem_object *obj)
 	struct nouveau_bo *nvbo = nouveau_gem_object(obj);
 	int npages = nvbo->bo.num_pages;
 
-	return drm_prime_pages_to_sg(nvbo->bo.ttm->pages, npages);
+	return drm_prime_pages_to_sg(nvbo->bo.ttm->pages, npages,
+				     obj->max_segment);
 }
 
 void *nouveau_gem_prime_vmap(struct drm_gem_object *obj)
diff --git a/drivers/gpu/drm/radeon/radeon_prime.c
b/drivers/gpu/drm/radeon/radeon_prime.c
index b906e8fbd5f3..503e35625045 100644
--- a/drivers/gpu/drm/radeon/radeon_prime.c
+++ b/drivers/gpu/drm/radeon/radeon_prime.c
@@ -36,7 +36,8 @@ struct sg_table *radeon_gem_prime_get_sg_table(struct
drm_gem_object *obj)
 	struct radeon_bo *bo = gem_to_radeon_bo(obj);
 	int npages = bo->tbo.num_pages;
 
-	return drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages);
+	return drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages,
+				     obj->max_segment);
 }
 
 void *radeon_gem_prime_vmap(struct drm_gem_object *obj)
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index b9275ba7c5a5..444657e03c16 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
@@ -85,7 +85,8 @@ static int rockchip_gem_get_pages(struct rockchip_gem_object
*rk_obj)
 
 	rk_obj->num_pages = rk_obj->base.size >> PAGE_SHIFT;
 
-	rk_obj->sgt = drm_prime_pages_to_sg(rk_obj->pages,
rk_obj->num_pages);
+	rk_obj->sgt = drm_prime_pages_to_sg(rk_obj->pages, rk_obj->num_pages,
+					    rk_obj->base.max_segment);
 	if (IS_ERR(rk_obj->sgt)) {
 		ret = PTR_ERR(rk_obj->sgt);
 		goto err_put_pages;
@@ -442,7 +443,8 @@ struct sg_table *rockchip_gem_prime_get_sg_table(struct
drm_gem_object *obj)
 	int ret;
 
 	if (rk_obj->pages)
-		return drm_prime_pages_to_sg(rk_obj->pages, rk_obj->num_pages);
+		return drm_prime_pages_to_sg(rk_obj->pages, rk_obj->num_pages,
+					     obj->max_segment);
 
 	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 	if (!sgt)
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 723df142a981..8d98b02a8d21 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -284,7 +284,8 @@ static int tegra_bo_get_pages(struct drm_device *drm, struct
tegra_bo *bo)
 
 	bo->num_pages = bo->gem.size >> PAGE_SHIFT;
 
-	bo->sgt = drm_prime_pages_to_sg(bo->pages, bo->num_pages);
+	bo->sgt = drm_prime_pages_to_sg(bo->pages, bo->num_pages,
+					bo->gem.max_segment);
 	if (IS_ERR(bo->sgt)) {
 		err = PTR_ERR(bo->sgt);
 		goto put_pages;
diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index 313339bbff90..d25c93b5a2c1 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -321,7 +321,8 @@ static struct sg_table *vgem_prime_get_sg_table(struct
drm_gem_object *obj)
 {
 	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
 
-	return drm_prime_pages_to_sg(bo->pages, bo->base.size >>
PAGE_SHIFT);
+	return drm_prime_pages_to_sg(bo->pages, bo->base.size >>
PAGE_SHIFT,
+				     obj->max_segment);
 }
 
 static struct drm_gem_object* vgem_prime_import(struct drm_device *dev,
diff --git a/drivers/gpu/drm/xen/xen_drm_front_gem.c
b/drivers/gpu/drm/xen/xen_drm_front_gem.c
index f0b85e094111..362fe5311b1b 100644
--- a/drivers/gpu/drm/xen/xen_drm_front_gem.c
+++ b/drivers/gpu/drm/xen/xen_drm_front_gem.c
@@ -179,7 +179,8 @@ struct sg_table *xen_drm_front_gem_get_sg_table(struct
drm_gem_object *gem_obj)
 	if (!xen_obj->pages)
 		return ERR_PTR(-ENOMEM);
 
-	return drm_prime_pages_to_sg(xen_obj->pages, xen_obj->num_pages);
+	return drm_prime_pages_to_sg(xen_obj->pages, xen_obj->num_pages,
+				     gem_obj->max_segment);
 }
 
 struct drm_gem_object *
-- 
2.18.4

Christian König

2020-Aug-18 07:57 UTC

head link

[Nouveau] [PATCH 1/2] drm: allow limiting the scatter list size.

Am 18.08.20 um 09:48 schrieb Gerd Hoffmann:> Add max_segment argument to drm_prime_pages_to_sg().  When set pass it
> through to the __sg_alloc_table_from_pages() call, otherwise use
> SCATTERLIST_MAX_SEGMENT.
>
> Also add max_segment field to gem objects and pass it to
> drm_prime_pages_to_sg() calls in drivers and helpers.
>
> Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
I'm missing an explanation why this should be useful (it certainly is).

And the maximum segment size seems misplaced in the GEM object. This is 
usually a property of the device or even completely constant.

Christian.
> ---
>   include/drm/drm_gem.h                       |  8 ++++++++
>   include/drm/drm_prime.h                     |  3 ++-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c |  3 ++-
>   drivers/gpu/drm/drm_gem_shmem_helper.c      |  3 ++-
>   drivers/gpu/drm/drm_prime.c                 | 10 +++++++---
>   drivers/gpu/drm/etnaviv/etnaviv_gem.c       |  3 ++-
>   drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c |  3 ++-
>   drivers/gpu/drm/msm/msm_gem.c               |  3 ++-
>   drivers/gpu/drm/msm/msm_gem_prime.c         |  3 ++-
>   drivers/gpu/drm/nouveau/nouveau_prime.c     |  3 ++-
>   drivers/gpu/drm/radeon/radeon_prime.c       |  3 ++-
>   drivers/gpu/drm/rockchip/rockchip_drm_gem.c |  6 ++++--
>   drivers/gpu/drm/tegra/gem.c                 |  3 ++-
>   drivers/gpu/drm/vgem/vgem_drv.c             |  3 ++-
>   drivers/gpu/drm/xen/xen_drm_front_gem.c     |  3 ++-
>   15 files changed, 43 insertions(+), 17 deletions(-)
>
> diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
> index 337a48321705..dea5e92e745b 100644
> --- a/include/drm/drm_gem.h
> +++ b/include/drm/drm_gem.h
> @@ -241,6 +241,14 @@ struct drm_gem_object {
>   	 */
>   	size_t size;
>   
> +	/**
> +	 * @max_segment:
> +	 *
> +	 * Max size for scatter list segments.  When unset the default
> +	 * (SCATTERLIST_MAX_SEGMENT) is used.
> +	 */
> +	size_t max_segment;
> +
>   	/**
>   	 * @name:
>   	 *
> diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h
> index 9af7422b44cf..2c3689435cb4 100644
> --- a/include/drm/drm_prime.h
> +++ b/include/drm/drm_prime.h
> @@ -88,7 +88,8 @@ void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void
*vaddr);
>   int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct
*vma);
>   int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct
*vma);
>   
> -struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int
nr_pages);
> +struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int
nr_pages,
> +				       size_t max_segment);
>   struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
>   				     int flags);
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> index 519ce4427fce..5e8a9760b33f 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> @@ -303,7 +303,8 @@ static struct sg_table *amdgpu_dma_buf_map(struct
dma_buf_attachment *attach,
>   	switch (bo->tbo.mem.mem_type) {
>   	case TTM_PL_TT:
>   		sgt = drm_prime_pages_to_sg(bo->tbo.ttm->pages,
> -					    bo->tbo.num_pages);
> +					    bo->tbo.num_pages,
> +					    obj->max_segment);
>   		if (IS_ERR(sgt))
>   			return sgt;
>   
> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c
b/drivers/gpu/drm/drm_gem_shmem_helper.c
> index 4b7cfbac4daa..cfb979d808fd 100644
> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> @@ -656,7 +656,8 @@ struct sg_table *drm_gem_shmem_get_sg_table(struct
drm_gem_object *obj)
>   
>   	WARN_ON(shmem->base.import_attach);
>   
> -	return drm_prime_pages_to_sg(shmem->pages, obj->size >>
PAGE_SHIFT);
> +	return drm_prime_pages_to_sg(shmem->pages, obj->size >>
PAGE_SHIFT,
> +				     obj->max_segment);
>   }
>   EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
>   
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index 1693aa7c14b5..27c783fd6633 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -802,7 +802,8 @@ static const struct dma_buf_ops
drm_gem_prime_dmabuf_ops =  {
>    *
>    * This is useful for implementing
&drm_gem_object_funcs.get_sg_table.
>    */
> -struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int
nr_pages)
> +struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int
nr_pages,
> +				       size_t max_segment)
>   {
>   	struct sg_table *sg = NULL;
>   	int ret;
> @@ -813,8 +814,11 @@ struct sg_table *drm_prime_pages_to_sg(struct page
**pages, unsigned int nr_page
>   		goto out;
>   	}
>   
> -	ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
> -				nr_pages << PAGE_SHIFT, GFP_KERNEL);
> +	if (max_segment == 0 || max_segment > SCATTERLIST_MAX_SEGMENT)
> +		max_segment = SCATTERLIST_MAX_SEGMENT;
> +	ret = __sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
> +					  nr_pages << PAGE_SHIFT,
> +					  max_segment, GFP_KERNEL);
>   	if (ret)
>   		goto out;
>   
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> index f06e19e7be04..e5b6e7996f80 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> @@ -103,7 +103,8 @@ struct page **etnaviv_gem_get_pages(struct
etnaviv_gem_object *etnaviv_obj)
>   		int npages = etnaviv_obj->base.size >> PAGE_SHIFT;
>   		struct sg_table *sgt;
>   
> -		sgt = drm_prime_pages_to_sg(etnaviv_obj->pages, npages);
> +		sgt = drm_prime_pages_to_sg(etnaviv_obj->pages, npages,
> +					    etnaviv_obj->base.max_segment);
>   		if (IS_ERR(sgt)) {
>   			dev_err(dev->dev, "failed to allocate sgt: %ld\n",
>   				PTR_ERR(sgt));
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
> index 6d9e5c3c4dd5..f327676450bd 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
> @@ -19,7 +19,8 @@ struct sg_table *etnaviv_gem_prime_get_sg_table(struct
drm_gem_object *obj)
>   	if (WARN_ON(!etnaviv_obj->pages))  /* should have already pinned! */
>   		return ERR_PTR(-EINVAL);
>   
> -	return drm_prime_pages_to_sg(etnaviv_obj->pages, npages);
> +	return drm_prime_pages_to_sg(etnaviv_obj->pages, npages,
> +				     obj->max_segment);
>   }
>   
>   void *etnaviv_gem_prime_vmap(struct drm_gem_object *obj)
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index b2f49152b4d4..f805419bb84a 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -126,7 +126,8 @@ static struct page **get_pages(struct drm_gem_object
*obj)
>   
>   		msm_obj->pages = p;
>   
> -		msm_obj->sgt = drm_prime_pages_to_sg(p, npages);
> +		msm_obj->sgt = drm_prime_pages_to_sg(p, npages,
> +						     obj->max_segment);
>   		if (IS_ERR(msm_obj->sgt)) {
>   			void *ptr = ERR_CAST(msm_obj->sgt);
>   
> diff --git a/drivers/gpu/drm/msm/msm_gem_prime.c
b/drivers/gpu/drm/msm/msm_gem_prime.c
> index d7c8948427fe..a5a412564c7f 100644
> --- a/drivers/gpu/drm/msm/msm_gem_prime.c
> +++ b/drivers/gpu/drm/msm/msm_gem_prime.c
> @@ -19,7 +19,8 @@ struct sg_table *msm_gem_prime_get_sg_table(struct
drm_gem_object *obj)
>   	if (WARN_ON(!msm_obj->pages))  /* should have already pinned! */
>   		return NULL;
>   
> -	return drm_prime_pages_to_sg(msm_obj->pages, npages);
> +	return drm_prime_pages_to_sg(msm_obj->pages, npages,
> +				     obj->max_segment);
>   }
>   
>   void *msm_gem_prime_vmap(struct drm_gem_object *obj)
> diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c
b/drivers/gpu/drm/nouveau/nouveau_prime.c
> index bae6a3eccee0..56a2e916d51a 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_prime.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
> @@ -32,7 +32,8 @@ struct sg_table *nouveau_gem_prime_get_sg_table(struct
drm_gem_object *obj)
>   	struct nouveau_bo *nvbo = nouveau_gem_object(obj);
>   	int npages = nvbo->bo.num_pages;
>   
> -	return drm_prime_pages_to_sg(nvbo->bo.ttm->pages, npages);
> +	return drm_prime_pages_to_sg(nvbo->bo.ttm->pages, npages,
> +				     obj->max_segment);
>   }
>   
>   void *nouveau_gem_prime_vmap(struct drm_gem_object *obj)
> diff --git a/drivers/gpu/drm/radeon/radeon_prime.c
b/drivers/gpu/drm/radeon/radeon_prime.c
> index b906e8fbd5f3..503e35625045 100644
> --- a/drivers/gpu/drm/radeon/radeon_prime.c
> +++ b/drivers/gpu/drm/radeon/radeon_prime.c
> @@ -36,7 +36,8 @@ struct sg_table *radeon_gem_prime_get_sg_table(struct
drm_gem_object *obj)
>   	struct radeon_bo *bo = gem_to_radeon_bo(obj);
>   	int npages = bo->tbo.num_pages;
>   
> -	return drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages);
> +	return drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages,
> +				     obj->max_segment);
>   }
>   
>   void *radeon_gem_prime_vmap(struct drm_gem_object *obj)
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> index b9275ba7c5a5..444657e03c16 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> @@ -85,7 +85,8 @@ static int rockchip_gem_get_pages(struct
rockchip_gem_object *rk_obj)
>   
>   	rk_obj->num_pages = rk_obj->base.size >> PAGE_SHIFT;
>   
> -	rk_obj->sgt = drm_prime_pages_to_sg(rk_obj->pages,
rk_obj->num_pages);
> +	rk_obj->sgt = drm_prime_pages_to_sg(rk_obj->pages,
rk_obj->num_pages,
> +					    rk_obj->base.max_segment);
>   	if (IS_ERR(rk_obj->sgt)) {
>   		ret = PTR_ERR(rk_obj->sgt);
>   		goto err_put_pages;
> @@ -442,7 +443,8 @@ struct sg_table *rockchip_gem_prime_get_sg_table(struct
drm_gem_object *obj)
>   	int ret;
>   
>   	if (rk_obj->pages)
> -		return drm_prime_pages_to_sg(rk_obj->pages, rk_obj->num_pages);
> +		return drm_prime_pages_to_sg(rk_obj->pages, rk_obj->num_pages,
> +					     obj->max_segment);
>   
>   	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
>   	if (!sgt)
> diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
> index 723df142a981..8d98b02a8d21 100644
> --- a/drivers/gpu/drm/tegra/gem.c
> +++ b/drivers/gpu/drm/tegra/gem.c
> @@ -284,7 +284,8 @@ static int tegra_bo_get_pages(struct drm_device *drm,
struct tegra_bo *bo)
>   
>   	bo->num_pages = bo->gem.size >> PAGE_SHIFT;
>   
> -	bo->sgt = drm_prime_pages_to_sg(bo->pages, bo->num_pages);
> +	bo->sgt = drm_prime_pages_to_sg(bo->pages, bo->num_pages,
> +					bo->gem.max_segment);
>   	if (IS_ERR(bo->sgt)) {
>   		err = PTR_ERR(bo->sgt);
>   		goto put_pages;
> diff --git a/drivers/gpu/drm/vgem/vgem_drv.c
b/drivers/gpu/drm/vgem/vgem_drv.c
> index 313339bbff90..d25c93b5a2c1 100644
> --- a/drivers/gpu/drm/vgem/vgem_drv.c
> +++ b/drivers/gpu/drm/vgem/vgem_drv.c
> @@ -321,7 +321,8 @@ static struct sg_table *vgem_prime_get_sg_table(struct
drm_gem_object *obj)
>   {
>   	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
>   
> -	return drm_prime_pages_to_sg(bo->pages, bo->base.size >>
PAGE_SHIFT);
> +	return drm_prime_pages_to_sg(bo->pages, bo->base.size >>
PAGE_SHIFT,
> +				     obj->max_segment);
>   }
>   
>   static struct drm_gem_object* vgem_prime_import(struct drm_device *dev,
> diff --git a/drivers/gpu/drm/xen/xen_drm_front_gem.c
b/drivers/gpu/drm/xen/xen_drm_front_gem.c
> index f0b85e094111..362fe5311b1b 100644
> --- a/drivers/gpu/drm/xen/xen_drm_front_gem.c
> +++ b/drivers/gpu/drm/xen/xen_drm_front_gem.c
> @@ -179,7 +179,8 @@ struct sg_table *xen_drm_front_gem_get_sg_table(struct
drm_gem_object *gem_obj)
>   	if (!xen_obj->pages)
>   		return ERR_PTR(-ENOMEM);
>   
> -	return drm_prime_pages_to_sg(xen_obj->pages, xen_obj->num_pages);
> +	return drm_prime_pages_to_sg(xen_obj->pages, xen_obj->num_pages,
> +				     gem_obj->max_segment);
>   }
>   
>   struct drm_gem_object *

Gerd Hoffmann

2020-Aug-18 08:27 UTC

head link

[Nouveau] [PATCH 1/2] drm: allow limiting the scatter list size.

On Tue, Aug 18, 2020 at 09:57:59AM +0200, Christian K?nig
wrote:> Am 18.08.20 um 09:48 schrieb Gerd Hoffmann:
> > Add max_segment argument to drm_prime_pages_to_sg().  When set pass it
> > through to the __sg_alloc_table_from_pages() call, otherwise use
> > SCATTERLIST_MAX_SEGMENT.
> > 
> > Also add max_segment field to gem objects and pass it to
> > drm_prime_pages_to_sg() calls in drivers and helpers.
> > 
> > Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
> 
> I'm missing an explanation why this should be useful (it certainly is).
virtio-gpu needs this to work properly with SEV (see patch 2/2 of this
series).
> And the maximum segment size seems misplaced in the GEM object. This is
> usually a property of the device or even completely constant.
Placing it in drm_device instead would indeed work for virtio-gpu, so I
guess you are suggesting that instead?

take care,
  Gerd

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