Re: [PATCH 9/9] drm/exynos: Convert g2d_userptr_get_dma_addr() to use get_vaddr_frames()

[Hans Verkuil <hverkuil@xs4all.nl>]

On 07/13/2015 04:55 PM, Jan Kara wrote:
> From: Jan Kara <jack@suse.cz>
> 
> Convert g2d_userptr_get_dma_addr() to pin pages using get_vaddr_frames().
> This removes the knowledge about vmas and mmap_sem locking from exynos
> driver. Also it fixes a problem that the function has been mapping user
> provided address without holding mmap_sem.

I'd like to see an Ack from one of the exynos drm driver maintainers before
I merge this.

Inki, Marek?

Regards,

	Hans

> 
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  drivers/gpu/drm/exynos/Kconfig          |  1 +
>  drivers/gpu/drm/exynos/exynos_drm_g2d.c | 91 ++++++++++---------------------
>  drivers/gpu/drm/exynos/exynos_drm_gem.c | 97 ---------------------------------
>  3 files changed, 30 insertions(+), 159 deletions(-)
> 
> diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
> index 43003c4ad80b..b364562dc6c1 100644
> --- a/drivers/gpu/drm/exynos/Kconfig
> +++ b/drivers/gpu/drm/exynos/Kconfig
> @@ -77,6 +77,7 @@ config DRM_EXYNOS_VIDI
>  config DRM_EXYNOS_G2D
>  	bool "Exynos DRM G2D"
>  	depends on DRM_EXYNOS && !VIDEO_SAMSUNG_S5P_G2D
> +	select FRAME_VECTOR
>  	help
>  	  Choose this option if you want to use Exynos G2D for DRM.
>  
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_g2d.c b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
> index 81a250830808..1d8d9a508373 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_g2d.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
> @@ -190,10 +190,8 @@ struct g2d_cmdlist_userptr {
>  	dma_addr_t		dma_addr;
>  	unsigned long		userptr;
>  	unsigned long		size;
> -	struct page		**pages;
> -	unsigned int		npages;
> +	struct frame_vector	*vec;
>  	struct sg_table		*sgt;
> -	struct vm_area_struct	*vma;
>  	atomic_t		refcount;
>  	bool			in_pool;
>  	bool			out_of_list;
> @@ -363,6 +361,7 @@ static void g2d_userptr_put_dma_addr(struct drm_device *drm_dev,
>  {
>  	struct g2d_cmdlist_userptr *g2d_userptr =
>  					(struct g2d_cmdlist_userptr *)obj;
> +	struct page **pages;
>  
>  	if (!obj)
>  		return;
> @@ -382,19 +381,21 @@ out:
>  	exynos_gem_unmap_sgt_from_dma(drm_dev, g2d_userptr->sgt,
>  					DMA_BIDIRECTIONAL);
>  
> -	exynos_gem_put_pages_to_userptr(g2d_userptr->pages,
> -					g2d_userptr->npages,
> -					g2d_userptr->vma);
> +	pages = frame_vector_pages(g2d_userptr->vec);
> +	if (!IS_ERR(pages)) {
> +		int i;
>  
> -	exynos_gem_put_vma(g2d_userptr->vma);
> +		for (i = 0; i < frame_vector_count(g2d_userptr->vec); i++)
> +			set_page_dirty_lock(pages[i]);
> +	}
> +	put_vaddr_frames(g2d_userptr->vec);
> +	frame_vector_destroy(g2d_userptr->vec);
>  
>  	if (!g2d_userptr->out_of_list)
>  		list_del_init(&g2d_userptr->list);
>  
>  	sg_free_table(g2d_userptr->sgt);
>  	kfree(g2d_userptr->sgt);
> -
> -	drm_free_large(g2d_userptr->pages);
>  	kfree(g2d_userptr);
>  }
>  
> @@ -408,9 +409,7 @@ static dma_addr_t *g2d_userptr_get_dma_addr(struct drm_device *drm_dev,
>  	struct exynos_drm_g2d_private *g2d_priv = file_priv->g2d_priv;
>  	struct g2d_cmdlist_userptr *g2d_userptr;
>  	struct g2d_data *g2d;
> -	struct page **pages;
>  	struct sg_table	*sgt;
> -	struct vm_area_struct *vma;
>  	unsigned long start, end;
>  	unsigned int npages, offset;
>  	int ret;
> @@ -456,65 +455,38 @@ static dma_addr_t *g2d_userptr_get_dma_addr(struct drm_device *drm_dev,
>  		return ERR_PTR(-ENOMEM);
>  
>  	atomic_set(&g2d_userptr->refcount, 1);
> +	g2d_userptr->size = size;
>  
>  	start = userptr & PAGE_MASK;
>  	offset = userptr & ~PAGE_MASK;
>  	end = PAGE_ALIGN(userptr + size);
>  	npages = (end - start) >> PAGE_SHIFT;
> -	g2d_userptr->npages = npages;
> -
> -	pages = drm_calloc_large(npages, sizeof(struct page *));
> -	if (!pages) {
> -		DRM_ERROR("failed to allocate pages.\n");
> -		ret = -ENOMEM;
> +	g2d_userptr->vec = frame_vector_create(npages);
> +	if (!g2d_userptr->vec)
>  		goto err_free;
> -	}
>  
> -	down_read(&current->mm->mmap_sem);
> -	vma = find_vma(current->mm, userptr);
> -	if (!vma) {
> -		up_read(&current->mm->mmap_sem);
> -		DRM_ERROR("failed to get vm region.\n");
> +	ret = get_vaddr_frames(start, npages, true, true, g2d_userptr->vec);
> +	if (ret != npages) {
> +		DRM_ERROR("failed to get user pages from userptr.\n");
> +		if (ret < 0)
> +			goto err_destroy_framevec;
>  		ret = -EFAULT;
> -		goto err_free_pages;
> +		goto err_put_framevec;
>  	}
> -
> -	if (vma->vm_end < userptr + size) {
> -		up_read(&current->mm->mmap_sem);
> -		DRM_ERROR("vma is too small.\n");
> +	if (frame_vector_to_pages(g2d_userptr->vec) < 0) {
>  		ret = -EFAULT;
> -		goto err_free_pages;
> +		goto err_put_framevec;
>  	}
>  
> -	g2d_userptr->vma = exynos_gem_get_vma(vma);
> -	if (!g2d_userptr->vma) {
> -		up_read(&current->mm->mmap_sem);
> -		DRM_ERROR("failed to copy vma.\n");
> -		ret = -ENOMEM;
> -		goto err_free_pages;
> -	}
> -
> -	g2d_userptr->size = size;
> -
> -	ret = exynos_gem_get_pages_from_userptr(start & PAGE_MASK,
> -						npages, pages, vma);
> -	if (ret < 0) {
> -		up_read(&current->mm->mmap_sem);
> -		DRM_ERROR("failed to get user pages from userptr.\n");
> -		goto err_put_vma;
> -	}
> -
> -	up_read(&current->mm->mmap_sem);
> -	g2d_userptr->pages = pages;
> -
>  	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
>  	if (!sgt) {
>  		ret = -ENOMEM;
> -		goto err_free_userptr;
> +		goto err_put_framevec;
>  	}
>  
> -	ret = sg_alloc_table_from_pages(sgt, pages, npages, offset,
> -					size, GFP_KERNEL);
> +	ret = sg_alloc_table_from_pages(sgt,
> +					frame_vector_pages(g2d_userptr->vec),
> +					npages, offset, size, GFP_KERNEL);
>  	if (ret < 0) {
>  		DRM_ERROR("failed to get sgt from pages.\n");
>  		goto err_free_sgt;
> @@ -549,16 +521,11 @@ err_sg_free_table:
>  err_free_sgt:
>  	kfree(sgt);
>  
> -err_free_userptr:
> -	exynos_gem_put_pages_to_userptr(g2d_userptr->pages,
> -					g2d_userptr->npages,
> -					g2d_userptr->vma);
> -
> -err_put_vma:
> -	exynos_gem_put_vma(g2d_userptr->vma);
> +err_put_framevec:
> +	put_vaddr_frames(g2d_userptr->vec);
>  
> -err_free_pages:
> -	drm_free_large(pages);
> +err_destroy_framevec:
> +	frame_vector_destroy(g2d_userptr->vec);
>  
>  err_free:
>  	kfree(g2d_userptr);
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> index 0d5b9698d384..47068ae44ced 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> @@ -378,103 +378,6 @@ int exynos_drm_gem_get_ioctl(struct drm_device *dev, void *data,
>  	return 0;
>  }
>  
> -struct vm_area_struct *exynos_gem_get_vma(struct vm_area_struct *vma)
> -{
> -	struct vm_area_struct *vma_copy;
> -
> -	vma_copy = kmalloc(sizeof(*vma_copy), GFP_KERNEL);
> -	if (!vma_copy)
> -		return NULL;
> -
> -	if (vma->vm_ops && vma->vm_ops->open)
> -		vma->vm_ops->open(vma);
> -
> -	if (vma->vm_file)
> -		get_file(vma->vm_file);
> -
> -	memcpy(vma_copy, vma, sizeof(*vma));
> -
> -	vma_copy->vm_mm = NULL;
> -	vma_copy->vm_next = NULL;
> -	vma_copy->vm_prev = NULL;
> -
> -	return vma_copy;
> -}
> -
> -void exynos_gem_put_vma(struct vm_area_struct *vma)
> -{
> -	if (!vma)
> -		return;
> -
> -	if (vma->vm_ops && vma->vm_ops->close)
> -		vma->vm_ops->close(vma);
> -
> -	if (vma->vm_file)
> -		fput(vma->vm_file);
> -
> -	kfree(vma);
> -}
> -
> -int exynos_gem_get_pages_from_userptr(unsigned long start,
> -						unsigned int npages,
> -						struct page **pages,
> -						struct vm_area_struct *vma)
> -{
> -	int get_npages;
> -
> -	/* the memory region mmaped with VM_PFNMAP. */
> -	if (vma_is_io(vma)) {
> -		unsigned int i;
> -
> -		for (i = 0; i < npages; ++i, start += PAGE_SIZE) {
> -			unsigned long pfn;
> -			int ret = follow_pfn(vma, start, &pfn);
> -			if (ret)
> -				return ret;
> -
> -			pages[i] = pfn_to_page(pfn);
> -		}
> -
> -		if (i != npages) {
> -			DRM_ERROR("failed to get user_pages.\n");
> -			return -EINVAL;
> -		}
> -
> -		return 0;
> -	}
> -
> -	get_npages = get_user_pages(current, current->mm, start,
> -					npages, 1, 1, pages, NULL);
> -	get_npages = max(get_npages, 0);
> -	if (get_npages != npages) {
> -		DRM_ERROR("failed to get user_pages.\n");
> -		while (get_npages)
> -			put_page(pages[--get_npages]);
> -		return -EFAULT;
> -	}
> -
> -	return 0;
> -}
> -
> -void exynos_gem_put_pages_to_userptr(struct page **pages,
> -					unsigned int npages,
> -					struct vm_area_struct *vma)
> -{
> -	if (!vma_is_io(vma)) {
> -		unsigned int i;
> -
> -		for (i = 0; i < npages; i++) {
> -			set_page_dirty_lock(pages[i]);
> -
> -			/*
> -			 * undo the reference we took when populating
> -			 * the table.
> -			 */
> -			put_page(pages[i]);
> -		}
> -	}
> -}
> -
>  int exynos_gem_map_sgt_with_dma(struct drm_device *drm_dev,
>  				struct sg_table *sgt,
>  				enum dma_data_direction dir)
> 

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