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

Hans Verkuil
2015-07-17T10:21:53Z

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)
>