On Thu, 17 Apr 2025 14:19:42 +0200
Boris Brezillon <boris.brezil...@collabora.com> wrote:
> Right now the DRM_PANTHOR_BO_NO_MMAP flag is ignored by
> panthor_ioctl_bo_mmap_offset(), meaning BOs with this flag set can
> have a file offset but can't be mapped anyway, because
> panthor_gem_mmap() will filter them out.
>
> If we error out at mmap_offset creation time, we can get rid of
> panthor_gem_mmap() and call drm_gem_shmem_object_mmap directly, and
> we get rid of this inconsistency of having an mmap offset for a
> BO that can never be mmap-ed.
>
> Changes in v2:
> - Get rid of panthor_gem_mmap()
> - Get rid of the Fixes tag and adjust the commit message accordingly
> - Return ENOPERM instead of EINVAL
>
> Changes in v3:
> - Don't leak the BO ref
> - Add R-bs
>
> Signed-off-by: Boris Brezillon <boris.brezil...@collabora.com>
> Reviewed-by: Steven Price <steven.pr...@arm.com>
> Reviewed-by: Liviu Dudau <liviu.du...@arm.com>
Queued to drm-misc-next.
> ---
> drivers/gpu/drm/panthor/panthor_drv.c | 7 +++++++
> drivers/gpu/drm/panthor/panthor_gem.c | 13 +------------
> 2 files changed, 8 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c
> b/drivers/gpu/drm/panthor/panthor_drv.c
> index 06fe46e32073..4d4a52a033f6 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -940,6 +940,7 @@ static int panthor_ioctl_bo_mmap_offset(struct drm_device
> *ddev, void *data,
> struct drm_file *file)
> {
> struct drm_panthor_bo_mmap_offset *args = data;
> + struct panthor_gem_object *bo;
> struct drm_gem_object *obj;
> int ret;
>
> @@ -950,6 +951,12 @@ static int panthor_ioctl_bo_mmap_offset(struct
> drm_device *ddev, void *data,
> if (!obj)
> return -ENOENT;
>
> + bo = to_panthor_bo(obj);
> + if (bo->flags & DRM_PANTHOR_BO_NO_MMAP) {
> + ret = -EPERM;
> + goto out;
> + }
> +
> ret = drm_gem_create_mmap_offset(obj);
> if (ret)
> goto out;
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.c
> b/drivers/gpu/drm/panthor/panthor_gem.c
> index fd014ccc3bfc..22d78cef9c66 100644
> --- a/drivers/gpu/drm/panthor/panthor_gem.c
> +++ b/drivers/gpu/drm/panthor/panthor_gem.c
> @@ -129,17 +129,6 @@ panthor_kernel_bo_create(struct panthor_device *ptdev,
> struct panthor_vm *vm,
> return ERR_PTR(ret);
> }
>
> -static int panthor_gem_mmap(struct drm_gem_object *obj, struct
> vm_area_struct *vma)
> -{
> - struct panthor_gem_object *bo = to_panthor_bo(obj);
> -
> - /* Don't allow mmap on objects that have the NO_MMAP flag set. */
> - if (bo->flags & DRM_PANTHOR_BO_NO_MMAP)
> - return -EINVAL;
> -
> - return drm_gem_shmem_object_mmap(obj, vma);
> -}
> -
> static struct dma_buf *
> panthor_gem_prime_export(struct drm_gem_object *obj, int flags)
> {
> @@ -169,7 +158,7 @@ static const struct drm_gem_object_funcs
> panthor_gem_funcs = {
> .get_sg_table = drm_gem_shmem_object_get_sg_table,
> .vmap = drm_gem_shmem_object_vmap,
> .vunmap = drm_gem_shmem_object_vunmap,
> - .mmap = panthor_gem_mmap,
> + .mmap = drm_gem_shmem_object_mmap,
> .status = panthor_gem_status,
> .export = panthor_gem_prime_export,
> .vm_ops = &drm_gem_shmem_vm_ops,
