[PATCH] drm/vgem: Implement mmap as GEM object function

[Daniel Vetter]

On Thu, Jun 24, 2021 at 11:52 AM Thomas Zimmermann <tzimmermann at suse.de> wrote:
>
> Moving the driver-specific mmap code into a GEM object function allows
> for using DRM helpers for various mmap callbacks.
>
> The respective vgem functions are being removed. The file_operations
> structure vgem_driver_fops is now being created by the helper macro
> DEFINE_DRM_GEM_FOPS().
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>

Might be this one, might be a different one (there's also a bunch of
core kernel patches that got into drm-tip together with this patch),
but vgem goes boom after this landed in CI:

https://intel-gfx-ci.01.org/tree/drm-tip/igt@vgem_basic@unload.html

Can you pls take a quick look? It's in dma-buf fault stuff, so not
entirely unlikely. Ville pointed this out on irc.
-Daniel

> ---
>  drivers/gpu/drm/vgem/vgem_drv.c | 46 ++++-----------------------------
>  1 file changed, 5 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
> index bf38a7e319d1..df634aa52638 100644
> --- a/drivers/gpu/drm/vgem/vgem_drv.c
> +++ b/drivers/gpu/drm/vgem/vgem_drv.c
> @@ -239,32 +239,7 @@ static struct drm_ioctl_desc vgem_ioctls[] = {
>         DRM_IOCTL_DEF_DRV(VGEM_FENCE_SIGNAL, vgem_fence_signal_ioctl, DRM_RENDER_ALLOW),
>  };
>
> -static int vgem_mmap(struct file *filp, struct vm_area_struct *vma)
> -{
> -       unsigned long flags = vma->vm_flags;
> -       int ret;
> -
> -       ret = drm_gem_mmap(filp, vma);
> -       if (ret)
> -               return ret;
> -
> -       /* Keep the WC mmaping set by drm_gem_mmap() but our pages
> -        * are ordinary and not special.
> -        */
> -       vma->vm_flags = flags | VM_DONTEXPAND | VM_DONTDUMP;
> -       return 0;
> -}
> -
> -static const struct file_operations vgem_driver_fops = {
> -       .owner          = THIS_MODULE,
> -       .open           = drm_open,
> -       .mmap           = vgem_mmap,
> -       .poll           = drm_poll,
> -       .read           = drm_read,
> -       .unlocked_ioctl = drm_ioctl,
> -       .compat_ioctl   = drm_compat_ioctl,
> -       .release        = drm_release,
> -};
> +DEFINE_DRM_GEM_FOPS(vgem_driver_fops);
>
>  static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo)
>  {
> @@ -387,24 +362,12 @@ static void vgem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *ma
>         vgem_unpin_pages(bo);
>  }
>
> -static int vgem_prime_mmap(struct drm_gem_object *obj,
> -                          struct vm_area_struct *vma)
> +static int vgem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>  {
> -       int ret;
> -
> -       if (obj->size < vma->vm_end - vma->vm_start)
> -               return -EINVAL;
> -
> -       if (!obj->filp)
> -               return -ENODEV;
> -
> -       ret = call_mmap(obj->filp, vma);
> -       if (ret)
> -               return ret;
> -
>         vma_set_file(vma, obj->filp);
>         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
>         vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
> +       vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
>
>         return 0;
>  }
> @@ -416,6 +379,7 @@ static const struct drm_gem_object_funcs vgem_gem_object_funcs = {
>         .get_sg_table = vgem_prime_get_sg_table,
>         .vmap = vgem_prime_vmap,
>         .vunmap = vgem_prime_vunmap,
> +       .mmap = vgem_prime_mmap,
>         .vm_ops = &vgem_gem_vm_ops,
>  };
>
> @@ -433,7 +397,7 @@ static const struct drm_driver vgem_driver = {
>         .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>         .gem_prime_import = vgem_prime_import,
>         .gem_prime_import_sg_table = vgem_prime_import_sg_table,
> -       .gem_prime_mmap = vgem_prime_mmap,
> +       .gem_prime_mmap = drm_gem_prime_mmap,
>
>         .name   = DRIVER_NAME,
>         .desc   = DRIVER_DESC,
> --
> 2.32.0
>


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch