[PATCH 1/2] drm/amdgpu: drop multiple bo_unreserve() calls in amdgpu_gem_op_ioctl()

[Christian König]

NAK, we need to drop the reservation before calling copy_to_user().

Otherwise you run into a double locking error when copy_to_user() is 
trying to copy to the BO in question.

Regards,
Christian.

Am 09.02.2017 um 23:28 schrieb Samuel Pitoiset:
> Move amdgpu_bo_unreserve() outside of the switch. While we are
> at it, add a missing break in the default case.
>
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 7 ++-----
>   1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> index 1dc59aafec71..ae4658a10e2c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> @@ -660,7 +660,6 @@ int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
>   		info.alignment = robj->tbo.mem.page_alignment << PAGE_SHIFT;
>   		info.domains = robj->prefered_domains;
>   		info.domain_flags = robj->flags;
> -		amdgpu_bo_unreserve(robj);
>   		if (copy_to_user(out, &info, sizeof(info)))
>   			r = -EFAULT;
>   		break;
> @@ -668,7 +667,6 @@ int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
>   	case AMDGPU_GEM_OP_SET_PLACEMENT:
>   		if (amdgpu_ttm_tt_get_usermm(robj->tbo.ttm)) {
>   			r = -EPERM;
> -			amdgpu_bo_unreserve(robj);
>   			break;
>   		}
>   		robj->prefered_domains = args->value & (AMDGPU_GEM_DOMAIN_VRAM |
> @@ -677,14 +675,13 @@ int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
>   		robj->allowed_domains = robj->prefered_domains;
>   		if (robj->allowed_domains == AMDGPU_GEM_DOMAIN_VRAM)
>   			robj->allowed_domains |= AMDGPU_GEM_DOMAIN_GTT;
> -
> -		amdgpu_bo_unreserve(robj);
>   		break;
>   	default:
> -		amdgpu_bo_unreserve(robj);
>   		r = -EINVAL;
> +		break;
>   	}
>   
> +	amdgpu_bo_unreserve(robj);
>   out:
>   	drm_gem_object_unreference_unlocked(gobj);
>   	return r;