Re: [PATCH] drm/nouveau: add locking around instobj list operations

[Marcin Slusarz <marcin.slusarz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Sun, Dec 02, 2012 at 02:53:01PM +0100, Marcin Slusarz wrote:
> Fixes memory corruptions (unrelated to nouveau!), oopses, gpu lockups and
> xserver crashes when multiple gpuobjs are simultaneously created / destroyed.
> 
> Signed-off-by: Marcin Slusarz <marcin.slusarz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
> Piglit, with concurrency enabled, can finally finish without crashes or lockups
> (most of the time :).

It would be awesome to have this in 3.7/3.7.x ;).

> ---
>  drivers/gpu/drm/nouveau/core/subdev/instmem/base.c | 35 +++++++++++++++++-----
>  1 file changed, 27 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/core/subdev/instmem/base.c b/drivers/gpu/drm/nouveau/core/subdev/instmem/base.c
> index 1188227..6565f3d 100644
> --- a/drivers/gpu/drm/nouveau/core/subdev/instmem/base.c
> +++ b/drivers/gpu/drm/nouveau/core/subdev/instmem/base.c
> @@ -40,15 +40,21 @@ nouveau_instobj_create_(struct nouveau_object *parent,
>  	if (ret)
>  		return ret;
>  
> +	mutex_lock(&imem->base.mutex);
>  	list_add(&iobj->head, &imem->list);
> +	mutex_unlock(&imem->base.mutex);
>  	return 0;
>  }
>  
>  void
>  nouveau_instobj_destroy(struct nouveau_instobj *iobj)
>  {
> -	if (iobj->head.prev)
> -		list_del(&iobj->head);
> +	struct nouveau_subdev *subdev = nv_subdev(iobj->base.engine);
> +
> +	mutex_lock(&subdev->mutex);
> +	list_del(&iobj->head);
> +	mutex_unlock(&subdev->mutex);
> +
>  	return nouveau_object_destroy(&iobj->base);
>  }
>  
> @@ -88,6 +94,8 @@ nouveau_instmem_init(struct nouveau_instmem *imem)
>  	if (ret)
>  		return ret;
>  
> +	mutex_lock(&imem->base.mutex);
> +
>  	list_for_each_entry(iobj, &imem->list, head) {
>  		if (iobj->suspend) {
>  			for (i = 0; i < iobj->size; i += 4)
> @@ -97,6 +105,8 @@ nouveau_instmem_init(struct nouveau_instmem *imem)
>  		}
>  	}
>  
> +	mutex_unlock(&imem->base.mutex);
> +
>  	return 0;
>  }
>  
> @@ -104,17 +114,26 @@ int
>  nouveau_instmem_fini(struct nouveau_instmem *imem, bool suspend)
>  {
>  	struct nouveau_instobj *iobj;
> -	int i;
> +	int i, ret = 0;
>  
>  	if (suspend) {
> +		mutex_lock(&imem->base.mutex);
> +
>  		list_for_each_entry(iobj, &imem->list, head) {
>  			iobj->suspend = vmalloc(iobj->size);
> -			if (iobj->suspend) {
> -				for (i = 0; i < iobj->size; i += 4)
> -					iobj->suspend[i / 4] = nv_ro32(iobj, i);
> -			} else
> -				return -ENOMEM;
> +			if (!iobj->suspend) {
> +				ret = -ENOMEM;
> +				break;
> +			}
> +
> +			for (i = 0; i < iobj->size; i += 4)
> +				iobj->suspend[i / 4] = nv_ro32(iobj, i);
>  		}
> +
> +		mutex_unlock(&imem->base.mutex);
> +
> +		if (ret)
> +			return ret;
>  	}
>  
>  	return nouveau_subdev_fini(&imem->base, suspend);
> -- 
> 1.7.12
>