Re: [RFC 02/18] remoteproc: Introduce virtio device add/remove functions in core.

[Mathieu Poirier]

Hey Arnaud,

I have started to review this set. Comments will come in over the next few days
and I will be sure to let you know when I'm done.

On Thu, Apr 16, 2020 at 06:13:15PM +0200, Arnaud Pouliquen wrote:
> In preparation of the migration of the management of rvdev in
> rproc_virtio, this patch spins off new functions to manage the
> virtio device.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx>
> ---
>  drivers/remoteproc/remoteproc_core.c | 149 +++++++++++++++------------
>  1 file changed, 83 insertions(+), 66 deletions(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 2a0425ab82a7..5c90d569c0f7 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -441,6 +441,86 @@ static void rproc_rvdev_release(struct device *dev)
>  	kfree(rvdev);
>  }
>  
> +static int rproc_rvdev_add_device(struct rproc_vdev *rvdev)
> +{
> +	struct rproc *rproc = rvdev->rproc;
> +	struct fw_rsc_vdev *rsc = rvdev->rsc;
> +	char name[16];
> +	int ret, i;
> +
> +	/* Initialise vdev subdevice */
> +	snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
> +	rvdev->dev.parent = &rproc->dev;
> +	rvdev->dev.dma_pfn_offset = rproc->dev.parent->dma_pfn_offset;
> +	rvdev->dev.release = rproc_rvdev_release;
> +	dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);
> +	dev_set_drvdata(&rvdev->dev, rvdev);
> +
> +	ret = device_register(&rvdev->dev);
> +	if (ret) {
> +		put_device(&rvdev->dev);
> +		return ret;
> +	}
> +	/* Make device dma capable by inheriting from parent's capabilities */
> +	set_dma_ops(&rvdev->dev, get_dma_ops(rproc->dev.parent));
> +
> +	ret = dma_coerce_mask_and_coherent(&rvdev->dev,
> +					   dma_get_mask(rproc->dev.parent));
> +	if (ret) {
> +		dev_warn(&rvdev->dev,
> +			 "Failed to set DMA mask %llx. Trying to continue... %x\n",
> +			 dma_get_mask(rproc->dev.parent), ret);
> +	}
> +
> +	/* parse the vrings */
> +	for (i = 0; i < rsc->num_of_vrings; i++) {
> +		ret = rproc_parse_vring(rvdev, rsc, i);
> +		if (ret)
> +			goto free_rvdev;
> +	}
> +
> +	/* allocate the vring resources */
> +	for (i = 0; i < rsc->num_of_vrings; i++) {
> +		ret = rproc_alloc_vring(rvdev, i);
> +		if (ret)
> +			goto free_vg;

I don't get the "free_vg" part... At the moment this patch is only about
refactoring and as such I would encourage you to keep things the same as
much as possible.  It is certainly ok to make modifications but they should be
done in an incremental patch.  Otherwise reviewers needlessly have to scrutinize
the changes thinking there is something more to figure out.

> +	}
> +
> +	rvdev->subdev.start = rproc_vdev_do_start;
> +	rvdev->subdev.stop = rproc_vdev_do_stop;
> +
> +	rproc_add_subdev(rproc, &rvdev->subdev);
> +
> +	return 0;
> +
> +free_vg:
> +	for (i--; i >= 0; i--) {
> +		struct rproc_vring *rvring = &rvdev->vring[i];
> +
> +		rproc_free_vring(rvring);
> +	}
> +
> +free_rvdev:
> +	device_unregister(&rvdev->dev);
> +
> +	return ret;
> +}
> +
> +static void rproc_rvdev_remove_device(struct rproc_vdev *rvdev)
> +{
> +	struct rproc *rproc = rvdev->rproc;
> +	struct rproc_vring *rvring;
> +	int id;
> +
> +	for (id = 0; id < ARRAY_SIZE(rvdev->vring); id++) {
> +		rvring = &rvdev->vring[id];
> +		rproc_free_vring(rvring);
> +	}
> +
> +	rproc_remove_subdev(rproc, &rvdev->subdev);
> +	device_unregister(&rvdev->dev);
> +}
> +
>  /**
>   * rproc_handle_vdev() - handle a vdev fw resource
>   * @rproc: the remote processor
> @@ -473,8 +553,6 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
>  {
>  	struct device *dev = &rproc->dev;
>  	struct rproc_vdev *rvdev;
> -	int i, ret;
> -	char name[16];
>  
>  	/* make sure resource isn't truncated */
>  	if (struct_size(rsc, vring, rsc->num_of_vrings) + rsc->config_len >
> @@ -505,83 +583,22 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
>  	kref_init(&rvdev->refcount);
>  
>  	rvdev->rsc = rsc;
> +	rvdev->rsc_offset = offset;
>  	rvdev->id = rsc->id;
>  	rvdev->rproc = rproc;
>  	rvdev->index = rproc->nb_vdev++;
>  
> -	/* Initialise vdev subdevice */
> -	snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
> -	rvdev->dev.parent = rproc->dev.parent;
> -	rvdev->dev.dma_pfn_offset = rproc->dev.parent->dma_pfn_offset;
> -	rvdev->dev.release = rproc_rvdev_release;
> -	dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);
> -	dev_set_drvdata(&rvdev->dev, rvdev);
> -
> -	ret = device_register(&rvdev->dev);
> -	if (ret) {
> -		put_device(&rvdev->dev);
> -		return ret;
> -	}
> -	/* Make device dma capable by inheriting from parent's capabilities */
> -	set_dma_ops(&rvdev->dev, get_dma_ops(rproc->dev.parent));
> -
> -	ret = dma_coerce_mask_and_coherent(&rvdev->dev,
> -					   dma_get_mask(rproc->dev.parent));
> -	if (ret) {
> -		dev_warn(dev,
> -			 "Failed to set DMA mask %llx. Trying to continue... %x\n",
> -			 dma_get_mask(rproc->dev.parent), ret);
> -	}
> -
> -	/* parse the vrings */
> -	for (i = 0; i < rsc->num_of_vrings; i++) {
> -		ret = rproc_parse_vring(rvdev, rsc, i);
> -		if (ret)
> -			goto free_rvdev;
> -	}
> -
> -	/* remember the resource offset*/
> -	rvdev->rsc_offset = offset;
> -
> -	/* allocate the vring resources */
> -	for (i = 0; i < rsc->num_of_vrings; i++) {
> -		ret = rproc_alloc_vring(rvdev, i);
> -		if (ret)
> -			goto unwind_vring_allocations;
> -	}
> -
>  	list_add_tail(&rvdev->node, &rproc->rvdevs);
>  
> -	rvdev->subdev.start = rproc_vdev_do_start;
> -	rvdev->subdev.stop = rproc_vdev_do_stop;
> -
> -	rproc_add_subdev(rproc, &rvdev->subdev);
> -
> -	return 0;
> -
> -unwind_vring_allocations:
> -	for (i--; i >= 0; i--)
> -		rproc_free_vring(&rvdev->vring[i]);
> -free_rvdev:
> -	device_unregister(&rvdev->dev);
> -	return ret;
> +	return rproc_rvdev_add_device(rvdev);
>  }
>  
>  void rproc_vdev_release(struct kref *ref)
>  {
>  	struct rproc_vdev *rvdev = container_of(ref, struct rproc_vdev, refcount);
> -	struct rproc_vring *rvring;
> -	struct rproc *rproc = rvdev->rproc;
> -	int id;
> -
> -	for (id = 0; id < ARRAY_SIZE(rvdev->vring); id++) {
> -		rvring = &rvdev->vring[id];
> -		rproc_free_vring(rvring);
> -	}
>  
> -	rproc_remove_subdev(rproc, &rvdev->subdev);
> +	rproc_rvdev_remove_device(rvdev);

At this time I don't see how introducing rproc_rvdev_remore_device() is
advantageous.  Maybe I'll find an answer as I review upcoming patches...

Thanks,
Mathieu 

>  	list_del(&rvdev->node);
> -	device_unregister(&rvdev->dev);
>  }
>  
>  /**
> -- 
> 2.17.1
>