linux-kernel - Re: [PATCH] rpmsg: Release rpmsg devices in backends

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Date:   Fri, 2 Jun 2017 12:07:46 +0200
From:   Henri Roosen <henri.roosen@...zinger.com>
To:     <bjorn.andersson@...aro.org>
CC:     <ohad@...ery.com>, <linux-remoteproc@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] rpmsg: Release rpmsg devices in backends

> The rpmsg devices are allocated in the backends and as such must be
> freed there as well.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
>  drivers/rpmsg/qcom_smd.c         | 11 +++++++++++
>  drivers/rpmsg/virtio_rpmsg_bus.c |  9 +++++++++
>  2 files changed, 20 insertions(+)
>
> diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
> index beaef5dd973e..a0a39a8821a3 100644
> --- a/drivers/rpmsg/qcom_smd.c
> +++ b/drivers/rpmsg/qcom_smd.c
> @@ -969,6 +969,14 @@ static const struct rpmsg_endpoint_ops qcom_smd_endpoint_ops = {
>  	.poll = qcom_smd_poll,
>  };
>
> +static void qcom_smd_release_device(struct device *dev)
> +{
> +	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
> +	struct qcom_smd_device *qsdev = to_smd_device(rpdev);
> +
> +	kfree(qsdev);
> +}
> +
>  /*
>   * Create a smd client device for channel that is being opened.
>   */
> @@ -998,6 +1006,7 @@ static int qcom_smd_create_device(struct qcom_smd_channel *channel)
>
>  	rpdev->dev.of_node = qcom_smd_match_channel(edge->of_node, channel->name);
>  	rpdev->dev.parent = &edge->dev;
> +	rpdev->dev.release = qcom_smd_release_device;
>
>  	return rpmsg_register_device(rpdev);

This will not work: the registration of qcom_smd_release_device at 
rpdev->dev.release gets overwritten inside rpmsg_register_device() and 
will then point to the function rpmsg_release_device().

My suggestion would be to additionally change/fix 
rpmsg_register_device() so it will not overwrite the release callback.

>  }
> @@ -1013,6 +1022,8 @@ static int qcom_smd_create_chrdev(struct qcom_smd_edge *edge)
>  	qsdev->edge = edge;
>  	qsdev->rpdev.ops = &qcom_smd_device_ops;
>  	qsdev->rpdev.dev.parent = &edge->dev;
> +	qsdev->rpdev.dev.release = qcom_smd_release_device;
> +
>  	return rpmsg_chrdev_register_device(&qsdev->rpdev);

This will not work either: same reason as described above because 
rpmsg_chrdev_register_device() will call rpmsg_register_device().

>  }
>
> diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
> index 5e66e081027e..7f8c5cc1c118 100644
> --- a/drivers/rpmsg/virtio_rpmsg_bus.c
> +++ b/drivers/rpmsg/virtio_rpmsg_bus.c
> @@ -360,6 +360,14 @@ static const struct rpmsg_device_ops virtio_rpmsg_ops = {
>  	.announce_destroy = virtio_rpmsg_announce_destroy,
>  };
>
> +static void virtio_rpmsg_release_device(struct device *dev)
> +{
> +	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
> +	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
> +
> +	kfree(vch);
> +}
> +
>  /*
>   * create an rpmsg channel using its name and address info.
>   * this function will be used to create both static and dynamic
> @@ -408,6 +416,7 @@ static struct rpmsg_device *rpmsg_create_channel(struct virtproc_info *vrp,
>  	strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE);
>
>  	rpdev->dev.parent = &vrp->vdev->dev;
> +	rpdev->dev.release = virtio_rpmsg_release_device;
>  	ret = rpmsg_register_device(rpdev);

The same issue as described above.

>  	if (ret)
>  		return NULL;