Re: [PATCH v9 08/22] s390: vfio-ap: base implementation of VFIO AP device driver

[Tony Krowiak <akrowiak@xxxxxxxxxxxxx>]

On 08/14/2018 06:42 AM, Cornelia Huck wrote:
> On Mon, 13 Aug 2018 17:48:05 -0400
> Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote:
>
>
> > diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> > new file mode 100644
> > index 0000000..5069580
> > --- /dev/null
> > +++ b/drivers/s390/crypto/vfio_ap_drv.c
> > @@ -0,0 +1,118 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * VFIO based AP device driver
> > + *
> > + * Copyright IBM Corp. 2018
> > + *
> > + * Author(s): Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/slab.h>
> > +#include <linux/string.h>
> > +#include "vfio_ap_private.h"
> > +
> > +#define VFIO_AP_ROOT_NAME "vfio_ap"
> > +#define VFIO_AP_DEV_TYPE_NAME "ap_matrix"
> > +#define VFIO_AP_DEV_NAME "matrix"
> > +
> > +MODULE_AUTHOR("IBM Corporation");
> > +MODULE_DESCRIPTION("VFIO AP device driver, Copyright IBM Corp. 2018");
> > +MODULE_LICENSE("GPL v2");
> > +
> > +static struct ap_driver vfio_ap_drv;
> > +
> > +static struct device_type vfio_ap_dev_type = {
> > +	.name = VFIO_AP_DEV_TYPE_NAME,
> > +};
> > +
> > +struct ap_matrix_dev matrix_dev;
> Please don't add new statically allocated devices, but allocate it
> dynamically (see the comment in device_add()).

Okay, I'll dynamically allocate it.

> > +
> > +/* Only type 10 adapters (CEX4 and later) are supported
> > + * by the AP matrix device driver
> > + */
> > +static struct ap_device_id ap_queue_ids[] = {
> > +	{ .dev_type = AP_DEVICE_TYPE_CEX4,
> > +	  .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
> > +	{ .dev_type = AP_DEVICE_TYPE_CEX5,
> > +	  .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
> > +	{ .dev_type = AP_DEVICE_TYPE_CEX6,
> > +	  .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
> > +	{ /* end of sibling */ },
> > +};
> > +
> > +MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids);
> > +
> > +static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
> > +{
> > +	return 0;
> > +}
> > +
> > +static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
> > +{
> > +	/* Nothing to do yet */
> > +}
> You need a release callback as well.

Will do.

> > +
> > +static int vfio_ap_matrix_dev_init(void)
> > +{
> > +	int ret;
> > +	struct device *root_device;
> > +
> > +	root_device = root_device_register(VFIO_AP_ROOT_NAME);
> > +	if (IS_ERR(root_device)) {
> > +		ret = PTR_ERR(root_device);
> > +		return ret;
> > +	}
> > +
> > +	matrix_dev.device.type = &vfio_ap_dev_type;
> > +	dev_set_name(&matrix_dev.device, "%s", VFIO_AP_DEV_NAME);
> > +	matrix_dev.device.type = &vfio_ap_dev_type;
> > +	matrix_dev.device.parent = root_device;
> > +	matrix_dev.device.driver = &vfio_ap_drv.driver;
> > +
> > +	ret = device_register(&matrix_dev.device);
> > +	if (ret) {
> > +		root_device_unregister(root_device);
> And this needs a put_device() for the matrix device. (It is getting
> ugly with a statically allocated device.)

Will do.

> > +		return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static void vfio_ap_matrix_dev_destroy(void)
> > +{
> > +	device_unregister(&matrix_dev.device);
> This one already does a put_device(). Didn't the driver core complain?

The driver core did not complain.

> > +	root_device_unregister(matrix_dev.device.parent);
> > +}