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Subject: Re: [PATCH v9 08/22] s390: vfio-ap: base implementation of VFIO AP
 device driver
To:     Cornelia Huck <cohuck@redhat.com>,
        Tony Krowiak <akrowiak@linux.vnet.ibm.com>
Cc:     linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, freude@de.ibm.com, schwidefsky@de.ibm.com,
        heiko.carstens@de.ibm.com, borntraeger@de.ibm.com,
        kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com,
        pbonzini@redhat.com, alex.williamson@redhat.com,
        pmorel@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com,
        mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com,
        thuth@redhat.com, pasic@linux.vnet.ibm.com, berrange@redhat.com,
        fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com,
        frankja@linux.ibm.com
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 <1534196899-16987-9-git-send-email-akrowiak@linux.vnet.ibm.com>
 <20180814124220.355f2ffa.cohuck@redhat.com>
From:   Tony Krowiak <akrowiak@linux.ibm.com>
Date:   Tue, 14 Aug 2018 19:30:41 -0400
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On 08/14/2018 06:42 AM, Cornelia Huck wrote:
> On Mon, 13 Aug 2018 17:48:05 -0400
> Tony Krowiak <akrowiak@linux.vnet.ibm.com> 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@linux.ibm.com>
>> + */
>> +
>> +#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);
>> +}