Date:   Tue, 24 May 2022 10:49:56 -0400
From:   "Jason J. Herne" <jjherne@...ux.ibm.com>
To:     Tony Krowiak <akrowiak@...ux.ibm.com>, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     freude@...ux.ibm.com, borntraeger@...ibm.com, cohuck@...hat.com,
        mjrosato@...ux.ibm.com, pasic@...ux.ibm.com,
        alex.williamson@...hat.com, kwankhede@...dia.com,
        fiuczy@...ux.ibm.com
Subject: Re: [PATCH v19 02/20] s390/vfio-ap: move probe and remove callbacks
 to vfio_ap_ops.c

On 4/4/22 18:10, Tony Krowiak wrote:
> Let's move the probe and remove callbacks into the vfio_ap_ops.c
> file to keep all code related to managing queues in a single file. This
> way, all functions related to queue management can be removed from the
> vfio_ap_private.h header file defining the public interfaces for the
> vfio_ap device driver.
> 
> Signed-off-by: Tony Krowiak <akrowiak@...ux.ibm.com>
> Reviewed-by: Halil Pasic <pasic@...ux.ibm.com>
> ---
>   drivers/s390/crypto/vfio_ap_drv.c     | 59 +--------------------------
>   drivers/s390/crypto/vfio_ap_ops.c     | 31 +++++++++++++-
>   drivers/s390/crypto/vfio_ap_private.h |  5 ++-
>   3 files changed, 34 insertions(+), 61 deletions(-)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index 29ebd54f8919..9a300dd3b6f7 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -104,64 +104,9 @@ static const struct attribute_group vfio_queue_attr_group = {
>   	.attrs = vfio_queue_attrs,
>   };
>   
> -/**
> - * vfio_ap_queue_dev_probe: Allocate a vfio_ap_queue structure and associate it
> - *			    with the device as driver_data.
> - *
> - * @apdev: the AP device being probed
> - *
> - * Return: returns 0 if the probe succeeded; otherwise, returns an error if
> - *	   storage could not be allocated for a vfio_ap_queue object or the
> - *	   sysfs 'status' attribute could not be created for the queue device.
> - */
> -static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
> -{
> -	int ret;
> -	struct vfio_ap_queue *q;
> -
> -	q = kzalloc(sizeof(*q), GFP_KERNEL);
> -	if (!q)
> -		return -ENOMEM;
> -
> -	mutex_lock(&matrix_dev->lock);
> -	dev_set_drvdata(&apdev->device, q);
> -	q->apqn = to_ap_queue(&apdev->device)->qid;
> -	q->saved_isc = VFIO_AP_ISC_INVALID;
> -
> -	ret = sysfs_create_group(&apdev->device.kobj, &vfio_queue_attr_group);
> -	if (ret) {
> -		dev_set_drvdata(&apdev->device, NULL);
> -		kfree(q);
> -	}
> -
> -	mutex_unlock(&matrix_dev->lock);
> -
> -	return ret;
> -}
> -
> -/**
> - * vfio_ap_queue_dev_remove: Free the associated vfio_ap_queue structure.
> - *
> - * @apdev: the AP device being removed
> - *
> - * Takes the matrix lock to avoid actions on this device while doing the remove.
> - */
> -static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
> -{
> -	struct vfio_ap_queue *q;
> -
> -	mutex_lock(&matrix_dev->lock);
> -	sysfs_remove_group(&apdev->device.kobj, &vfio_queue_attr_group);
> -	q = dev_get_drvdata(&apdev->device);
> -	vfio_ap_mdev_reset_queue(q, 1);
> -	dev_set_drvdata(&apdev->device, NULL);
> -	kfree(q);
> -	mutex_unlock(&matrix_dev->lock);
> -}
> -
>   static struct ap_driver vfio_ap_drv = {
> -	.probe = vfio_ap_queue_dev_probe,
> -	.remove = vfio_ap_queue_dev_remove,
> +	.probe = vfio_ap_mdev_probe_queue,
> +	.remove = vfio_ap_mdev_remove_queue,
>   	.ids = ap_queue_ids,
>   };
>   
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 2227919fde13..16220157dbe3 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -1314,8 +1314,7 @@ static struct vfio_ap_queue *vfio_ap_find_queue(int apqn)
>   	return q;
>   }
>   
> -int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
> -			     unsigned int retry)
> +static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q, unsigned int retry)
>   {
>   	struct ap_queue_status status;
>   	int ret;
> @@ -1524,3 +1523,31 @@ void vfio_ap_mdev_unregister(void)
>   	mdev_unregister_device(&matrix_dev->device);
>   	mdev_unregister_driver(&vfio_ap_matrix_driver);
>   }
> +
> +int vfio_ap_mdev_probe_queue(struct ap_device *apdev)
> +{
> +	struct vfio_ap_queue *q;
> +
> +	q = kzalloc(sizeof(*q), GFP_KERNEL);
> +	if (!q)
> +		return -ENOMEM;
> +	mutex_lock(&matrix_dev->lock);
> +	q->apqn = to_ap_queue(&apdev->device)->qid;
> +	q->saved_isc = VFIO_AP_ISC_INVALID;
> +	dev_set_drvdata(&apdev->device, q);
> +	mutex_unlock(&matrix_dev->lock);
> +
> +	return 0;
> +}
> +
> +void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
> +{
> +	struct vfio_ap_queue *q;
> +
> +	mutex_lock(&matrix_dev->lock);
> +	q = dev_get_drvdata(&apdev->device);
> +	vfio_ap_mdev_reset_queue(q, 1);
> +	dev_set_drvdata(&apdev->device, NULL);
> +	kfree(q);
> +	mutex_unlock(&matrix_dev->lock);
> +}
> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
> index 648fcaf8104a..3cade25a1620 100644
> --- a/drivers/s390/crypto/vfio_ap_private.h
> +++ b/drivers/s390/crypto/vfio_ap_private.h
> @@ -119,7 +119,8 @@ struct vfio_ap_queue {
>   
>   int vfio_ap_mdev_register(void);
>   void vfio_ap_mdev_unregister(void);
> -int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
> -			     unsigned int retry);
> +
> +int vfio_ap_mdev_probe_queue(struct ap_device *queue);
> +void vfio_ap_mdev_remove_queue(struct ap_device *queue);
>   
>   #endif /* _VFIO_AP_PRIVATE_H_ */


With this commit, you did more than just move the probe/remove functions. You also changed 
their behavior. The call to sysfs_create_group has been removed. So the following in 
vfop_ap_drv.c becomes dead code:

     vfio_ap_mdev_for_queue
     status_show
     static DEVICE_ATTR_RO(status);
     vfio_queue_attrs
     vfio_queue_attr_group

Is this what you intended? If so, I assume we can live without the status attribute?
If this is the case then you'll want to remove all the dead code.

-- 
-- Jason J. Herne (jjherne@...ux.ibm.com)

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