Re: [PATCH v3] vfio/ap_ops: Convert to use vfio_register_group_dev()

From: Christoph Hellwig <hch@lst.de>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Tony Krowiak <akrowiak@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Harald Freudenberger <freude@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Jason Herne <jjherne@linux.ibm.com>,
	linux-s390@vger.kernel.org, Halil Pasic <pasic@linux.ibm.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>, Christoph Hellwig <hch@lst.de>,
	kvm@vger.kernel.org
Subject: Re: [PATCH v3] vfio/ap_ops: Convert to use vfio_register_group_dev()
Date: Tue, 10 Aug 2021 10:33:55 +0200	[thread overview]
Message-ID: <20210810083355.GB21036@lst.de> (raw)
In-Reply-To: <0-v3-9f48485c5e22+3cb9-vfio_ap_jgg@nvidia.com>

On Fri, Aug 06, 2021 at 04:51:15PM -0300, Jason Gunthorpe wrote:
> This is straightforward conversion, the ap_matrix_mdev is actually serving as
> the vfio_device and we can replace all the mdev_get_drvdata()'s with a
> simple container_of() or a dev_get_drvdata() for sysfs paths.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/s390/crypto/vfio_ap_ops.c     | 155 +++++++++++++++-----------
>  drivers/s390/crypto/vfio_ap_private.h |   2 +
>  2 files changed, 91 insertions(+), 66 deletions(-)
> 
> Alex,
> 
> This is after the reflck series and should thus go to the vfio tree. Thanks
> 
> v3:
>  - Rebase ontop of the reflk patch series
>  - Remove module get/put
>  - Update commit message
> v2: https://lore.kernel.org/linux-s390/6-v2-7667f42c9bad+935-vfio3_jgg@nvidia.com/
> v1: https://lore.kernel.org/linux-s390/6-v1-d88406ed308e+418-vfio3_jgg@nvidia.com/
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index cee5626fe0a4ef..0828c188babedf 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -24,8 +24,9 @@
>  #define VFIO_AP_MDEV_TYPE_HWVIRT "passthrough"
>  #define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device"
>  
> -static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
> +static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev);
>  static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
> +static const struct vfio_device_ops vfio_ap_matrix_dev_ops;
>  
>  static int match_apqn(struct device *dev, const void *data)
>  {
> @@ -335,45 +336,59 @@ static void vfio_ap_matrix_init(struct ap_config_info *info,
>  	matrix->adm_max = info->apxa ? info->Nd : 15;
>  }
>  
> -static int vfio_ap_mdev_create(struct mdev_device *mdev)
> +static int vfio_ap_mdev_probe(struct mdev_device *mdev)
>  {
>  	struct ap_matrix_mdev *matrix_mdev;
> +	int ret;
>  
>  	if ((atomic_dec_if_positive(&matrix_dev->available_instances) < 0))
>  		return -EPERM;
>  
>  	matrix_mdev = kzalloc(sizeof(*matrix_mdev), GFP_KERNEL);
>  	if (!matrix_mdev) {
> -		atomic_inc(&matrix_dev->available_instances);
> -		return -ENOMEM;
> +		ret = -ENOMEM;
> +		goto err_atomic;

Nit: the label naming here is very strange.  Somethig like
err_dec_avaiable would be much more descriptive.

> +static struct mdev_driver vfio_ap_matrix_driver = {
> +	.driver = {
> +		.name = "vfio_ap_mdev",
> +		.owner = THIS_MODULE,
> +		.mod_name = KBUILD_MODNAME,

No need to set mod_name.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>