Re: [PATCH v5 2/7] s390: ap: new vfio_ap_queue structure

Cornelia Huck
2019-03-15T10:33:30Z

On Wed, 13 Mar 2019 17:04:59 +0100
Pierre Morel <pmorel@linux.ibm.com> wrote:

> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index e9824c3..df6f21a 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -40,14 +40,42 @@ static struct ap_device_id ap_queue_ids[] = {
>
> MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids);
>
> +/**
> + * vfio_ap_queue_dev_probe:
> + *
> + * Allocate a vfio_ap_queue structure and associate it
> + * with the device as driver_data.
> + */
> static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
> {
> + struct vfio_ap_queue *q;
> +
> + q = kzalloc(sizeof(*q), GFP_KERNEL);
> + if (!q)
> + return -ENOMEM;
> + dev_set_drvdata(&apdev->device, q);
> + q->apqn = to_ap_queue(&apdev->device)->qid;
> + INIT_LIST_HEAD(&q->list);
> + mutex_lock(&matrix_dev->lock);
> + list_add(&q->list, &matrix_dev->free_list);
> + mutex_unlock(&matrix_dev->lock);

From what I can see, dealing with the free_list is supposed to be
protected by the matrix_dev mutex, and at a glance, it indeed seems to
be held every time you interact with the list. I think it would be good
to document that with a comment.

(I have not reviewed this deeply, and I won't be able to look at this
more until April, sorry.)

> return 0;
> }