On 6/16/20 11:45 AM, Christian Borntraeger wrote:
On 05.06.20 23:39, Tony Krowiak wrote:This patch refactor's the vfio_ap device driver to use the AP bus's ap_get_qdev() function to retrieve the vfio_ap_queue struct containing information about a queue that is bound to the vfio_ap device driver. The bus's ap_get_qdev() function retrieves the queue device from a hashtable keyed by APQN. This is much more efficient than looping over the list of devices attached to the AP bus by several orders of magnitude. Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx> --- drivers/s390/crypto/vfio_ap_drv.c | 27 ++------- drivers/s390/crypto/vfio_ap_ops.c | 82 +++++++++++++++------------ drivers/s390/crypto/vfio_ap_private.h | 8 ++- 3 files changed, 58 insertions(+), 59 deletions(-) diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c index be2520cc010b..59233cf7419d 100644 --- a/drivers/s390/crypto/vfio_ap_drv.c +++ b/drivers/s390/crypto/vfio_ap_drv.c @@ -51,15 +51,9 @@ MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids); */ 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; - q->saved_isc = VFIO_AP_ISC_INVALID; - return 0; + struct ap_queue *queue = to_ap_queue(&apdev->device); + + return vfio_ap_mdev_probe_queue(queue); }Here we did not hold a mutex in the old code [...]+int vfio_ap_mdev_probe_queue(struct ap_queue *queue) +{ + struct vfio_ap_queue *q; + + q = kzalloc(sizeof(*q), GFP_KERNEL); + if (!q) + return -ENOMEM; + + mutex_lock(&matrix_dev->lock); + dev_set_drvdata(&queue->ap_dev.device, q); + q->apqn = queue->qid; + q->saved_isc = VFIO_AP_ISC_INVALID; + mutex_unlock(&matrix_dev->lock); +here we do. Why do we need the matrix_dev->lock here?
You are correct, we don't need it here; but, we will need it in a subsequent patch where we introduce linking the q to the matrix mdev to which it is assigned. Perhaps the locking should be introduced in that patch.
