On 9/29/20 9:37 AM, Halil Pasic wrote:
On Tue, 29 Sep 2020 09:07:40 -0400
Tony Krowiak <[email protected]> wrote:
On 9/24/20 10:27 PM, Halil Pasic wrote:
On Fri, 21 Aug 2020 15:56:02 -0400
Tony Krowiak <[email protected]> wrote:
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -26,43 +26,26 @@
static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
-static int match_apqn(struct device *dev, const void *data)
-{
- struct vfio_ap_queue *q = dev_get_drvdata(dev);
-
- return (q->apqn == *(int *)(data)) ? 1 : 0;
-}
-
/**
- * vfio_ap_get_queue: Retrieve a queue with a specific APQN from a list
- * @matrix_mdev: the associated mediated matrix
+ * vfio_ap_get_queue: Retrieve a queue with a specific APQN.
* @apqn: The queue APQN
*
- * Retrieve a queue with a specific APQN from the list of the
- * devices of the vfio_ap_drv.
- * Verify that the APID and the APQI are set in the matrix.
+ * Retrieve a queue with a specific APQN from the AP queue devices attached to
+ * the AP bus.
*
- * Returns the pointer to the associated vfio_ap_queue
+ * Returns the pointer to the vfio_ap_queue with the specified APQN, or NULL.
*/
-static struct vfio_ap_queue *vfio_ap_get_queue(
- struct ap_matrix_mdev *matrix_mdev,
- int apqn)
+static struct vfio_ap_queue *vfio_ap_get_queue(unsigned long apqn)
{
+ struct ap_queue *queue;
struct vfio_ap_queue *q;
- struct device *dev;
- if (!test_bit_inv(AP_QID_CARD(apqn), matrix_mdev->matrix.apm))
- return NULL;
- if (!test_bit_inv(AP_QID_QUEUE(apqn), matrix_mdev->matrix.aqm))
+ queue = ap_get_qdev(apqn);
+ if (!queue)
return NULL;
- dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,
- &apqn, match_apqn);
- if (!dev)
- return NULL;
- q = dev_get_drvdata(dev);
- q->matrix_mdev = matrix_mdev;
- put_device(dev);
+ q = dev_get_drvdata(&queue->ap_dev.device);
Is this cast here safe? (I don't think it is.)
In the probe, we execute:
dev_set_drvdata(&queue->ap_dev.device, q);
I don't get any compile nor execution errors. Why wouldn't it be safe?
Because the queue may or may not be bound to the vfio_ap driver. AFAICT
this function can be called with an arbitrary APQN.
If it is bound to another driver then drvdata is not likely to hold a
struct vfio_ap_queue.
Then the function will return NULL. All callers must check for
NULL before using it which is the case in all places where this
function is called.
+ put_device(&queue->ap_dev.device);
return q;
}
