Messages in this thread | | | Subject | Re: [PATCH v11 02/14] 390/vfio-ap: use new AP bus interface to search for queue devices | From | Tony Krowiak <> | Date | Mon, 2 Nov 2020 16:57:08 -0500 |
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On 10/27/20 3:01 AM, Halil Pasic wrote: > On Thu, 22 Oct 2020 13:11:57 -0400 > Tony Krowiak <akrowiak@linux.ibm.com> wrote: > >> This patch refactors 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@linux.ibm.com> > Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Thank you for your review.
> >> --- >> drivers/s390/crypto/vfio_ap_ops.c | 35 +++++++++++++------------------ >> 1 file changed, 14 insertions(+), 21 deletions(-) >> >> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c >> index c471832f0a30..049b97d7444c 100644 >> --- a/drivers/s390/crypto/vfio_ap_ops.c >> +++ b/drivers/s390/crypto/vfio_ap_ops.c >> @@ -26,43 +26,36 @@ >> >> 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 >> + * vfio_ap_get_queue: Retrieve a queue with a specific APQN. >> * @matrix_mdev: the associated mediated matrix >> * @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) >> + unsigned long apqn) >> { >> - struct vfio_ap_queue *q; >> - struct device *dev; >> + struct ap_queue *queue; >> + struct vfio_ap_queue *q = NULL; >> >> 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)) >> return NULL; >> >> - dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL, >> - &apqn, match_apqn); >> - if (!dev) >> + queue = ap_get_qdev(apqn); >> + if (!queue) >> return NULL; >> - q = dev_get_drvdata(dev); >> - q->matrix_mdev = matrix_mdev; >> - put_device(dev); >> + >> + if (queue->ap_dev.device.driver == &matrix_dev->vfio_ap_drv->driver) >> + q = dev_get_drvdata(&queue->ap_dev.device); >> + > Needs to be called with the vfio_ap lock held, right? Otherwise the queue could > get unbound while we are working with it as a vfio_ap_queue... Noting > new, but might we worth documenting.
This is always called with the vfio_ap lock held.
> >> + put_device(&queue->ap_dev.device); >> >> return q; >> }
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