Re: [PATCH V5 6/9] virtio-ccw: implement synchronize_cbs()
From: Cornelia Huck <cohuck@redhat.com>
Date: 2022-05-18 09:32:47
Also in:
linux-s390, lkml
On Wed, May 18 2022, Jason Wang [off-list ref] wrote:
This patch tries to implement the synchronize_cbs() for ccw. For the vring_interrupt() that is called via virtio_airq_handler(), the synchronization is simply done via the airq_info's lock. For the vring_interrupt() that is called via virtio_ccw_int_handler(), a per device rwlock is introduced ans used in the synchronization method.
s/ans/and/
quoted hunk ↗ jump to hunk
Cc: Thomas Gleixner <redacted> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Halil Pasic <pasic@linux.ibm.com> Cc: Cornelia Huck <cohuck@redhat.com> Cc: Vineeth Vijayan <vneethv@linux.ibm.com> Cc: Peter Oberparleiter <oberpar@linux.ibm.com> Cc: linux-s390@vger.kernel.org Signed-off-by: Jason Wang <redacted> --- drivers/s390/virtio/virtio_ccw.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c index d35e7a3f7067..22d36594bcdd 100644 --- a/drivers/s390/virtio/virtio_ccw.c +++ b/drivers/s390/virtio/virtio_ccw.c@@ -62,6 +62,7 @@ struct virtio_ccw_device { unsigned int revision; /* Transport revision */ wait_queue_head_t wait_q; spinlock_t lock; + rwlock_t irq_lock; struct mutex io_lock; /* Serializes I/O requests */ struct list_head virtqueues; bool is_thinint;@@ -984,6 +985,27 @@ static const char *virtio_ccw_bus_name(struct virtio_device *vdev) return dev_name(&vcdev->cdev->dev); } +static void virtio_ccw_synchronize_cbs(struct virtio_device *vdev) +{ + struct virtio_ccw_device *vcdev = to_vc_device(vdev); + struct airq_info *info = vcdev->airq_info; + + if (info) { + /* + * Synchronize with the vring_interrupt() with airq indicator
Maybe /* * This device uses adapter interrupts: synchronize with * vring_interrupt() called by virtio_airq_handler() via the indicator * area lock. */
+ */
+ write_lock_irq(&info->lock);
+ write_unlock_irq(&info->lock);
+ } else {
+ /*
+ * Synchronize with the vring_interrupt() called by
+ * virtio_ccw_int_handler()./* * This device uses classic interrupts: synchronize with * vring_interrupt() called by virtio_ccw_int_handler() via the * per-device irq_lock. */
quoted hunk ↗ jump to hunk
+ */ + write_lock_irq(&vcdev->irq_lock); + write_unlock_irq(&vcdev->irq_lock); + } +} + static const struct virtio_config_ops virtio_ccw_config_ops = { .get_features = virtio_ccw_get_features, .finalize_features = virtio_ccw_finalize_features,@@ -995,6 +1017,7 @@ static const struct virtio_config_ops virtio_ccw_config_ops = { .find_vqs = virtio_ccw_find_vqs, .del_vqs = virtio_ccw_del_vqs, .bus_name = virtio_ccw_bus_name, + .synchronize_cbs = virtio_ccw_synchronize_cbs, };@@ -1106,6 +1129,8 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev, vcdev->err = -EIO; } virtio_ccw_check_activity(vcdev, activity); + /* Local interrupt should be disabled at this time */
/* Interrupts are disabled here. */ ? Interrupts enabled here would surely be a bug.
+ read_lock(&vcdev->irq_lock);
for_each_set_bit(i, indicators(vcdev),
sizeof(*indicators(vcdev)) * BITS_PER_BYTE) {
/* The bit clear must happen before the vring kick. */_______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization