On Mon, Oct 14, 2019 at 06:54:40PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> Use RCU_READ_LOCK_GUARD and WITH_RCU_READ_LOCK_GUARD
> to replace the manual rcu_read_(un)lock calls.
>
> I think the only change is virtio_load which was missing unlocks
> in error paths; those end up being fatal errors so it's not
> that important anyway.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
Can you rebase on top of packed ring support please?
They are in my queue now.
> ---
> hw/virtio/virtio.c | 46 ++++++++++++++++------------------------------
> 1 file changed, 16 insertions(+), 30 deletions(-)
>
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 527df03bfd..15ae9da60b 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -337,7 +337,7 @@ void virtio_queue_set_notification(VirtQueue *vq, int
> enable)
> return;
> }
>
> - rcu_read_lock();
> + RCU_READ_LOCK_GUARD();
> if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
> vring_set_avail_event(vq, vring_avail_idx(vq));
> } else if (enable) {
> @@ -349,7 +349,6 @@ void virtio_queue_set_notification(VirtQueue *vq, int
> enable)
> /* Expose avail event/used flags before caller checks the avail idx.
> */
> smp_mb();
> }
> - rcu_read_unlock();
> }
>
> int virtio_queue_ready(VirtQueue *vq)
> @@ -393,9 +392,8 @@ int virtio_queue_empty(VirtQueue *vq)
> return 0;
> }
>
> - rcu_read_lock();
> + RCU_READ_LOCK_GUARD();
> empty = vring_avail_idx(vq) == vq->last_avail_idx;
> - rcu_read_unlock();
> return empty;
> }
>
> @@ -530,10 +528,9 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count)
> void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
> unsigned int len)
> {
> - rcu_read_lock();
> + RCU_READ_LOCK_GUARD();
> virtqueue_fill(vq, elem, len, 0);
> virtqueue_flush(vq, 1);
> - rcu_read_unlock();
> }
>
> /* Called within rcu_read_lock(). */
> @@ -624,7 +621,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned
> int *in_bytes,
> return;
> }
>
> - rcu_read_lock();
> + RCU_READ_LOCK_GUARD();
> idx = vq->last_avail_idx;
> total_bufs = in_total = out_total = 0;
>
> @@ -719,7 +716,6 @@ done:
> if (out_bytes) {
> *out_bytes = out_total;
> }
> - rcu_read_unlock();
> return;
>
> err:
> @@ -869,7 +865,7 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
> if (unlikely(vdev->broken)) {
> return NULL;
> }
> - rcu_read_lock();
> + RCU_READ_LOCK_GUARD();
> if (virtio_queue_empty_rcu(vq)) {
> goto done;
> }
> @@ -977,7 +973,6 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
> trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
> done:
> address_space_cache_destroy(&indirect_desc_cache);
> - rcu_read_unlock();
>
> return elem;
>
> @@ -1680,13 +1675,10 @@ static bool virtio_should_notify(VirtIODevice *vdev,
> VirtQueue *vq)
>
> void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
> {
> - bool should_notify;
> - rcu_read_lock();
> - should_notify = virtio_should_notify(vdev, vq);
> - rcu_read_unlock();
> -
> - if (!should_notify) {
> - return;
> + WITH_RCU_READ_LOCK_GUARD() {
> + if (!virtio_should_notify(vdev, vq)) {
> + return;
> + }
> }
>
> trace_virtio_notify_irqfd(vdev, vq);
> @@ -1718,13 +1710,10 @@ static void virtio_irq(VirtQueue *vq)
>
> void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
> {
> - bool should_notify;
> - rcu_read_lock();
> - should_notify = virtio_should_notify(vdev, vq);
> - rcu_read_unlock();
> -
> - if (!should_notify) {
> - return;
> + WITH_RCU_READ_LOCK_GUARD() {
> + if (!virtio_should_notify(vdev, vq)) {
> + return;
> + }
> }
>
> trace_virtio_notify(vdev, vq);
> @@ -2241,7 +2230,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int
> version_id)
> vdev->start_on_kick = true;
> }
>
> - rcu_read_lock();
> + RCU_READ_LOCK_GUARD();
> for (i = 0; i < num; i++) {
> if (vdev->vq[i].vring.desc) {
> uint16_t nheads;
> @@ -2289,7 +2278,6 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int
> version_id)
> }
> }
> }
> - rcu_read_unlock();
>
> return 0;
> }
> @@ -2422,21 +2410,19 @@ void virtio_queue_set_last_avail_idx(VirtIODevice
> *vdev, int n, uint16_t idx)
>
> void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n)
> {
> - rcu_read_lock();
> + RCU_READ_LOCK_GUARD();
> if (vdev->vq[n].vring.desc) {
> vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]);
> vdev->vq[n].shadow_avail_idx = vdev->vq[n].last_avail_idx;
> }
> - rcu_read_unlock();
> }
>
> void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
> {
> - rcu_read_lock();
> + RCU_READ_LOCK_GUARD();
> if (vdev->vq[n].vring.desc) {
> vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
> }
> - rcu_read_unlock();
> }
>
> void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
> --
> 2.23.0
