* Michael S. Tsirkin (m...@redhat.com) wrote:
> 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.
Sent; fixed up in about the same way but not tested much.
Dave
>
> > ---
> > 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
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
