Re: [PATCH] virtio: Introduce a new kick interface virtqueue_kick_try()

---
  drivers/net/virtio_net.c     |  8 ++++----
  drivers/virtio/virtio_ring.c | 20 ++++++++++++++++++++
  include/linux/virtio.h       |  2 ++
  3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 9b6a4a875c55..167697030cb6 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -617,7 +617,7 @@ static int virtnet_xdp_xmit(struct net_device *dev,
  	ret = nxmit;
  
  	if (flags & XDP_XMIT_FLUSH) {
-		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))
+		if (virtqueue_kick_try(sq->vq))
  			kicks = 1;
  	}
  out:

@@ -1325,7 +1325,7 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
  		if (err)
  			break;
  	} while (rq->vq->num_free);
-	if (virtqueue_kick_prepare(rq->vq) && virtqueue_notify(rq->vq)) {
+	if (virtqueue_kick_try(rq->vq)) {
  		unsigned long flags;
  
  		flags = u64_stats_update_begin_irqsave(&rq->stats.syncp);

@@ -1533,7 +1533,7 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
  
  	if (xdp_xmit & VIRTIO_XDP_TX) {
  		sq = virtnet_xdp_get_sq(vi);
-		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {
+		if (virtqueue_kick_try(sq->vq)) {
  			u64_stats_update_begin(&sq->stats.syncp);
  			sq->stats.kicks++;
  			u64_stats_update_end(&sq->stats.syncp);

@@ -1710,7 +1710,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
  	}
  
  	if (kick || netif_xmit_stopped(txq)) {
-		if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {
+		if (virtqueue_kick_try(sq->vq)) {
  			u64_stats_update_begin(&sq->stats.syncp);
  			sq->stats.kicks++;
  			u64_stats_update_end(&sq->stats.syncp);

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 71e16b53e9c1..1462be756875 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c

@@ -1874,6 +1874,26 @@ bool virtqueue_kick(struct virtqueue *vq)
  }
  EXPORT_SYMBOL_GPL(virtqueue_kick);
  
+/**
+ * virtqueue_kick_try - try update after add_buf
+ * @vq: the struct virtqueue
+ *
+ * After one or more virtqueue_add_* calls, invoke this to kick
+ * the other side.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ *
+ * Returns true if kick success, otherwise false.
+ */
+bool virtqueue_kick_try(struct virtqueue *vq)
+{
+	if (virtqueue_kick_prepare(vq) && virtqueue_notify(vq))
+		return true;
+	return false;
+}
+EXPORT_SYMBOL_GPL(virtqueue_kick_try);
+
  /**
   * virtqueue_get_buf - get the next used buffer
   * @_vq: the struct virtqueue we're talking about.

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index b1894e0323fa..45cd6a0af24d 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h

@@ -59,6 +59,8 @@ int virtqueue_add_sgs(struct virtqueue *vq,
  
  bool virtqueue_kick(struct virtqueue *vq);
  
+bool virtqueue_kick_try(struct virtqueue *vq);
+
  bool virtqueue_kick_prepare(struct virtqueue *vq);
  
  bool virtqueue_notify(struct virtqueue *vq);