Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio updates from Michael Tsirkin:
 "Several new features here:

   - virtio-balloon supports new stats

   - vdpa supports setting mac address

   - vdpa/mlx5 suspend/resume as well as MKEY ops are now faster

   - virtio_fs supports new sysfs entries for queue info

   - virtio/vsock performance has been improved

  And fixes, cleanups all over the place"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (34 commits)
  vsock/virtio: avoid queuing packets when intermediate queue is empty
  vsock/virtio: refactor virtio_transport_send_pkt_work
  fw_cfg: Constify struct kobj_type
  vdpa/mlx5: Postpone MR deletion
  vdpa/mlx5: Introduce init/destroy for MR resources
  vdpa/mlx5: Rename mr_mtx -> lock
  vdpa/mlx5: Extract mr members in own resource struct
  vdpa/mlx5: Rename function
  vdpa/mlx5: Delete direct MKEYs in parallel
  vdpa/mlx5: Create direct MKEYs in parallel
  MAINTAINERS: add virtio-vsock driver in the VIRTIO CORE section
  virtio_fs: add sysfs entries for queue information
  virtio_fs: introduce virtio_fs_put_locked helper
  vdpa: Remove unused declarations
  vdpa/mlx5: Parallelize VQ suspend/resume for CVQ MQ command
  vdpa/mlx5: Small improvement for change_num_qps()
  vdpa/mlx5: Keep notifiers during suspend but ignore
  vdpa/mlx5: Parallelize device resume
  vdpa/mlx5: Parallelize device suspend
  vdpa/mlx5: Use async API for vq modify commands
  ...

1 files changed, 94 insertions, 50 deletions

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index e0160da4ef43..85e423921734 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -94,6 +94,63 @@ out_rcu:
 	return ret;
 }
 
+/* Caller need to hold vsock->tx_lock on vq */
+static int virtio_transport_send_skb(struct sk_buff *skb, struct virtqueue *vq,
+				     struct virtio_vsock *vsock)
+{
+	int ret, in_sg = 0, out_sg = 0;
+	struct scatterlist **sgs;
+
+	sgs = vsock->out_sgs;
+	sg_init_one(sgs[out_sg], virtio_vsock_hdr(skb),
+		    sizeof(*virtio_vsock_hdr(skb)));
+	out_sg++;
+
+	if (!skb_is_nonlinear(skb)) {
+		if (skb->len > 0) {
+			sg_init_one(sgs[out_sg], skb->data, skb->len);
+			out_sg++;
+		}
+	} else {
+		struct skb_shared_info *si;
+		int i;
+
+		/* If skb is nonlinear, then its buffer must contain
+		 * only header and nothing more. Data is stored in
+		 * the fragged part.
+		 */
+		WARN_ON_ONCE(skb_headroom(skb) != sizeof(*virtio_vsock_hdr(skb)));
+
+		si = skb_shinfo(skb);
+
+		for (i = 0; i < si->nr_frags; i++) {
+			skb_frag_t *skb_frag = &si->frags[i];
+			void *va;
+
+			/* We will use 'page_to_virt()' for the userspace page
+			 * here, because virtio or dma-mapping layers will call
+			 * 'virt_to_phys()' later to fill the buffer descriptor.
+			 * We don't touch memory at "virtual" address of this page.
+			 */
+			va = page_to_virt(skb_frag_page(skb_frag));
+			sg_init_one(sgs[out_sg],
+				    va + skb_frag_off(skb_frag),
+				    skb_frag_size(skb_frag));
+			out_sg++;
+		}
+	}
+
+	ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
+	/* Usually this means that there is no more space available in
+	 * the vq
+	 */
+	if (ret < 0)
+		return ret;
+
+	virtio_transport_deliver_tap_pkt(skb);
+	return 0;
+}
+
 static void
 virtio_transport_send_pkt_work(struct work_struct *work)
 {
@@ -111,66 +168,22 @@ virtio_transport_send_pkt_work(struct work_struct *work)
 	vq = vsock->vqs[VSOCK_VQ_TX];
 
 	for (;;) {
-		int ret, in_sg = 0, out_sg = 0;
-		struct scatterlist **sgs;
 		struct sk_buff *skb;
 		bool reply;
+		int ret;
 
 		skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue);
 		if (!skb)
 			break;
 
 		reply = virtio_vsock_skb_reply(skb);
-		sgs = vsock->out_sgs;
-		sg_init_one(sgs[out_sg], virtio_vsock_hdr(skb),
-			    sizeof(*virtio_vsock_hdr(skb)));
-		out_sg++;
-
-		if (!skb_is_nonlinear(skb)) {
-			if (skb->len > 0) {
-				sg_init_one(sgs[out_sg], skb->data, skb->len);
-				out_sg++;
-			}
-		} else {
-			struct skb_shared_info *si;
-			int i;
-
-			/* If skb is nonlinear, then its buffer must contain
-			 * only header and nothing more. Data is stored in
-			 * the fragged part.
-			 */
-			WARN_ON_ONCE(skb_headroom(skb) != sizeof(*virtio_vsock_hdr(skb)));
-
-			si = skb_shinfo(skb);
-
-			for (i = 0; i < si->nr_frags; i++) {
-				skb_frag_t *skb_frag = &si->frags[i];
-				void *va;
 
-				/* We will use 'page_to_virt()' for the userspace page
-				 * here, because virtio or dma-mapping layers will call
-				 * 'virt_to_phys()' later to fill the buffer descriptor.
-				 * We don't touch memory at "virtual" address of this page.
-				 */
-				va = page_to_virt(skb_frag_page(skb_frag));
-				sg_init_one(sgs[out_sg],
-					    va + skb_frag_off(skb_frag),
-					    skb_frag_size(skb_frag));
-				out_sg++;
-			}
-		}
-
-		ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
-		/* Usually this means that there is no more space available in
-		 * the vq
-		 */
+		ret = virtio_transport_send_skb(skb, vq, vsock);
 		if (ret < 0) {
 			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
 			break;
 		}
 
-		virtio_transport_deliver_tap_pkt(skb);
-
 		if (reply) {
 			struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 			int val;
@@ -195,6 +208,28 @@ out:
 		queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 }
 
+/* Caller need to hold RCU for vsock.
+ * Returns 0 if the packet is successfully put on the vq.
+ */
+static int virtio_transport_send_skb_fast_path(struct virtio_vsock *vsock, struct sk_buff *skb)
+{
+	struct virtqueue *vq = vsock->vqs[VSOCK_VQ_TX];
+	int ret;
+
+	/* Inside RCU, can't sleep! */
+	ret = mutex_trylock(&vsock->tx_lock);
+	if (unlikely(ret == 0))
+		return -EBUSY;
+
+	ret = virtio_transport_send_skb(skb, vq, vsock);
+	if (ret == 0)
+		virtqueue_kick(vq);
+
+	mutex_unlock(&vsock->tx_lock);
+
+	return ret;
+}
+
 static int
 virtio_transport_send_pkt(struct sk_buff *skb)
 {
@@ -218,11 +253,20 @@ virtio_transport_send_pkt(struct sk_buff *skb)
 		goto out_rcu;
 	}
 
-	if (virtio_vsock_skb_reply(skb))
-		atomic_inc(&vsock->queued_replies);
+	/* If send_pkt_queue is empty, we can safely bypass this queue
+	 * because packet order is maintained and (try) to put the packet
+	 * on the virtqueue using virtio_transport_send_skb_fast_path.
+	 * If this fails we simply put the packet on the intermediate
+	 * queue and schedule the worker.
+	 */
+	if (!skb_queue_empty_lockless(&vsock->send_pkt_queue) ||
+	    virtio_transport_send_skb_fast_path(vsock, skb)) {
+		if (virtio_vsock_skb_reply(skb))
+			atomic_inc(&vsock->queued_replies);
 
-	virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
-	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
+		virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
+		queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
+	}
 
 out_rcu:
 	rcu_read_unlock();