1 files changed, 22 insertions, 9 deletions

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index bb5fc0e9fbc2..6a50e1d0529c 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -1,11 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * vhost transport for vsock
  *
  * Copyright (C) 2013-2015 Red Hat, Inc.
  * Author: Asias He <asias@redhat.com>
  *         Stefan Hajnoczi <stefanha@redhat.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2.
  */
 #include <linux/miscdevice.h>
 #include <linux/atomic.h>
@@ -21,6 +20,14 @@
 #include "vhost.h"
 
 #define VHOST_VSOCK_DEFAULT_HOST_CID	2
+/* Max number of bytes transferred before requeueing the job.
+ * Using this limit prevents one virtqueue from starving others. */
+#define VHOST_VSOCK_WEIGHT 0x80000
+/* Max number of packets transferred before requeueing the job.
+ * Using this limit prevents one virtqueue from starving others with
+ * small pkts.
+ */
+#define VHOST_VSOCK_PKT_WEIGHT 256
 
 enum {
 	VHOST_VSOCK_FEATURES = VHOST_FEATURES,
@@ -78,6 +85,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 			    struct vhost_virtqueue *vq)
 {
 	struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
+	int pkts = 0, total_len = 0;
 	bool added = false;
 	bool restart_tx = false;
 
@@ -89,7 +97,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 	/* Avoid further vmexits, we're already processing the virtqueue */
 	vhost_disable_notify(&vsock->dev, vq);
 
-	for (;;) {
+	do {
 		struct virtio_vsock_pkt *pkt;
 		struct iov_iter iov_iter;
 		unsigned out, in;
@@ -174,8 +182,9 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 		 */
 		virtio_transport_deliver_tap_pkt(pkt);
 
+		total_len += pkt->len;
 		virtio_transport_free_pkt(pkt);
-	}
+	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
 	if (added)
 		vhost_signal(&vsock->dev, vq);
 
@@ -350,7 +359,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
 						 dev);
 	struct virtio_vsock_pkt *pkt;
-	int head;
+	int head, pkts = 0, total_len = 0;
 	unsigned int out, in;
 	bool added = false;
 
@@ -360,7 +369,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 		goto out;
 
 	vhost_disable_notify(&vsock->dev, vq);
-	for (;;) {
+	do {
 		u32 len;
 
 		if (!vhost_vsock_more_replies(vsock)) {
@@ -401,9 +410,11 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 		else
 			virtio_transport_free_pkt(pkt);
 
-		vhost_add_used(vq, head, sizeof(pkt->hdr) + len);
+		len += sizeof(pkt->hdr);
+		vhost_add_used(vq, head, len);
+		total_len += len;
 		added = true;
-	}
+	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
 
 no_more_replies:
 	if (added)
@@ -531,7 +542,9 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
 	vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
 	vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
 
-	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), UIO_MAXIOV);
+	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs),
+		       UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT,
+		       VHOST_VSOCK_WEIGHT);
 
 	file->private_data = vsock;
 	spin_lock_init(&vsock->send_pkt_list_lock);