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authorStefano Garzarella <sgarzare@redhat.com>2019-07-30 17:43:33 +0200
committerDavid S. Miller <davem@davemloft.net>2019-07-31 00:00:00 +0200
commit6dbd3e66e7785a2f055bf84d98de9b8fd31ff3f5 (patch)
treeae2446395722f6e26af872493a533ec97c691b20
parentvsock/virtio: fix locking in virtio_transport_inc_tx_pkt() (diff)
downloadlinux-6dbd3e66e7785a2f055bf84d98de9b8fd31ff3f5.tar.xz
linux-6dbd3e66e7785a2f055bf84d98de9b8fd31ff3f5.zip
vhost/vsock: split packets to send using multiple buffers
If the packets to sent to the guest are bigger than the buffer available, we can split them, using multiple buffers and fixing the length in the packet header. This is safe since virtio-vsock supports only stream sockets. Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/vhost/vsock.c66
-rw-r--r--net/vmw_vsock/virtio_transport_common.c15
2 files changed, 60 insertions, 21 deletions
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 6c8390a2af52..9f57736fe15e 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -102,7 +102,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
struct iov_iter iov_iter;
unsigned out, in;
size_t nbytes;
- size_t len;
+ size_t iov_len, payload_len;
int head;
spin_lock_bh(&vsock->send_pkt_list_lock);
@@ -147,8 +147,24 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
break;
}
- len = iov_length(&vq->iov[out], in);
- iov_iter_init(&iov_iter, READ, &vq->iov[out], in, len);
+ iov_len = iov_length(&vq->iov[out], in);
+ if (iov_len < sizeof(pkt->hdr)) {
+ virtio_transport_free_pkt(pkt);
+ vq_err(vq, "Buffer len [%zu] too small\n", iov_len);
+ break;
+ }
+
+ iov_iter_init(&iov_iter, READ, &vq->iov[out], in, iov_len);
+ payload_len = pkt->len - pkt->off;
+
+ /* If the packet is greater than the space available in the
+ * buffer, we split it using multiple buffers.
+ */
+ if (payload_len > iov_len - sizeof(pkt->hdr))
+ payload_len = iov_len - sizeof(pkt->hdr);
+
+ /* Set the correct length in the header */
+ pkt->hdr.len = cpu_to_le32(payload_len);
nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
if (nbytes != sizeof(pkt->hdr)) {
@@ -157,33 +173,47 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
break;
}
- nbytes = copy_to_iter(pkt->buf, pkt->len, &iov_iter);
- if (nbytes != pkt->len) {
+ nbytes = copy_to_iter(pkt->buf + pkt->off, payload_len,
+ &iov_iter);
+ if (nbytes != payload_len) {
virtio_transport_free_pkt(pkt);
vq_err(vq, "Faulted on copying pkt buf\n");
break;
}
- vhost_add_used(vq, head, sizeof(pkt->hdr) + pkt->len);
+ vhost_add_used(vq, head, sizeof(pkt->hdr) + payload_len);
added = true;
- if (pkt->reply) {
- int val;
-
- val = atomic_dec_return(&vsock->queued_replies);
-
- /* Do we have resources to resume tx processing? */
- if (val + 1 == tx_vq->num)
- restart_tx = true;
- }
-
/* Deliver to monitoring devices all correctly transmitted
* packets.
*/
virtio_transport_deliver_tap_pkt(pkt);
- total_len += pkt->len;
- virtio_transport_free_pkt(pkt);
+ pkt->off += payload_len;
+ total_len += payload_len;
+
+ /* If we didn't send all the payload we can requeue the packet
+ * to send it with the next available buffer.
+ */
+ if (pkt->off < pkt->len) {
+ spin_lock_bh(&vsock->send_pkt_list_lock);
+ list_add(&pkt->list, &vsock->send_pkt_list);
+ spin_unlock_bh(&vsock->send_pkt_list_lock);
+ } else {
+ if (pkt->reply) {
+ int val;
+
+ val = atomic_dec_return(&vsock->queued_replies);
+
+ /* Do we have resources to resume tx
+ * processing?
+ */
+ if (val + 1 == tx_vq->num)
+ restart_tx = true;
+ }
+
+ virtio_transport_free_pkt(pkt);
+ }
} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
if (added)
vhost_signal(&vsock->dev, vq);
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 34a2b42313b7..56fab3f03d0e 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -97,8 +97,17 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
struct virtio_vsock_pkt *pkt = opaque;
struct af_vsockmon_hdr *hdr;
struct sk_buff *skb;
+ size_t payload_len;
+ void *payload_buf;
- skb = alloc_skb(sizeof(*hdr) + sizeof(pkt->hdr) + pkt->len,
+ /* A packet could be split to fit the RX buffer, so we can retrieve
+ * the payload length from the header and the buffer pointer taking
+ * care of the offset in the original packet.
+ */
+ payload_len = le32_to_cpu(pkt->hdr.len);
+ payload_buf = pkt->buf + pkt->off;
+
+ skb = alloc_skb(sizeof(*hdr) + sizeof(pkt->hdr) + payload_len,
GFP_ATOMIC);
if (!skb)
return NULL;
@@ -138,8 +147,8 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
skb_put_data(skb, &pkt->hdr, sizeof(pkt->hdr));
- if (pkt->len) {
- skb_put_data(skb, pkt->buf, pkt->len);
+ if (payload_len) {
+ skb_put_data(skb, payload_buf, payload_len);
}
return skb;