vhost_net: introduce get_tx_bufs()

Factor out logic of getting tx buffer and iov iter
initialization. This will be used for reducing codes duplication in
the future.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index b9e1674..a014ca0 100644 (file)
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -484,6 +484,36 @@ static bool vhost_exceeds_weight(int pkts, int total_len)
               pkts >= VHOST_NET_PKT_WEIGHT;
 }
 
+static int get_tx_bufs(struct vhost_net *net,
+                      struct vhost_net_virtqueue *nvq,
+                      struct msghdr *msg,
+                      unsigned int *out, unsigned int *in,
+                      size_t *len, bool *busyloop_intr)
+{
+       struct vhost_virtqueue *vq = &nvq->vq;
+       int ret;
+
+       ret = vhost_net_tx_get_vq_desc(net, vq, out, in, busyloop_intr);
+       if (ret < 0 || ret == vq->num)
+               return ret;
+
+       if (*in) {
+               vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n",
+                       *out, *in);
+               return -EFAULT;
+       }
+
+       /* Sanity check */
+       *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out);
+       if (*len == 0) {
+               vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n",
+                       *len, nvq->vhost_hlen);
+               return -EFAULT;
+       }
+
+       return ret;
+}
+
 /* Expects to be always run from workqueue - which acts as
  * read-size critical section for our kind of RCU. */
 static void handle_tx(struct vhost_net *net)
@@ -501,7 +531,6 @@ static void handle_tx(struct vhost_net *net)
        };
        size_t len, total_len = 0;
        int err;
-       size_t hdr_size;
        struct socket *sock;
        struct vhost_net_ubuf_ref *uninitialized_var(ubufs);
        bool zcopy, zcopy_used;
@@ -518,7 +547,6 @@ static void handle_tx(struct vhost_net *net)
        vhost_disable_notify(&net->dev, vq);
        vhost_net_disable_vq(net, vq);
 
-       hdr_size = nvq->vhost_hlen;
        zcopy = nvq->ubufs;
 
        for (;;) {
@@ -529,8 +557,8 @@ static void handle_tx(struct vhost_net *net)
                        vhost_zerocopy_signal_used(net, vq);
 
                busyloop_intr = false;
-               head = vhost_net_tx_get_vq_desc(net, vq, &out, &in,
-                                               &busyloop_intr);
+               head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
+                                  &busyloop_intr);
                /* On error, stop handling until the next kick. */
                if (unlikely(head < 0))
                        break;
@@ -544,19 +572,6 @@ static void handle_tx(struct vhost_net *net)
                        }
                        break;
                }
-               if (in) {
-                       vq_err(vq, "Unexpected descriptor format for TX: "
-                              "out %d, int %d\n", out, in);
-                       break;
-               }
-
-               /* Sanity check */
-               len = init_iov_iter(vq, &msg.msg_iter, hdr_size, out);
-               if (!len) {
-                       vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n",
-                       len, hdr_size);
-                       break;
-               }
 
                zcopy_used = zcopy && len >= VHOST_GOODCOPY_LEN
                                   && !vhost_exceeds_maxpend(net)