vhost-net: check the support of mergeable buffer outside the receive loop
No need to check the support of mergeable buffer inside the recevie
loop as the whole handle_rx()_xx is in the read critical region. So
this patch move it ahead of the receiving loop.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 59dad9f..9f57cd4 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -411,7 +411,7 @@
.hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE
};
size_t total_len = 0;
- int err, headcount;
+ int err, headcount, mergeable;
size_t vhost_hlen, sock_hlen;
size_t vhost_len, sock_len;
/* TODO: check that we are running from vhost_worker? */
@@ -427,6 +427,7 @@
vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
vq->log : NULL;
+ mergeable = vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF);
while ((sock_len = peek_head_len(sock->sk))) {
sock_len += sock_hlen;
@@ -476,7 +477,7 @@
break;
}
/* TODO: Should check and handle checksum. */
- if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF) &&
+ if (likely(mergeable) &&
memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount,
offsetof(typeof(hdr), num_buffers),
sizeof hdr.num_buffers)) {