vhost_net: fix wrong iter offset when setting number of buffers (0960b641) · Commits · 戴 / test

In commit ("vhost: don't bother copying iovecs in handle_rx(), kill memcpy_toiovecend()"), we advance iov iter fixup sizeof(struct virtio_net_hdr) bytes and fill the number of buffers after doing the socket recvmsg(). This work well but was broken after commit ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net") which tries to advance sizeof(struct virtio_net_hdr_mrg_rxbuf). It will fill the number of buffers at the wrong place. This patch fixes this. Fixes ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net" ) Cc: David S. Miller <davem@davemloft.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Michael S. Tsirkin <mst@redhat.com> Signed-off-by:

Jason Wang <jasowang@redhat.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/vhost/net.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -528,9 +528,9 @@ static void handle_rx(struct vhost_net *net)
		.msg_controllen = 0,
		.msg_flags = MSG_DONTWAIT,
		};
		struct virtio_net_hdr_mrg_rxbuf hdr = {
		.hdr.flags = 0,
		.hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE
		struct virtio_net_hdr hdr = {
		.flags = 0,
		.gso_type = VIRTIO_NET_HDR_GSO_NONE
		};
		size_t total_len = 0;
		int err, mergeable;
		@@ -539,6 +539,7 @@ static void handle_rx(struct vhost_net *net)
		size_t vhost_len, sock_len;
		struct socket *sock;
		struct iov_iter fixup;
		__virtio16 num_buffers;

		mutex_lock(&vq->mutex);
		sock = vq->private_data;
		@@ -616,9 +617,9 @@ static void handle_rx(struct vhost_net *net)
		}
		/* TODO: Should check and handle checksum. */

		hdr.num_buffers = cpu_to_vhost16(vq, headcount);
		num_buffers = cpu_to_vhost16(vq, headcount);
		if (likely(mergeable) &&
		copy_to_iter(&hdr.num_buffers, 2, &fixup) != 2) {
		copy_to_iter(&num_buffers, 2, &fixup) != 2) {
		vq_err(vq, "Failed num_buffers write");
		vhost_discard_vq_desc(vq, headcount);
		break;

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