virtio: Compile with -Wextra

-Wextra enables a bunch of rather useful checks which this fixes.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

lib/libvirtio/p9.c

diff --git a/lib/libvirtio/p9.c b/lib/libvirtio/p9.c
index 0e59530..e9ba228 100644
--- a/lib/libvirtio/p9.c
+++ b/lib/libvirtio/p9.c
@@ -142,7 +142,7 @@
 int p9_transaction(p9_connection_t *connection)
 {
 	int rc;
-	int tx_size = GET_SIZE;
+	uint32_t tx_size = GET_SIZE;
 	uint32_t rx_size = connection->message_size;
 
 	if (transact == NULL) {
@@ -248,7 +248,7 @@
 int p9_attach(p9_connection_t *connection)
 {
 	int rc;
-	int length = 19 + strlen(connection->uname) + strlen(connection->aname);
+	unsigned length = 19 + strlen(connection->uname) + strlen(connection->aname);
 
 	if (length > connection->message_size) {
 		return P9_MSG_TOO_LONG;
@@ -372,8 +372,8 @@
 			s_tok = e_tok;
 			continue;
 		}
-		int tx_size = (e_tok - s_tok + 2 + GET_SIZE);
-		int rx_size = ((element_count + 1) * MSG_QID_SIZE
+		unsigned tx_size = (e_tok - s_tok + 2 + GET_SIZE);
+		unsigned rx_size = ((element_count + 1) * MSG_QID_SIZE
 				+ MSG_WALK_RX_HDR_SIZE);
 		if ((tx_size > connection->message_size)
 			|| (rx_size > connection->message_size)) {

lib/libvirtio/virtio.c

diff --git a/lib/libvirtio/virtio.c b/lib/libvirtio/virtio.c
index 69ac439..9dfc93c 100644
--- a/lib/libvirtio/virtio.c
+++ b/lib/libvirtio/virtio.c
@@ -436,7 +436,7 @@
 void virtio_queue_term_vq(struct virtio_device *dev, struct vqs *vq, unsigned int id)
 {
 	if (vq->desc_gpas) {
-		int i;
+		unsigned i;
 
 		for (i = 0; i < vq->size; ++i)
 			virtio_free_desc(vq, i, dev->features);