virtio: console: statically initialize virtio_cons

That way, we can make it const as is good kernel style.  We use a separate
indirection for the early console, rather than mugging ops.put_chars.

We rename it hv_ops, too.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/char/virtio_console.c

@@ -28,12 +28,12 @@ static struct virtio_device *vdev;
 static unsigned int in_len;
 static char *in, *inbuf;
 
-/* The operations for our console. */
-static struct hv_ops virtio_cons;
-
 /* The hvc device */
 static struct hvc_struct *hvc;
 
+/* This is the very early arch-specified put chars function. */
+static int (*early_put_chars)(u32, const char *, int);
+
 /*
  * The put_chars() callback is pretty straightforward.
  *
@@ -47,6 +47,9 @@ static int put_chars(u32 vtermno, const char *buf, int count)
 	struct scatterlist sg[1];
 	unsigned int len;
 
+	if (unlikely(early_put_chars))
+		return early_put_chars(vtermno, buf, count);
+
 	/* This is a convenient routine to initialize a single-elem sg list */
 	sg_init_one(sg, buf, count);
 
@@ -117,21 +120,6 @@ static int get_chars(u32 vtermno, char *buf, int count)
 	return count;
 }
 
-/*
- * Console drivers are initialized very early so boot messages can go
- * out, so we do things slightly differently from the generic virtio
- * initialization of the net and block drivers.
- *
- * At this stage, the console is output-only.  It's too early to set
- * up a virtqueue, so we let the drivers do some boutique early-output
- * thing.
- */
-int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
-{
-	virtio_cons.put_chars = put_chars;
-	return hvc_instantiate(0, 0, &virtio_cons);
-}
-
 /*
  * virtio console configuration. This supports:
  * - console resize
@@ -174,6 +162,30 @@ static void hvc_handle_input(struct virtqueue *vq)
 		hvc_kick();
 }
 
+/* The operations for the console. */
+static struct hv_ops hv_ops = {
+	.get_chars = get_chars,
+	.put_chars = put_chars,
+	.notifier_add = notifier_add_vio,
+	.notifier_del = notifier_del_vio,
+	.notifier_hangup = notifier_del_vio,
+};
+
+/*
+ * Console drivers are initialized very early so boot messages can go
+ * out, so we do things slightly differently from the generic virtio
+ * initialization of the net and block drivers.
+ *
+ * At this stage, the console is output-only.  It's too early to set
+ * up a virtqueue, so we let the drivers do some boutique early-output
+ * thing.
+ */
+int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
+{
+	early_put_chars = put_chars;
+	return hvc_instantiate(0, 0, &hv_ops);
+}
+
 /*
  * Once we're further in boot, we get probed like any other virtio
  * device.  At this stage we set up the output virtqueue.
@@ -209,13 +221,6 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
 	in_vq = vqs[0];
 	out_vq = vqs[1];
 
-	/* Start using the new console output. */
-	virtio_cons.get_chars = get_chars;
-	virtio_cons.put_chars = put_chars;
-	virtio_cons.notifier_add = notifier_add_vio;
-	virtio_cons.notifier_del = notifier_del_vio;
-	virtio_cons.notifier_hangup = notifier_del_vio;
-
 	/*
 	 * The first argument of hvc_alloc() is the virtual console
 	 * number, so we use zero.  The second argument is the
@@ -228,7 +233,7 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
 	 * pointers.  The final argument is the output buffer size: we
 	 * can do any size, so we put PAGE_SIZE here.
 	 */
-	hvc = hvc_alloc(0, 0, &virtio_cons, PAGE_SIZE);
+	hvc = hvc_alloc(0, 0, &hv_ops, PAGE_SIZE);
 	if (IS_ERR(hvc)) {
 		err = PTR_ERR(hvc);
 		goto free_vqs;
@@ -236,6 +241,9 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
 
 	/* Register the input buffer the first time. */
 	add_inbuf();
+
+	/* Start using the new console output. */
+	early_put_chars = NULL;
 	return 0;
 
 free_vqs: