Re: [PATCH] virtio_console: Add support for multiple ports for generic guest and host communication

From: Christian Borntraeger
Date: Tue Sep 29 2009 - 08:03:18 EST


Am Dienstag 29 September 2009 11:24:31 schrieb Amit Shah:
> -static void hvc_handle_input(struct virtqueue *vq)
> +/* The operations for our console. */
> +static struct hv_ops virtio_cons = {
> + .get_chars = cons_get_chars,
> + .put_chars = cons_put_chars,
> + .notifier_add = cons_notifier_add_vio,
> + .notifier_del = cons_notifier_del_vio,
> + .notifier_hangup = cons_notifier_del_vio,
> +};
[...]
> +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);
> +}
[...]
> +static int __devinit virtcons_probe(struct virtio_device *vdev)
[...]
> - /* Start using the new console output. */
> - virtio_cons.get_chars = get_chars;
> - virtio_cons.put_chars = put_chars;

Ok, that wont work for systems that use virtio_cons_early_init. The early
put_chars method was replaced by the final one, but these hunks changed that
behaviour. Something like the following restores the old behaviour: (only
tested on s390)

Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
If you agree, you can merge this snipped into your big patch.

---
drivers/char/virtio_console.c | 3 +++
1 file changed, 3 insertions(+)

Index: linux-2.6/drivers/char/virtio_console.c
===================================================================
--- linux-2.6.orig/drivers/char/virtio_console.c
+++ linux-2.6/drivers/char/virtio_console.c
@@ -590,6 +590,9 @@ int init_port_console(struct virtio_cons
pr_err("%s: Could not alloc hvc for virtio console port, ret = %d\n",
__func__, ret);
port->hvc = NULL;
+ } else {
+ /* get rid of early put char variants */
+ virtio_cons.put_chars = cons_put_chars;
}
return ret;
}
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