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Commit 431edb8a authored by Amit Shah's avatar Amit Shah Committed by Rusty Russell
Browse files

virtio: console: Register with sysfs and create a 'name' attribute for ports 



The host can set a name for ports so that they're easily discoverable
instead of going by the /dev/vportNpn naming. This attribute will be
placed in /sys/class/virtio-ports/vportNpn/name. udev scripts can then
create symlinks to the port using the name.

Signed-off-by: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 3c7969cc

drivers/char/virtio_console.c

+57 −0
Original line number Diff line number Diff line
@@ -170,6 +170,9 @@ struct port { 
	/* A waitqueue for poll() or blocking read operations */

	wait_queue_head_t waitqueue;



	/* The 'name' of the port that we expose via sysfs properties */

	char *name;



	/* The 'id' to identify the port with the Host */

	u32 id;
@@ -732,12 +735,36 @@ int init_port_console(struct port *port) 
	return 0;

}



static ssize_t show_port_name(struct device *dev,

			      struct device_attribute *attr, char *buffer)

{

	struct port *port;



	port = dev_get_drvdata(dev);



	return sprintf(buffer, "%s\n", port->name);

}



static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);



static struct attribute *port_sysfs_entries[] = {

	&dev_attr_name.attr,

	NULL

};



static struct attribute_group port_attribute_group = {

	.name = NULL,		/* put in device directory */

	.attrs = port_sysfs_entries,

};



/* Any private messages that the Host and Guest want to share */

static void handle_control_message(struct ports_device *portdev,

				   struct port_buffer *buf)

{

	struct virtio_console_control *cpkt;

	struct port *port;

	size_t name_size;

	int err;



	cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
@@ -772,6 +799,35 @@ static void handle_control_message(struct ports_device *portdev, 
		port->host_connected = cpkt->value;

		wake_up_interruptible(&port->waitqueue);

		break;

	case VIRTIO_CONSOLE_PORT_NAME:

		/*

		 * Skip the size of the header and the cpkt to get the size

		 * of the name that was sent

		 */

		name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;



		port->name = kmalloc(name_size, GFP_KERNEL);

		if (!port->name) {

			dev_err(port->dev,

				"Not enough space to store port name\n");

			break;

		}

		strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),

			name_size - 1);

		port->name[name_size - 1] = 0;



		/*

		 * Since we only have one sysfs attribute, 'name',

		 * create it only if we have a name for the port.

		 */

		err = sysfs_create_group(&port->dev->kobj,

					 &port_attribute_group);

		if (err)

			dev_err(port->dev,

				"Error %d creating sysfs device attributes\n",

				err);



		break;

	}

}
@@ -869,6 +925,7 @@ static int add_port(struct ports_device *portdev, u32 id) 
	port->portdev = portdev;

	port->id = id;



	port->name = NULL;

	port->inbuf = NULL;

	port->cons.hvc = NULL;

include/linux/virtio_console.h

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ struct virtio_console_control { 
#define VIRTIO_CONSOLE_CONSOLE_PORT	1

#define VIRTIO_CONSOLE_RESIZE		2

#define VIRTIO_CONSOLE_PORT_OPEN	3

#define VIRTIO_CONSOLE_PORT_NAME	4



#ifdef __KERNEL__

int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int));