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

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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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Amit Shah 2009-12-21 21:57:40 +05:30 committed by Rusty Russell
parent 3c7969ccb5
commit 431edb8a8b
2 changed files with 58 additions and 0 deletions
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57
drivers/char/virtio_console.c
View File

@ -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;

1
include/linux/virtio_console.h
View File

@ -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));