From 431edb8a8bca71008fefceadf53b9315ef7196ec Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Mon, 21 Dec 2009 21:57:40 +0530 Subject: [PATCH] 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: Amit Shah Signed-off-by: Rusty Russell --- drivers/char/virtio_console.c | 57 ++++++++++++++++++++++++++++++++++ include/linux/virtio_console.h | 1 + 2 files changed, 58 insertions(+) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 5e3503a31312..99d182b132c4 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -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; diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h index bd0e2a596f93..1ebf007812a8 100644 --- a/include/linux/virtio_console.h +++ b/include/linux/virtio_console.h @@ -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)); -- 2.20.1