drivers/usb/usbip/stub_dev.c

Source file repositories/reference/linux-study-clean/drivers/usb/usbip/stub_dev.c

File Facts

System
Linux kernel
Corpus path
drivers/usb/usbip/stub_dev.c
Extension
.c
Size
12428 bytes
Lines
535
Domain
Driver Families
Bucket
drivers/usb
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (sdev->ud.status != SDEV_ST_AVAILABLE) {
			dev_err(dev, "not ready\n");
			goto err;
		}

		socket = sockfd_lookup(sockfd, &err);
		if (!socket) {
			dev_err(dev, "failed to lookup sock");
			goto err;
		}

		if (socket->type != SOCK_STREAM) {
			dev_err(dev, "Expecting SOCK_STREAM - found %d",
				socket->type);
			goto sock_err;
		}

		/* unlock and create threads and get tasks */
		spin_unlock_irq(&sdev->ud.lock);
		tcp_rx = kthread_create(stub_rx_loop, &sdev->ud, "stub_rx");
		if (IS_ERR(tcp_rx)) {
			sockfd_put(socket);
			goto unlock_mutex;
		}
		tcp_tx = kthread_create(stub_tx_loop, &sdev->ud, "stub_tx");
		if (IS_ERR(tcp_tx)) {
			kthread_stop(tcp_rx);
			sockfd_put(socket);
			goto unlock_mutex;
		}

		/* get task structs now */
		get_task_struct(tcp_rx);
		get_task_struct(tcp_tx);

		/* lock and update sdev->ud state */
		spin_lock_irq(&sdev->ud.lock);
		sdev->ud.tcp_socket = socket;
		sdev->ud.sockfd = sockfd;
		sdev->ud.tcp_rx = tcp_rx;
		sdev->ud.tcp_tx = tcp_tx;
		sdev->ud.status = SDEV_ST_USED;
		spin_unlock_irq(&sdev->ud.lock);

		wake_up_process(sdev->ud.tcp_rx);
		wake_up_process(sdev->ud.tcp_tx);

		mutex_unlock(&sdev->ud.sysfs_lock);

	} else {
		dev_info(dev, "stub down\n");

		mutex_lock(&sdev->ud.sysfs_lock);

		spin_lock_irq(&sdev->ud.lock);
		if (sdev->ud.status != SDEV_ST_USED)
			goto err;

		spin_unlock_irq(&sdev->ud.lock);

		usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
		mutex_unlock(&sdev->ud.sysfs_lock);
	}

	return count;

sock_err:
	sockfd_put(socket);
err:
	spin_unlock_irq(&sdev->ud.lock);
unlock_mutex:
	mutex_unlock(&sdev->ud.sysfs_lock);
	return -EINVAL;
}
static DEVICE_ATTR_WO(usbip_sockfd);

static struct attribute *usbip_attrs[] = {
	&dev_attr_usbip_status.attr,
	&dev_attr_usbip_sockfd.attr,
	&dev_attr_usbip_debug.attr,
	NULL,
};
ATTRIBUTE_GROUPS(usbip);

static void stub_shutdown_connection(struct usbip_device *ud)
{
	struct stub_device *sdev = container_of(ud, struct stub_device, ud);

	/*
	 * When removing an exported device, kernel panic sometimes occurred

Annotation

Implementation Notes