drivers/usb/usbip/stub_main.c

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

File Facts

System
Linux kernel
Corpus path
drivers/usb/usbip/stub_main.c
Extension
.c
Size
9018 bytes
Lines
429
Domain
Driver Families
Bucket
drivers/usb
Inferred role
Driver Families: operation-table or driver-model contract
Status
pattern 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

static ssize_t match_busid_show(struct device_driver *drv, char *buf)
{
	int i;
	char *out = buf;

	spin_lock(&busid_table_lock);
	for (i = 0; i < MAX_BUSID; i++) {
		spin_lock(&busid_table[i].busid_lock);
		if (busid_table[i].name[0])
			out += sprintf(out, "%s ", busid_table[i].name);
		spin_unlock(&busid_table[i].busid_lock);
	}
	spin_unlock(&busid_table_lock);
	out += sprintf(out, "\n");

	return out - buf;
}

static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
				 size_t count)
{
	char busid[BUSID_SIZE];

	if (count < 5)
		return -EINVAL;

	/* busid needs to include \0 termination */
	if (strscpy(busid, buf + 4, BUSID_SIZE) < 0)
		return -EINVAL;

	if (!strncmp(buf, "add ", 4)) {
		if (add_match_busid(busid) < 0)
			return -ENOMEM;

		pr_debug("add busid %s\n", busid);
		return count;
	}

	if (!strncmp(buf, "del ", 4)) {
		if (del_match_busid(busid) < 0)
			return -ENODEV;

		pr_debug("del busid %s\n", busid);
		return count;
	}

	return -EINVAL;
}
static DRIVER_ATTR_RW(match_busid);

static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
{
	int ret = 0;

	/* device_attach() callers should hold parent lock for USB */
	if (busid_priv->udev->dev.parent)
		device_lock(busid_priv->udev->dev.parent);
	ret = device_attach(&busid_priv->udev->dev);
	if (busid_priv->udev->dev.parent)
		device_unlock(busid_priv->udev->dev.parent);
	if (ret < 0)
		dev_err(&busid_priv->udev->dev, "rebind failed\n");
	return ret;
}

static void stub_device_rebind(void)
{
#if IS_MODULE(CONFIG_USBIP_HOST)
	struct bus_id_priv *busid_priv;
	int i;

	/* update status to STUB_BUSID_OTHER so probe ignores the device */
	spin_lock(&busid_table_lock);
	for (i = 0; i < MAX_BUSID; i++) {
		if (busid_table[i].name[0] &&
		    busid_table[i].shutdown_busid) {
			busid_priv = &(busid_table[i]);
			busid_priv->status = STUB_BUSID_OTHER;
		}
	}
	spin_unlock(&busid_table_lock);

	/* now run rebind - no need to hold locks. driver files are removed */
	for (i = 0; i < MAX_BUSID; i++) {
		if (busid_table[i].name[0] &&
		    busid_table[i].shutdown_busid) {
			busid_priv = &(busid_table[i]);
			do_rebind(busid_table[i].name, busid_priv);
		}
	}

Annotation

Implementation Notes