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Commit c066475e authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

USB: create a new thread for every USB device found during the probe sequence 



Might speed up some systems.  If nothing else, a bad driver should not
take the whole USB subsystem down with it.

Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 958e8741

drivers/usb/core/Kconfig

+15 −0
Original line number Diff line number Diff line
@@ -72,6 +72,21 @@ config USB_SUSPEND 


	  If you are unsure about this, say N here.



config USB_MULTITHREAD_PROBE

	bool "USB Multi-threaded probe (EXPERIMENTAL)"

	depends on USB && EXPERIMENTAL

	default n

	help

	  Say Y here if you want the USB core to spawn a new thread for

	  every USB device that is probed.  This can cause a small speedup

	  in boot times on systems with a lot of different USB devices.



	  This option should be safe to enable, but if any odd probing

	  problems are found, please disable it, or dynamically turn it

	  off in the /sys/module/usbcore/parameters/multithread_probe

	  file



	  When in doubt, say N.



config USB_OTG

	bool

drivers/usb/core/hub.c

+59 −22
Original line number Diff line number Diff line
@@ -87,6 +87,16 @@ static DECLARE_WAIT_QUEUE_HEAD(khubd_wait); 


static struct task_struct *khubd_task;



/* multithreaded probe logic */

static int multithread_probe =

#ifdef CONFIG_USB_MULTITHREAD_PROBE

	1;

#else

	0;

#endif

module_param(multithread_probe, bool, S_IRUGO);

MODULE_PARM_DESC(multithread_probe, "Run each USB device probe in a new thread");



/* cycle leds on hubs that aren't blinking for attention */

static int blinkenlights = 0;

module_param (blinkenlights, bool, S_IRUGO);
@@ -1238,29 +1248,17 @@ static inline void show_string(struct usb_device *udev, char *id, char *string) 
static int __usb_port_suspend(struct usb_device *, int port1);

#endif



/**

 * usb_new_device - perform initial device setup (usbcore-internal)

 * @udev: newly addressed device (in ADDRESS state)

 *

 * This is called with devices which have been enumerated, but not yet

 * configured.  The device descriptor is available, but not descriptors

 * for any device configuration.  The caller must have locked either

 * the parent hub (if udev is a normal device) or else the

 * usb_bus_list_lock (if udev is a root hub).  The parent's pointer to

 * udev has already been installed, but udev is not yet visible through

 * sysfs or other filesystem code.

 *

 * Returns 0 for success (device is configured and listed, with its

 * interfaces, in sysfs); else a negative errno value.

 *

 * This call is synchronous, and may not be used in an interrupt context.

 *

 * Only the hub driver or root-hub registrar should ever call this.

 */

int usb_new_device(struct usb_device *udev)

static int __usb_new_device(void *void_data)

{

	struct usb_device *udev = void_data;

	int err;



	/* Lock ourself into memory in order to keep a probe sequence

	 * sleeping in a new thread from allowing us to be unloaded.

	 */

	if (!try_module_get(THIS_MODULE))

		return -EINVAL;



	err = usb_get_configuration(udev);

	if (err < 0) {

		dev_err(&udev->dev, "can't read configurations, error %d\n",
@@ -1356,13 +1354,52 @@ int usb_new_device(struct usb_device *udev) 
		goto fail;

	}



	return 0;

exit:

	module_put(THIS_MODULE);

	return err;



fail:

	usb_set_device_state(udev, USB_STATE_NOTATTACHED);

	return err;

	goto exit;

}



/**

 * usb_new_device - perform initial device setup (usbcore-internal)

 * @udev: newly addressed device (in ADDRESS state)

 *

 * This is called with devices which have been enumerated, but not yet

 * configured.  The device descriptor is available, but not descriptors

 * for any device configuration.  The caller must have locked either

 * the parent hub (if udev is a normal device) or else the

 * usb_bus_list_lock (if udev is a root hub).  The parent's pointer to

 * udev has already been installed, but udev is not yet visible through

 * sysfs or other filesystem code.

 *

 * The return value for this function depends on if the

 * multithread_probe variable is set or not.  If it's set, it will

 * return a if the probe thread was successfully created or not.  If the

 * variable is not set, it will return if the device is configured

 * properly or not.  interfaces, in sysfs); else a negative errno value.

 *

 * This call is synchronous, and may not be used in an interrupt context.

 *

 * Only the hub driver or root-hub registrar should ever call this.

 */

int usb_new_device(struct usb_device *udev)

{

	struct task_struct *probe_task;

	int ret = 0;



	if (multithread_probe) {

		probe_task = kthread_run(__usb_new_device, udev,

					 "usb-probe-%s", udev->devnum);

		if (IS_ERR(probe_task))

			ret = PTR_ERR(probe_task);

	} else

		ret = __usb_new_device(udev);



	return ret;

}



static int hub_port_status(struct usb_hub *hub, int port1,

			       u16 *status, u16 *change)