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Commit 3ede760f authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
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USB: total removal of multithreaded probing in usb 



The whole approach is simply wrong.  Forking a thread means that
  - errors are ignored
  - locking is ignored

Doing this correctly would require major surgery for questionable benefit.

Signed-off-by: default avatarOliver Neukum <oneukum@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 66e56ce7

drivers/usb/core/hub.c

+21 −43
Original line number Diff line number Diff line
@@ -87,9 +87,6 @@ static DECLARE_WAIT_QUEUE_HEAD(khubd_wait); 


static struct task_struct *khubd_task;



/* multithreaded probe logic */

static int multithread_probe = 0;



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

static int blinkenlights = 0;

module_param (blinkenlights, bool, S_IRUGO);
@@ -1256,9 +1253,28 @@ static inline void show_string(struct usb_device *udev, char *id, char *string) 
static int __usb_port_suspend(struct usb_device *, int port1);

#endif



static int __usb_new_device(void *void_data)

/**

 * 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.

 *

 * It will return if the device is configured properly or not.  Zero if

 * the interface was registered with the driver core; 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 usb_device *udev = void_data;

	int err;



	/* Lock ourself into memory in order to keep a probe sequence
@@ -1375,44 +1391,6 @@ fail: 
	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)

{