From 3ede760f0e46317c6716ead8facff88f6a924a49 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Thu, 11 Jan 2007 14:35:50 +0100 Subject: [PATCH] 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: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 64 ++++++++++++++---------------------------- 1 file changed, 21 insertions(+), 43 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 1988224b362b..590ec82d0515 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -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 @@ static int __usb_new_device(void *void_data) 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) { -- GitLab