diff options
| -rw-r--r-- | drivers/usb/core/Kconfig | 15 | ||||
| -rw-r--r-- | drivers/usb/core/hub.c | 81 |
2 files changed, 74 insertions, 22 deletions
diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig index 6e3b5358a76..f8324d8d06a 100644 --- a/drivers/usb/core/Kconfig +++ b/drivers/usb/core/Kconfig @@ -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 diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index c961a32f317..f6e69218058 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -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) |