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: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Greg Kroah-Hartman
parent
958e8741bf
commit
c066475e1f
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@ -72,6 +72,21 @@ config USB_SUSPEND
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If you are unsure about this, say N here.
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config USB_MULTITHREAD_PROBE
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bool "USB Multi-threaded probe (EXPERIMENTAL)"
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depends on USB && EXPERIMENTAL
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default n
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help
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Say Y here if you want the USB core to spawn a new thread for
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every USB device that is probed. This can cause a small speedup
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in boot times on systems with a lot of different USB devices.
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This option should be safe to enable, but if any odd probing
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problems are found, please disable it, or dynamically turn it
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off in the /sys/module/usbcore/parameters/multithread_probe
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file
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When in doubt, say N.
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config USB_OTG
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bool
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@ -87,6 +87,16 @@ static DECLARE_WAIT_QUEUE_HEAD(khubd_wait);
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static struct task_struct *khubd_task;
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/* multithreaded probe logic */
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static int multithread_probe =
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#ifdef CONFIG_USB_MULTITHREAD_PROBE
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1;
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#else
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0;
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#endif
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module_param(multithread_probe, bool, S_IRUGO);
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MODULE_PARM_DESC(multithread_probe, "Run each USB device probe in a new thread");
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/* cycle leds on hubs that aren't blinking for attention */
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static int blinkenlights = 0;
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module_param (blinkenlights, bool, S_IRUGO);
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@ -1238,29 +1248,17 @@ static inline void show_string(struct usb_device *udev, char *id, char *string)
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static int __usb_port_suspend(struct usb_device *, int port1);
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#endif
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/**
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* usb_new_device - perform initial device setup (usbcore-internal)
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* @udev: newly addressed device (in ADDRESS state)
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*
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* This is called with devices which have been enumerated, but not yet
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* configured. The device descriptor is available, but not descriptors
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* for any device configuration. The caller must have locked either
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* the parent hub (if udev is a normal device) or else the
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* usb_bus_list_lock (if udev is a root hub). The parent's pointer to
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* udev has already been installed, but udev is not yet visible through
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* sysfs or other filesystem code.
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*
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* Returns 0 for success (device is configured and listed, with its
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* interfaces, in sysfs); else a negative errno value.
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*
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* This call is synchronous, and may not be used in an interrupt context.
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*
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* Only the hub driver or root-hub registrar should ever call this.
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*/
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int usb_new_device(struct usb_device *udev)
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static int __usb_new_device(void *void_data)
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{
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struct usb_device *udev = void_data;
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int err;
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/* Lock ourself into memory in order to keep a probe sequence
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* sleeping in a new thread from allowing us to be unloaded.
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*/
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if (!try_module_get(THIS_MODULE))
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return -EINVAL;
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err = usb_get_configuration(udev);
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if (err < 0) {
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dev_err(&udev->dev, "can't read configurations, error %d\n",
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@ -1356,13 +1354,52 @@ int usb_new_device(struct usb_device *udev)
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goto fail;
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}
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return 0;
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exit:
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module_put(THIS_MODULE);
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return err;
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fail:
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usb_set_device_state(udev, USB_STATE_NOTATTACHED);
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return err;
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goto exit;
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}
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/**
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* usb_new_device - perform initial device setup (usbcore-internal)
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* @udev: newly addressed device (in ADDRESS state)
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*
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* This is called with devices which have been enumerated, but not yet
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* configured. The device descriptor is available, but not descriptors
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* for any device configuration. The caller must have locked either
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* the parent hub (if udev is a normal device) or else the
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* usb_bus_list_lock (if udev is a root hub). The parent's pointer to
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* udev has already been installed, but udev is not yet visible through
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* sysfs or other filesystem code.
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*
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* The return value for this function depends on if the
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* multithread_probe variable is set or not. If it's set, it will
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* return a if the probe thread was successfully created or not. If the
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* variable is not set, it will return if the device is configured
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* properly or not. interfaces, in sysfs); else a negative errno value.
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*
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* This call is synchronous, and may not be used in an interrupt context.
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*
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* Only the hub driver or root-hub registrar should ever call this.
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*/
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int usb_new_device(struct usb_device *udev)
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{
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struct task_struct *probe_task;
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int ret = 0;
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if (multithread_probe) {
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probe_task = kthread_run(__usb_new_device, udev,
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"usb-probe-%s", udev->devnum);
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if (IS_ERR(probe_task))
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ret = PTR_ERR(probe_task);
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} else
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ret = __usb_new_device(udev);
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return ret;
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}
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static int hub_port_status(struct usb_hub *hub, int port1,
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u16 *status, u16 *change)
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