diff options
| -rw-r--r-- | drivers/usb/core/hub.c | 143 | ||||
| -rw-r--r-- | drivers/usb/core/hub.h | 2 |
2 files changed, 61 insertions, 84 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index b75749c3029a..ed7db5104bcd 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -22,9 +22,8 @@ #include <linux/usb/hcd.h> #include <linux/usb/otg.h> #include <linux/usb/quirks.h> -#include <linux/kthread.h> +#include <linux/workqueue.h> #include <linux/mutex.h> -#include <linux/freezer.h> #include <linux/random.h> #include <linux/pm_qos.h> @@ -42,14 +41,9 @@ * change to USB_STATE_NOTATTACHED even when the semaphore isn't held. */ static DEFINE_SPINLOCK(device_state_lock); -/* khubd's worklist and its lock */ -static DEFINE_SPINLOCK(hub_event_lock); -static LIST_HEAD(hub_event_list); /* List of hubs needing servicing */ - -/* Wakes up khubd */ -static DECLARE_WAIT_QUEUE_HEAD(khubd_wait); - -static struct task_struct *khubd_task; +/* workqueue to process hub events */ +static struct workqueue_struct *hub_wq; +static void hub_event(struct work_struct *work); /* synchronize hub-port add/remove and peering operations */ DEFINE_MUTEX(usb_port_peer_mutex); @@ -105,6 +99,7 @@ EXPORT_SYMBOL_GPL(ehci_cf_port_reset_rwsem); #define HUB_DEBOUNCE_STEP 25 #define HUB_DEBOUNCE_STABLE 100 +static void hub_release(struct kref *kref); static int usb_reset_and_verify_device(struct usb_device *udev); static inline char *portspeed(struct usb_hub *hub, int portstatus) @@ -576,20 +571,31 @@ static int hub_port_status(struct usb_hub *hub, int port1, return ret; } -static void kick_khubd(struct usb_hub *hub) +static void kick_hub_wq(struct usb_hub *hub) { - unsigned long flags; + struct usb_interface *intf; - spin_lock_irqsave(&hub_event_lock, flags); - if (!hub->disconnected && list_empty(&hub->event_list)) { - list_add_tail(&hub->event_list, &hub_event_list); + if (hub->disconnected || work_pending(&hub->events)) + return; - /* Suppress autosuspend until khubd runs */ - usb_autopm_get_interface_no_resume( - to_usb_interface(hub->intfdev)); - wake_up(&khubd_wait); - } - spin_unlock_irqrestore(&hub_event_lock, flags); + /* + * Suppress autosuspend until the event is proceed. + * + * Be careful and make sure that the symmetric operation is + * always called. We are here only when there is no pending + * work for this hub. Therefore put the interface either when + * the new work is called or when it is canceled. + */ + intf = to_usb_interface(hub->intfdev); + usb_autopm_get_interface_no_resume(intf); + kref_get(&hub->kref); + + if (queue_work(hub_wq, &hub->events)) + return; + + /* the work has already been scheduled */ + usb_autopm_put_interface_async(intf); + kref_put(&hub->kref, hub_release); } void usb_kick_khubd(struct usb_device *hdev) @@ -597,7 +603,7 @@ void usb_kick_khubd(struct usb_device *hdev) struct usb_hub *hub = usb_hub_to_struct_hub(hdev); if (hub) - kick_khubd(hub); + kick_hub_wq(hub); } /* @@ -619,7 +625,7 @@ void usb_wakeup_notification(struct usb_device *hdev, hub = usb_hub_to_struct_hub(hdev); if (hub) { set_bit(portnum, hub->wakeup_bits); - kick_khubd(hub); + kick_hub_wq(hub); } } EXPORT_SYMBOL_GPL(usb_wakeup_notification); @@ -659,7 +665,7 @@ static void hub_irq(struct urb *urb) hub->nerrors = 0; /* Something happened, let khubd figure it out */ - kick_khubd(hub); + kick_hub_wq(hub); resubmit: if (hub->quiescing) @@ -973,7 +979,7 @@ static void hub_port_logical_disconnect(struct usb_hub *hub, int port1) */ set_bit(port1, hub->change_bits); - kick_khubd(hub); + kick_hub_wq(hub); } /** @@ -1241,7 +1247,7 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type) &hub->leds, LED_CYCLE_PERIOD); /* Scan all ports that need attention */ - kick_khubd(hub); + kick_hub_wq(hub); /* Allow autosuspend if it was suppressed */ if (type <= HUB_INIT3) @@ -1648,14 +1654,11 @@ static void hub_disconnect(struct usb_interface *intf) struct usb_device *hdev = interface_to_usbdev(intf); int port1; - /* Take the hub off the event list and don't let it be added again */ - spin_lock_irq(&hub_event_lock); - if (!list_empty(&hub->event_list)) { - list_del_init(&hub->event_list); - usb_autopm_put_interface_no_suspend(intf); - } + /* + * Stop adding new hub events. We do not want to block here and thus + * will not try to remove any pending work item. + */ hub->disconnected = 1; - spin_unlock_irq(&hub_event_lock); /* Disconnect all children and quiesce the hub */ hub->error = 0; @@ -1795,11 +1798,11 @@ descriptor_error: } kref_init(&hub->kref); - INIT_LIST_HEAD(&hub->event_list); hub->intfdev = &intf->dev; hub->hdev = hdev; INIT_DELAYED_WORK(&hub->leds, led_work); INIT_DELAYED_WORK(&hub->init_work, NULL); + INIT_WORK(&hub->events, hub_event); usb_get_intf(intf); usb_get_dev(hdev); @@ -4996,9 +4999,8 @@ static void port_event(struct usb_hub *hub, int port1) hub_port_connect_change(hub, port1, portstatus, portchange); } -static void hub_event(void) +static void hub_event(struct work_struct *work) { - struct list_head *tmp; struct usb_device *hdev; struct usb_interface *intf; struct usb_hub *hub; @@ -5007,23 +5009,11 @@ static void hub_event(void) u16 hubchange; int i, ret; - /* Grab the first entry at the beginning of the list */ - spin_lock_irq(&hub_event_lock); - if (list_empty(&hub_event_list)) { - spin_unlock_irq(&hub_event_lock); - return; - } - - tmp = hub_event_list.next; - list_del_init(tmp); - - hub = list_entry(tmp, struct usb_hub, event_list); - kref_get(&hub->kref); - spin_unlock_irq(&hub_event_lock); - + hub = container_of(work, struct usb_hub, events); hdev = hub->hdev; hub_dev = hub->intfdev; intf = to_usb_interface(hub_dev); + dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n", hdev->state, hdev->maxchild, /* NOTE: expects max 15 ports... */ @@ -5034,20 +5024,20 @@ static void hub_event(void) * disconnected while waiting for the lock to succeed. */ usb_lock_device(hdev); if (unlikely(hub->disconnected)) - goto out_disconnected; + goto out_hdev_lock; /* If the hub has died, clean up after it */ if (hdev->state == USB_STATE_NOTATTACHED) { hub->error = -ENODEV; hub_quiesce(hub, HUB_DISCONNECT); - goto out; + goto out_hdev_lock; } /* Autoresume */ ret = usb_autopm_get_interface(intf); if (ret) { dev_dbg(hub_dev, "Can't autoresume: %d\n", ret); - goto out; + goto out_hdev_lock; } /* If this is an inactive hub, do nothing */ @@ -5124,34 +5114,12 @@ static void hub_event(void) out_autopm: /* Balance the usb_autopm_get_interface() above */ usb_autopm_put_interface_no_suspend(intf); -out: - /* Balance the usb_autopm_get_interface_no_resume() in - * kick_khubd() and allow autosuspend. - */ - usb_autopm_put_interface(intf); -out_disconnected: +out_hdev_lock: usb_unlock_device(hdev); - kref_put(&hub->kref, hub_release); -} -static int hub_thread(void *__unused) -{ - /* khubd needs to be freezable to avoid interfering with USB-PERSIST - * port handover. Otherwise it might see that a full-speed device - * was gone before the EHCI controller had handed its port over to - * the companion full-speed controller. - */ - set_freezable(); - - do { - hub_event(); - wait_event_freezable(khubd_wait, - !list_empty(&hub_event_list) || - kthread_should_stop()); - } while (!kthread_should_stop() || !list_empty(&hub_event_list)); - - pr_debug("%s: khubd exiting\n", usbcore_name); - return 0; + /* Balance the stuff in kick_hub_wq() and allow autosuspend */ + usb_autopm_put_interface(intf); + kref_put(&hub->kref, hub_release); } static const struct usb_device_id hub_id_table[] = { @@ -5191,20 +5159,29 @@ int usb_hub_init(void) return -1; } - khubd_task = kthread_run(hub_thread, NULL, "khubd"); - if (!IS_ERR(khubd_task)) + /* + * The workqueue needs to be freezable to avoid interfering with + * USB-PERSIST port handover. Otherwise it might see that a full-speed + * device was gone before the EHCI controller had handed its port + * over to the companion full-speed controller. + * + * Also we use ordered workqueue because the code is not ready + * for parallel execution of hub events, see choose_devnum(). + */ + hub_wq = alloc_ordered_workqueue("usb_hub_wq", WQ_FREEZABLE); + if (hub_wq) return 0; /* Fall through if kernel_thread failed */ usb_deregister(&hub_driver); - printk(KERN_ERR "%s: can't start khubd\n", usbcore_name); + pr_err("%s: can't allocate workqueue for usb hub\n", usbcore_name); return -1; } void usb_hub_cleanup(void) { - kthread_stop(khubd_task); + destroy_workqueue(hub_wq); /* * Hub resources are freed for us by usb_deregister. It calls diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index c77d8778af4b..688817fb3246 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -41,7 +41,6 @@ struct usb_hub { int error; /* last reported error */ int nerrors; /* track consecutive errors */ - struct list_head event_list; /* hubs w/data or errs ready */ unsigned long event_bits[1]; /* status change bitmask */ unsigned long change_bits[1]; /* ports with logical connect status change */ @@ -77,6 +76,7 @@ struct usb_hub { u8 indicator[USB_MAXCHILDREN]; struct delayed_work leds; struct delayed_work init_work; + struct work_struct events; struct usb_port **ports; }; |
