diff options
| -rw-r--r-- | drivers/usb/core/hcd.c | 147 | ||||
| -rw-r--r-- | include/linux/usb/hcd.h | 17 |
2 files changed, 134 insertions, 30 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index dc1346fee76c..0ffe016f4036 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -696,15 +696,7 @@ error: /* any errors get returned through the urb completion */ spin_lock_irq(&hcd_root_hub_lock); usb_hcd_unlink_urb_from_ep(hcd, urb); - - /* This peculiar use of spinlocks echoes what real HC drivers do. - * Avoiding calls to local_irq_disable/enable makes the code - * RT-friendly. - */ - spin_unlock(&hcd_root_hub_lock); usb_hcd_giveback_urb(hcd, urb, status); - spin_lock(&hcd_root_hub_lock); - spin_unlock_irq(&hcd_root_hub_lock); return 0; } @@ -744,9 +736,7 @@ void usb_hcd_poll_rh_status(struct usb_hcd *hcd) memcpy(urb->transfer_buffer, buffer, length); usb_hcd_unlink_urb_from_ep(hcd, urb); - spin_unlock(&hcd_root_hub_lock); usb_hcd_giveback_urb(hcd, urb, 0); - spin_lock(&hcd_root_hub_lock); } else { length = 0; set_bit(HCD_FLAG_POLL_PENDING, &hcd->flags); @@ -836,10 +826,7 @@ static int usb_rh_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status) if (urb == hcd->status_urb) { hcd->status_urb = NULL; usb_hcd_unlink_urb_from_ep(hcd, urb); - - spin_unlock(&hcd_root_hub_lock); usb_hcd_giveback_urb(hcd, urb, status); - spin_lock(&hcd_root_hub_lock); } } done: @@ -1656,6 +1643,72 @@ int usb_hcd_unlink_urb (struct urb *urb, int status) /*-------------------------------------------------------------------------*/ +static void __usb_hcd_giveback_urb(struct urb *urb) +{ + struct usb_hcd *hcd = bus_to_hcd(urb->dev->bus); + int status = urb->unlinked; + unsigned long flags; + + urb->hcpriv = NULL; + if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) && + urb->actual_length < urb->transfer_buffer_length && + !status)) + status = -EREMOTEIO; + + unmap_urb_for_dma(hcd, urb); + usbmon_urb_complete(&hcd->self, urb, status); + usb_unanchor_urb(urb); + + /* pass ownership to the completion handler */ + urb->status = status; + + /* + * We disable local IRQs here avoid possible deadlock because + * drivers may call spin_lock() to hold lock which might be + * acquired in one hard interrupt handler. + * + * The local_irq_save()/local_irq_restore() around complete() + * will be removed if current USB drivers have been cleaned up + * and no one may trigger the above deadlock situation when + * running complete() in tasklet. + */ + local_irq_save(flags); + urb->complete(urb); + local_irq_restore(flags); + + atomic_dec(&urb->use_count); + if (unlikely(atomic_read(&urb->reject))) + wake_up(&usb_kill_urb_queue); + usb_put_urb(urb); +} + +static void usb_giveback_urb_bh(unsigned long param) +{ + struct giveback_urb_bh *bh = (struct giveback_urb_bh *)param; + struct list_head local_list; + + spin_lock_irq(&bh->lock); + bh->running = true; + restart: + list_replace_init(&bh->head, &local_list); + spin_unlock_irq(&bh->lock); + + while (!list_empty(&local_list)) { + struct urb *urb; + + urb = list_entry(local_list.next, struct urb, urb_list); + list_del_init(&urb->urb_list); + __usb_hcd_giveback_urb(urb); + } + + /* check if there are new URBs to giveback */ + spin_lock_irq(&bh->lock); + if (!list_empty(&bh->head)) + goto restart; + bh->running = false; + spin_unlock_irq(&bh->lock); +} + /** * usb_hcd_giveback_urb - return URB from HCD to device driver * @hcd: host controller returning the URB @@ -1675,25 +1728,37 @@ int usb_hcd_unlink_urb (struct urb *urb, int status) */ void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status) { - urb->hcpriv = NULL; - if (unlikely(urb->unlinked)) - status = urb->unlinked; - else if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) && - urb->actual_length < urb->transfer_buffer_length && - !status)) - status = -EREMOTEIO; + struct giveback_urb_bh *bh; + bool running, high_prio_bh; - unmap_urb_for_dma(hcd, urb); - usbmon_urb_complete(&hcd->self, urb, status); - usb_unanchor_urb(urb); + /* pass status to tasklet via unlinked */ + if (likely(!urb->unlinked)) + urb->unlinked = status; - /* pass ownership to the completion handler */ - urb->status = status; - urb->complete (urb); - atomic_dec (&urb->use_count); - if (unlikely(atomic_read(&urb->reject))) - wake_up (&usb_kill_urb_queue); - usb_put_urb (urb); + if (!hcd_giveback_urb_in_bh(hcd) && !is_root_hub(urb->dev)) { + __usb_hcd_giveback_urb(urb); + return; + } + + if (usb_pipeisoc(urb->pipe) || usb_pipeint(urb->pipe)) { + bh = &hcd->high_prio_bh; + high_prio_bh = true; + } else { + bh = &hcd->low_prio_bh; + high_prio_bh = false; + } + + spin_lock(&bh->lock); + list_add_tail(&urb->urb_list, &bh->head); + running = bh->running; + spin_unlock(&bh->lock); + + if (running) + ; + else if (high_prio_bh) + tasklet_hi_schedule(&bh->bh); + else + tasklet_schedule(&bh->bh); } EXPORT_SYMBOL_GPL(usb_hcd_giveback_urb); @@ -2322,6 +2387,14 @@ EXPORT_SYMBOL_GPL (usb_hc_died); /*-------------------------------------------------------------------------*/ +static void init_giveback_urb_bh(struct giveback_urb_bh *bh) +{ + + spin_lock_init(&bh->lock); + INIT_LIST_HEAD(&bh->head); + tasklet_init(&bh->bh, usb_giveback_urb_bh, (unsigned long)bh); +} + /** * usb_create_shared_hcd - create and initialize an HCD structure * @driver: HC driver that will use this hcd @@ -2590,6 +2663,10 @@ int usb_add_hcd(struct usb_hcd *hcd, && device_can_wakeup(&hcd->self.root_hub->dev)) dev_dbg(hcd->self.controller, "supports USB remote wakeup\n"); + /* initialize tasklets */ + init_giveback_urb_bh(&hcd->high_prio_bh); + init_giveback_urb_bh(&hcd->low_prio_bh); + /* enable irqs just before we start the controller, * if the BIOS provides legacy PCI irqs. */ @@ -2698,6 +2775,16 @@ void usb_remove_hcd(struct usb_hcd *hcd) usb_disconnect(&rhdev); /* Sets rhdev to NULL */ mutex_unlock(&usb_bus_list_lock); + /* + * tasklet_kill() isn't needed here because: + * - driver's disconnect() called from usb_disconnect() should + * make sure its URBs are completed during the disconnect() + * callback + * + * - it is too late to run complete() here since driver may have + * been removed already now + */ + /* Prevent any more root-hub status calls from the timer. * The HCD might still restart the timer (if a port status change * interrupt occurs), but usb_hcd_poll_rh_status() won't invoke diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h index 1e88377e22f4..a9c7d44bd2ed 100644 --- a/include/linux/usb/hcd.h +++ b/include/linux/usb/hcd.h @@ -22,6 +22,7 @@ #ifdef __KERNEL__ #include <linux/rwsem.h> +#include <linux/interrupt.h> #define MAX_TOPO_LEVEL 6 @@ -67,6 +68,13 @@ /*-------------------------------------------------------------------------*/ +struct giveback_urb_bh { + bool running; + spinlock_t lock; + struct list_head head; + struct tasklet_struct bh; +}; + struct usb_hcd { /* @@ -139,6 +147,9 @@ struct usb_hcd { resource_size_t rsrc_len; /* memory/io resource length */ unsigned power_budget; /* in mA, 0 = no limit */ + struct giveback_urb_bh high_prio_bh; + struct giveback_urb_bh low_prio_bh; + /* bandwidth_mutex should be taken before adding or removing * any new bus bandwidth constraints: * 1. Before adding a configuration for a new device. @@ -221,6 +232,7 @@ struct hc_driver { #define HCD_USB25 0x0030 /* Wireless USB 1.0 (USB 2.5)*/ #define HCD_USB3 0x0040 /* USB 3.0 */ #define HCD_MASK 0x0070 +#define HCD_BH 0x0100 /* URB complete in BH context */ /* called to init HCD and root hub */ int (*reset) (struct usb_hcd *hcd); @@ -361,6 +373,11 @@ struct hc_driver { int (*find_raw_port_number)(struct usb_hcd *, int); }; +static inline int hcd_giveback_urb_in_bh(struct usb_hcd *hcd) +{ + return hcd->driver->flags & HCD_BH; +} + extern int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb); extern int usb_hcd_check_unlink_urb(struct usb_hcd *hcd, struct urb *urb, int status); |