diff options
Diffstat (limited to 'drivers/usb/core/urb.c')
| -rw-r--r-- | drivers/usb/core/urb.c | 510 |
1 files changed, 436 insertions, 74 deletions
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c index 9d7e63292c0..991386ceb4e 100644 --- a/drivers/usb/core/urb.c +++ b/drivers/usb/core/urb.c @@ -2,14 +2,15 @@ #include <linux/string.h> #include <linux/bitops.h> #include <linux/slab.h> -#include <linux/init.h> #include <linux/log2.h> #include <linux/usb.h> #include <linux/wait.h> -#include "hcd.h" +#include <linux/usb/hcd.h> +#include <linux/scatterlist.h> #define to_urb(d) container_of(d, struct urb, kref) + static void urb_destroy(struct kref *kref) { struct urb *urb = to_urb(kref); @@ -51,14 +52,14 @@ EXPORT_SYMBOL_GPL(usb_init_urb); * valid options for this. * * Creates an urb for the USB driver to use, initializes a few internal - * structures, incrementes the usage counter, and returns a pointer to it. - * - * If no memory is available, NULL is returned. + * structures, increments the usage counter, and returns a pointer to it. * * If the driver want to use this urb for interrupt, control, or bulk * endpoints, pass '0' as the number of iso packets. * * The driver must call usb_free_urb() when it is finished with the urb. + * + * Return: A pointer to the new urb, or %NULL if no memory is available. */ struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags) { @@ -68,7 +69,7 @@ struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags) iso_packets * sizeof(struct usb_iso_packet_descriptor), mem_flags); if (!urb) { - err("alloc_urb: kmalloc failed"); + printk(KERN_ERR "alloc_urb: kmalloc failed\n"); return NULL; } usb_init_urb(urb); @@ -83,8 +84,8 @@ EXPORT_SYMBOL_GPL(usb_alloc_urb); * Must be called when a user of a urb is finished with it. When the last user * of the urb calls this function, the memory of the urb is freed. * - * Note: The transfer buffer associated with the urb is not freed, that must be - * done elsewhere. + * Note: The transfer buffer associated with the urb is not freed unless the + * URB_FREE_BUFFER transfer flag is set. */ void usb_free_urb(struct urb *urb) { @@ -101,7 +102,7 @@ EXPORT_SYMBOL_GPL(usb_free_urb); * host controller driver. This allows proper reference counting to happen * for urbs. * - * A pointer to the urb with the incremented reference counter is returned. + * Return: A pointer to the urb with the incremented reference counter. */ struct urb *usb_get_urb(struct urb *urb) { @@ -127,10 +128,31 @@ void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor) usb_get_urb(urb); list_add_tail(&urb->anchor_list, &anchor->urb_list); urb->anchor = anchor; + + if (unlikely(anchor->poisoned)) { + atomic_inc(&urb->reject); + } + spin_unlock_irqrestore(&anchor->lock, flags); } EXPORT_SYMBOL_GPL(usb_anchor_urb); +static int usb_anchor_check_wakeup(struct usb_anchor *anchor) +{ + return atomic_read(&anchor->suspend_wakeups) == 0 && + list_empty(&anchor->urb_list); +} + +/* Callers must hold anchor->lock */ +static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor) +{ + urb->anchor = NULL; + list_del(&urb->anchor_list); + usb_put_urb(urb); + if (usb_anchor_check_wakeup(anchor)) + wake_up(&anchor->wait); +} + /** * usb_unanchor_urb - unanchors an URB * @urb: pointer to the urb to anchor @@ -150,17 +172,14 @@ void usb_unanchor_urb(struct urb *urb) return; spin_lock_irqsave(&anchor->lock, flags); - if (unlikely(anchor != urb->anchor)) { - /* we've lost the race to another thread */ - spin_unlock_irqrestore(&anchor->lock, flags); - return; - } - urb->anchor = NULL; - list_del(&urb->anchor_list); + /* + * At this point, we could be competing with another thread which + * has the same intention. To protect the urb from being unanchored + * twice, only the winner of the race gets the job. + */ + if (likely(anchor == urb->anchor)) + __usb_unanchor_urb(urb, anchor); spin_unlock_irqrestore(&anchor->lock, flags); - usb_put_urb(urb); - if (list_empty(&anchor->urb_list)) - wake_up(&anchor->wait); } EXPORT_SYMBOL_GPL(usb_unanchor_urb); @@ -186,13 +205,12 @@ EXPORT_SYMBOL_GPL(usb_unanchor_urb); * the particular kind of transfer, although they will not initialize * any transfer flags. * - * Successful submissions return 0; otherwise this routine returns a - * negative error number. If the submission is successful, the complete() - * callback from the URB will be called exactly once, when the USB core and - * Host Controller Driver (HCD) are finished with the URB. When the completion - * function is called, control of the URB is returned to the device - * driver which issued the request. The completion handler may then - * immediately free or reuse that URB. + * If the submission is successful, the complete() callback from the URB + * will be called exactly once, when the USB core and Host Controller Driver + * (HCD) are finished with the URB. When the completion function is called, + * control of the URB is returned to the device driver which issued the + * request. The completion handler may then immediately free or reuse that + * URB. * * With few exceptions, USB device drivers should never access URB fields * provided by usbcore or the HCD until its complete() is called. @@ -201,9 +219,25 @@ EXPORT_SYMBOL_GPL(usb_unanchor_urb); * urb->interval is modified to reflect the actual transfer period used * (normally some power of two units). And for isochronous urbs, * urb->start_frame is modified to reflect when the URB's transfers were - * scheduled to start. Not all isochronous transfer scheduling policies - * will work, but most host controller drivers should easily handle ISO - * queues going from now until 10-200 msec into the future. + * scheduled to start. + * + * Not all isochronous transfer scheduling policies will work, but most + * host controller drivers should easily handle ISO queues going from now + * until 10-200 msec into the future. Drivers should try to keep at + * least one or two msec of data in the queue; many controllers require + * that new transfers start at least 1 msec in the future when they are + * added. If the driver is unable to keep up and the queue empties out, + * the behavior for new submissions is governed by the URB_ISO_ASAP flag. + * If the flag is set, or if the queue is idle, then the URB is always + * assigned to the first available (and not yet expired) slot in the + * endpoint's schedule. If the flag is not set and the queue is active + * then the URB is always assigned to the next slot in the schedule + * following the end of the endpoint's previous URB, even if that slot is + * in the past. When a packet is assigned in this way to a slot that has + * already expired, the packet is not transmitted and the corresponding + * usb_iso_packet_descriptor's status field will return -EXDEV. If this + * would happen to all the packets in the URB, submission fails with a + * -EXDEV error code. * * For control endpoints, the synchronous usb_control_msg() call is * often used (in non-interrupt context) instead of this call. @@ -211,6 +245,9 @@ EXPORT_SYMBOL_GPL(usb_unanchor_urb); * that are standardized in the USB 2.0 specification. For bulk * endpoints, a synchronous usb_bulk_msg() call is available. * + * Return: + * 0 on successful submissions. A negative error number otherwise. + * * Request Queuing: * * URBs may be submitted to endpoints before previous ones complete, to @@ -235,9 +272,15 @@ EXPORT_SYMBOL_GPL(usb_unanchor_urb); * If the USB subsystem can't allocate sufficient bandwidth to perform * the periodic request, submitting such a periodic request should fail. * + * For devices under xHCI, the bandwidth is reserved at configuration time, or + * when the alt setting is selected. If there is not enough bus bandwidth, the + * configuration/alt setting request will fail. Therefore, submissions to + * periodic endpoints on devices under xHCI should never fail due to bandwidth + * constraints. + * * Device drivers must explicitly request that repetition, by ensuring that * some URB is always on the endpoint's queue (except possibly for short - * periods during completion callacks). When there is no longer an urb + * periods during completion callbacks). When there is no longer an urb * queued, the endpoint's bandwidth reservation is canceled. This means * drivers can use their completion handlers to ensure they keep bandwidth * they need, by reinitializing and resubmitting the just-completed urb @@ -281,23 +324,31 @@ EXPORT_SYMBOL_GPL(usb_unanchor_urb); */ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) { + static int pipetypes[4] = { + PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT + }; int xfertype, max; struct usb_device *dev; struct usb_host_endpoint *ep; int is_out; + unsigned int allowed; - if (!urb || urb->hcpriv || !urb->complete) + if (!urb || !urb->complete) return -EINVAL; + if (urb->hcpriv) { + WARN_ONCE(1, "URB %p submitted while active\n", urb); + return -EBUSY; + } + dev = urb->dev; - if ((!dev) || (dev->state < USB_STATE_DEFAULT)) + if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED)) return -ENODEV; /* For now, get the endpoint from the pipe. Eventually drivers * will be required to set urb->ep directly and we will eliminate * urb->pipe. */ - ep = (usb_pipein(urb->pipe) ? dev->ep_in : dev->ep_out) - [usb_pipeendpoint(urb->pipe)]; + ep = usb_pipe_endpoint(dev, urb->pipe); if (!ep) return -ENOENT; @@ -321,20 +372,23 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) is_out = usb_endpoint_dir_out(&ep->desc); } - /* Cache the direction for later use */ - urb->transfer_flags = (urb->transfer_flags & ~URB_DIR_MASK) | - (is_out ? URB_DIR_OUT : URB_DIR_IN); + /* Clear the internal flags and cache the direction for later use */ + urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE | + URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL | + URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL | + URB_DMA_SG_COMBINED); + urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN); if (xfertype != USB_ENDPOINT_XFER_CONTROL && dev->state < USB_STATE_CONFIGURED) return -ENODEV; - max = le16_to_cpu(ep->desc.wMaxPacketSize); + max = usb_endpoint_maxp(&ep->desc); if (max <= 0) { dev_dbg(&dev->dev, "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n", usb_endpoint_num(&ep->desc), is_out ? "out" : "in", - __FUNCTION__, max); + __func__, max); return -EMSGSIZE; } @@ -345,6 +399,16 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) if (xfertype == USB_ENDPOINT_XFER_ISOC) { int n, len; + /* SuperSpeed isoc endpoints have up to 16 bursts of up to + * 3 packets each + */ + if (dev->speed == USB_SPEED_SUPER) { + int burst = 1 + ep->ss_ep_comp.bMaxBurst; + int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes); + max *= burst; + max *= mult; + } + /* "high bandwidth" mode, 1-3 packets/uframe? */ if (dev->speed == USB_SPEED_HIGH) { int mult = 1 + ((max >> 11) & 0x03); @@ -361,23 +425,33 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) urb->iso_frame_desc[n].status = -EXDEV; urb->iso_frame_desc[n].actual_length = 0; } + } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint && + dev->speed != USB_SPEED_WIRELESS) { + struct scatterlist *sg; + int i; + + for_each_sg(urb->sg, sg, urb->num_sgs - 1, i) + if (sg->length % max) + return -EINVAL; } /* the I/O buffer must be mapped/unmapped, except when length=0 */ - if (urb->transfer_buffer_length < 0) + if (urb->transfer_buffer_length > INT_MAX) return -EMSGSIZE; -#ifdef DEBUG - /* stuff that drivers shouldn't do, but which shouldn't + /* + * stuff that drivers shouldn't do, but which shouldn't * cause problems in HCDs if they get it wrong. */ - { - unsigned int orig_flags = urb->transfer_flags; - unsigned int allowed; - /* enforce simple/standard policy */ - allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP | - URB_NO_INTERRUPT | URB_DIR_MASK | URB_FREE_BUFFER); + /* Check that the pipe's type matches the endpoint's type */ + if (usb_pipetype(urb->pipe) != pipetypes[xfertype]) + dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n", + usb_pipetype(urb->pipe), pipetypes[xfertype]); + + /* Check against a simple/standard policy */ + allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK | + URB_FREE_BUFFER); switch (xfertype) { case USB_ENDPOINT_XFER_BULK: if (is_out) @@ -394,16 +468,13 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) allowed |= URB_ISO_ASAP; break; } - urb->transfer_flags &= allowed; + allowed &= urb->transfer_flags; + + /* warn if submitter gave bogus flags */ + if (allowed != urb->transfer_flags) + dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n", + urb->transfer_flags, allowed); - /* fail if submitter gave bogus flags */ - if (urb->transfer_flags != orig_flags) { - err("BOGUS urb flags, %x --> %x", - orig_flags, urb->transfer_flags); - return -EINVAL; - } - } -#endif /* * Force periodic transfer intervals to be legal values that are * a power of two (so HCDs don't need to). @@ -416,10 +487,28 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) case USB_ENDPOINT_XFER_ISOC: case USB_ENDPOINT_XFER_INT: /* too small? */ - if (urb->interval <= 0) - return -EINVAL; + switch (dev->speed) { + case USB_SPEED_WIRELESS: + if ((urb->interval < 6) + && (xfertype == USB_ENDPOINT_XFER_INT)) + return -EINVAL; + default: + if (urb->interval <= 0) + return -EINVAL; + break; + } /* too big? */ switch (dev->speed) { + case USB_SPEED_SUPER: /* units are 125us */ + /* Handle up to 2^(16-1) microframes */ + if (urb->interval > (1 << 15)) + return -EINVAL; + max = 1 << 15; + break; + case USB_SPEED_WIRELESS: + if (urb->interval > 16) + return -EINVAL; + break; case USB_SPEED_HIGH: /* units are microframes */ /* NOTE usb handles 2^15 */ if (urb->interval > (1024 * 8)) @@ -443,8 +532,10 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) default: return -EINVAL; } - /* Round down to a power of 2, no more than max */ - urb->interval = min(max, 1 << ilog2(urb->interval)); + if (dev->speed != USB_SPEED_WIRELESS) { + /* Round down to a power of 2, no more than max */ + urb->interval = min(max, 1 << ilog2(urb->interval)); + } } return usb_hcd_submit_urb(urb, mem_flags); @@ -465,15 +556,31 @@ EXPORT_SYMBOL_GPL(usb_submit_urb); * indicating that the request has been canceled (rather than any other * code). * - * This request is always asynchronous. Success is indicated by - * returning -EINPROGRESS, at which time the URB will probably not yet - * have been given back to the device driver. When it is eventually - * called, the completion function will see @urb->status == -ECONNRESET. + * Drivers should not call this routine or related routines, such as + * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect + * method has returned. The disconnect function should synchronize with + * a driver's I/O routines to insure that all URB-related activity has + * completed before it returns. + * + * This request is asynchronous, however the HCD might call the ->complete() + * callback during unlink. Therefore when drivers call usb_unlink_urb(), they + * must not hold any locks that may be taken by the completion function. + * Success is indicated by returning -EINPROGRESS, at which time the URB will + * probably not yet have been given back to the device driver. When it is + * eventually called, the completion function will see @urb->status == + * -ECONNRESET. * Failure is indicated by usb_unlink_urb() returning any other value. * Unlinking will fail when @urb is not currently "linked" (i.e., it was * never submitted, or it was unlinked before, or the hardware is already * finished with it), even if the completion handler has not yet run. * + * The URB must not be deallocated while this routine is running. In + * particular, when a driver calls this routine, it must insure that the + * completion handler cannot deallocate the URB. + * + * Return: -EINPROGRESS on success. See description for other values on + * failure. + * * Unlinking and Endpoint Queues: * * [The behaviors and guarantees described below do not apply to virtual @@ -538,36 +645,112 @@ EXPORT_SYMBOL_GPL(usb_unlink_urb); * with error -EPERM. Thus even if the URB's completion handler always * tries to resubmit, it will not succeed and the URB will become idle. * + * The URB must not be deallocated while this routine is running. In + * particular, when a driver calls this routine, it must insure that the + * completion handler cannot deallocate the URB. + * * This routine may not be used in an interrupt context (such as a bottom * half or a completion handler), or when holding a spinlock, or in other * situations where the caller can't schedule(). + * + * This routine should not be called by a driver after its disconnect + * method has returned. */ void usb_kill_urb(struct urb *urb) { - static DEFINE_MUTEX(reject_mutex); - might_sleep(); if (!(urb && urb->dev && urb->ep)) return; - mutex_lock(&reject_mutex); - ++urb->reject; - mutex_unlock(&reject_mutex); + atomic_inc(&urb->reject); usb_hcd_unlink_urb(urb, -ENOENT); wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); - mutex_lock(&reject_mutex); - --urb->reject; - mutex_unlock(&reject_mutex); + atomic_dec(&urb->reject); } EXPORT_SYMBOL_GPL(usb_kill_urb); /** + * usb_poison_urb - reliably kill a transfer and prevent further use of an URB + * @urb: pointer to URB describing a previously submitted request, + * may be NULL + * + * This routine cancels an in-progress request. It is guaranteed that + * upon return all completion handlers will have finished and the URB + * will be totally idle and cannot be reused. These features make + * this an ideal way to stop I/O in a disconnect() callback. + * If the request has not already finished or been unlinked + * the completion handler will see urb->status == -ENOENT. + * + * After and while the routine runs, attempts to resubmit the URB will fail + * with error -EPERM. Thus even if the URB's completion handler always + * tries to resubmit, it will not succeed and the URB will become idle. + * + * The URB must not be deallocated while this routine is running. In + * particular, when a driver calls this routine, it must insure that the + * completion handler cannot deallocate the URB. + * + * This routine may not be used in an interrupt context (such as a bottom + * half or a completion handler), or when holding a spinlock, or in other + * situations where the caller can't schedule(). + * + * This routine should not be called by a driver after its disconnect + * method has returned. + */ +void usb_poison_urb(struct urb *urb) +{ + might_sleep(); + if (!urb) + return; + atomic_inc(&urb->reject); + + if (!urb->dev || !urb->ep) + return; + + usb_hcd_unlink_urb(urb, -ENOENT); + wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); +} +EXPORT_SYMBOL_GPL(usb_poison_urb); + +void usb_unpoison_urb(struct urb *urb) +{ + if (!urb) + return; + + atomic_dec(&urb->reject); +} +EXPORT_SYMBOL_GPL(usb_unpoison_urb); + +/** + * usb_block_urb - reliably prevent further use of an URB + * @urb: pointer to URB to be blocked, may be NULL + * + * After the routine has run, attempts to resubmit the URB will fail + * with error -EPERM. Thus even if the URB's completion handler always + * tries to resubmit, it will not succeed and the URB will become idle. + * + * The URB must not be deallocated while this routine is running. In + * particular, when a driver calls this routine, it must insure that the + * completion handler cannot deallocate the URB. + */ +void usb_block_urb(struct urb *urb) +{ + if (!urb) + return; + + atomic_inc(&urb->reject); +} +EXPORT_SYMBOL_GPL(usb_block_urb); + +/** * usb_kill_anchored_urbs - cancel transfer requests en masse * @anchor: anchor the requests are bound to * * this allows all outstanding URBs to be killed starting * from the back of the queue + * + * This routine should not be called by a driver after its disconnect + * method has returned. */ void usb_kill_anchored_urbs(struct usb_anchor *anchor) { @@ -589,6 +772,115 @@ void usb_kill_anchored_urbs(struct usb_anchor *anchor) } EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs); + +/** + * usb_poison_anchored_urbs - cease all traffic from an anchor + * @anchor: anchor the requests are bound to + * + * this allows all outstanding URBs to be poisoned starting + * from the back of the queue. Newly added URBs will also be + * poisoned + * + * This routine should not be called by a driver after its disconnect + * method has returned. + */ +void usb_poison_anchored_urbs(struct usb_anchor *anchor) +{ + struct urb *victim; + + spin_lock_irq(&anchor->lock); + anchor->poisoned = 1; + while (!list_empty(&anchor->urb_list)) { + victim = list_entry(anchor->urb_list.prev, struct urb, + anchor_list); + /* we must make sure the URB isn't freed before we kill it*/ + usb_get_urb(victim); + spin_unlock_irq(&anchor->lock); + /* this will unanchor the URB */ + usb_poison_urb(victim); + usb_put_urb(victim); + spin_lock_irq(&anchor->lock); + } + spin_unlock_irq(&anchor->lock); +} +EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs); + +/** + * usb_unpoison_anchored_urbs - let an anchor be used successfully again + * @anchor: anchor the requests are bound to + * + * Reverses the effect of usb_poison_anchored_urbs + * the anchor can be used normally after it returns + */ +void usb_unpoison_anchored_urbs(struct usb_anchor *anchor) +{ + unsigned long flags; + struct urb *lazarus; + + spin_lock_irqsave(&anchor->lock, flags); + list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) { + usb_unpoison_urb(lazarus); + } + anchor->poisoned = 0; + spin_unlock_irqrestore(&anchor->lock, flags); +} +EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs); +/** + * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse + * @anchor: anchor the requests are bound to + * + * this allows all outstanding URBs to be unlinked starting + * from the back of the queue. This function is asynchronous. + * The unlinking is just triggered. It may happen after this + * function has returned. + * + * This routine should not be called by a driver after its disconnect + * method has returned. + */ +void usb_unlink_anchored_urbs(struct usb_anchor *anchor) +{ + struct urb *victim; + + while ((victim = usb_get_from_anchor(anchor)) != NULL) { + usb_unlink_urb(victim); + usb_put_urb(victim); + } +} +EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs); + +/** + * usb_anchor_suspend_wakeups + * @anchor: the anchor you want to suspend wakeups on + * + * Call this to stop the last urb being unanchored from waking up any + * usb_wait_anchor_empty_timeout waiters. This is used in the hcd urb give- + * back path to delay waking up until after the completion handler has run. + */ +void usb_anchor_suspend_wakeups(struct usb_anchor *anchor) +{ + if (anchor) + atomic_inc(&anchor->suspend_wakeups); +} +EXPORT_SYMBOL_GPL(usb_anchor_suspend_wakeups); + +/** + * usb_anchor_resume_wakeups + * @anchor: the anchor you want to resume wakeups on + * + * Allow usb_wait_anchor_empty_timeout waiters to be woken up again, and + * wake up any current waiters if the anchor is empty. + */ +void usb_anchor_resume_wakeups(struct usb_anchor *anchor) +{ + if (!anchor) + return; + + atomic_dec(&anchor->suspend_wakeups); + if (usb_anchor_check_wakeup(anchor)) + wake_up(&anchor->wait); +} +EXPORT_SYMBOL_GPL(usb_anchor_resume_wakeups); + /** * usb_wait_anchor_empty_timeout - wait for an anchor to be unused * @anchor: the anchor you want to become unused @@ -596,11 +888,81 @@ EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs); * * Call this is you want to be sure all an anchor's * URBs have finished + * + * Return: Non-zero if the anchor became unused. Zero on timeout. */ int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor, unsigned int timeout) { - return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list), + return wait_event_timeout(anchor->wait, + usb_anchor_check_wakeup(anchor), msecs_to_jiffies(timeout)); } EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout); + +/** + * usb_get_from_anchor - get an anchor's oldest urb + * @anchor: the anchor whose urb you want + * + * This will take the oldest urb from an anchor, + * unanchor and return it + * + * Return: The oldest urb from @anchor, or %NULL if @anchor has no + * urbs associated with it. + */ +struct urb *usb_get_from_anchor(struct usb_anchor *anchor) +{ + struct urb *victim; + unsigned long flags; + + spin_lock_irqsave(&anchor->lock, flags); + if (!list_empty(&anchor->urb_list)) { + victim = list_entry(anchor->urb_list.next, struct urb, + anchor_list); + usb_get_urb(victim); + __usb_unanchor_urb(victim, anchor); + } else { + victim = NULL; + } + spin_unlock_irqrestore(&anchor->lock, flags); + + return victim; +} + +EXPORT_SYMBOL_GPL(usb_get_from_anchor); + +/** + * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs + * @anchor: the anchor whose urbs you want to unanchor + * + * use this to get rid of all an anchor's urbs + */ +void usb_scuttle_anchored_urbs(struct usb_anchor *anchor) +{ + struct urb *victim; + unsigned long flags; + + spin_lock_irqsave(&anchor->lock, flags); + while (!list_empty(&anchor->urb_list)) { + victim = list_entry(anchor->urb_list.prev, struct urb, + anchor_list); + __usb_unanchor_urb(victim, anchor); + } + spin_unlock_irqrestore(&anchor->lock, flags); +} + +EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs); + +/** + * usb_anchor_empty - is an anchor empty + * @anchor: the anchor you want to query + * + * Return: 1 if the anchor has no urbs associated with it. + */ +int usb_anchor_empty(struct usb_anchor *anchor) +{ + return list_empty(&anchor->urb_list); +} + +EXPORT_SYMBOL_GPL(usb_anchor_empty); + |