diff options
Diffstat (limited to 'drivers/usb/core/urb.c')
| -rw-r--r-- | drivers/usb/core/urb.c | 193 |
1 files changed, 147 insertions, 46 deletions
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c index 94ea9727ff55..be630228461c 100644 --- a/drivers/usb/core/urb.c +++ b/drivers/usb/core/urb.c @@ -4,6 +4,7 @@ #include <linux/slab.h> #include <linux/init.h> #include <linux/usb.h> +#include <linux/wait.h> #include "hcd.h" #define to_urb(d) container_of(d, struct urb, kref) @@ -11,6 +12,10 @@ static void urb_destroy(struct kref *kref) { struct urb *urb = to_urb(kref); + + if (urb->transfer_flags & URB_FREE_BUFFER) + kfree(urb->transfer_buffer); + kfree(urb); } @@ -34,6 +39,7 @@ void usb_init_urb(struct urb *urb) memset(urb, 0, sizeof(*urb)); kref_init(&urb->kref); spin_lock_init(&urb->lock); + INIT_LIST_HEAD(&urb->anchor_list); } } @@ -100,8 +106,60 @@ struct urb * usb_get_urb(struct urb *urb) kref_get(&urb->kref); return urb; } - - + +/** + * usb_anchor_urb - anchors an URB while it is processed + * @urb: pointer to the urb to anchor + * @anchor: pointer to the anchor + * + * This can be called to have access to URBs which are to be executed + * without bothering to track them + */ +void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor) +{ + unsigned long flags; + + spin_lock_irqsave(&anchor->lock, flags); + usb_get_urb(urb); + list_add_tail(&urb->anchor_list, &anchor->urb_list); + urb->anchor = anchor; + spin_unlock_irqrestore(&anchor->lock, flags); +} +EXPORT_SYMBOL_GPL(usb_anchor_urb); + +/** + * usb_unanchor_urb - unanchors an URB + * @urb: pointer to the urb to anchor + * + * Call this to stop the system keeping track of this URB + */ +void usb_unanchor_urb(struct urb *urb) +{ + unsigned long flags; + struct usb_anchor *anchor; + + if (!urb) + return; + + anchor = urb->anchor; + if (!anchor) + 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); + 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); + /*-------------------------------------------------------------------*/ /** @@ -382,55 +440,57 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) * @urb: pointer to urb describing a previously submitted request, * may be NULL * - * This routine cancels an in-progress request. URBs complete only - * once per submission, and may be canceled only once per submission. - * Successful cancellation means the requests's completion handler will - * be called with a status code indicating that the request has been - * canceled (rather than any other code) and will quickly be removed - * from host controller data structures. - * - * This request is always asynchronous. - * Success is indicated by returning -EINPROGRESS, - * at which time the URB will normally have been unlinked but not yet - * given back to the device driver. When it is called, the completion - * function will see urb->status == -ECONNRESET. Failure is indicated - * by any other return value. Unlinking will fail when the 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. + * This routine cancels an in-progress request. URBs complete only once + * per submission, and may be canceled only once per submission. + * Successful cancellation means termination of @urb will be expedited + * and the completion handler will be called with a status code + * 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. + * 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. * * Unlinking and Endpoint Queues: * + * [The behaviors and guarantees described below do not apply to virtual + * root hubs but only to endpoint queues for physical USB devices.] + * * Host Controller Drivers (HCDs) place all the URBs for a particular * endpoint in a queue. Normally the queue advances as the controller * hardware processes each request. But when an URB terminates with an - * error its queue stops, at least until that URB's completion routine - * returns. It is guaranteed that the queue will not restart until all - * its unlinked URBs have been fully retired, with their completion - * routines run, even if that's not until some time after the original - * completion handler returns. Normally the same behavior and guarantees - * apply when an URB terminates because it was unlinked; however if an - * URB is unlinked before the hardware has started to execute it, then - * its queue is not guaranteed to stop until all the preceding URBs have - * completed. - * - * This means that USB device drivers can safely build deep queues for - * large or complex transfers, and clean them up reliably after any sort - * of aborted transfer by unlinking all pending URBs at the first fault. - * - * Note that an URB terminating early because a short packet was received - * will count as an error if and only if the URB_SHORT_NOT_OK flag is set. - * Also, that all unlinks performed in any URB completion handler must - * be asynchronous. - * - * Queues for isochronous endpoints are treated differently, because they - * advance at fixed rates. Such queues do not stop when an URB is unlinked. - * An unlinked URB may leave a gap in the stream of packets. It is undefined - * whether such gaps can be filled in. - * - * When a control URB terminates with an error, it is likely that the - * status stage of the transfer will not take place, even if it is merely - * a soft error resulting from a short-packet with URB_SHORT_NOT_OK set. + * error its queue generally stops (see below), at least until that URB's + * completion routine returns. It is guaranteed that a stopped queue + * will not restart until all its unlinked URBs have been fully retired, + * with their completion routines run, even if that's not until some time + * after the original completion handler returns. The same behavior and + * guarantee apply when an URB terminates because it was unlinked. + * + * Bulk and interrupt endpoint queues are guaranteed to stop whenever an + * URB terminates with any sort of error, including -ECONNRESET, -ENOENT, + * and -EREMOTEIO. Control endpoint queues behave the same way except + * that they are not guaranteed to stop for -EREMOTEIO errors. Queues + * for isochronous endpoints are treated differently, because they must + * advance at fixed rates. Such queues do not stop when an URB + * encounters an error or is unlinked. An unlinked isochronous URB may + * leave a gap in the stream of packets; it is undefined whether such + * gaps can be filled in. + * + * Note that early termination of an URB because a short packet was + * received will generate a -EREMOTEIO error if and only if the + * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device + * drivers can build deep queues for large or complex bulk transfers + * and clean them up reliably after any sort of aborted transfer by + * unlinking all pending URBs at the first fault. + * + * When a control URB terminates with an error other than -EREMOTEIO, it + * is quite likely that the status stage of the transfer will not take + * place. */ int usb_unlink_urb(struct urb *urb) { @@ -478,6 +538,48 @@ void usb_kill_urb(struct urb *urb) spin_unlock_irq(&urb->lock); } +/** + * 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 + */ +void usb_kill_anchored_urbs(struct usb_anchor *anchor) +{ + struct urb *victim; + + spin_lock_irq(&anchor->lock); + 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_kill_urb(victim); + usb_put_urb(victim); + spin_lock_irq(&anchor->lock); + } + spin_unlock_irq(&anchor->lock); +} +EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs); + +/** + * usb_wait_anchor_empty_timeout - wait for an anchor to be unused + * @anchor: the anchor you want to become unused + * @timeout: how long you are willing to wait in milliseconds + * + * Call this is you want to be sure all an anchor's + * URBs have finished + */ +int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor, + unsigned int timeout) +{ + return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list), + msecs_to_jiffies(timeout)); +} +EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout); + EXPORT_SYMBOL(usb_init_urb); EXPORT_SYMBOL(usb_alloc_urb); EXPORT_SYMBOL(usb_free_urb); @@ -485,4 +587,3 @@ EXPORT_SYMBOL(usb_get_urb); EXPORT_SYMBOL(usb_submit_urb); EXPORT_SYMBOL(usb_unlink_urb); EXPORT_SYMBOL(usb_kill_urb); - |