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| author | Alan Stern <stern@rowland.harvard.edu> | 2013-09-03 21:58:43 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-09-17 20:49:24 +0400 |
| commit | c7ccde6eac6d3c4bc6110cc3fd76ef3823bc0831 (patch) | |
| tree | f5221b8296a245cb9f3e3f84801b1d5d8feb12f9 | |
| parent | 272b98c6455f00884f0350f775c5342358ebb73f (diff) | |
| download | linux-c7ccde6eac6d3c4bc6110cc3fd76ef3823bc0831.tar.xz | |
USB: see if URB comes from a completion handler
Now that URBs can be completed inside tasklets, we need a way of
determining whether a completion handler for a given endpoint is
currently running. Otherwise it's not possible to maintain the API
guarantee about keeping isochronous streams synchronous when an
underrun occurs.
This patch adds a field and a routine to check whether a completion
handler for a periodic endpoint is running. At the moment no
analogous routine appears to be necessary for async endpoints, but one
can always be added.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/core/hcd.c | 2 | ||||
| -rw-r--r-- | include/linux/usb/hcd.h | 7 |
2 files changed, 9 insertions, 0 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index d6a8d23f047b..3a2e82a9c115 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1703,7 +1703,9 @@ static void usb_giveback_urb_bh(unsigned long param) urb = list_entry(local_list.next, struct urb, urb_list); list_del_init(&urb->urb_list); + bh->completing_ep = urb->ep; __usb_hcd_giveback_urb(urb); + bh->completing_ep = NULL; } /* check if there are new URBs to giveback */ diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h index 75efc45eaa2f..8c865134c881 100644 --- a/include/linux/usb/hcd.h +++ b/include/linux/usb/hcd.h @@ -73,6 +73,7 @@ struct giveback_urb_bh { spinlock_t lock; struct list_head head; struct tasklet_struct bh; + struct usb_host_endpoint *completing_ep; }; struct usb_hcd { @@ -378,6 +379,12 @@ static inline int hcd_giveback_urb_in_bh(struct usb_hcd *hcd) return hcd->driver->flags & HCD_BH; } +static inline bool hcd_periodic_completion_in_progress(struct usb_hcd *hcd, + struct usb_host_endpoint *ep) +{ + return hcd->high_prio_bh.completing_ep == ep; +} + 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); |