diff options
| -rw-r--r-- | drivers/usb/core/urb.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c index f4f20c7b7765..7239a73c1b8c 100644 --- a/drivers/usb/core/urb.c +++ b/drivers/usb/core/urb.c @@ -527,10 +527,13 @@ EXPORT_SYMBOL_GPL(usb_submit_urb); * a driver's I/O routines to insure that all URB-related activity has * completed before it returns. * - * 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. + * 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 |