diff options
Diffstat (limited to 'drivers/usb/core/urb.c')
| -rw-r--r-- | drivers/usb/core/urb.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c index cd9b3a2cd8a7..9d912bfdcffe 100644 --- a/drivers/usb/core/urb.c +++ b/drivers/usb/core/urb.c @@ -681,6 +681,27 @@ void usb_unpoison_urb(struct urb *urb) 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 * |