/**
* Get the amount of buffer space available and enable notifications if needed.
*/
static inline int fast_get_buffer_space(struct libxenvchan *ctrl, size_t request)
{
int ready = wr_ring_size(ctrl) - (wr_prod(ctrl) - wr_cons(ctrl));
if (ready >= request)
return ready;
/* We plan to fill the buffer; please tell us when you've read it */
request_notify(ctrl, VCHAN_NOTIFY_READ);
/*
* If the reader moved wr_cons after our read but before request, we
* will not get notified even though the actual amount of buffer space
* is above request. Reread wr_cons to cover this case.
*/
return wr_ring_size(ctrl) - (wr_prod(ctrl) - wr_cons(ctrl));
}
int libxenvchan_buffer_space(struct libxenvchan *ctrl)
{
/* Since this value is being used outside libxenvchan, request notification
* when it changes
*/
request_notify(ctrl, VCHAN_NOTIFY_READ);
return wr_ring_size(ctrl) - (wr_prod(ctrl) - wr_cons(ctrl));
}
/**
* Get the amount of buffer space available, and do nothing
* about notifications
*/
static inline int raw_get_buffer_space(struct libxenvchan *ctrl)
{
uint32_t ready = wr_ring_size(ctrl) - (wr_prod(ctrl) - wr_cons(ctrl));
if (ready > wr_ring_size(ctrl))
/* We have no way to return errors. Locking up the ring is
* better than the alternatives. */
return 0;
return ready;
}
int libvchan_buffer_space(struct libvchan *ctrl)
{
return wr_ring_size(ctrl) - (wr_prod(ctrl) - wr_cons(ctrl));
}
