RQUEUESIZE
#define EQUEUESIZE RQUEUESIZE
n = min(((u32) total), (RQUEUESIZE - (u32) head));
channel->ch_rqueue = kzalloc(RQUEUESIZE, GFP_KERNEL);
s = ((head >= tail) ? head : RQUEUESIZE) - tail;
if (qleft > (RQUEUESIZE / 2)) {