29     uint32_t tail;  member
101     return ring->head == ring->tail;  in desc_ring_empty()
137     ring->head = ring->tail = 0;  in desc_ring_set_size()
187     return desc_read(ring, ring->tail);  in __desc_ring_fetch_desc()
196     return desc_read(ring, ring->tail);  in desc_ring_fetch_desc()
202     DescInfo *info = &ring->info[ring->tail];  in __desc_ring_post_desc()
205     desc_write(ring, ring->tail);  in __desc_ring_post_desc()
206     ring->tail = (ring->tail + 1) % ring->size;  in __desc_ring_post_desc()
235      * desc starting at tail and stopping when tail reaches  in ring_pump()
240         while (ring->head != ring->tail) {  in ring_pump()
254     uint32_t tail = ring->tail;  in desc_ring_set_head()  local
267     if (((head < tail) && ((new >= tail) || (new < head))) ||  in desc_ring_set_head()
268         ((head > tail) && ((new >= tail) && (new < head)))) {  in desc_ring_set_head()
270                 "(head %d, tail %d, new head %d)\n",  in desc_ring_set_head()
271                 ring->index, head, tail, new);  in desc_ring_set_head()
291     return ring->tail;  in desc_ring_get_tail()
358     ring->tail = 0;  in desc_ring_reset()