-/*
- * As many data cores may want to access available buffers
- * they need to be reserved.
- */
-static inline uint32_t
-reserve_avail_buf(struct vhost_virtqueue *vq, uint32_t count,
- uint16_t *start, uint16_t *end)
-{
- uint16_t res_start_idx;
- uint16_t res_end_idx;
- uint16_t avail_idx;
- uint16_t free_entries;
- int success;
-
- count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
-
-again:
- res_start_idx = vq->last_used_idx_res;
- avail_idx = *((volatile uint16_t *)&vq->avail->idx);
-
- free_entries = avail_idx - res_start_idx;
- count = RTE_MIN(count, free_entries);
- if (count == 0)
- return 0;
-
- res_end_idx = res_start_idx + count;
-
- /*
- * update vq->last_used_idx_res atomically; try again if failed.
- *
- * TODO: Allow to disable cmpset if no concurrency in application.
- */
- success = rte_atomic16_cmpset(&vq->last_used_idx_res,
- res_start_idx, res_end_idx);
- if (unlikely(!success))
- goto again;
-
- *start = res_start_idx;
- *end = res_end_idx;
-
- return count;
-}
-