- n = entries;
- }
- }
-
- cons_next = cons_head + n;
- success = rte_atomic32_cmpset(&r->cons.head, cons_head,
- cons_next);
- } while (unlikely(success == 0));
-
- /* copy in table */
- DEQUEUE_PTRS();
- rte_smp_rmb();
-
- /*
- * If there are other dequeues in progress that preceded us,
- * we need to wait for them to complete
- */
- while (unlikely(r->cons.tail != cons_head)) {
- rte_pause();
-
- /* Set RTE_RING_PAUSE_REP_COUNT to avoid spin too long waiting
- * for other thread finish. It gives pre-empted thread a chance
- * to proceed and finish with ring dequeue operation. */
- if (RTE_RING_PAUSE_REP_COUNT &&
- ++rep == RTE_RING_PAUSE_REP_COUNT) {
- rep = 0;
- sched_yield();
- }
- }
- __RING_STAT_ADD(r, deq_success, n);
- r->cons.tail = cons_next;
-
- return behavior == RTE_RING_QUEUE_FIXED ? 0 : n;
-}
-
-/**
- * @internal Dequeue several objects from a ring (NOT multi-consumers safe).
- * When the request objects are more than the available objects, only dequeue
- * the actual number of objects
- *
- * @param r
- * A pointer to the ring structure.
- * @param obj_table
- * A pointer to a table of void * pointers (objects) that will be filled.
- * @param n
- * The number of objects to dequeue from the ring to the obj_table.
- * @param behavior
- * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
- * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
- * @return
- * Depend on the behavior value
- * if behavior = RTE_RING_QUEUE_FIXED
- * - 0: Success; objects dequeued.
- * - -ENOENT: Not enough entries in the ring to dequeue; no object is
- * dequeued.
- * if behavior = RTE_RING_QUEUE_VARIABLE
- * - n: Actual number of objects dequeued.
- */
-static inline int __attribute__((always_inline))
-__rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
- unsigned n, enum rte_ring_queue_behavior behavior)
-{
- uint32_t cons_head, prod_tail;
- uint32_t cons_next, entries;
- unsigned i;
- uint32_t mask = r->prod.mask;
-
- cons_head = r->cons.head;
- prod_tail = r->prod.tail;
- /* The subtraction is done between two unsigned 32bits value
- * (the result is always modulo 32 bits even if we have
- * cons_head > prod_tail). So 'entries' is always between 0
- * and size(ring)-1. */
- entries = prod_tail - cons_head;
-
- if (n > entries) {
- if (behavior == RTE_RING_QUEUE_FIXED) {
- __RING_STAT_ADD(r, deq_fail, n);
- return -ENOENT;
- }
- else {
- if (unlikely(entries == 0)){
- __RING_STAT_ADD(r, deq_fail, n);
- return 0;
- }
-
- n = entries;
- }
- }
-
- cons_next = cons_head + n;
- r->cons.head = cons_next;
-
- /* copy in table */
- DEQUEUE_PTRS();
- rte_smp_wmb();
-
- __RING_STAT_ADD(r, deq_success, n);
- r->cons.tail = cons_next;
- return behavior == RTE_RING_QUEUE_FIXED ? 0 : n;