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+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2010-2012 Intel Corporation. All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * version: DPDK.L.1.2.3-3
+ */
+
+/*
+ * Derived from FreeBSD's bufring.h
+ *
+ **************************************************************************
+ *
+ * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. The name of Kip Macy nor the names of other
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ***************************************************************************/
+
+#ifndef _RTE_RING_H_
+#define _RTE_RING_H_
+
+/**
+ * @file
+ * RTE Ring
+ *
+ * The Ring Manager is a fixed-size queue, implemented as a table of
+ * pointers. Head and tail pointers are modified atomically, allowing
+ * concurrent access to it. It has the following features:
+ *
+ * - FIFO (First In First Out)
+ * - Maximum size is fixed; the pointers are stored in a table.
+ * - Lockless implementation.
+ * - Multi- or single-consumer dequeue.
+ * - Multi- or single-producer enqueue.
+ * - Bulk dequeue.
+ * - Bulk enqueue.
+ *
+ * Note: the ring implementation is not preemptable. A lcore must not
+ * be interrupted by another task that uses the same ring.
+ *
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <sys/queue.h>
+#include <errno.h>
+#include <rte_common.h>
+#include <rte_memory.h>
+#include <rte_lcore.h>
+#include <rte_atomic.h>
+#include <rte_branch_prediction.h>
+
+
+#ifdef RTE_LIBRTE_RING_DEBUG
+/**
+ * A structure that stores the ring statistics (per-lcore).
+ */
+struct rte_ring_debug_stats {
+ uint64_t enq_success_bulk; /**< Successful enqueues number. */
+ uint64_t enq_success_objs; /**< Objects successfully enqueued. */
+ uint64_t enq_quota_bulk; /**< Successful enqueues above watermark. */
+ uint64_t enq_quota_objs; /**< Objects enqueued above watermark. */
+ uint64_t enq_fail_bulk; /**< Failed enqueues number. */
+ uint64_t enq_fail_objs; /**< Objects that failed to be enqueued. */
+ uint64_t deq_success_bulk; /**< Successful dequeues number. */
+ uint64_t deq_success_objs; /**< Objects successfully dequeued. */
+ uint64_t deq_fail_bulk; /**< Failed dequeues number. */
+ uint64_t deq_fail_objs; /**< Objects that failed to be dequeued. */
+} __rte_cache_aligned;
+#endif
+
+#define RTE_RING_NAMESIZE 32 /**< The maximum length of a ring name. */
+
+/**
+ * An RTE ring structure.
+ *
+ * The producer and the consumer have a head and a tail index. The particularity
+ * of these index is that they are not between 0 and size(ring). These indexes
+ * are between 0 and 2^32, and we mask their value when we access the ring[]
+ * field. Thanks to this assumption, we can do subtractions between 2 index
+ * values in a modulo-32bit base: that's why the overflow of the indexes is not
+ * a problem.
+ */
+struct rte_ring {
+ TAILQ_ENTRY(rte_ring) next; /**< Next in list. */
+
+ char name[RTE_RING_NAMESIZE]; /**< Name of the ring. */
+ int flags; /**< Flags supplied at creation. */
+
+ /** Ring producer status. */
+ struct prod {
+ volatile uint32_t bulk_default; /**< Default bulk count. */
+ uint32_t watermark; /**< Maximum items before EDQUOT. */
+ uint32_t sp_enqueue; /**< True, if single producer. */
+ uint32_t size; /**< Size of ring. */
+ uint32_t mask; /**< Mask (size-1) of ring. */
+ volatile uint32_t head; /**< Producer head. */
+ volatile uint32_t tail; /**< Producer tail. */
+ } prod __rte_cache_aligned;
+
+ /** Ring consumer status. */
+ struct cons {
+ volatile uint32_t bulk_default; /**< Default bulk count. */
+ uint32_t sc_dequeue; /**< True, if single consumer. */
+ uint32_t size; /**< Size of the ring. */
+ uint32_t mask; /**< Mask (size-1) of ring. */
+ volatile uint32_t head; /**< Consumer head. */
+ volatile uint32_t tail; /**< Consumer tail. */
+ } cons __rte_cache_aligned;
+
+
+#ifdef RTE_LIBRTE_RING_DEBUG
+ struct rte_ring_debug_stats stats[RTE_MAX_LCORE];
+#endif
+
+ void * volatile ring[0] \
+ __rte_cache_aligned; /**< Memory space of ring starts here. */
+};
+
+#define RING_F_SP_ENQ 0x0001 /**< The default enqueue is "single-producer". */
+#define RING_F_SC_DEQ 0x0002 /**< The default dequeue is "single-consumer". */
+
+/**
+ * When debug is enabled, store ring statistics.
+ * @param r
+ * A pointer to the ring.
+ * @param name
+ * The name of the statistics field to increment in the ring.
+ * @param n
+ * The number to add to the object-oriented statistics.
+ */
+#ifdef RTE_LIBRTE_RING_DEBUG
+#define __RING_STAT_ADD(r, name, n) do { \
+ unsigned __lcore_id = rte_lcore_id(); \
+ r->stats[__lcore_id].name##_objs += n; \
+ r->stats[__lcore_id].name##_bulk += 1; \
+ } while(0)
+#else
+#define __RING_STAT_ADD(r, name, n) do {} while(0)
+#endif
+
+/**
+ * Create a new ring named *name* in memory.
+ *
+ * This function uses ``memzone_reserve()`` to allocate memory. Its size is
+ * set to *count*, which must be a power of two. Water marking is
+ * disabled by default. The default bulk count is initialized to 1.
+ * Note that the real usable ring size is *count-1* instead of
+ * *count*.
+ *
+ * @param name
+ * The name of the ring.
+ * @param count
+ * The size of the ring (must be a power of 2).
+ * @param socket_id
+ * The *socket_id* argument is the socket identifier in case of
+ * NUMA. The value can be *SOCKET_ID_ANY* if there is no NUMA
+ * constraint for the reserved zone.
+ * @param flags
+ * An OR of the following:
+ * - RING_F_SP_ENQ: If this flag is set, the default behavior when
+ * using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
+ * is "single-producer". Otherwise, it is "multi-producers".
+ * - RING_F_SC_DEQ: If this flag is set, the default behavior when
+ * using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
+ * is "single-consumer". Otherwise, it is "multi-consumers".
+ * @return
+ * On success, the pointer to the new allocated ring. NULL on error with
+ * rte_errno set appropriately. Possible errno values include:
+ * - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
+ * - E_RTE_SECONDARY - function was called from a secondary process instance
+ * - E_RTE_NO_TAILQ - no tailq list could be got for the ring list
+ * - EINVAL - count provided is not a power of 2
+ * - ENOSPC - the maximum number of memzones has already been allocated
+ * - EEXIST - a memzone with the same name already exists
+ * - ENOMEM - no appropriate memory area found in which to create memzone
+ */
+struct rte_ring *rte_ring_create(const char *name, unsigned count,
+ int socket_id, unsigned flags);
+
+/**
+ * Set the default bulk count for enqueue/dequeue.
+ *
+ * The parameter *count* is the default number of bulk elements to
+ * get/put when using ``rte_ring_*_{en,de}queue_bulk()``. It must be
+ * greater than 0 and less than half of the ring size.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param count
+ * A new water mark value.
+ * @return
+ * - 0: Success; default_bulk_count changed.
+ * - -EINVAL: Invalid count value.
+ */
+static inline int
+rte_ring_set_bulk_count(struct rte_ring *r, unsigned count)
+{
+ if (unlikely(count == 0 || count >= r->prod.size))
+ return -EINVAL;
+
+ r->prod.bulk_default = r->cons.bulk_default = count;
+ return 0;
+}
+
+/**
+ * Get the default bulk count for enqueue/dequeue.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * The default bulk count for enqueue/dequeue.
+ */
+static inline unsigned
+rte_ring_get_bulk_count(struct rte_ring *r)
+{
+ return r->prod.bulk_default;
+}
+
+/**
+ * Change the high water mark.
+ *
+ * If *count* is 0, water marking is disabled. Otherwise, it is set to the
+ * *count* value. The *count* value must be greater than 0 and less
+ * than the ring size.
+ *
+ * This function can be called at any time (not necessarilly at
+ * initialization).
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param count
+ * The new water mark value.
+ * @return
+ * - 0: Success; water mark changed.
+ * - -EINVAL: Invalid water mark value.
+ */
+int rte_ring_set_water_mark(struct rte_ring *r, unsigned count);
+
+/**
+ * Dump the status of the ring to the console.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ */
+void rte_ring_dump(const struct rte_ring *r);
+
+/**
+ * Enqueue several objects on the ring (multi-producers safe).
+ *
+ * This function uses a "compare and set" instruction to move the
+ * producer index atomically.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj_table
+ * A pointer to a table of void * pointers (objects).
+ * @param n
+ * The number of objects to add in the ring from the obj_table. The
+ * value must be strictly positive.
+ * @return
+ * - 0: Success; objects enqueue.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
+ */
+static inline int
+rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
+ unsigned n)
+{
+ uint32_t prod_head, prod_next;
+ uint32_t cons_tail, free_entries;
+ int success;
+ unsigned i;
+ uint32_t mask = r->prod.mask;
+ int ret;
+
+ /* move prod.head atomically */
+ do {
+ prod_head = r->prod.head;
+ cons_tail = r->cons.tail;
+ /* The subtraction is done between two unsigned 32bits value
+ * (the result is always modulo 32 bits even if we have
+ * prod_head > cons_tail). So 'free_entries' is always between 0
+ * and size(ring)-1. */
+ free_entries = (mask + cons_tail - prod_head);
+
+ /* check that we have enough room in ring */
+ if (unlikely(n > free_entries)) {
+ __RING_STAT_ADD(r, enq_fail, n);
+ return -ENOBUFS;
+ }
+
+ prod_next = prod_head + n;
+ success = rte_atomic32_cmpset(&r->prod.head, prod_head,
+ prod_next);
+ } while (unlikely(success == 0));
+
+ /* write entries in ring */
+ for (i = 0; likely(i < n); i++)
+ r->ring[(prod_head + i) & mask] = obj_table[i];
+ rte_wmb();
+
+ /* return -EDQUOT if we exceed the watermark */
+ if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
+ ret = -EDQUOT;
+ __RING_STAT_ADD(r, enq_quota, n);
+ }
+ else {
+ ret = 0;
+ __RING_STAT_ADD(r, enq_success, n);
+ }
+
+ /*
+ * If there are other enqueues in progress that preceeded us,
+ * we need to wait for them to complete
+ */
+ while (unlikely(r->prod.tail != prod_head))
+ rte_pause();
+
+ r->prod.tail = prod_next;
+ return ret;
+}
+
+/**
+ * Enqueue several objects on a ring (NOT multi-producers safe).
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj_table
+ * A pointer to a table of void * pointers (objects).
+ * @param n
+ * The number of objects to add in the ring from the obj_table. The
+ * value must be strictly positive.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int
+rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
+ unsigned n)
+{
+ uint32_t prod_head, cons_tail;
+ uint32_t prod_next, free_entries;
+ unsigned i;
+ uint32_t mask = r->prod.mask;
+ int ret;
+
+ prod_head = r->prod.head;
+ cons_tail = r->cons.tail;
+ /* The subtraction is done between two unsigned 32bits value
+ * (the result is always modulo 32 bits even if we have
+ * prod_head > cons_tail). So 'free_entries' is always between 0
+ * and size(ring)-1. */
+ free_entries = mask + cons_tail - prod_head;
+
+ /* check that we have enough room in ring */
+ if (unlikely(n > free_entries)) {
+ __RING_STAT_ADD(r, enq_fail, n);
+ return -ENOBUFS;
+ }
+
+ prod_next = prod_head + n;
+ r->prod.head = prod_next;
+
+ /* write entries in ring */
+ for (i = 0; likely(i < n); i++)
+ r->ring[(prod_head + i) & mask] = obj_table[i];
+ rte_wmb();
+
+ /* return -EDQUOT if we exceed the watermark */
+ if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
+ ret = -EDQUOT;
+ __RING_STAT_ADD(r, enq_quota, n);
+ }
+ else {
+ ret = 0;
+ __RING_STAT_ADD(r, enq_success, n);
+ }
+
+ r->prod.tail = prod_next;
+ return ret;
+}
+
+/**
+ * Enqueue several objects on a ring.
+ *
+ * This function calls the multi-producer or the single-producer
+ * version depending on the default behavior that was specified at
+ * ring creation time (see flags).
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj_table
+ * A pointer to a table of void * pointers (objects).
+ * @param n
+ * The number of objects to add in the ring from the obj_table.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int
+rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
+ unsigned n)
+{
+ if (r->prod.sp_enqueue)
+ return rte_ring_sp_enqueue_bulk(r, obj_table, n);
+ else
+ return rte_ring_mp_enqueue_bulk(r, obj_table, n);
+}
+
+/**
+ * Enqueue one object on a ring (multi-producers safe).
+ *
+ * This function uses a "compare and set" instruction to move the
+ * producer index atomically.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj
+ * A pointer to the object to be added.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int
+rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
+{
+ return rte_ring_mp_enqueue_bulk(r, &obj, 1);
+}
+
+/**
+ * Enqueue one object on a ring (NOT multi-producers safe).
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj
+ * A pointer to the object to be added.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int
+rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
+{
+ return rte_ring_sp_enqueue_bulk(r, &obj, 1);
+}
+
+/**
+ * Enqueue one object on a ring.
+ *
+ * This function calls the multi-producer or the single-producer
+ * version, depending on the default behaviour that was specified at
+ * ring creation time (see flags).
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj
+ * A pointer to the object to be added.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int
+rte_ring_enqueue(struct rte_ring *r, void *obj)
+{
+ if (r->prod.sp_enqueue)
+ return rte_ring_sp_enqueue(r, obj);
+ else
+ return rte_ring_mp_enqueue(r, obj);
+}
+
+/**
+ * Dequeue several objects from a ring (multi-consumers safe).
+ *
+ * This function uses a "compare and set" instruction to move the
+ * consumer index atomically.
+ *
+ * @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,
+ * must be strictly positive
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ * dequeued.
+ */
+static inline int
+rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+{
+ uint32_t cons_head, prod_tail;
+ uint32_t cons_next, entries;
+ int success;
+ unsigned i;
+ uint32_t mask = r->prod.mask;
+
+ /* move cons.head atomically */
+ do {
+ 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);
+
+ /* check that we have enough entries in ring */
+ if (unlikely(n > entries)) {
+ __RING_STAT_ADD(r, deq_fail, n);
+ return -ENOENT;
+ }
+
+ cons_next = cons_head + n;
+ success = rte_atomic32_cmpset(&r->cons.head, cons_head,
+ cons_next);
+ } while (unlikely(success == 0));
+
+ /* copy in table */
+ rte_rmb();
+ for (i = 0; likely(i < n); i++) {
+ obj_table[i] = r->ring[(cons_head + i) & mask];
+ }
+
+ /*
+ * If there are other dequeues in progress that preceeded us,
+ * we need to wait for them to complete
+ */
+ while (unlikely(r->cons.tail != cons_head))
+ rte_pause();
+
+ __RING_STAT_ADD(r, deq_success, n);
+ r->cons.tail = cons_next;
+ return 0;
+}
+
+/**
+ * Dequeue several objects from a ring (NOT multi-consumers safe).
+ *
+ * @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,
+ * must be strictly positive.
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ * dequeued.
+ */
+static inline int
+rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+{
+ 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;
+
+ /* check that we have enough entries in ring */
+ if (unlikely(n > entries)) {
+ __RING_STAT_ADD(r, deq_fail, n);
+ return -ENOENT;
+ }
+
+ cons_next = cons_head + n;
+ r->cons.head = cons_next;
+
+ /* copy in table */
+ rte_rmb();
+ for (i = 0; likely(i < n); i++) {
+ obj_table[i] = r->ring[(cons_head + i) & mask];
+ }
+
+ __RING_STAT_ADD(r, deq_success, n);
+ r->cons.tail = cons_next;
+ return 0;
+}
+
+/**
+ * Dequeue several objects from a ring.
+ *
+ * This function calls the multi-consumers or the single-consumer
+ * version, depending on the default behaviour that was specified at
+ * ring creation time (see flags).
+ *
+ * @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.
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue, no object is
+ * dequeued.
+ */
+static inline int
+rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+{
+ if (r->cons.sc_dequeue)
+ return rte_ring_sc_dequeue_bulk(r, obj_table, n);
+ else
+ return rte_ring_mc_dequeue_bulk(r, obj_table, n);
+}
+
+/**
+ * Dequeue one object from a ring (multi-consumers safe).
+ *
+ * This function uses a "compare and set" instruction to move the
+ * consumer index atomically.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj_p
+ * A pointer to a void * pointer (object) that will be filled.
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ * dequeued.
+ */
+static inline int
+rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
+{
+ return rte_ring_mc_dequeue_bulk(r, obj_p, 1);
+}
+
+/**
+ * Dequeue one object from a ring (NOT multi-consumers safe).
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj_p
+ * A pointer to a void * pointer (object) that will be filled.
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue, no object is
+ * dequeued.
+ */
+static inline int
+rte_ring_sc_dequeue(struct rte_ring *r, void **obj_p)
+{
+ return rte_ring_sc_dequeue_bulk(r, obj_p, 1);
+}
+
+/**
+ * Dequeue one object from a ring.
+ *
+ * This function calls the multi-consumers or the single-consumer
+ * version depending on the default behaviour that was specified at
+ * ring creation time (see flags).
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj_p
+ * A pointer to a void * pointer (object) that will be filled.
+ * @return
+ * - 0: Success, objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue, no object is
+ * dequeued.
+ */
+static inline int
+rte_ring_dequeue(struct rte_ring *r, void **obj_p)
+{
+ if (r->cons.sc_dequeue)
+ return rte_ring_sc_dequeue(r, obj_p);
+ else
+ return rte_ring_mc_dequeue(r, obj_p);
+}
+
+/**
+ * Test if a ring is full.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * - 1: The ring is full.
+ * - 0: The ring is not full.
+ */
+static inline int
+rte_ring_full(const struct rte_ring *r)
+{
+ uint32_t prod_tail = r->prod.tail;
+ uint32_t cons_tail = r->cons.tail;
+ return (((cons_tail - prod_tail - 1) & r->prod.mask) == 0);
+}
+
+/**
+ * Test if a ring is empty.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * - 1: The ring is empty.
+ * - 0: The ring is not empty.
+ */
+static inline int
+rte_ring_empty(const struct rte_ring *r)
+{
+ uint32_t prod_tail = r->prod.tail;
+ uint32_t cons_tail = r->cons.tail;
+ return !!(cons_tail == prod_tail);
+}
+
+/**
+ * Return the number of entries in a ring.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * The number of entries in the ring.
+ */
+static inline unsigned
+rte_ring_count(const struct rte_ring *r)
+{
+ uint32_t prod_tail = r->prod.tail;
+ uint32_t cons_tail = r->cons.tail;
+ return ((prod_tail - cons_tail) & r->prod.mask);
+}
+
+/**
+ * Return the number of free entries in a ring.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * The number of free entries in the ring.
+ */
+static inline unsigned
+rte_ring_free_count(const struct rte_ring *r)
+{
+ uint32_t prod_tail = r->prod.tail;
+ uint32_t cons_tail = r->cons.tail;
+ return ((cons_tail - prod_tail - 1) & r->prod.mask);
+}
+
+/**
+ * Dump the status of all rings on the console
+ */
+void rte_ring_list_dump(void);
+
+/**
+ * Search a ring from its name
+ *
+ * @param name
+ * The name of the ring.
+ * @return
+ * The pointer to the ring matching the name, or NULL if not found,
+ * with rte_errno set appropriately. Possible rte_errno values include:
+ * - ENOENT - required entry not available to return.
+ */
+struct rte_ring *rte_ring_lookup(const char *name);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_RING_H_ */