Imported Upstream version 16.04

Change-Id: I77eadcd8538a9122e4773cbe55b24033dc451757
Signed-off-by: C.J. Collier <cjcollier@linuxfoundation.org>

1 files changed, 1261 insertions, 0 deletions

diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
new file mode 100644
index 00000000..eb45e414
--- /dev/null
+++ b/lib/librte_ring/rte_ring.h
@@ -0,0 +1,1261 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2014 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.
+ */
+
+/*
+ * 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 <stdio.h>
+#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>
+
+#define RTE_TAILQ_RING_NAME "RTE_RING"
+
+enum rte_ring_queue_behavior {
+	RTE_RING_QUEUE_FIXED = 0, /* Enq/Deq a fixed number of items from a ring */
+	RTE_RING_QUEUE_VARIABLE   /* Enq/Deq as many items a possible from ring */
+};
+
+#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. */
+#define RTE_RING_MZ_PREFIX "RG_"
+
+#ifndef RTE_RING_PAUSE_REP_COUNT
+#define RTE_RING_PAUSE_REP_COUNT 0 /**< Yield after pause num of times, no yield
+                                    *   if RTE_RING_PAUSE_REP not defined. */
+#endif
+
+struct rte_memzone; /* forward declaration, so as not to require memzone.h */
+
+/**
+ * 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 {
+	char name[RTE_RING_NAMESIZE];    /**< Name of the ring. */
+	int flags;                       /**< Flags supplied at creation. */
+	const struct rte_memzone *memzone;
+			/**< Memzone, if any, containing the rte_ring */
+
+	/** Ring producer status. */
+	struct prod {
+		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 {
+		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. */
+#ifdef RTE_RING_SPLIT_PROD_CONS
+	} cons __rte_cache_aligned;
+#else
+	} cons;
+#endif
+
+#ifdef RTE_LIBRTE_RING_DEBUG
+	struct rte_ring_debug_stats stats[RTE_MAX_LCORE];
+#endif
+
+	void * ring[0] __rte_cache_aligned; /**< Memory space of ring starts here.
+	                                     * not volatile so need to be careful
+	                                     * about compiler re-ordering */
+};
+
+#define RING_F_SP_ENQ 0x0001 /**< The default enqueue is "single-producer". */
+#define RING_F_SC_DEQ 0x0002 /**< The default dequeue is "single-consumer". */
+#define RTE_RING_QUOT_EXCEED (1 << 31)  /**< Quota exceed for burst ops */
+#define RTE_RING_SZ_MASK  (unsigned)(0x0fffffff) /**< Ring size mask */
+
+/**
+ * @internal 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();           \
+		if (__lcore_id < RTE_MAX_LCORE) {               \
+			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
+
+/**
+ * Calculate the memory size needed for a ring
+ *
+ * This function returns the number of bytes needed for a ring, given
+ * the number of elements in it. This value is the sum of the size of
+ * the structure rte_ring and the size of the memory needed by the
+ * objects pointers. The value is aligned to a cache line size.
+ *
+ * @param count
+ *   The number of elements in the ring (must be a power of 2).
+ * @return
+ *   - The memory size needed for the ring on success.
+ *   - -EINVAL if count is not a power of 2.
+ */
+ssize_t rte_ring_get_memsize(unsigned count);
+
+/**
+ * Initialize a ring structure.
+ *
+ * Initialize a ring structure in memory pointed by "r". The size of the
+ * memory area must be large enough to store the ring structure and the
+ * object table. It is advised to use rte_ring_get_memsize() to get the
+ * appropriate size.
+ *
+ * The ring size is set to *count*, which must be a power of two. Water
+ * marking is disabled by default. The real usable ring size is
+ * *count-1* instead of *count* to differentiate a free ring from an
+ * empty ring.
+ *
+ * The ring is not added in RTE_TAILQ_RING global list. Indeed, the
+ * memory given by the caller may not be shareable among dpdk
+ * processes.
+ *
+ * @param r
+ *   The pointer to the ring structure followed by the objects table.
+ * @param name
+ *   The name of the ring.
+ * @param count
+ *   The number of elements in the ring (must be a power of 2).
+ * @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
+ *   0 on success, or a negative value on error.
+ */
+int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
+	unsigned flags);
+
+/**
+ * Create a new ring named *name* in memory.
+ *
+ * This function uses ``memzone_reserve()`` to allocate memory. Then it
+ * calls rte_ring_init() to initialize an empty ring.
+ *
+ * The new ring size is set to *count*, which must be a power of
+ * two. Water marking is disabled by default. The real usable ring size
+ * is *count-1* instead of *count* to differentiate a free ring from an
+ * empty ring.
+ *
+ * The ring is added in RTE_TAILQ_RING list.
+ *
+ * @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
+ *    - 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);
+/**
+ * De-allocate all memory used by the ring.
+ *
+ * @param r
+ *   Ring to free
+ */
+void rte_ring_free(struct rte_ring *r);
+
+/**
+ * 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 necessarily 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 f
+ *   A pointer to a file for output
+ * @param r
+ *   A pointer to the ring structure.
+ */
+void rte_ring_dump(FILE *f, const struct rte_ring *r);
+
+/* the actual enqueue of pointers on the ring.
+ * Placed here since identical code needed in both
+ * single and multi producer enqueue functions */
+#define ENQUEUE_PTRS() do { \
+	const uint32_t size = r->prod.size; \
+	uint32_t idx = prod_head & mask; \
+	if (likely(idx + n < size)) { \
+		for (i = 0; i < (n & ((~(unsigned)0x3))); i+=4, idx+=4) { \
+			r->ring[idx] = obj_table[i]; \
+			r->ring[idx+1] = obj_table[i+1]; \
+			r->ring[idx+2] = obj_table[i+2]; \
+			r->ring[idx+3] = obj_table[i+3]; \
+		} \
+		switch (n & 0x3) { \
+			case 3: r->ring[idx++] = obj_table[i++]; \
+			case 2: r->ring[idx++] = obj_table[i++]; \
+			case 1: r->ring[idx++] = obj_table[i++]; \
+		} \
+	} else { \
+		for (i = 0; idx < size; i++, idx++)\
+			r->ring[idx] = obj_table[i]; \
+		for (idx = 0; i < n; i++, idx++) \
+			r->ring[idx] = obj_table[i]; \
+	} \
+} while(0)
+
+/* the actual copy of pointers on the ring to obj_table.
+ * Placed here since identical code needed in both
+ * single and multi consumer dequeue functions */
+#define DEQUEUE_PTRS() do { \
+	uint32_t idx = cons_head & mask; \
+	const uint32_t size = r->cons.size; \
+	if (likely(idx + n < size)) { \
+		for (i = 0; i < (n & (~(unsigned)0x3)); i+=4, idx+=4) {\
+			obj_table[i] = r->ring[idx]; \
+			obj_table[i+1] = r->ring[idx+1]; \
+			obj_table[i+2] = r->ring[idx+2]; \
+			obj_table[i+3] = r->ring[idx+3]; \
+		} \
+		switch (n & 0x3) { \
+			case 3: obj_table[i++] = r->ring[idx++]; \
+			case 2: obj_table[i++] = r->ring[idx++]; \
+			case 1: obj_table[i++] = r->ring[idx++]; \
+		} \
+	} else { \
+		for (i = 0; idx < size; i++, idx++) \
+			obj_table[i] = r->ring[idx]; \
+		for (idx = 0; i < n; i++, idx++) \
+			obj_table[i] = r->ring[idx]; \
+	} \
+} while (0)
+
+/**
+ * @internal 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.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items from a ring
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items a possible from ring
+ * @return
+ *   Depend on the behavior value
+ *   if behavior = RTE_RING_QUEUE_FIXED
+ *   - 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.
+ *   if behavior = RTE_RING_QUEUE_VARIABLE
+ *   - n: Actual number of objects enqueued.
+ */
+static inline int __attribute__((always_inline))
+__rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
+			 unsigned n, enum rte_ring_queue_behavior behavior)
+{
+	uint32_t prod_head, prod_next;
+	uint32_t cons_tail, free_entries;
+	const unsigned max = n;
+	int success;
+	unsigned i, rep = 0;
+	uint32_t mask = r->prod.mask;
+	int ret;
+
+	/* Avoid the unnecessary cmpset operation below, which is also
+	 * potentially harmful when n equals 0. */
+	if (n == 0)
+		return 0;
+
+	/* move prod.head atomically */
+	do {
+		/* Reset n to the initial burst count */
+		n = max;
+
+		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)) {
+			if (behavior == RTE_RING_QUEUE_FIXED) {
+				__RING_STAT_ADD(r, enq_fail, n);
+				return -ENOBUFS;
+			}
+			else {
+				/* No free entry available */
+				if (unlikely(free_entries == 0)) {
+					__RING_STAT_ADD(r, enq_fail, n);
+					return 0;
+				}
+
+				n = free_entries;
+			}
+		}
+
+		prod_next = prod_head + n;
+		success = rte_atomic32_cmpset(&r->prod.head, prod_head,
+					      prod_next);
+	} while (unlikely(success == 0));
+
+	/* write entries in ring */
+	ENQUEUE_PTRS();
+	rte_smp_wmb();
+
+	/* if we exceed the watermark */
+	if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
+		ret = (behavior == RTE_RING_QUEUE_FIXED) ? -EDQUOT :
+				(int)(n | RTE_RING_QUOT_EXCEED);
+		__RING_STAT_ADD(r, enq_quota, n);
+	}
+	else {
+		ret = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : n;
+		__RING_STAT_ADD(r, enq_success, n);
+	}
+
+	/*
+	 * If there are other enqueues in progress that preceded us,
+	 * we need to wait for them to complete
+	 */
+	while (unlikely(r->prod.tail != prod_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();
+		}
+	}
+	r->prod.tail = prod_next;
+	return ret;
+}
+
+/**
+ * @internal 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.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items from a ring
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items a possible from ring
+ * @return
+ *   Depend on the behavior value
+ *   if behavior = RTE_RING_QUEUE_FIXED
+ *   - 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.
+ *   if behavior = RTE_RING_QUEUE_VARIABLE
+ *   - n: Actual number of objects enqueued.
+ */
+static inline int __attribute__((always_inline))
+__rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
+			 unsigned n, enum rte_ring_queue_behavior behavior)
+{
+	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)) {
+		if (behavior == RTE_RING_QUEUE_FIXED) {
+			__RING_STAT_ADD(r, enq_fail, n);
+			return -ENOBUFS;
+		}
+		else {
+			/* No free entry available */
+			if (unlikely(free_entries == 0)) {
+				__RING_STAT_ADD(r, enq_fail, n);
+				return 0;
+			}
+
+			n = free_entries;
+		}
+	}
+
+	prod_next = prod_head + n;
+	r->prod.head = prod_next;
+
+	/* write entries in ring */
+	ENQUEUE_PTRS();
+	rte_smp_wmb();
+
+	/* if we exceed the watermark */
+	if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
+		ret = (behavior == RTE_RING_QUEUE_FIXED) ? -EDQUOT :
+			(int)(n | RTE_RING_QUOT_EXCEED);
+		__RING_STAT_ADD(r, enq_quota, n);
+	}
+	else {
+		ret = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : n;
+		__RING_STAT_ADD(r, enq_success, n);
+	}
+
+	r->prod.tail = prod_next;
+	return ret;
+}
+
+/**
+ * @internal Dequeue several objects from a ring (multi-consumers safe). When
+ * the request objects are more than the available objects, only dequeue the
+ * actual number of objects
+ *
+ * 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.
+ * @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_mc_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;
+	const unsigned max = n;
+	int success;
+	unsigned i, rep = 0;
+	uint32_t mask = r->prod.mask;
+
+	/* Avoid the unnecessary cmpset operation below, which is also
+	 * potentially harmful when n equals 0. */
+	if (n == 0)
+		return 0;
+
+	/* move cons.head atomically */
+	do {
+		/* Restore n as it may change every loop */
+		n = max;
+
+		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);
+
+		/* Set the actual entries for dequeue */
+		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;
+		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_rmb();
+
+	__RING_STAT_ADD(r, deq_success, n);
+	r->cons.tail = cons_next;
+	return behavior == RTE_RING_QUEUE_FIXED ? 0 : n;
+}
+
+/**
+ * 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.
+ * @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 __attribute__((always_inline))
+rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
+			 unsigned n)
+{
+	return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+}
+
+/**
+ * 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.
+ * @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 __attribute__((always_inline))
+rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
+			 unsigned n)
+{
+	return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+}
+
+/**
+ * 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 __attribute__((always_inline))
+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 __attribute__((always_inline))
+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 __attribute__((always_inline))
+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 __attribute__((always_inline))
+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.
+ * @return
+ *   - 0: Success; objects dequeued.
+ *   - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ *     dequeued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+{
+	return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+}
+
+/**
+ * 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 __attribute__((always_inline))
+rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+{
+	return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+}
+
+/**
+ * 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 __attribute__((always_inline))
+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 __attribute__((always_inline))
+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 __attribute__((always_inline))
+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 __attribute__((always_inline))
+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
+ *
+ * @param f
+ *   A pointer to a file for output
+ */
+void rte_ring_list_dump(FILE *f);
+
+/**
+ * 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);
+
+/**
+ * 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.
+ * @return
+ *   - n: Actual number of objects enqueued.
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
+			 unsigned n)
+{
+	return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+}
+
+/**
+ * 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.
+ * @return
+ *   - n: Actual number of objects enqueued.
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
+			 unsigned n)
+{
+	return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+}
+
+/**
+ * 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
+ *   - n: Actual number of objects enqueued.
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
+		      unsigned n)
+{
+	if (r->prod.sp_enqueue)
+		return rte_ring_sp_enqueue_burst(r, obj_table, n);
+	else
+		return rte_ring_mp_enqueue_burst(r, obj_table, n);
+}
+
+/**
+ * Dequeue several objects from a ring (multi-consumers safe). When the request
+ * objects are more than the available objects, only dequeue the actual number
+ * of objects
+ *
+ * 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.
+ * @return
+ *   - n: Actual number of objects dequeued, 0 if ring is empty
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
+{
+	return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+}
+
+/**
+ * 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.
+ * @return
+ *   - n: Actual number of objects dequeued, 0 if ring is empty
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
+{
+	return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+}
+
+/**
+ * Dequeue multiple objects from a ring up to a maximum number.
+ *
+ * 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
+ *   - Number of objects dequeued
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
+{
+	if (r->cons.sc_dequeue)
+		return rte_ring_sc_dequeue_burst(r, obj_table, n);
+	else
+		return rte_ring_mc_dequeue_burst(r, obj_table, n);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_RING_H_ */