X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=lib%2Flibrte_ring%2Frte_ring.h;h=3400ed885939c5b8c626a899e72945059dc6f4ad;hb=7555c20f2c2df8dbcf648e97a7005966048a0353;hp=f928324d959784069017864ef75963c9352bfd3c;hpb=7b53c036e6bf56623b8273018ff1c8cc62847857;p=deb_dpdk.git

diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index f928324d..3400ed88 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -1,7 +1,7 @@
 /*-
  *   BSD LICENSE
  *
- *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   Copyright(c) 2010-2017 Intel Corporation. All rights reserved.
  *   All rights reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
@@ -106,38 +106,30 @@ extern "C" {
 
 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 */
+	RTE_RING_QUEUE_VARIABLE   /* Enq/Deq as many items as 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_MZ_PREFIX "RG_"
 /**< The maximum length of a ring name. */
 #define RTE_RING_NAMESIZE (RTE_MEMZONE_NAMESIZE - \
 			   sizeof(RTE_RING_MZ_PREFIX) + 1)
 
-#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. */
+struct rte_memzone; /* forward declaration, so as not to require memzone.h */
+
+#if RTE_CACHE_LINE_SIZE < 128
+#define PROD_ALIGN (RTE_CACHE_LINE_SIZE * 2)
+#define CONS_ALIGN (RTE_CACHE_LINE_SIZE * 2)
+#else
+#define PROD_ALIGN RTE_CACHE_LINE_SIZE
+#define CONS_ALIGN RTE_CACHE_LINE_SIZE
 #endif
 
-struct rte_memzone; /* forward declaration, so as not to require memzone.h */
+/* structure to hold a pair of head/tail values and other metadata */
+struct rte_ring_headtail {
+	volatile uint32_t head;  /**< Prod/consumer head. */
+	volatile uint32_t tail;  /**< Prod/consumer tail. */
+	uint32_t single;         /**< True if single prod/cons */
+};
 
 /**
  * An RTE ring structure.
@@ -155,68 +147,29 @@ struct rte_ring {
 	 * compatibility requirements, it could be changed to RTE_RING_NAMESIZE
 	 * next time the ABI changes
 	 */
-	char name[RTE_MEMZONE_NAMESIZE];    /**< Name of the ring. */
-	int flags;                       /**< Flags supplied at creation. */
+	char name[RTE_MEMZONE_NAMESIZE] __rte_cache_aligned; /**< Name of the ring. */
+	int flags;               /**< Flags supplied at creation. */
 	const struct rte_memzone *memzone;
 			/**< Memzone, if any, containing the rte_ring */
+	uint32_t size;           /**< Size of ring. */
+	uint32_t mask;           /**< Mask (size-1) of 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;
+	struct rte_ring_headtail prod __rte_aligned(PROD_ALIGN);
 
 	/** 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 */
+	struct rte_ring_headtail cons __rte_aligned(CONS_ALIGN);
 };
 
 #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
+/* @internal defines for passing to the enqueue dequeue worker functions */
+#define __IS_SP 1
+#define __IS_MP 0
+#define __IS_SC 1
+#define __IS_MC 0
 
 /**
  * Calculate the memory size needed for a ring
@@ -321,27 +274,7 @@ struct rte_ring *rte_ring_create(const char *name, unsigned count,
 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.
+ * Dump the status of the ring to a file.
  *
  * @param f
  *   A pointer to a file for output
@@ -353,171 +286,147 @@ 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; \
+#define ENQUEUE_PTRS(r, ring_start, prod_head, obj_table, n, obj_type) do { \
+	unsigned int i; \
+	const uint32_t size = (r)->size; \
+	uint32_t idx = prod_head & (r)->mask; \
+	obj_type *ring = (obj_type *)ring_start; \
 	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]; \
+			ring[idx] = obj_table[i]; \
+			ring[idx+1] = obj_table[i+1]; \
+			ring[idx+2] = obj_table[i+2]; \
+			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++]; \
+		case 3: \
+			ring[idx++] = obj_table[i++]; /* fallthrough */ \
+		case 2: \
+			ring[idx++] = obj_table[i++]; /* fallthrough */ \
+		case 1: \
+			ring[idx++] = obj_table[i++]; \
 		} \
 	} else { \
 		for (i = 0; idx < size; i++, idx++)\
-			r->ring[idx] = obj_table[i]; \
+			ring[idx] = obj_table[i]; \
 		for (idx = 0; i < n; i++, idx++) \
-			r->ring[idx] = obj_table[i]; \
+			ring[idx] = obj_table[i]; \
 	} \
-} while(0)
+} 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; \
+#define DEQUEUE_PTRS(r, ring_start, cons_head, obj_table, n, obj_type) do { \
+	unsigned int i; \
+	uint32_t idx = cons_head & (r)->mask; \
+	const uint32_t size = (r)->size; \
+	obj_type *ring = (obj_type *)ring_start; \
 	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]; \
+			obj_table[i] = ring[idx]; \
+			obj_table[i+1] = ring[idx+1]; \
+			obj_table[i+2] = ring[idx+2]; \
+			obj_table[i+3] = 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++]; \
+		case 3: \
+			obj_table[i++] = ring[idx++]; /* fallthrough */ \
+		case 2: \
+			obj_table[i++] = ring[idx++]; /* fallthrough */ \
+		case 1: \
+			obj_table[i++] = ring[idx++]; \
 		} \
 	} else { \
 		for (i = 0; idx < size; i++, idx++) \
-			obj_table[i] = r->ring[idx]; \
+			obj_table[i] = ring[idx]; \
 		for (idx = 0; i < n; i++, idx++) \
-			obj_table[i] = r->ring[idx]; \
+			obj_table[i] = ring[idx]; \
 	} \
 } while (0)
 
+static inline __attribute__((always_inline)) void
+update_tail(struct rte_ring_headtail *ht, uint32_t old_val, uint32_t new_val,
+		uint32_t single)
+{
+	/*
+	 * If there are other enqueues/dequeues in progress that preceded us,
+	 * we need to wait for them to complete
+	 */
+	if (!single)
+		while (unlikely(ht->tail != old_val))
+			rte_pause();
+
+	ht->tail = new_val;
+}
+
 /**
- * @internal Enqueue several objects on the ring (multi-producers safe).
- *
- * This function uses a "compare and set" instruction to move the
- * producer index atomically.
+ * @internal This function updates the producer head for enqueue
  *
  * @param r
- *   A pointer to the ring structure.
- * @param obj_table
- *   A pointer to a table of void * pointers (objects).
+ *   A pointer to the ring structure
+ * @param is_sp
+ *   Indicates whether multi-producer path is needed or not
  * @param n
- *   The number of objects to add in the ring from the obj_table.
+ *   The number of elements we will want to enqueue, i.e. how far should the
+ *   head be moved
  * @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
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible from ring
+ * @param old_head
+ *   Returns head value as it was before the move, i.e. where enqueue starts
+ * @param new_head
+ *   Returns the current/new head value i.e. where enqueue finishes
+ * @param free_entries
+ *   Returns the amount of free space in the ring BEFORE head was moved
  * @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.
+ *   Actual number of objects enqueued.
+ *   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
  */
-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)
+static inline __attribute__((always_inline)) unsigned int
+__rte_ring_move_prod_head(struct rte_ring *r, int is_sp,
+		unsigned int n, enum rte_ring_queue_behavior behavior,
+		uint32_t *old_head, uint32_t *new_head,
+		uint32_t *free_entries)
 {
-	uint32_t prod_head, prod_next;
-	uint32_t cons_tail, free_entries;
-	const unsigned max = n;
+	const uint32_t mask = r->mask;
+	unsigned int 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;
+		*old_head = r->prod.head;
+		const uint32_t 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
+		 * *old_head > cons_tail). So 'free_entries' is always between 0
 		 * and size(ring)-1. */
-		free_entries = (mask + cons_tail - prod_head);
+		*free_entries = (mask + cons_tail - *old_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);
+		if (unlikely(n > *free_entries))
+			n = (behavior == RTE_RING_QUEUE_FIXED) ?
+					0 : *free_entries;
+
+		if (n == 0)
+			return 0;
+
+		*new_head = *old_head + n;
+		if (is_sp)
+			r->prod.head = *new_head, success = 1;
+		else
+			success = rte_atomic32_cmpset(&r->prod.head,
+					*old_head, *new_head);
 	} 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;
+	return n;
 }
 
 /**
- * @internal Enqueue several objects on a ring (NOT multi-producers safe).
+ * @internal Enqueue several objects on the ring
  *
- * @param r
+  * @param r
  *   A pointer to the ring structure.
  * @param obj_table
  *   A pointer to a table of void * pointers (objects).
@@ -525,242 +434,142 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
  *   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
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible from ring
+ * @param is_sp
+ *   Indicates whether to use single producer or multi-producer head update
+ * @param free_space
+ *   returns the amount of space after the enqueue operation has finished
  * @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.
+ *   Actual number of objects enqueued.
+ *   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
  */
-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)
+static inline __attribute__((always_inline)) unsigned int
+__rte_ring_do_enqueue(struct rte_ring *r, void * const *obj_table,
+		 unsigned int n, enum rte_ring_queue_behavior behavior,
+		 int is_sp, unsigned int *free_space)
 {
-	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();
+	uint32_t prod_head, prod_next;
+	uint32_t free_entries;
+
+	n = __rte_ring_move_prod_head(r, is_sp, n, behavior,
+			&prod_head, &prod_next, &free_entries);
+	if (n == 0)
+		goto end;
+
+	ENQUEUE_PTRS(r, &r[1], prod_head, obj_table, n, void *);
 	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;
+	update_tail(&r->prod, prod_head, prod_next, is_sp);
+end:
+	if (free_space != NULL)
+		*free_space = free_entries - n;
+	return n;
 }
 
 /**
- * @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.
+ * @internal This function updates the consumer head for dequeue
  *
  * @param r
- *   A pointer to the ring structure.
- * @param obj_table
- *   A pointer to a table of void * pointers (objects) that will be filled.
+ *   A pointer to the ring structure
+ * @param is_sc
+ *   Indicates whether multi-consumer path is needed or not
  * @param n
- *   The number of objects to dequeue from the ring to the obj_table.
+ *   The number of elements we will want to enqueue, i.e. how far should the
+ *   head be moved
  * @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
+ *   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from ring
+ * @param old_head
+ *   Returns head value as it was before the move, i.e. where dequeue starts
+ * @param new_head
+ *   Returns the current/new head value i.e. where dequeue finishes
+ * @param entries
+ *   Returns the number of entries in the ring BEFORE head was moved
  * @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.
+ *   - Actual number of objects dequeued.
+ *     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
  */
-
-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)
+static inline __attribute__((always_inline)) unsigned int
+__rte_ring_move_cons_head(struct rte_ring *r, int is_sc,
+		unsigned int n, enum rte_ring_queue_behavior behavior,
+		uint32_t *old_head, uint32_t *new_head,
+		uint32_t *entries)
 {
-	uint32_t cons_head, prod_tail;
-	uint32_t cons_next, entries;
-	const unsigned max = n;
+	unsigned int 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;
+		*old_head = r->cons.head;
+		const uint32_t 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);
+		*entries = (prod_tail - *old_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);
+		if (n > *entries)
+			n = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : *entries;
+
+		if (unlikely(n == 0))
+			return 0;
+
+		*new_head = *old_head + n;
+		if (is_sc)
+			r->cons.head = *new_head, success = 1;
+		else
+			success = rte_atomic32_cmpset(&r->cons.head, *old_head,
+					*new_head);
 	} 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;
+	return 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
+ * @internal Dequeue several objects from the ring
  *
  * @param r
  *   A pointer to the ring structure.
  * @param obj_table
- *   A pointer to a table of void * pointers (objects) that will be filled.
+ *   A pointer to a table of void * pointers (objects).
  * @param n
- *   The number of objects to dequeue from the ring to the obj_table.
+ *   The number of objects to pull from the ring.
  * @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
+ *   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from ring
+ * @param is_sc
+ *   Indicates whether to use single consumer or multi-consumer head update
+ * @param available
+ *   returns the number of remaining ring entries after the dequeue has finished
  * @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.
+ *   - Actual number of objects dequeued.
+ *     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
  */
-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)
+static inline __attribute__((always_inline)) unsigned int
+__rte_ring_do_dequeue(struct rte_ring *r, void **obj_table,
+		 unsigned int n, enum rte_ring_queue_behavior behavior,
+		 int is_sc, unsigned int *available)
 {
-	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();
+	uint32_t cons_head, cons_next;
+	uint32_t entries;
+
+	n = __rte_ring_move_cons_head(r, is_sc, n, behavior,
+			&cons_head, &cons_next, &entries);
+	if (n == 0)
+		goto end;
 
-	__RING_STAT_ADD(r, deq_success, n);
-	r->cons.tail = cons_next;
-	return behavior == RTE_RING_QUEUE_FIXED ? 0 : n;
+	DEQUEUE_PTRS(r, &r[1], cons_head, obj_table, n, void *);
+	rte_smp_rmb();
+
+	update_tail(&r->cons, cons_head, cons_next, is_sc);
+
+end:
+	if (available != NULL)
+		*available = entries - n;
+	return n;
 }
 
 /**
@@ -775,17 +584,18 @@ __rte_ring_sc_do_dequeue(struct rte_ring *r, void **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 free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @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.
+ *   The number of objects enqueued, either 0 or n
  */
-static inline int __attribute__((always_inline))
+static inline unsigned int __attribute__((always_inline))
 rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
-			 unsigned n)
+			 unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+	return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
+			__IS_MP, free_space);
 }
 
 /**
@@ -797,17 +607,18 @@ rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *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 free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @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.
+ *   The number of objects enqueued, either 0 or n
  */
-static inline int __attribute__((always_inline))
+static inline unsigned int __attribute__((always_inline))
 rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
-			 unsigned n)
+			 unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+	return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
+			__IS_SP, free_space);
 }
 
 /**
@@ -823,20 +634,18 @@ rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *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 free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @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.
+ *   The number of objects enqueued, either 0 or n
  */
-static inline int __attribute__((always_inline))
+static inline unsigned int __attribute__((always_inline))
 rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
-		      unsigned n)
+		      unsigned int n, unsigned int *free_space)
 {
-	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);
+	return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
+			r->prod.single, free_space);
 }
 
 /**
@@ -851,14 +660,12 @@ rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
  *   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);
+	return rte_ring_mp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
 }
 
 /**
@@ -870,14 +677,12 @@ rte_ring_mp_enqueue(struct rte_ring *r, void *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);
+	return rte_ring_sp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
 }
 
 /**
@@ -893,17 +698,12 @@ rte_ring_sp_enqueue(struct rte_ring *r, void *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);
+	return rte_ring_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
 }
 
 /**
@@ -918,15 +718,18 @@ rte_ring_enqueue(struct rte_ring *r, void *obj)
  *   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 available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
  * @return
- *   - 0: Success; objects dequeued.
- *   - -ENOENT: Not enough entries in the ring to dequeue; no object is
- *     dequeued.
+ *   The number of objects dequeued, either 0 or n
  */
-static inline int __attribute__((always_inline))
-rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+static inline unsigned int __attribute__((always_inline))
+rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table,
+		unsigned int n, unsigned int *available)
 {
-	return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+	return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
+			__IS_MC, available);
 }
 
 /**
@@ -939,15 +742,18 @@ rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
  * @param n
  *   The number of objects to dequeue from the ring to the obj_table,
  *   must be strictly positive.
+ * @param available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
  * @return
- *   - 0: Success; objects dequeued.
- *   - -ENOENT: Not enough entries in the ring to dequeue; no object is
- *     dequeued.
+ *   The number of objects dequeued, either 0 or n
  */
-static inline int __attribute__((always_inline))
-rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+static inline unsigned int __attribute__((always_inline))
+rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table,
+		unsigned int n, unsigned int *available)
 {
-	return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+	return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
+			__IS_SC, available);
 }
 
 /**
@@ -963,18 +769,18 @@ rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
  *   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 available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
  * @return
- *   - 0: Success; objects dequeued.
- *   - -ENOENT: Not enough entries in the ring to dequeue, no object is
- *     dequeued.
+ *   The number of objects dequeued, either 0 or n
  */
-static inline int __attribute__((always_inline))
-rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+static inline unsigned int __attribute__((always_inline))
+rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned int n,
+		unsigned int *available)
 {
-	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);
+	return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
+				r->cons.single, available);
 }
 
 /**
@@ -995,7 +801,7 @@ rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
 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);
+	return rte_ring_mc_dequeue_bulk(r, obj_p, 1, NULL)  ? 0 : -ENOENT;
 }
 
 /**
@@ -1013,7 +819,7 @@ rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
 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);
+	return rte_ring_sc_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
 }
 
 /**
@@ -1035,10 +841,7 @@ rte_ring_sc_dequeue(struct rte_ring *r, void **obj_p)
 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);
+	return rte_ring_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
 }
 
 /**
@@ -1055,7 +858,7 @@ 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;
+	return ((cons_tail - prod_tail - 1) & r->mask) == 0;
 }
 
 /**
@@ -1088,7 +891,7 @@ 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 (prod_tail - cons_tail) & r->mask;
 }
 
 /**
@@ -1104,7 +907,21 @@ 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;
+	return (cons_tail - prod_tail - 1) & r->mask;
+}
+
+/**
+ * Return the size of the ring.
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @return
+ *   The number of elements which can be stored in the ring.
+ */
+static inline unsigned int
+rte_ring_get_size(const struct rte_ring *r)
+{
+	return r->size;
 }
 
 /**
@@ -1139,14 +956,18 @@ struct rte_ring *rte_ring_lookup(const char *name);
  *   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 free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @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)
+			 unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+	return __rte_ring_do_enqueue(r, obj_table, n,
+			RTE_RING_QUEUE_VARIABLE, __IS_MP, free_space);
 }
 
 /**
@@ -1158,14 +979,18 @@ rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *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 free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @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)
+			 unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+	return __rte_ring_do_enqueue(r, obj_table, n,
+			RTE_RING_QUEUE_VARIABLE, __IS_SP, free_space);
 }
 
 /**
@@ -1181,17 +1006,18 @@ rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *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 free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
  * @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)
+		      unsigned int n, unsigned int *free_space)
 {
-	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);
+	return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE,
+			r->prod.single, free_space);
 }
 
 /**
@@ -1208,13 +1034,18 @@ rte_ring_enqueue_burst(struct rte_ring *r, void * const *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 available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
  * @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)
+rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table,
+		unsigned int n, unsigned int *available)
 {
-	return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+	return __rte_ring_do_dequeue(r, obj_table, n,
+			RTE_RING_QUEUE_VARIABLE, __IS_MC, available);
 }
 
 /**
@@ -1228,13 +1059,18 @@ rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
  *   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 available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
  * @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)
+rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table,
+		unsigned int n, unsigned int *available)
 {
-	return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+	return __rte_ring_do_dequeue(r, obj_table, n,
+			RTE_RING_QUEUE_VARIABLE, __IS_SC, available);
 }
 
 /**
@@ -1250,16 +1086,19 @@ rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
  *   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 available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
  * @return
  *   - Number of objects dequeued
  */
 static inline unsigned __attribute__((always_inline))
-rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
+rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table,
+		unsigned int n, unsigned int *available)
 {
-	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);
+	return __rte_ring_do_dequeue(r, obj_table, n,
+				RTE_RING_QUEUE_VARIABLE,
+				r->cons.single, available);
 }
 
 #ifdef __cplusplus