[PATCH v6 1/5] mempool: support external handler

[David Hunt <david.hunt@intel.com>]

Until now, the objects stored in a mempool were internally stored in a
ring. This patch introduces the possibility to register external handlers
replacing the ring.

The default behavior remains unchanged, but calling the new function
rte_mempool_set_handler() right after rte_mempool_create_empty() allows
the user to change the handler that will be used when populating
the mempool.

v7 changes:
  * Moved the flags handling from rte_mempool_create_empty to
    rte_mempool_create, as it's only there for backward compatibility
  * Various comment additions and cleanup
  * Renamed rte_mempool_handler to rte_mempool_ops
  * Added a union for *pool and u64 pool_id in struct rte_mempool

v6 changes:
  * split the original patch into a few parts for easier review.
  * rename functions with _ext_ to _ops_.
  * addressed some review comments
  * renamed put and get functions to enqueue and dequeue
  * renamed rte_mempool_handler struct to rte_mempool_handler_ops
  * changed occurences of rte_mempool_handler_ops to const, as they
    contain function pointers (security)
  * added some extra comments

v5 changes: rebasing on top of 35 patch set mempool work.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Signed-off-by: David Hunt <david.hunt@intel.com>
---
 lib/librte_mempool/Makefile              |   1 +
 lib/librte_mempool/rte_mempool.c         |  71 ++++------
 lib/librte_mempool/rte_mempool.h         | 235 ++++++++++++++++++++++++++++---
 lib/librte_mempool/rte_mempool_handler.c | 141 +++++++++++++++++++
 4 files changed, 384 insertions(+), 64 deletions(-)
 create mode 100644 lib/librte_mempool/rte_mempool_handler.c

diff --git a/lib/librte_mempool/Makefile b/lib/librte_mempool/Makefile
index 43423e0..793745f 100644
--- a/lib/librte_mempool/Makefile
+++ b/lib/librte_mempool/Makefile
@@ -42,6 +42,7 @@ LIBABIVER := 2
 
 # all source are stored in SRCS-y
 SRCS-$(CONFIG_RTE_LIBRTE_MEMPOOL) +=  rte_mempool.c
+SRCS-$(CONFIG_RTE_LIBRTE_MEMPOOL) +=  rte_mempool_handler.c
 # install includes
 SYMLINK-$(CONFIG_RTE_LIBRTE_MEMPOOL)-include := rte_mempool.h
 
diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index b54de43..9f34d30 100644
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -148,7 +148,7 @@ mempool_add_elem(struct rte_mempool *mp, void *obj, phys_addr_t physaddr)
 #endif
 
 	/* enqueue in ring */
-	rte_ring_sp_enqueue(mp->ring, obj);
+	rte_mempool_ops_enqueue_bulk(mp, &obj, 1);
 }
 
 /* call obj_cb() for each mempool element */
@@ -303,40 +303,6 @@ rte_mempool_xmem_usage(__rte_unused void *vaddr, uint32_t elt_num,
 	return (size_t)paddr_idx << pg_shift;
 }
 
-/* create the internal ring */
-static int
-rte_mempool_ring_create(struct rte_mempool *mp)
-{
-	int rg_flags = 0, ret;
-	char rg_name[RTE_RING_NAMESIZE];
-	struct rte_ring *r;
-
-	ret = snprintf(rg_name, sizeof(rg_name),
-		RTE_MEMPOOL_MZ_FORMAT, mp->name);
-	if (ret < 0 || ret >= (int)sizeof(rg_name))
-		return -ENAMETOOLONG;
-
-	/* ring flags */
-	if (mp->flags & MEMPOOL_F_SP_PUT)
-		rg_flags |= RING_F_SP_ENQ;
-	if (mp->flags & MEMPOOL_F_SC_GET)
-		rg_flags |= RING_F_SC_DEQ;
-
-	/* Allocate the ring that will be used to store objects.
-	 * Ring functions will return appropriate errors if we are
-	 * running as a secondary process etc., so no checks made
-	 * in this function for that condition.
-	 */
-	r = rte_ring_create(rg_name, rte_align32pow2(mp->size + 1),
-		mp->socket_id, rg_flags);
-	if (r == NULL)
-		return -rte_errno;
-
-	mp->ring = r;
-	mp->flags |= MEMPOOL_F_RING_CREATED;
-	return 0;
-}
-
 /* free a memchunk allocated with rte_memzone_reserve() */
 static void
 rte_mempool_memchunk_mz_free(__rte_unused struct rte_mempool_memhdr *memhdr,
@@ -354,7 +320,7 @@ rte_mempool_free_memchunks(struct rte_mempool *mp)
 	void *elt;
 
 	while (!STAILQ_EMPTY(&mp->elt_list)) {
-		rte_ring_sc_dequeue(mp->ring, &elt);
+		rte_mempool_ops_dequeue_bulk(mp, &elt, 1);
 		(void)elt;
 		STAILQ_REMOVE_HEAD(&mp->elt_list, next);
 		mp->populated_size--;
@@ -383,13 +349,16 @@ rte_mempool_populate_phys(struct rte_mempool *mp, char *vaddr,
 	unsigned i = 0;
 	size_t off;
 	struct rte_mempool_memhdr *memhdr;
-	int ret;
 
 	/* create the internal ring if not already done */
 	if ((mp->flags & MEMPOOL_F_RING_CREATED) == 0) {
-		ret = rte_mempool_ring_create(mp);
-		if (ret < 0)
-			return ret;
+		rte_errno = 0;
+		mp->pool = rte_mempool_ops_alloc(mp);
+		if (mp->pool == NULL) {
+			if (rte_errno == 0)
+				return -EINVAL;
+			return -rte_errno;
+		}
 	}
 
 	/* mempool is already populated */
@@ -703,7 +672,7 @@ rte_mempool_free(struct rte_mempool *mp)
 	rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 
 	rte_mempool_free_memchunks(mp);
-	rte_ring_free(mp->ring);
+	rte_mempool_ops_free(mp);
 	rte_memzone_free(mp->mz);
 }
 
@@ -815,6 +784,20 @@ rte_mempool_create_empty(const char *name, unsigned n, unsigned elt_size,
 		RTE_PTR_ADD(mp, MEMPOOL_HEADER_SIZE(mp, 0));
 
 	te->data = mp;
+
+	/*
+	 * Since we have 4 combinations of the SP/SC/MP/MC examine the flags to
+	 * set the correct index into the handler table.
+	 */
+	if (flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET))
+		rte_mempool_set_handler(mp, "ring_sp_sc");
+	else if (flags & MEMPOOL_F_SP_PUT)
+		rte_mempool_set_handler(mp, "ring_sp_mc");
+	else if (flags & MEMPOOL_F_SC_GET)
+		rte_mempool_set_handler(mp, "ring_mp_sc");
+	else
+		rte_mempool_set_handler(mp, "ring_mp_mc");
+
 	rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 	TAILQ_INSERT_TAIL(mempool_list, te, next);
 	rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
@@ -930,7 +913,7 @@ rte_mempool_count(const struct rte_mempool *mp)
 	unsigned count;
 	unsigned lcore_id;
 
-	count = rte_ring_count(mp->ring);
+	count = rte_mempool_ops_get_count(mp);
 
 	if (mp->cache_size == 0)
 		return count;
@@ -1123,7 +1106,7 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
 
 	fprintf(f, "mempool <%s>@%p\n", mp->name, mp);
 	fprintf(f, "  flags=%x\n", mp->flags);
-	fprintf(f, "  ring=<%s>@%p\n", mp->ring->name, mp->ring);
+	fprintf(f, "  pool=%p\n", mp->pool);
 	fprintf(f, "  phys_addr=0x%" PRIx64 "\n", mp->mz->phys_addr);
 	fprintf(f, "  nb_mem_chunks=%u\n", mp->nb_mem_chunks);
 	fprintf(f, "  size=%"PRIu32"\n", mp->size);
@@ -1144,7 +1127,7 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
 	}
 
 	cache_count = rte_mempool_dump_cache(f, mp);
-	common_count = rte_ring_count(mp->ring);
+	common_count = rte_mempool_ops_get_count(mp);
 	if ((cache_count + common_count) > mp->size)
 		common_count = mp->size - cache_count;
 	fprintf(f, "  common_pool_count=%u\n", common_count);
diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
index 60339bd..b659565 100644
--- a/lib/librte_mempool/rte_mempool.h
+++ b/lib/librte_mempool/rte_mempool.h
@@ -67,6 +67,7 @@
 #include <inttypes.h>
 #include <sys/queue.h>
 
+#include <rte_spinlock.h>
 #include <rte_log.h>
 #include <rte_debug.h>
 #include <rte_lcore.h>
@@ -204,9 +205,13 @@ struct rte_mempool_memhdr {
 struct rte_mempool {
 	char name[RTE_MEMPOOL_NAMESIZE]; /**< Name of mempool. */
 	struct rte_ring *ring;           /**< Ring to store objects. */
+	union {
+		void *pool;              /**< Ring or pool to store objects */
+		uint64_t *pool_id;       /**< External mempool identifier */
+	};
 	const struct rte_memzone *mz;    /**< Memzone where pool is allocated */
 	int flags;                       /**< Flags of the mempool. */
-	int socket_id;                   /**< Socket id passed at mempool creation. */
+	int socket_id;                   /**< Socket id passed at create */
 	uint32_t size;                   /**< Max size of the mempool. */
 	uint32_t cache_size;             /**< Size of per-lcore local cache. */
 	uint32_t cache_flushthresh;
@@ -217,6 +222,14 @@ struct rte_mempool {
 	uint32_t trailer_size;           /**< Size of trailer (after elt). */
 
 	unsigned private_data_size;      /**< Size of private data. */
+	/**
+	 * Index into rte_mempool_handler_table array of mempool handler ops
+	 * structs, which contain callback function pointers.
+	 * We're using an index here rather than pointers to the callbacks
+	 * to facilitate any secondary processes that may want to use
+	 * this mempool.
+	 */
+	int32_t handler_idx;
 
 	struct rte_mempool_cache *local_cache; /**< Per-lcore local cache */
 
@@ -325,6 +338,199 @@ void rte_mempool_check_cookies(const struct rte_mempool *mp,
 #define __mempool_check_cookies(mp, obj_table_const, n, free) do {} while(0)
 #endif /* RTE_LIBRTE_MEMPOOL_DEBUG */
 
+#define RTE_MEMPOOL_HANDLER_NAMESIZE 32 /**< Max length of handler name. */
+
+/**
+ * typedef for allocating the external pool.
+ * The handler's alloc function does whatever it needs to do to grab memory
+ * for this handler, and sets the *pool opaque pointer in the rte_mempool
+ * struct. In the default handler, *pool points to a ring,in other handlers,
+ * it will mostlikely point to a different type of data structure.
+ * It will be transparent to the application programmer.
+ */
+typedef void *(*rte_mempool_alloc_t)(struct rte_mempool *mp);
+
+/** Free the external pool opaque data (that pointed to by *pool) */
+typedef void (*rte_mempool_free_t)(void *p);
+
+/**
+ * Put an object in the external pool.
+ * The *p pointer is the opaque data for a given mempool handler (ring,
+ * array, linked list, etc)
+ */
+typedef int (*rte_mempool_put_t)(void *p, void * const *obj_table, unsigned n);
+
+/** Get an object from the external pool. */
+typedef int (*rte_mempool_get_t)(void *p, void **obj_table, unsigned n);
+
+/** Return the number of available objects in the external pool. */
+typedef unsigned (*rte_mempool_get_count)(void *p);
+
+/** Structure defining a mempool handler. */
+struct rte_mempool_ops {
+	char name[RTE_MEMPOOL_HANDLER_NAMESIZE]; /**< Name of mempool handler */
+	rte_mempool_alloc_t alloc;       /**< Allocate the external pool. */
+	rte_mempool_free_t free;         /**< Free the external pool. */
+	rte_mempool_put_t put;           /**< Put an object. */
+	rte_mempool_get_t get;           /**< Get an object. */
+	rte_mempool_get_count get_count; /**< Get the number of available objs. */
+} __rte_cache_aligned;
+
+#define RTE_MEMPOOL_MAX_HANDLER_IDX 16  /**< Max registered handlers */
+
+/**
+ * Structure storing the table of registered handlers, each of which contain
+ * the function pointers for the mempool handler functions.
+ * Each process has it's own storage for this handler struct aray so that
+ * the mempools can be shared across primary and secondary processes.
+ * The indices used to access the array are valid across processes, whereas
+ * any function pointers stored directly in the mempool struct would not be.
+ * This results in us simply having "handler_idx" in the mempool struct.
+ */
+struct rte_mempool_handler_table {
+	rte_spinlock_t sl;     /**< Spinlock for add/delete. */
+	uint32_t num_handlers; /**< Number of handlers in the table. */
+	/**
+	 * Storage for all possible handlers.
+	 */
+	struct rte_mempool_ops handler_ops[RTE_MEMPOOL_MAX_HANDLER_IDX];
+} __rte_cache_aligned;
+
+/** Array of registered handlers */
+extern struct rte_mempool_handler_table rte_mempool_handler_table;
+
+/**
+ * @internal Get the mempool handler from its index.
+ *
+ * @param handler_idx
+ *   The index of the handler in the handler table. It must be a valid
+ *   index: (0 <= idx < num_handlers).
+ * @return
+ *   The pointer to the handler in the table.
+ */
+static inline struct rte_mempool_ops *
+rte_mempool_handler_get(int handler_idx)
+{
+	return &rte_mempool_handler_table.handler_ops[handler_idx];
+}
+
+/**
+ * @internal wrapper for external mempool manager alloc callback.
+ *
+ * @param mp
+ *   Pointer to the memory pool.
+ * @return
+ *   The opaque pointer to the external pool.
+ */
+void *
+rte_mempool_ops_alloc(struct rte_mempool *mp);
+
+/**
+ * @internal wrapper for external mempool manager get callback.
+ *
+ * @param mp
+ *   Pointer to the memory pool.
+ * @param obj_table
+ *   Pointer to a table of void * pointers (objects).
+ * @param n
+ *   Number of objects to get.
+ * @return
+ *   - 0: Success; got n objects.
+ *   - <0: Error; code of handler get function.
+ */
+static inline int
+rte_mempool_ops_dequeue_bulk(struct rte_mempool *mp,
+		void **obj_table, unsigned n)
+{
+	struct rte_mempool_ops *handler;
+
+	handler = rte_mempool_handler_get(mp->handler_idx);
+	return handler->get(mp->pool, obj_table, n);
+}
+
+/**
+ * @internal wrapper for external mempool manager put callback.
+ *
+ * @param mp
+ *   Pointer to the memory pool.
+ * @param obj_table
+ *   Pointer to a table of void * pointers (objects).
+ * @param n
+ *   Number of objects to put.
+ * @return
+ *   - 0: Success; n objects supplied.
+ *   - <0: Error; code of handler put function.
+ */
+static inline int
+rte_mempool_ops_enqueue_bulk(struct rte_mempool *mp, void * const *obj_table,
+		unsigned n)
+{
+	struct rte_mempool_ops *handler;
+
+	handler = rte_mempool_handler_get(mp->handler_idx);
+	return handler->put(mp->pool, obj_table, n);
+}
+
+/**
+ * @internal wrapper for external mempool manager get_count callback.
+ *
+ * @param mp
+ *   Pointer to the memory pool.
+ * @return
+ *   The number of available objects in the external pool.
+ */
+unsigned
+rte_mempool_ops_get_count(const struct rte_mempool *mp);
+
+/**
+ * @internal wrapper for external mempool manager free callback.
+ *
+ * @param mp
+ *   Pointer to the memory pool.
+ */
+void
+rte_mempool_ops_free(struct rte_mempool *mp);
+
+/**
+ * Set the handler of a mempool
+ *
+ * This can only be done on a mempool that is not populated, i.e. just after
+ * a call to rte_mempool_create_empty().
+ *
+ * @param mp
+ *   Pointer to the memory pool.
+ * @param name
+ *   Name of the handler.
+ * @return
+ *   - 0: Sucess; the new handler is configured.
+ *   - EINVAL - Invalid handler name provided
+ *   - EEXIST - mempool already has a handler assigned
+ */
+int
+rte_mempool_set_handler(struct rte_mempool *mp, const char *name);
+
+/**
+ * Register an external pool handler.
+ *
+ * @param h
+ *   Pointer to the external pool handler
+ * @return
+ *   - >=0: Sucess; return the index of the handler in the table.
+ *   - EINVAL - missing callbacks while registering handler
+ *   - ENOSPC - the maximum number of handlers has been reached
+ */
+int rte_mempool_handler_register(const struct rte_mempool_ops *h);
+
+/**
+ * Macro to statically register an external pool handler.
+ */
+#define MEMPOOL_REGISTER_HANDLER(h)					\
+	void mp_hdlr_init_##h(void);					\
+	void __attribute__((constructor, used)) mp_hdlr_init_##h(void)	\
+	{								\
+		rte_mempool_handler_register(&h);			\
+	}
+
 /**
  * An object callback function for mempool.
  *
@@ -774,7 +980,7 @@ __mempool_put_bulk(struct rte_mempool *mp, void * const *obj_table,
 	cache->len += n;
 
 	if (cache->len >= flushthresh) {
-		rte_ring_mp_enqueue_bulk(mp->ring, &cache->objs[cache_size],
+		rte_mempool_ops_enqueue_bulk(mp, &cache->objs[cache_size],
 				cache->len - cache_size);
 		cache->len = cache_size;
 	}
@@ -785,19 +991,10 @@ ring_enqueue:
 
 	/* push remaining objects in ring */
 #ifdef RTE_LIBRTE_MEMPOOL_DEBUG
-	if (is_mp) {
-		if (rte_ring_mp_enqueue_bulk(mp->ring, obj_table, n) < 0)
-			rte_panic("cannot put objects in mempool\n");
-	}
-	else {
-		if (rte_ring_sp_enqueue_bulk(mp->ring, obj_table, n) < 0)
-			rte_panic("cannot put objects in mempool\n");
-	}
+	if (rte_mempool_ops_enqueue_bulk(mp, obj_table, n) < 0)
+		rte_panic("cannot put objects in mempool\n");
 #else
-	if (is_mp)
-		rte_ring_mp_enqueue_bulk(mp->ring, obj_table, n);
-	else
-		rte_ring_sp_enqueue_bulk(mp->ring, obj_table, n);
+	rte_mempool_ops_enqueue_bulk(mp, obj_table, n);
 #endif
 }
 
@@ -922,7 +1119,7 @@ rte_mempool_put(struct rte_mempool *mp, void *obj)
  */
 static inline int __attribute__((always_inline))
 __mempool_get_bulk(struct rte_mempool *mp, void **obj_table,
-		   unsigned n, int is_mc)
+		   unsigned n, __rte_unused int is_mc)
 {
 	int ret;
 	struct rte_mempool_cache *cache;
@@ -945,7 +1142,8 @@ __mempool_get_bulk(struct rte_mempool *mp, void **obj_table,
 		uint32_t req = n + (cache_size - cache->len);
 
 		/* How many do we require i.e. number to fill the cache + the request */
-		ret = rte_ring_mc_dequeue_bulk(mp->ring, &cache->objs[cache->len], req);
+		ret = rte_mempool_ops_dequeue_bulk(mp,
+			&cache->objs[cache->len], req);
 		if (unlikely(ret < 0)) {
 			/*
 			 * In the offchance that we are buffer constrained,
@@ -972,10 +1170,7 @@ __mempool_get_bulk(struct rte_mempool *mp, void **obj_table,
 ring_dequeue:
 
 	/* get remaining objects from ring */
-	if (is_mc)
-		ret = rte_ring_mc_dequeue_bulk(mp->ring, obj_table, n);
-	else
-		ret = rte_ring_sc_dequeue_bulk(mp->ring, obj_table, n);
+	ret = rte_mempool_ops_dequeue_bulk(mp, obj_table, n);
 
 	if (ret < 0)
 		__MEMPOOL_STAT_ADD(mp, get_fail, n);
diff --git a/lib/librte_mempool/rte_mempool_handler.c b/lib/librte_mempool/rte_mempool_handler.c
new file mode 100644
index 0000000..ed85d65
--- /dev/null
+++ b/lib/librte_mempool/rte_mempool_handler.c
@@ -0,0 +1,141 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2016 Intel Corporation. All rights reserved.
+ *   Copyright(c) 2016 6WIND S.A.
+ *   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.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include <rte_mempool.h>
+
+/* indirect jump table to support external memory pools */
+struct rte_mempool_handler_table rte_mempool_handler_table = {
+	.sl =  RTE_SPINLOCK_INITIALIZER ,
+	.num_handlers = 0
+};
+
+/* add a new handler in rte_mempool_handler_table, return its index */
+int
+rte_mempool_handler_register(const struct rte_mempool_ops *h)
+{
+	struct rte_mempool_ops *handler;
+	int16_t handler_idx;
+
+	rte_spinlock_lock(&rte_mempool_handler_table.sl);
+
+	if (rte_mempool_handler_table.num_handlers >=
+			RTE_MEMPOOL_MAX_HANDLER_IDX) {
+		rte_spinlock_unlock(&rte_mempool_handler_table.sl);
+		RTE_LOG(ERR, MEMPOOL,
+			"Maximum number of mempool handlers exceeded\n");
+		return -ENOSPC;
+	}
+
+	if (h->put == NULL || h->get == NULL || h->get_count == NULL) {
+		rte_spinlock_unlock(&rte_mempool_handler_table.sl);
+		RTE_LOG(ERR, MEMPOOL,
+			"Missing callback while registering mempool handler\n");
+		return -EINVAL;
+	}
+
+	handler_idx = rte_mempool_handler_table.num_handlers++;
+	handler = &rte_mempool_handler_table.handler_ops[handler_idx];
+	snprintf(handler->name, sizeof(handler->name), "%s", h->name);
+	handler->alloc = h->alloc;
+	handler->put = h->put;
+	handler->get = h->get;
+	handler->get_count = h->get_count;
+
+	rte_spinlock_unlock(&rte_mempool_handler_table.sl);
+
+	return handler_idx;
+}
+
+/* wrapper to allocate an external pool handler */
+void *
+rte_mempool_ops_alloc(struct rte_mempool *mp)
+{
+	struct rte_mempool_ops *handler;
+
+	handler = rte_mempool_handler_get(mp->handler_idx);
+	if (handler->alloc == NULL)
+		return NULL;
+	return handler->alloc(mp);
+}
+
+/* wrapper to free an external pool handler */
+void
+rte_mempool_ops_free(struct rte_mempool *mp)
+{
+	struct rte_mempool_ops *handler;
+
+	handler = rte_mempool_handler_get(mp->handler_idx);
+	if (handler->free == NULL)
+		return;
+	return handler->free(mp);
+}
+
+/* wrapper to get available objects in an external pool handler */
+unsigned int
+rte_mempool_ops_get_count(const struct rte_mempool *mp)
+{
+	struct rte_mempool_ops *handler;
+
+	handler = rte_mempool_handler_get(mp->handler_idx);
+	return handler->get_count(mp->pool);
+}
+
+/* sets a handler previously registered by rte_mempool_handler_register */
+int
+rte_mempool_set_handler(struct rte_mempool *mp, const char *name)
+{
+	struct rte_mempool_ops *handler = NULL;
+	unsigned i;
+
+	/* too late, the mempool is already populated */
+	if (mp->flags & MEMPOOL_F_RING_CREATED)
+		return -EEXIST;
+
+	for (i = 0; i < rte_mempool_handler_table.num_handlers; i++) {
+		if (!strcmp(name,
+				rte_mempool_handler_table.handler_ops[i].name)) {
+			handler = &rte_mempool_handler_table.handler_ops[i];
+			break;
+		}
+	}
+
+	if (handler == NULL)
+		return -EINVAL;
+
+	mp->handler_idx = i;
+	return 0;
+}
-- 
2.5.5