env: added spdk_mempool_obj_iter

As the name suggests, this function iterates through all elements of the
mempool invoking a callback function on each one. It's particularly
useful when deinitializing mempool that requires freeing resources tied
to each element (e.g. allocated through spdk_mempool_create_ctor).

Change-Id: I3da1fee527a36bf99f0b0e2dd3d6f9297422ff25
Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/455971
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>

include/spdk/env.h

@@ -430,6 +430,18 @@ void spdk_mempool_put_bulk(struct spdk_mempool *mp, void **ele_arr, size_t count
  */
 size_t spdk_mempool_count(const struct spdk_mempool *pool);
 
+/**
+ * Iterate through all elements of the pool and call a function on each one.
+ *
+ * \param mp Memory pool to iterate on.
+ * \param obj_cb Function to call on each element.
+ * \param obj_cb_arg Opaque pointer passed to the callback function.
+ *
+ * \return Number of elements iterated.
+ */
+uint32_t spdk_mempool_obj_iter(struct spdk_mempool *mp, spdk_mempool_obj_cb_t obj_cb,
+			       void *obj_cb_arg);
+
 /**
  * Get the number of dedicated CPU cores utilized by this env abstraction.
  *

lib/env_dpdk/env.c

@@ -288,6 +288,14 @@ spdk_mempool_count(const struct spdk_mempool *pool)
 	return rte_mempool_avail_count((struct rte_mempool *)pool);
 }
 
+uint32_t
+spdk_mempool_obj_iter(struct spdk_mempool *mp, spdk_mempool_obj_cb_t obj_cb,
+		      void *obj_cb_arg)
+{
+	return rte_mempool_obj_iter((struct rte_mempool *)mp, (rte_mempool_obj_cb_t *)obj_cb,
+				    obj_cb_arg);
+}
+
 bool
 spdk_process_is_primary(void)
 {