Function rte_ring_create_elem

dpdk/lib/ring/rte_ring.c:239–305

create the ring for a given element size */

/* create the ring for a given element size */
struct rte_ring *
rte_ring_create_elem(const char *name, unsigned int esize, unsigned int count,
		int socket_id, unsigned int flags)
{
	char mz_name[RTE_MEMZONE_NAMESIZE];
	struct rte_ring *r;
	struct rte_tailq_entry *te;
	const struct rte_memzone *mz;
	ssize_t ring_size;
	int mz_flags = 0;
	struct rte_ring_list* ring_list = NULL;
	const unsigned int requested_count = count;
	int ret;

	ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);

	/* for an exact size ring, round up from count to a power of two */
	if (flags & RING_F_EXACT_SZ)
		count = rte_align32pow2(count + 1);

	ring_size = rte_ring_get_memsize_elem(esize, count);
	if (ring_size < 0) {
		rte_errno = -ring_size;
		return NULL;
	}

	ret = snprintf(mz_name, sizeof(mz_name), "%s%s",
		RTE_RING_MZ_PREFIX, name);
	if (ret < 0 || ret >= (int)sizeof(mz_name)) {
		rte_errno = ENAMETOOLONG;
		return NULL;
	}

	te = rte_zmalloc("RING_TAILQ_ENTRY", sizeof(*te), 0);
	if (te == NULL) {
		RTE_LOG(ERR, RING, "Cannot reserve memory for tailq\n");
		rte_errno = ENOMEM;
		return NULL;
	}

	rte_mcfg_tailq_write_lock();

	/* reserve a memory zone for this ring. If we can't get rte_config or
	 * we are secondary process, the memzone_reserve function will set
	 * rte_errno for us appropriately - hence no check in this function
	 */
	mz = rte_memzone_reserve_aligned(mz_name, ring_size, socket_id,
					 mz_flags, __alignof__(*r));
	if (mz != NULL) {
		r = mz->addr;
		/* no need to check return value here, we already checked the
		 * arguments above */
		rte_ring_init(r, name, requested_count, flags);

		te->data = (void *) r;
		r->memzone = mz;

		TAILQ_INSERT_TAIL(ring_list, te, next);