Intel PMD fast free layer violation

["Morten Brørup" <mb@smartsharesystems.com>]

Bruce,

I haven't looked at the Next-net-intel tree, so it might already have been fixed...

ci_tx_free_bufs_vec() in drivers/net/intel/common/tx.h has:

	/* is fast-free enabled? */
	struct rte_mempool *mp =
			likely(txq->fast_free_mp != (void *)UINTPTR_MAX) ?
			txq->fast_free_mp :
			(txq->fast_free_mp = txep[0].mbuf->pool);

	if (mp != NULL && (n & 31) == 0) {
		void **cache_objs;
		struct rte_mempool_cache *cache = rte_mempool_default_cache(mp, rte_lcore_id());

		if (cache == NULL)
			goto normal;

		cache_objs = &cache->objs[cache->len];

		if (n > RTE_MEMPOOL_CACHE_MAX_SIZE) {
			rte_mempool_ops_enqueue_bulk(mp, (void *)txep, n);
			goto done;
		}

		/* The cache follows the following algorithm
		 *   1. Add the objects to the cache
		 *   2. Anything greater than the cache min value (if it
		 *   crosses the cache flush threshold) is flushed to the ring.
		 */
		/* Add elements back into the cache */
		uint32_t copied = 0;
		/* n is multiple of 32 */
		while (copied < n) {
			memcpy(&cache_objs[copied], &txep[copied], 32 * sizeof(void *));
			copied += 32;
		}
		cache->len += n;

		if (cache->len >= cache->flushthresh) {
			rte_mempool_ops_enqueue_bulk(mp, &cache->objs[cache->size],
					cache->len - cache->size);
			cache->len = cache->size;
		}
		goto done;
	}

It should be replaced by:

	/* is fast-free enabled? */
	struct rte_mempool *mp =
			likely(txq->fast_free_mp != (void *)UINTPTR_MAX) ?
			txq->fast_free_mp :
			(txq->fast_free_mp = txep[0].mbuf->pool);

	if (mp != NULL) {
		rte_mbuf_raw_free_bulk(mp, txep, n);
		goto done;
	}

This removes a layer violation and adds the missing mbuf sanity checks and mbuf history marks due to that layer violation.
And it implements fast-free for bulks not a multiple of 32.

Venlig hilsen / Kind regards,
-Morten Brørup