static int gve_tx_alloc_ring_dqo()

in google/gve/gve_tx_dqo.c [283:376]

• 64 lines of code
• 9 McCabe index (conditional complexity)

static int gve_tx_alloc_ring_dqo(struct gve_priv *priv,
				 struct gve_tx_alloc_rings_cfg *cfg,
				 struct gve_tx_ring *tx,
				 int idx)
{
	struct device *hdev = &priv->pdev->dev;
	int num_pending_packets;
	int qpl_page_cnt;
	size_t bytes;
	u32 qpl_id;
	int i;

	memset(tx, 0, sizeof(*tx));
	tx->q_num = idx;
	tx->dev = hdev;
	atomic_set_release(&tx->dqo_compl.hw_tx_head, 0);

	/* Queue sizes must be a power of 2 */
	tx->mask = cfg->ring_size - 1;
	tx->dqo.complq_mask = tx->mask;

	/* The max number of pending packets determines the maximum number of
	 * descriptors which maybe written to the completion queue.
	 *
	 * We must set the number small enough to make sure we never overrun the
	 * completion queue.
	 */
	num_pending_packets = tx->dqo.complq_mask + 1;

	/* Reserve space for descriptor completions, which will be reported at
	 * most every GVE_TX_MIN_RE_INTERVAL packets.
	 */
	num_pending_packets -=
		(tx->dqo.complq_mask + 1) / GVE_TX_MIN_RE_INTERVAL;

	/* Each packet may have at most 2 buffer completions if it receives both
	 * a miss and reinjection completion.
	 */
	num_pending_packets /= 2;

	tx->dqo.num_pending_packets = min_t(int, num_pending_packets, S16_MAX);
	tx->dqo.pending_packets = kvcalloc(tx->dqo.num_pending_packets,
					   sizeof(tx->dqo.pending_packets[0]),
					   GFP_KERNEL);
	if (!tx->dqo.pending_packets)
		goto err;

	/* Set up linked list of pending packets */
	for (i = 0; i < tx->dqo.num_pending_packets - 1; i++)
		tx->dqo.pending_packets[i].next = i + 1;

	tx->dqo.pending_packets[tx->dqo.num_pending_packets - 1].next = -1;
	atomic_set_release(&tx->dqo_compl.free_pending_packets, -1);
	tx->dqo_compl.miss_completions.head = -1;
	tx->dqo_compl.miss_completions.tail = -1;
	tx->dqo_compl.timed_out_completions.head = -1;
	tx->dqo_compl.timed_out_completions.tail = -1;

	bytes = sizeof(tx->dqo.tx_ring[0]) * (tx->mask + 1);
	tx->dqo.tx_ring = dma_alloc_coherent(hdev, bytes, &tx->bus, GFP_KERNEL);
	if (!tx->dqo.tx_ring)
		goto err;

	bytes = sizeof(tx->dqo.compl_ring[0]) * (tx->dqo.complq_mask + 1);
	tx->dqo.compl_ring = dma_alloc_coherent(hdev, bytes,
						&tx->complq_bus_dqo,
						GFP_KERNEL);
	if (!tx->dqo.compl_ring)
		goto err;

	tx->q_resources = dma_alloc_coherent(hdev, sizeof(*tx->q_resources),
					     &tx->q_resources_bus, GFP_KERNEL);
	if (!tx->q_resources)
		goto err;

	if (!cfg->raw_addressing) {
		qpl_id = gve_tx_qpl_id(priv, tx->q_num);
		qpl_page_cnt = priv->tx_pages_per_qpl;

		tx->dqo.qpl = gve_alloc_queue_page_list(priv, qpl_id,
							qpl_page_cnt);
		if (!tx->dqo.qpl)
			goto err;

		if (gve_tx_qpl_buf_init(tx))
			goto err;
	}

	return 0;

err:
	gve_tx_free_ring_dqo(priv, tx, cfg);
	return -ENOMEM;
}