[PATCH net-next v2 01/15] ibmveth: Refactor RX resource allocation for MQ RX bring-up

From: Mingming Cao <hidden>
Date: 2026-07-01 22:25:24
Also in: netdev
Subsystem: ibm power virtual ethernet device driver, linux for powerpc (32-bit and 64-bit), networking drivers, the rest · Maintainers: Nick Child, Madhavan Srinivasan, Michael Ellerman, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

ibmveth_open() allocates the filter list and every RX queue inline.
That's already ~160 lines and would get ugly once we loop over
num_rx_queues, especially on error unwind.

Pull the RX bits into helpers:

  ibmveth_alloc_filter_list() / ibmveth_free_filter_list()
    — shared multicast filter list (one per adapter, not per queue)

  ibmveth_alloc_rx_queues() / ibmveth_cleanup_rx_resources()
    — per-queue buffer lists and RX rings, looping [0, num_rx_queues)

alloc_rx_queues() rolls back on failure so open() does not need nested
goto chains for every queue index.

This is the first of several helper-only patches (pools, IRQ, TX, PHYP
registration, open/close wiring, buffer submit) that reshape bring-up
ahead of MQ datapath commit later in the series.

Signed-off-by: Mingming Cao <redacted>
Reviewed-by: Dave Marquardt <redacted>
---
 drivers/net/ethernet/ibm/ibmveth.c | 168 +++++++++++++++++++++++++++++
 1 file changed, 168 insertions(+)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 8f9f927bff23..b8adc9935471 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c

@@ -147,6 +147,174 @@ static unsigned int ibmveth_real_max_tx_queues(void)
 	return min(n_cpu, IBMVETH_MAX_QUEUES);
 }
 
+/**
+ * ibmveth_alloc_filter_list - Allocate and map filter list
+ * @adapter: ibmveth adapter structure
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+static int __maybe_unused ibmveth_alloc_filter_list(struct ibmveth_adapter *adapter)
+{
+	struct device *dev = &adapter->vdev->dev;
+	struct net_device *netdev = adapter->netdev;
+
+	adapter->filter_list_addr = (void *)get_zeroed_page(GFP_KERNEL);
+	if (!adapter->filter_list_addr) {
+		netdev_err(netdev, "unable to allocate filter pages\n");
+		return -ENOMEM;
+	}
+
+	adapter->filter_list_dma = dma_map_single(dev,
+						  adapter->filter_list_addr,
+						  4096, DMA_BIDIRECTIONAL);
+	if (dma_mapping_error(dev, adapter->filter_list_dma)) {
+		netdev_err(netdev, "unable to map filter list pages\n");
+		free_page((unsigned long)adapter->filter_list_addr);
+		adapter->filter_list_addr = NULL;
+		return -ENOMEM;
+	}
+
+	netdev_dbg(netdev, "filter list @ 0x%p (DMA: 0x%llx)\n",
+		   adapter->filter_list_addr,
+		   (unsigned long long)adapter->filter_list_dma);
+
+	return 0;
+}
+
+/**
+ * ibmveth_free_filter_list - Free filter list resources
+ * @adapter: ibmveth adapter structure
+ */
+static void __maybe_unused ibmveth_free_filter_list(struct ibmveth_adapter *adapter)
+{
+	struct device *dev = &adapter->vdev->dev;
+
+	if (adapter->filter_list_dma) {
+		dma_unmap_single(dev, adapter->filter_list_dma, 4096,
+				 DMA_BIDIRECTIONAL);
+		adapter->filter_list_dma = 0;
+	}
+
+	if (adapter->filter_list_addr) {
+		free_page((unsigned long)adapter->filter_list_addr);
+		adapter->filter_list_addr = NULL;
+	}
+}
+
+/**
+ * ibmveth_alloc_rx_queues - Allocate per-queue RX resources
+ * @adapter: ibmveth adapter structure
+ * @rxq_entries: Number of entries per RX queue
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+static int __maybe_unused
+ibmveth_alloc_rx_queues(struct ibmveth_adapter *adapter, int rxq_entries)
+{
+	struct device *dev = &adapter->vdev->dev;
+	struct net_device *netdev = adapter->netdev;
+	int i;
+
+	for (i = 0; i < adapter->num_rx_queues; i++) {
+		adapter->buffer_list_addr[i] = (void *)get_zeroed_page(GFP_KERNEL);
+		if (!adapter->buffer_list_addr[i]) {
+			netdev_err(netdev, "unable to allocate buffer list for queue %d\n", i);
+			goto err_cleanup;
+		}
+
+		adapter->rx_queue[i].queue_len =
+			sizeof(struct ibmveth_rx_q_entry) * rxq_entries;
+		adapter->rx_queue[i].queue_addr =
+			dma_alloc_coherent(dev, adapter->rx_queue[i].queue_len,
+					   &adapter->rx_queue[i].queue_dma,
+					   GFP_KERNEL);
+		if (!adapter->rx_queue[i].queue_addr) {
+			netdev_err(netdev, "unable to allocate RX queue for queue %d\n", i);
+			goto err_cleanup;
+		}
+
+		adapter->buffer_list_dma[i] = dma_map_single(dev,
+							     adapter->buffer_list_addr[i],
+							     4096, DMA_BIDIRECTIONAL);
+		if (dma_mapping_error(dev, adapter->buffer_list_dma[i])) {
+			netdev_err(netdev, "unable to map buffer list for queue %d\n", i);
+			adapter->buffer_list_dma[i] = 0;
+			goto err_cleanup;
+		}
+
+		adapter->rx_queue[i].index = 0;
+		adapter->rx_queue[i].num_slots = rxq_entries;
+		adapter->rx_queue[i].toggle = 1;
+
+		netdev_dbg(netdev, "queue %d: buffer_list @ 0x%p (DMA: 0x%llx), rx_queue @ 0x%p (DMA: 0x%llx), %llu entries\n",
+			   i, adapter->buffer_list_addr[i],
+			   (unsigned long long)adapter->buffer_list_dma[i],
+			   adapter->rx_queue[i].queue_addr,
+			   (unsigned long long)adapter->rx_queue[i].queue_dma,
+			   (unsigned long long)rxq_entries);
+	}
+
+	netdev_dbg(netdev, "allocated %d RX queue(s) with %d entries each\n",
+		   adapter->num_rx_queues, rxq_entries);
+
+	return 0;
+
+err_cleanup:
+	/* Clean up previously allocated queues */
+	for (; i >= 0; i--) {
+		if (adapter->buffer_list_dma[i]) {
+			dma_unmap_single(dev, adapter->buffer_list_dma[i],
+					 4096, DMA_BIDIRECTIONAL);
+			adapter->buffer_list_dma[i] = 0;
+		}
+		if (adapter->rx_queue[i].queue_addr) {
+			dma_free_coherent(dev, adapter->rx_queue[i].queue_len,
+					  adapter->rx_queue[i].queue_addr,
+					  adapter->rx_queue[i].queue_dma);
+			adapter->rx_queue[i].queue_addr = NULL;
+		}
+		if (adapter->buffer_list_addr[i]) {
+			free_page((unsigned long)adapter->buffer_list_addr[i]);
+			adapter->buffer_list_addr[i] = NULL;
+		}
+	}
+
+	return -ENOMEM;
+}
+
+/**
+ * ibmveth_cleanup_rx_resources - Free all RX queue resources
+ * @adapter: ibmveth adapter structure
+ */
+static void __maybe_unused ibmveth_cleanup_rx_resources(struct ibmveth_adapter *adapter)
+{
+	struct device *dev = &adapter->vdev->dev;
+	int i;
+
+	netdev_dbg(adapter->netdev, "cleaning up %d RX queue(s)\n",
+		   adapter->num_rx_queues);
+
+	for (i = 0; i < adapter->num_rx_queues; i++) {
+		if (adapter->buffer_list_dma[i]) {
+			dma_unmap_single(dev, adapter->buffer_list_dma[i],
+					 4096, DMA_BIDIRECTIONAL);
+			adapter->buffer_list_dma[i] = 0;
+		}
+
+		if (adapter->rx_queue[i].queue_addr) {
+			dma_free_coherent(dev, adapter->rx_queue[i].queue_len,
+					  adapter->rx_queue[i].queue_addr,
+					  adapter->rx_queue[i].queue_dma);
+			adapter->rx_queue[i].queue_addr = NULL;
+		}
+
+		if (adapter->buffer_list_addr[i]) {
+			free_page((unsigned long)adapter->buffer_list_addr[i]);
+			adapter->buffer_list_addr[i] = NULL;
+		}
+	}
+}
+
 /* setup the initial settings for a buffer pool */
 static void ibmveth_init_buffer_pool(struct ibmveth_buff_pool *pool,
 				     u32 pool_index, u32 pool_size,

-- 
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