1 files changed, 74 insertions, 0 deletions
diff --git a/net/core/netdev_rx_queue.c b/net/core/netdev_rx_queue.c
new file mode 100644
index 000000000000..da11720a5983
--- /dev/null
+++ b/net/core/netdev_rx_queue.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/netdevice.h>
+#include <net/netdev_queues.h>
+#include <net/netdev_rx_queue.h>
+
+int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx)
+{
+	void *new_mem, *old_mem;
+	int err;
+
+	if (!dev->queue_mgmt_ops || !dev->queue_mgmt_ops->ndo_queue_stop ||
+	    !dev->queue_mgmt_ops->ndo_queue_mem_free ||
+	    !dev->queue_mgmt_ops->ndo_queue_mem_alloc ||
+	    !dev->queue_mgmt_ops->ndo_queue_start)
+		return -EOPNOTSUPP;
+
+	ASSERT_RTNL();
+
+	new_mem = kvzalloc(dev->queue_mgmt_ops->ndo_queue_mem_size, GFP_KERNEL);
+	if (!new_mem)
+		return -ENOMEM;
+
+	old_mem = kvzalloc(dev->queue_mgmt_ops->ndo_queue_mem_size, GFP_KERNEL);
+	if (!old_mem) {
+		err = -ENOMEM;
+		goto err_free_new_mem;
+	}
+
+	err = dev->queue_mgmt_ops->ndo_queue_mem_alloc(dev, new_mem, rxq_idx);
+	if (err)
+		goto err_free_old_mem;
+
+	err = dev->queue_mgmt_ops->ndo_queue_stop(dev, old_mem, rxq_idx);
+	if (err)
+		goto err_free_new_queue_mem;
+
+	err = dev->queue_mgmt_ops->ndo_queue_start(dev, new_mem, rxq_idx);
+	if (err)
+		goto err_start_queue;
+
+	dev->queue_mgmt_ops->ndo_queue_mem_free(dev, old_mem);
+
+	kvfree(old_mem);
+	kvfree(new_mem);
+
+	return 0;
+
+err_start_queue:
+	/* Restarting the queue with old_mem should be successful as we haven't
+	 * changed any of the queue configuration, and there is not much we can
+	 * do to recover from a failure here.
+	 *
+	 * WARN if we fail to recover the old rx queue, and at least free
+	 * old_mem so we don't also leak that.
+	 */
+	if (dev->queue_mgmt_ops->ndo_queue_start(dev, old_mem, rxq_idx)) {
+		WARN(1,
+		     "Failed to restart old queue in error path. RX queue %d may be unhealthy.",
+		     rxq_idx);
+		dev->queue_mgmt_ops->ndo_queue_mem_free(dev, old_mem);
+	}
+
+err_free_new_queue_mem:
+	dev->queue_mgmt_ops->ndo_queue_mem_free(dev, new_mem);
+
+err_free_old_mem:
+	kvfree(old_mem);
+
+err_free_new_mem:
+	kvfree(new_mem);
+
+	return err;
+}