include/net/netdev_rx_queue.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_NETDEV_RX_QUEUE_H
#define _LINUX_NETDEV_RX_QUEUE_H

#include <linux/dma-buf.h>
#include <linux/kobject.h>
#include <linux/netdevice.h>
#include <linux/sysfs.h>
#include <net/xdp.h>

/* This structure contains an instance of an RX queue. */
struct netdev_rx_queue {
	struct xdp_rxq_info		xdp_rxq;
#ifdef CONFIG_RPS
	struct rps_map __rcu		*rps_map;
	struct rps_dev_flow_table __rcu	*rps_flow_table;
#endif
	struct kobject			kobj;
	struct net_device		*dev;
	netdevice_tracker		dev_tracker;

#ifdef CONFIG_XDP_SOCKETS
	struct xsk_buff_pool            *pool;
#endif
	struct file __rcu		*dmabuf_pages;
} ____cacheline_aligned_in_smp;

struct page *
__netdev_rxq_alloc_page_from_dmabuf_pool(struct netdev_rx_queue *rxq,
					 unsigned int order);

static inline struct page *netdev_rxq_alloc_dma_buf_page(struct netdev_rx_queue *rxq,
						 unsigned int order)
{

	/* Return NULL if we can't allocate a dma_buf page, instead of trying
	 * to fallback to alloc_page(). The reason we do this is because we
	 * don't want to confuse the caller with respect to whether the page
	 * they are getting is a dma_buf page or otherwise. dma_buf pages and
	 * devmem skbs require special handling, so the distinction is
	 * important. Let the caller fall back to allocating a non-dma_buf page
	 * if they know what they're doing.
	 */
	if (unlikely(!rcu_access_pointer(rxq->dmabuf_pages)))
		return NULL;

	return __netdev_rxq_alloc_page_from_dmabuf_pool(rxq, order);
}

static inline void netdev_rxq_free_page(struct page *pg)
{
	if (is_dma_buf_page(pg)) {
		put_page(pg);
		return;
	}

	__free_page(pg);
}

/*
 * RX queue sysfs structures and functions.
 */
struct rx_queue_attribute {
	struct attribute attr;
	ssize_t (*show)(struct netdev_rx_queue *queue, char *buf);
	ssize_t (*store)(struct netdev_rx_queue *queue,
			 const char *buf, size_t len);
};

static inline struct netdev_rx_queue *
__netif_get_rx_queue(struct net_device *dev, unsigned int rxq)
{
	return dev->_rx + rxq;
}

#ifdef CONFIG_SYSFS
static inline unsigned int
get_netdev_rx_queue_index(struct netdev_rx_queue *queue)
{
	struct net_device *dev = queue->dev;
	int index = queue - dev->_rx;

	BUG_ON(index >= dev->num_rx_queues);
	return index;
}
#endif
#endif