[linux-block.git] / include / net / xdp.h

/* include/net/xdp.h
 *
 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
 * Released under terms in GPL version 2.  See COPYING.
 */
#ifndef __LINUX_NET_XDP_H__
#define __LINUX_NET_XDP_H__

/**
 * DOC: XDP RX-queue information
 *
 * The XDP RX-queue info (xdp_rxq_info) is associated with the driver
 * level RX-ring queues.  It is information that is specific to how
 * the driver have configured a given RX-ring queue.
 *
 * Each xdp_buff frame received in the driver carry a (pointer)
 * reference to this xdp_rxq_info structure.  This provides the XDP
 * data-path read-access to RX-info for both kernel and bpf-side
 * (limited subset).
 *
 * For now, direct access is only safe while running in NAPI/softirq
 * context.  Contents is read-mostly and must not be updated during
 * driver NAPI/softirq poll.
 *
 * The driver usage API is a register and unregister API.
 *
 * The struct is not directly tied to the XDP prog.  A new XDP prog
 * can be attached as long as it doesn't change the underlying
 * RX-ring.  If the RX-ring does change significantly, the NIC driver
 * naturally need to stop the RX-ring before purging and reallocating
 * memory.  In that process the driver MUST call unregistor (which
 * also apply for driver shutdown and unload).  The register API is
 * also mandatory during RX-ring setup.
 */

struct xdp_rxq_info {
	struct net_device *dev;
	u32 queue_index;
	u32 reg_state;
} ____cacheline_aligned; /* perf critical, avoid false-sharing */

int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
		     struct net_device *dev, u32 queue_index);
void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);

#endif /* __LINUX_NET_XDP_H__ */
Commit	Line	Data
aecd67b6 JDB	1	/* include/net/xdp.h
	2	*
	3	* Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
	4	* Released under terms in GPL version 2. See COPYING.
	5	*/
	6	#ifndef __LINUX_NET_XDP_H__
	7	#define __LINUX_NET_XDP_H__
	8
	9	/**
	10	* DOC: XDP RX-queue information
	11	*
	12	* The XDP RX-queue info (xdp_rxq_info) is associated with the driver
	13	* level RX-ring queues. It is information that is specific to how
	14	* the driver have configured a given RX-ring queue.
	15	*
	16	* Each xdp_buff frame received in the driver carry a (pointer)
	17	* reference to this xdp_rxq_info structure. This provides the XDP
	18	* data-path read-access to RX-info for both kernel and bpf-side
	19	* (limited subset).
	20	*
	21	* For now, direct access is only safe while running in NAPI/softirq
	22	* context. Contents is read-mostly and must not be updated during
	23	* driver NAPI/softirq poll.
	24	*
	25	* The driver usage API is a register and unregister API.
	26	*
	27	* The struct is not directly tied to the XDP prog. A new XDP prog
	28	* can be attached as long as it doesn't change the underlying
	29	* RX-ring. If the RX-ring does change significantly, the NIC driver
	30	* naturally need to stop the RX-ring before purging and reallocating
	31	* memory. In that process the driver MUST call unregistor (which
	32	* also apply for driver shutdown and unload). The register API is
	33	* also mandatory during RX-ring setup.
	34	*/
	35
	36	struct xdp_rxq_info {
	37	struct net_device *dev;
	38	u32 queue_index;
	39	u32 reg_state;
	40	} ____cacheline_aligned; /* perf critical, avoid false-sharing */
	41
	42	int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
	43	struct net_device *dev, u32 queue_index);
	44	void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
	45	void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
	46
	47	#endif /* __LINUX_NET_XDP_H__ */