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__ */ 48