LXR linux/include/net/xdp.h

   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
  36struct 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
  42int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
  43                     struct net_device *dev, u32 queue_index);
  44void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
  45void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
  46bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
  47
  48#endif /* __LINUX_NET_XDP_H__ */
  49