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
  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 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
  47
  48 #endif /* __LINUX_NET_XDP_H__ */