net/core/xdp.c

   1 /* net/core/xdp.c
   2  *
   3  * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
   4  * Released under terms in GPL version 2.  See COPYING.
   5  */
   6 #include <linux/types.h>
   7 #include <linux/mm.h>
   8
   9 #include <net/xdp.h>
  10
  11 #define REG_STATE_NEW           0x0
  12 #define REG_STATE_REGISTERED    0x1
  13 #define REG_STATE_UNREGISTERED  0x2
  14 #define REG_STATE_UNUSED        0x3
  15
  16 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
  17 {
  18         /* Simplify driver cleanup code paths, allow unreg "unused" */
  19         if (xdp_rxq->reg_state == REG_STATE_UNUSED)
  20                 return;
  21
  22         WARN(!(xdp_rxq->reg_state == REG_STATE_REGISTERED), "Driver BUG");
  23
  24         xdp_rxq->reg_state = REG_STATE_UNREGISTERED;
  25         xdp_rxq->dev = NULL;
  26 }
  27 EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);
  28
  29 static void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq)
  30 {
  31         memset(xdp_rxq, 0, sizeof(*xdp_rxq));
  32 }
  33
  34 /* Returns 0 on success, negative on failure */
  35 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
  36                      struct net_device *dev, u32 queue_index)
  37 {
  38         if (xdp_rxq->reg_state == REG_STATE_UNUSED) {
  39                 WARN(1, "Driver promised not to register this");
  40                 return -EINVAL;
  41         }
  42
  43         if (xdp_rxq->reg_state == REG_STATE_REGISTERED) {
  44                 WARN(1, "Missing unregister, handled but fix driver");
  45                 xdp_rxq_info_unreg(xdp_rxq);
  46         }
  47
  48         if (!dev) {
  49                 WARN(1, "Missing net_device from driver");
  50                 return -ENODEV;
  51         }
  52
  53         /* State either UNREGISTERED or NEW */
  54         xdp_rxq_info_init(xdp_rxq);
  55         xdp_rxq->dev = dev;
  56         xdp_rxq->queue_index = queue_index;
  57
  58         xdp_rxq->reg_state = REG_STATE_REGISTERED;
  59         return 0;
  60 }
  61 EXPORT_SYMBOL_GPL(xdp_rxq_info_reg);
  62
  63 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq)
  64 {
  65         xdp_rxq->reg_state = REG_STATE_UNUSED;
  66 }
  67 EXPORT_SYMBOL_GPL(xdp_rxq_info_unused);
  68
  69 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq)
  70 {
  71         return (xdp_rxq->reg_state == REG_STATE_REGISTERED);
  72 }
  73 EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);