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
16void 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}
27EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);
28
29static 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 */
35int 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}
61EXPORT_SYMBOL_GPL(xdp_rxq_info_reg);
62
63void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq)
64{
65	xdp_rxq->reg_state = REG_STATE_UNUSED;
66}
67EXPORT_SYMBOL_GPL(xdp_rxq_info_unused);
68
69bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq)
70{
71	return (xdp_rxq->reg_state == REG_STATE_REGISTERED);
72}
73EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);