1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * net busy poll support
4 * Copyright(c) 2013 Intel Corporation.
5 *
6 * Author: Eliezer Tamir
7 *
8 * Contact Information:
9 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
10 */
11
12#ifndef _LINUX_NET_BUSY_POLL_H
13#define _LINUX_NET_BUSY_POLL_H
14
15#include <linux/netdevice.h>
16#include <linux/sched/clock.h>
17#include <linux/sched/signal.h>
18#include <net/ip.h>
19#include <net/xdp.h>
20
21/* 0 - Reserved to indicate value not set
22 * 1..NR_CPUS - Reserved for sender_cpu
23 * NR_CPUS+1..~0 - Region available for NAPI IDs
24 */
25#define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1))
26
27static inline bool napi_id_valid(unsigned int napi_id)
28{
29 return napi_id >= MIN_NAPI_ID;
30}
31
32#define BUSY_POLL_BUDGET 8
33
34#ifdef CONFIG_NET_RX_BUSY_POLL
35
36struct napi_struct;
37extern unsigned int sysctl_net_busy_read __read_mostly;
38extern unsigned int sysctl_net_busy_poll __read_mostly;
39
40static inline bool net_busy_loop_on(void)
41{
42 return READ_ONCE(sysctl_net_busy_poll);
43}
44
45static inline bool sk_can_busy_loop(const struct sock *sk)
46{
47 return READ_ONCE(sk->sk_ll_usec) && !signal_pending(current);
48}
49
50bool sk_busy_loop_end(void *p, unsigned long start_time);
51
52void napi_busy_loop(unsigned int napi_id,
53 bool (*loop_end)(void *, unsigned long),
54 void *loop_end_arg, bool prefer_busy_poll, u16 budget);
55
56void napi_busy_loop_rcu(unsigned int napi_id,
57 bool (*loop_end)(void *, unsigned long),
58 void *loop_end_arg, bool prefer_busy_poll, u16 budget);
59
60void napi_suspend_irqs(unsigned int napi_id);
61void napi_resume_irqs(unsigned int napi_id);
62
63#else /* CONFIG_NET_RX_BUSY_POLL */
64static inline unsigned long net_busy_loop_on(void)
65{
66 return 0;
67}
68
69static inline bool sk_can_busy_loop(struct sock *sk)
70{
71 return false;
72}
73
74#endif /* CONFIG_NET_RX_BUSY_POLL */
75
76static inline unsigned long busy_loop_current_time(void)
77{
78#ifdef CONFIG_NET_RX_BUSY_POLL
79 return (unsigned long)(ktime_get_ns() >> 10);
80#else
81 return 0;
82#endif
83}
84
85/* in poll/select we use the global sysctl_net_ll_poll value */
86static inline bool busy_loop_timeout(unsigned long start_time)
87{
88#ifdef CONFIG_NET_RX_BUSY_POLL
89 unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);
90
91 if (bp_usec) {
92 unsigned long end_time = start_time + bp_usec;
93 unsigned long now = busy_loop_current_time();
94
95 return time_after(now, end_time);
96 }
97#endif
98 return true;
99}
100
101static inline bool sk_busy_loop_timeout(struct sock *sk,
102 unsigned long start_time)
103{
104#ifdef CONFIG_NET_RX_BUSY_POLL
105 unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
106
107 if (bp_usec) {
108 unsigned long end_time = start_time + bp_usec;
109 unsigned long now = busy_loop_current_time();
110
111 return time_after(now, end_time);
112 }
113#endif
114 return true;
115}
116
117static inline void sk_busy_loop(struct sock *sk, int nonblock)
118{
119#ifdef CONFIG_NET_RX_BUSY_POLL
120 unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
121
122 if (napi_id_valid(napi_id))
123 napi_busy_loop(napi_id, loop_end: nonblock ? NULL : sk_busy_loop_end, loop_end_arg: sk,
124 READ_ONCE(sk->sk_prefer_busy_poll),
125 READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET);
126#endif
127}
128
129/* used in the NIC receive handler to mark the skb */
130static inline void __skb_mark_napi_id(struct sk_buff *skb,
131 const struct gro_node *gro)
132{
133#ifdef CONFIG_NET_RX_BUSY_POLL
134 /* If the skb was already marked with a valid NAPI ID, avoid overwriting
135 * it.
136 */
137 if (!napi_id_valid(napi_id: skb->napi_id))
138 skb->napi_id = gro->cached_napi_id;
139#endif
140}
141
142static inline void skb_mark_napi_id(struct sk_buff *skb,
143 const struct napi_struct *napi)
144{
145 __skb_mark_napi_id(skb, gro: &napi->gro);
146}
147
148/* used in the protocol handler to propagate the napi_id to the socket */
149static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
150{
151#ifdef CONFIG_NET_RX_BUSY_POLL
152 if (unlikely(READ_ONCE(sk->sk_napi_id) != skb->napi_id))
153 WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
154#endif
155 sk_rx_queue_update(sk, skb);
156}
157
158/* Variant of sk_mark_napi_id() for passive flow setup,
159 * as sk->sk_napi_id and sk->sk_rx_queue_mapping content
160 * needs to be set.
161 */
162static inline void sk_mark_napi_id_set(struct sock *sk,
163 const struct sk_buff *skb)
164{
165#ifdef CONFIG_NET_RX_BUSY_POLL
166 WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
167#endif
168 sk_rx_queue_set(sk, skb);
169}
170
171static inline void __sk_mark_napi_id_once(struct sock *sk, unsigned int napi_id)
172{
173#ifdef CONFIG_NET_RX_BUSY_POLL
174 if (!READ_ONCE(sk->sk_napi_id))
175 WRITE_ONCE(sk->sk_napi_id, napi_id);
176#endif
177}
178
179/* variant used for unconnected sockets */
180static inline void sk_mark_napi_id_once(struct sock *sk,
181 const struct sk_buff *skb)
182{
183#ifdef CONFIG_NET_RX_BUSY_POLL
184 __sk_mark_napi_id_once(sk, napi_id: skb->napi_id);
185#endif
186}
187
188#endif /* _LINUX_NET_BUSY_POLL_H */
189

source code of linux/include/net/busy_poll.h