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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
27#define BUSY_POLL_BUDGET 8
28
29#ifdef CONFIG_NET_RX_BUSY_POLL
30
31struct napi_struct;
32extern unsigned int sysctl_net_busy_read __read_mostly;
33extern unsigned int sysctl_net_busy_poll __read_mostly;
34
35static inline bool net_busy_loop_on(void)
36{
37 return READ_ONCE(sysctl_net_busy_poll);
38}
39
40static inline bool sk_can_busy_loop(const struct sock *sk)
41{
42 return READ_ONCE(sk->sk_ll_usec) && !signal_pending(current);
43}
44
45bool sk_busy_loop_end(void *p, unsigned long start_time);
46
47void napi_busy_loop(unsigned int napi_id,
48 bool (*loop_end)(void *, unsigned long),
49 void *loop_end_arg, bool prefer_busy_poll, u16 budget);
50
51void napi_busy_loop_rcu(unsigned int napi_id,
52 bool (*loop_end)(void *, unsigned long),
53 void *loop_end_arg, bool prefer_busy_poll, u16 budget);
54
55void napi_suspend_irqs(unsigned int napi_id);
56void napi_resume_irqs(unsigned int napi_id);
57
58#else /* CONFIG_NET_RX_BUSY_POLL */
59static inline unsigned long net_busy_loop_on(void)
60{
61 return 0;
62}
63
64static inline bool sk_can_busy_loop(struct sock *sk)
65{
66 return false;
67}
68
69#endif /* CONFIG_NET_RX_BUSY_POLL */
70
71static inline unsigned long busy_loop_current_time(void)
72{
73#ifdef CONFIG_NET_RX_BUSY_POLL
74 return (unsigned long)(ktime_get_ns() >> 10);
75#else
76 return 0;
77#endif
78}
79
80/* in poll/select we use the global sysctl_net_ll_poll value */
81static inline bool busy_loop_timeout(unsigned long start_time)
82{
83#ifdef CONFIG_NET_RX_BUSY_POLL
84 unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);
85
86 if (bp_usec) {
87 unsigned long end_time = start_time + bp_usec;
88 unsigned long now = busy_loop_current_time();
89
90 return time_after(now, end_time);
91 }
92#endif
93 return true;
94}
95
96static inline bool sk_busy_loop_timeout(struct sock *sk,
97 unsigned long start_time)
98{
99#ifdef CONFIG_NET_RX_BUSY_POLL
100 unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
101
102 if (bp_usec) {
103 unsigned long end_time = start_time + bp_usec;
104 unsigned long now = busy_loop_current_time();
105
106 return time_after(now, end_time);
107 }
108#endif
109 return true;
110}
111
112static inline void sk_busy_loop(struct sock *sk, int nonblock)
113{
114#ifdef CONFIG_NET_RX_BUSY_POLL
115 unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
116
117 if (napi_id >= MIN_NAPI_ID)
118 napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk,
119 READ_ONCE(sk->sk_prefer_busy_poll),
120 READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET);
121#endif
122}
123
124/* used in the NIC receive handler to mark the skb */
125static inline void skb_mark_napi_id(struct sk_buff *skb,
126 struct napi_struct *napi)
127{
128#ifdef CONFIG_NET_RX_BUSY_POLL
129 /* If the skb was already marked with a valid NAPI ID, avoid overwriting
130 * it.
131 */
132 if (skb->napi_id < MIN_NAPI_ID)
133 skb->napi_id = napi->napi_id;
134#endif
135}
136
137/* used in the protocol handler to propagate the napi_id to the socket */
138static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
139{
140#ifdef CONFIG_NET_RX_BUSY_POLL
141 if (unlikely(READ_ONCE(sk->sk_napi_id) != skb->napi_id))
142 WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
143#endif
144 sk_rx_queue_update(sk, skb);
145}
146
147/* Variant of sk_mark_napi_id() for passive flow setup,
148 * as sk->sk_napi_id and sk->sk_rx_queue_mapping content
149 * needs to be set.
150 */
151static inline void sk_mark_napi_id_set(struct sock *sk,
152 const struct sk_buff *skb)
153{
154#ifdef CONFIG_NET_RX_BUSY_POLL
155 WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
156#endif
157 sk_rx_queue_set(sk, skb);
158}
159
160static inline void __sk_mark_napi_id_once(struct sock *sk, unsigned int napi_id)
161{
162#ifdef CONFIG_NET_RX_BUSY_POLL
163 if (!READ_ONCE(sk->sk_napi_id))
164 WRITE_ONCE(sk->sk_napi_id, napi_id);
165#endif
166}
167
168/* variant used for unconnected sockets */
169static inline void sk_mark_napi_id_once(struct sock *sk,
170 const struct sk_buff *skb)
171{
172#ifdef CONFIG_NET_RX_BUSY_POLL
173 __sk_mark_napi_id_once(sk, skb->napi_id);
174#endif
175}
176
177#endif /* _LINUX_NET_BUSY_POLL_H */