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
20 /* 0 - Reserved to indicate value not set
21 * 1..NR_CPUS - Reserved for sender_cpu
22 * NR_CPUS+1..~0 - Region available for NAPI IDs
23 */
24 #define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1))
25
26 #ifdef CONFIG_NET_RX_BUSY_POLL
27
28 struct napi_struct;
29 extern unsigned int sysctl_net_busy_read __read_mostly;
30 extern unsigned int sysctl_net_busy_poll __read_mostly;
31
net_busy_loop_on(void)32 static inline bool net_busy_loop_on(void)
33 {
34 return sysctl_net_busy_poll;
35 }
36
sk_can_busy_loop(const struct sock * sk)37 static inline bool sk_can_busy_loop(const struct sock *sk)
38 {
39 return sk->sk_ll_usec && !signal_pending(current);
40 }
41
42 bool sk_busy_loop_end(void *p, unsigned long start_time);
43
44 void napi_busy_loop(unsigned int napi_id,
45 bool (*loop_end)(void *, unsigned long),
46 void *loop_end_arg);
47
48 #else /* CONFIG_NET_RX_BUSY_POLL */
net_busy_loop_on(void)49 static inline unsigned long net_busy_loop_on(void)
50 {
51 return 0;
52 }
53
sk_can_busy_loop(struct sock * sk)54 static inline bool sk_can_busy_loop(struct sock *sk)
55 {
56 return false;
57 }
58
59 #endif /* CONFIG_NET_RX_BUSY_POLL */
60
busy_loop_current_time(void)61 static inline unsigned long busy_loop_current_time(void)
62 {
63 #ifdef CONFIG_NET_RX_BUSY_POLL
64 return (unsigned long)(local_clock() >> 10);
65 #else
66 return 0;
67 #endif
68 }
69
70 /* in poll/select we use the global sysctl_net_ll_poll value */
busy_loop_timeout(unsigned long start_time)71 static inline bool busy_loop_timeout(unsigned long start_time)
72 {
73 #ifdef CONFIG_NET_RX_BUSY_POLL
74 unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);
75
76 if (bp_usec) {
77 unsigned long end_time = start_time + bp_usec;
78 unsigned long now = busy_loop_current_time();
79
80 return time_after(now, end_time);
81 }
82 #endif
83 return true;
84 }
85
sk_busy_loop_timeout(struct sock * sk,unsigned long start_time)86 static inline bool sk_busy_loop_timeout(struct sock *sk,
87 unsigned long start_time)
88 {
89 #ifdef CONFIG_NET_RX_BUSY_POLL
90 unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
91
92 if (bp_usec) {
93 unsigned long end_time = start_time + bp_usec;
94 unsigned long now = busy_loop_current_time();
95
96 return time_after(now, end_time);
97 }
98 #endif
99 return true;
100 }
101
sk_busy_loop(struct sock * sk,int nonblock)102 static inline void sk_busy_loop(struct sock *sk, int nonblock)
103 {
104 #ifdef CONFIG_NET_RX_BUSY_POLL
105 unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
106
107 if (napi_id >= MIN_NAPI_ID)
108 napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk);
109 #endif
110 }
111
112 /* used in the NIC receive handler to mark the skb */
skb_mark_napi_id(struct sk_buff * skb,struct napi_struct * napi)113 static inline void skb_mark_napi_id(struct sk_buff *skb,
114 struct napi_struct *napi)
115 {
116 #ifdef CONFIG_NET_RX_BUSY_POLL
117 skb->napi_id = napi->napi_id;
118 #endif
119 }
120
121 /* used in the protocol hanlder to propagate the napi_id to the socket */
sk_mark_napi_id(struct sock * sk,const struct sk_buff * skb)122 static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
123 {
124 #ifdef CONFIG_NET_RX_BUSY_POLL
125 WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
126 #endif
127 sk_rx_queue_set(sk, skb);
128 }
129
130 /* variant used for unconnected sockets */
sk_mark_napi_id_once(struct sock * sk,const struct sk_buff * skb)131 static inline void sk_mark_napi_id_once(struct sock *sk,
132 const struct sk_buff *skb)
133 {
134 #ifdef CONFIG_NET_RX_BUSY_POLL
135 if (!READ_ONCE(sk->sk_napi_id))
136 WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
137 #endif
138 }
139
140 #endif /* _LINUX_NET_BUSY_POLL_H */
141
