LXR linux/include/net/busy

   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
  28struct napi_struct;
  29extern unsigned int sysctl_net_busy_read __read_mostly;
  30extern unsigned int sysctl_net_busy_poll __read_mostly;
  31
  32static inline bool net_busy_loop_on(void)
  33{
  34        return sysctl_net_busy_poll;
  35}
  36
  37static inline bool sk_can_busy_loop(const struct sock *sk)
  38{
  39        return sk->sk_ll_usec && !signal_pending(current);
  40}
  41
  42bool sk_busy_loop_end(void *p, unsigned long start_time);
  43
  44void 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 */
  49static inline unsigned long net_busy_loop_on(void)
  50{
  51        return 0;
  52}
  53
  54static inline bool sk_can_busy_loop(struct sock *sk)
  55{
  56        return false;
  57}
  58
  59#endif /* CONFIG_NET_RX_BUSY_POLL */
  60
  61static 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 */
  71static 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
  86static 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
 102static 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 */
 113static 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 */
 122static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
 123{
 124#ifdef CONFIG_NET_RX_BUSY_POLL
 125        sk->sk_napi_id = skb->napi_id;
 126#endif
 127        sk_rx_queue_set(sk, skb);
 128}
 129
 130/* variant used for unconnected sockets */
 131static 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 (!sk->sk_napi_id)
 136                sk->sk_napi_id = skb->napi_id;
 137#endif
 138}
 139
 140#endif /* _LINUX_NET_BUSY_POLL_H */
 141