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/*
* net busy poll support
* Copyright(c) 2013 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
* Author: Eliezer Tamir
*
* Contact Information:
* e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
*/
#ifndef _LINUX_NET_BUSY_POLL_H
#define _LINUX_NET_BUSY_POLL_H
#include <linux/netdevice.h>
#include <linux/sched/clock.h>
#include <linux/sched/signal.h>
#include <net/ip.h>
/* 0 - Reserved to indicate value not set
* 1..NR_CPUS - Reserved for sender_cpu
* NR_CPUS+1..~0 - Region available for NAPI IDs
*/
#define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1))
#ifdef CONFIG_NET_RX_BUSY_POLL
struct napi_struct;
extern unsigned int sysctl_net_busy_read __read_mostly;
extern unsigned int sysctl_net_busy_poll __read_mostly;
static inline bool net_busy_loop_on(void)
{
return READ_ONCE(sysctl_net_busy_poll);
}
static inline bool sk_can_busy_loop(const struct sock *sk)
{
return READ_ONCE(sk->sk_ll_usec) && !signal_pending(current);
}
bool sk_busy_loop_end(void *p, unsigned long start_time);
void napi_busy_loop(unsigned int napi_id,
bool (*loop_end)(void *, unsigned long),
void *loop_end_arg);
#else /* CONFIG_NET_RX_BUSY_POLL */
static inline unsigned long net_busy_loop_on(void)
{
return 0;
}
static inline bool sk_can_busy_loop(struct sock *sk)
{
return false;
}
#endif /* CONFIG_NET_RX_BUSY_POLL */
static inline unsigned long busy_loop_current_time(void)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
return (unsigned long)(local_clock() >> 10);
#else
return 0;
#endif
}
/* in poll/select we use the global sysctl_net_ll_poll value */
static inline bool busy_loop_timeout(unsigned long start_time)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);
if (bp_usec) {
unsigned long end_time = start_time + bp_usec;
unsigned long now = busy_loop_current_time();
return time_after(now, end_time);
}
#endif
return true;
}
static inline bool sk_busy_loop_timeout(struct sock *sk,
unsigned long start_time)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
if (bp_usec) {
unsigned long end_time = start_time + bp_usec;
unsigned long now = busy_loop_current_time();
return time_after(now, end_time);
}
#endif
return true;
}
static inline void sk_busy_loop(struct sock *sk, int nonblock)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
if (napi_id >= MIN_NAPI_ID)
napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk);
#endif
}
/* used in the NIC receive handler to mark the skb */
static inline void skb_mark_napi_id(struct sk_buff *skb,
struct napi_struct *napi)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
skb->napi_id = napi->napi_id;
#endif
}
/* used in the protocol hanlder to propagate the napi_id to the socket */
static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
#endif
sk_rx_queue_set(sk, skb);
}
/* variant used for unconnected sockets */
static inline void sk_mark_napi_id_once(struct sock *sk,
const struct sk_buff *skb)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
if (!READ_ONCE(sk->sk_napi_id))
WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
#endif
}
#endif /* _LINUX_NET_BUSY_POLL_H */
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