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freebsd/sys/net/netisr.h
Robert Watson 59dd72d040 Remove NETISR_MPSAFE, which allows specific netisr handlers to be directly
dispatched without Giant, and add NETISR_FORCEQUEUE, which allows specific
netisr handlers to always be dispatched via a queue (deferred).  Mark the
usb and if_ppp netisr handlers as NETISR_FORCEQUEUE, and explicitly
acquire Giant in those handlers.

Previously, any netisr handler not marked NETISR_MPSAFE would necessarily
run deferred and with Giant acquired.  This change removes Giant
scaffolding from the netisr infrastructure, but NETISR_FORCEQUEUE allows
non-MPSAFE handlers to continue to force deferred dispatch so as to avoid
lock order reversals between their acqusition of Giant and any calling
context.

It is likely we will be able to remove NETISR_FORCEQUEUE once
IFF_NEEDSGIANT is removed, as non-MPSAFE usb and if_ppp drivers will no
longer be supported.

Reviewed by:	bz
MFC after:	1 month
X-MFC note:	We can't remove NETISR_MPSAFE from stable/7 for KPI reasons,
		but the rest can go back.
2008-07-04 00:21:38 +00:00

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3.5 KiB
C

/*-
* Copyright (c) 1980, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)netisr.h 8.1 (Berkeley) 6/10/93
* $FreeBSD$
*/
#ifndef _NET_NETISR_H_
#define _NET_NETISR_H_
/*
* The netisr (network interrupt service routine) provides a deferred
* execution evironment in which (generally inbound) network processing can
* take place. Protocols register handlers and, optionally, packet queues;
* when packets are delivered to the queue, the protocol handler will be
* executed directly, or via deferred dispatch depending on the
* circumstances.
*
* Historically, this was implemented by the BSD software ISR facility; it is
* now implemented via a software ithread (SWI).
*/
#define NETISR_POLL 0 /* polling callback, must be first */
#define NETISR_IP 2 /* same as AF_INET */
#define NETISR_ROUTE 14 /* routing socket */
#define NETISR_AARP 15 /* Appletalk ARP */
#define NETISR_ATALK2 16 /* Appletalk phase 2 */
#define NETISR_ATALK1 17 /* Appletalk phase 1 */
#define NETISR_ARP 18 /* same as AF_LINK */
#define NETISR_IPX 23 /* same as AF_IPX */
#define NETISR_USB 25 /* USB soft interrupt */
#define NETISR_PPP 26 /* PPP soft interrupt */
#define NETISR_IPV6 27
#define NETISR_NATM 28
#define NETISR_ATM 29
#define NETISR_NETGRAPH 30
#define NETISR_POLLMORE 31 /* polling callback, must be last */
#ifndef LOCORE
#ifdef _KERNEL
void legacy_setsoftnet(void);
extern volatile unsigned int netisr; /* scheduling bits for network */
#define schednetisr(anisr) do { \
atomic_set_rel_int(&netisr, 1 << (anisr)); \
legacy_setsoftnet(); \
} while (0)
/* used to atomically schedule multiple netisrs */
#define schednetisrbits(isrbits) do { \
atomic_set_rel_int(&netisr, isrbits); \
legacy_setsoftnet(); \
} while (0)
struct ifqueue;
struct mbuf;
typedef void netisr_t (struct mbuf *);
void netisr_dispatch(int, struct mbuf *);
int netisr_queue(int, struct mbuf *);
#define NETISR_FORCEQUEUE 0x0002 /* Force queued dispatch. */
void netisr_register(int, netisr_t *, struct ifqueue *, int);
void netisr_unregister(int);
#endif
#endif
#endif