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/*-
* Copyright (c) 2001,2002,2003 Jonathan Lemon <jlemon@FreeBSD.org>
* Copyright (c) 1997, Stefan Esser <se@freebsd.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* $FreeBSD$
*/
#include "opt_device_polling.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/rtprio.h>
#include <sys/systm.h>
#include <sys/interrupt.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/random.h>
#include <sys/resourcevar.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>
#include <machine/atomic.h>
#include <machine/cpu.h>
#include <machine/stdarg.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/netisr.h>
volatile unsigned int netisr; /* scheduling bits for network */
struct netisr {
netisr_t *ni_handler;
struct ifqueue *ni_queue;
int ni_flags;
} netisrs[32];
static void *net_ih;
void
legacy_setsoftnet(void)
{
swi_sched(net_ih, 0);
}
void
netisr_register(int num, netisr_t *handler, struct ifqueue *inq, int flags)
{
KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
("bad isr %d", num));
KASSERT(flags == 0 || flags == NETISR_FORCEQUEUE,
("netisr_register: bad flags 0x%x\n", flags));
netisrs[num].ni_handler = handler;
netisrs[num].ni_queue = inq;
netisrs[num].ni_flags = flags;
}
void
netisr_unregister(int num)
{
struct netisr *ni;
KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
("bad isr %d", num));
ni = &netisrs[num];
ni->ni_handler = NULL;
if (ni->ni_queue != NULL)
IF_DRAIN(ni->ni_queue);
ni->ni_queue = NULL;
}
struct isrstat {
int isrs_count; /* dispatch count */
int isrs_directed; /* ...directly dispatched */
int isrs_deferred; /* ...queued instead */
int isrs_queued; /* intentionally queueued */
int isrs_drop; /* dropped 'cuz no handler */
int isrs_swi_count; /* swi_net handlers called */
};
static struct isrstat isrstat;
SYSCTL_NODE(_net, OID_AUTO, isr, CTLFLAG_RW, 0, "netisr counters");
static int netisr_direct = 1;
SYSCTL_INT(_net_isr, OID_AUTO, direct, CTLFLAG_RW,
&netisr_direct, 0, "enable direct dispatch");
TUNABLE_INT("net.isr.direct", &netisr_direct);
SYSCTL_INT(_net_isr, OID_AUTO, count, CTLFLAG_RD,
&isrstat.isrs_count, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, directed, CTLFLAG_RD,
&isrstat.isrs_directed, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, deferred, CTLFLAG_RD,
&isrstat.isrs_deferred, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, queued, CTLFLAG_RD,
&isrstat.isrs_queued, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, drop, CTLFLAG_RD,
&isrstat.isrs_drop, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, swi_count, CTLFLAG_RD,
&isrstat.isrs_swi_count, 0, "");
/*
* Process all packets currently present in a netisr queue. Used to
* drain an existing set of packets waiting for processing when we
* begin direct dispatch, to avoid processing packets out of order.
*/
static void
netisr_processqueue(struct netisr *ni)
{
struct mbuf *m;
for (;;) {
IF_DEQUEUE(ni->ni_queue, m);
if (m == NULL)
break;
ni->ni_handler(m);
}
}
/*
* Call the netisr directly instead of queueing the packet, if possible.
*/
void
netisr_dispatch(int num, struct mbuf *m)
{
struct netisr *ni;
isrstat.isrs_count++; /* XXX redundant */
KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
("bad isr %d", num));
ni = &netisrs[num];
if (ni->ni_queue == NULL) {
isrstat.isrs_drop++;
m_freem(m);
return;
}
/*
* Unless NETISR_FORCEQUEUE is set on the netisr (generally
* indicating that the handler still requires Giant, which cannot be
* acquired in arbitrary order with respect to a caller), directly
* dispatch handling of this packet. Source ordering is maintained
* by virtue of callers consistently calling one of queued or direct
* dispatch, and the forcequeue flag being immutable after
* registration.
*/
if (netisr_direct && !(ni->ni_flags & NETISR_FORCEQUEUE)) {
isrstat.isrs_directed++;
ni->ni_handler(m);
} else {
isrstat.isrs_deferred++;
if (IF_HANDOFF(ni->ni_queue, m, NULL))
schednetisr(num);
}
}
/*
* Same as above, but always queue.
* This is either used in places where we are not confident that
* direct dispatch is possible, or where queueing is required.
* It returns (0) on success and ERRNO on failure. On failure the
* mbuf has been free'd.
*/
int
netisr_queue(int num, struct mbuf *m)
{
struct netisr *ni;
KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
("bad isr %d", num));
ni = &netisrs[num];
if (ni->ni_queue == NULL) {
isrstat.isrs_drop++;
m_freem(m);
return (ENXIO);
}
isrstat.isrs_queued++;
if (!IF_HANDOFF(ni->ni_queue, m, NULL))
return (ENOBUFS); /* IF_HANDOFF has free'd the mbuf */
schednetisr(num);
return (0);
}
static void
swi_net(void *dummy)
{
struct netisr *ni;
u_int bits;
int i;
#ifdef DEVICE_POLLING
const int polling = 1;
#else
const int polling = 0;
#endif
do {
bits = atomic_readandclear_int(&netisr);
if (bits == 0)
break;
while ((i = ffs(bits)) != 0) {
isrstat.isrs_swi_count++;
i--;
bits &= ~(1 << i);
ni = &netisrs[i];
if (ni->ni_handler == NULL) {
printf("swi_net: unregistered isr %d.\n", i);
continue;
}
if (ni->ni_queue == NULL)
ni->ni_handler(NULL);
else
netisr_processqueue(ni);
}
} while (polling);
}
static void
start_netisr(void *dummy)
{
if (swi_add(NULL, "net", swi_net, NULL, SWI_NET, INTR_MPSAFE, &net_ih))
panic("start_netisr");
}
SYSINIT(start_netisr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_netisr, NULL);
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