252 lines
6.7 KiB
C
252 lines
6.7 KiB
C
/*-
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* Copyright (c) 2001,2002,2003 Jonathan Lemon <jlemon@FreeBSD.org>
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* Copyright (c) 1997, Stefan Esser <se@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/rtprio.h>
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#include <sys/systm.h>
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#include <sys/interrupt.h>
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#include <sys/kernel.h>
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#include <sys/kthread.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#include <sys/random.h>
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#include <sys/resourcevar.h>
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#include <sys/sysctl.h>
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#include <sys/unistd.h>
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#include <machine/atomic.h>
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#include <machine/cpu.h>
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#include <machine/stdarg.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <net/if_types.h>
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#include <net/if_var.h>
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#include <net/netisr.h>
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volatile unsigned int netisr; /* scheduling bits for network */
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struct netisr {
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netisr_t *ni_handler;
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struct ifqueue *ni_queue;
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} netisrs[32];
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static struct mtx netisr_mtx;
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static void *net_ih;
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void
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legacy_setsoftnet(void)
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{
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swi_sched(net_ih, 0);
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}
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void
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netisr_register(int num, netisr_t *handler, struct ifqueue *inq)
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{
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KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
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("bad isr %d", num));
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netisrs[num].ni_handler = handler;
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netisrs[num].ni_queue = inq;
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}
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void
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netisr_unregister(int num)
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{
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struct netisr *ni;
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int s;
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KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
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("bad isr %d", num));
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ni = &netisrs[num];
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ni->ni_handler = NULL;
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if (ni->ni_queue != NULL) {
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s = splimp();
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IF_DRAIN(ni->ni_queue);
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splx(s);
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}
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}
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struct isrstat {
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int isrs_count; /* dispatch count */
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int isrs_directed; /* ...successfully dispatched */
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int isrs_deferred; /* ...queued instead */
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int isrs_bypassed; /* bypassed queued packets */
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int isrs_queued; /* intentionally queueued */
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int isrs_swi_count; /* swi_net handlers called */
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};
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static struct isrstat isrstat;
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SYSCTL_NODE(_net, OID_AUTO, isr, CTLFLAG_RW, 0, "netisr counters");
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static int netisr_enable = 0;
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SYSCTL_INT(_net_isr, OID_AUTO, enable, CTLFLAG_RW,
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&netisr_enable, 0, "enable direct dispatch");
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SYSCTL_INT(_net_isr, OID_AUTO, count, CTLFLAG_RD,
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&isrstat.isrs_count, 0, "");
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SYSCTL_INT(_net_isr, OID_AUTO, directed, CTLFLAG_RD,
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&isrstat.isrs_directed, 0, "");
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SYSCTL_INT(_net_isr, OID_AUTO, deferred, CTLFLAG_RD,
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&isrstat.isrs_deferred, 0, "");
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SYSCTL_INT(_net_isr, OID_AUTO, bypassed, CTLFLAG_RD,
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&isrstat.isrs_bypassed, 0, "");
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SYSCTL_INT(_net_isr, OID_AUTO, queued, CTLFLAG_RD,
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&isrstat.isrs_queued, 0, "");
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SYSCTL_INT(_net_isr, OID_AUTO, swi_count, CTLFLAG_RD,
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&isrstat.isrs_swi_count, 0, "");
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/*
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* Call the netisr directly instead of queueing the packet, if possible.
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*
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* Ideally, the permissibility of calling the routine would be determined
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* by checking if splnet() was asserted at the time the device interrupt
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* occurred; if so, this indicates that someone is in the network stack.
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*
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* However, bus_setup_intr uses INTR_TYPE_NET, which sets splnet before
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* calling the interrupt handler, so the previous mask is unavailable.
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* Approximate this by checking intr_nesting_level instead; if any SWI
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* handlers are running, the packet is queued instead.
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*/
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void
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netisr_dispatch(int num, struct mbuf *m)
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{
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struct netisr *ni;
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isrstat.isrs_count++;
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KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
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("bad isr %d", num));
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ni = &netisrs[num];
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if (ni->ni_queue == NULL) {
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m_freem(m);
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return;
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}
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if (netisr_enable && mtx_trylock(&netisr_mtx)) {
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isrstat.isrs_directed++;
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/*
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* One slight problem here is that packets might bypass
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* each other in the stack, if an earlier one happened
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* to get stuck in the queue.
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*
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* we can either:
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* a. drain the queue before handling this packet,
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* b. fallback to queueing the packet,
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* c. sweep the issue under the rug and ignore it.
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*
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* Currently, we do c), and keep a rough event counter.
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*/
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if (_IF_QLEN(ni->ni_queue) > 0)
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isrstat.isrs_bypassed++;
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ni->ni_handler(m);
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mtx_unlock(&netisr_mtx);
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} else {
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isrstat.isrs_deferred++;
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if (IF_HANDOFF(ni->ni_queue, m, NULL))
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schednetisr(num);
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}
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}
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/*
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* Same as above, but always queue.
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* This is either used in places where we are not confident that
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* direct dispatch is possible, or where queueing is required.
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*/
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int
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netisr_queue(int num, struct mbuf *m)
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{
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struct netisr *ni;
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KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
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("bad isr %d", num));
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ni = &netisrs[num];
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if (ni->ni_queue == NULL) {
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m_freem(m);
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return (1);
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}
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isrstat.isrs_queued++;
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if (!IF_HANDOFF(ni->ni_queue, m, NULL))
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return (0);
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schednetisr(num);
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return (1);
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}
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static void
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swi_net(void *dummy)
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{
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struct netisr *ni;
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struct mbuf *m;
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u_int bits;
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int i;
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#ifdef DEVICE_POLLING
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const int polling = 1;
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#else
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const int polling = 0;
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#endif
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mtx_lock(&netisr_mtx);
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do {
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bits = atomic_readandclear_int(&netisr);
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if (bits == 0)
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break;
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while ((i = ffs(bits)) != 0) {
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isrstat.isrs_swi_count++;
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i--;
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bits &= ~(1 << i);
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ni = &netisrs[i];
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if (ni->ni_handler == NULL) {
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printf("swi_net: unregistered isr %d.\n", i);
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continue;
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}
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if (ni->ni_queue == NULL)
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ni->ni_handler(NULL);
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else
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for (;;) {
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IF_DEQUEUE(ni->ni_queue, m);
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if (m == NULL)
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break;
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ni->ni_handler(m);
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}
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}
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} while (polling);
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mtx_unlock(&netisr_mtx);
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}
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static void
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start_netisr(void *dummy)
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{
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mtx_init(&netisr_mtx, "netisr lock", NULL, MTX_DEF);
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if (swi_add(NULL, "net", swi_net, NULL, SWI_NET, 0, &net_ih))
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panic("start_netisr");
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}
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SYSINIT(start_netisr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_netisr, NULL)
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