uipc_mbuf.c

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/*
 * Copyright (c) 1982, 1986, 1988, 1991, 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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.
 *
 *	@(#)uipc_mbuf.c	8.2 (Berkeley) 1/4/94
 *	$Id: uipc_mbuf.c,v 1.37.2.1 1999/04/12 10:07:14 des Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/domain.h>
#include <sys/protosw.h>

#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>

#ifdef OSKIT
void mbinit __P((void *));
#else
static void mbinit __P((void *));
#endif
SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL)

#ifndef OSKIT
struct mbuf *mbutl;
char	*mclrefcnt;
#endif /* !OSKIT */
struct mbstat mbstat;
struct mbuf *mmbfree;
#ifndef OSKIT
union mcluster *mclfree;
#endif /* !OSKIT */
int	max_linkhdr;
int	max_protohdr;
int	max_hdr;
int	max_datalen;

SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW,
	   &max_linkhdr, 0, "");
SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW,
	   &max_protohdr, 0, "");
SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, "");
SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW,
	   &max_datalen, 0, "");
SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RW, &mbstat, mbstat, "");

static void	m_reclaim __P((void));

/* "number of clusters of pages" */
#define NCL_INIT	1

#define NMB_INIT	16

/* ARGSUSED*/
#ifdef OSKIT
void
#else
static void
#endif
mbinit(dummy)
	void *dummy;
{
	int s;

#ifdef OSKIT
	mmbfree = NULL; 
#else
	mmbfree = NULL; mclfree = NULL;
#endif
	mbstat.m_msize = MSIZE;
#ifndef OSKIT
	mbstat.m_mclbytes = MCLBYTES;
	mbstat.m_minclsize = MINCLSIZE;
#endif
	mbstat.m_mlen = MLEN;
	mbstat.m_mhlen = MHLEN;

	s = splimp();
	if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0)
		goto bad;
#ifndef OSKIT
#if MCLBYTES <= PAGE_SIZE
	if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0)
		goto bad;
#else
	/* It's OK to call contigmalloc in this context. */
	if (m_clalloc(16, M_WAIT) == 0)
		goto bad;
#endif
#endif /* !OSKIT */
	splx(s);
	return;
bad:
	panic("mbinit");
}

/*
 * Allocate at least nmb mbufs and place on mbuf free list.
 * Must be called at splimp.
 */
/* ARGSUSED */
int
m_mballoc(nmb, how)
	register int nmb;
	int how;
{
	register caddr_t p;
	register int i;
	int nbytes;

	/* Once we run out of map space, it will be impossible to get
	 * any more (nothing is ever freed back to the map) (XXX which
	 * is dumb). (however you are not dead as m_reclaim might
	 * still be able to free a substantial amount of space).
	 */
	if (mb_map_full)
		return (0);

	nbytes = round_page(nmb * MSIZE);
	p = (caddr_t)kmem_malloc(mb_map, nbytes, M_NOWAIT);
	if (p == 0 && how == M_WAIT) {
		mbstat.m_wait++;
		p = (caddr_t)kmem_malloc(mb_map, nbytes, M_WAITOK);
	}

	/*
	 * Either the map is now full, or `how' is M_NOWAIT and there
	 * are no pages left.
	 */
	if (p == NULL)
		return (0);

	nmb = nbytes / MSIZE;
	for (i = 0; i < nmb; i++) {
		((struct mbuf *)p)->m_next = mmbfree;
		mmbfree = (struct mbuf *)p;
		p += MSIZE;
	}
	mbstat.m_mbufs += nmb;
	return (1);
}

#ifndef OSKIT
#if MCLBYTES > PAGE_SIZE
static int i_want_my_mcl;

static void
kproc_mclalloc(void)
{
	int status;

	while (1) {
		tsleep(&i_want_my_mcl, PVM, "mclalloc", 0);

		for (; i_want_my_mcl; i_want_my_mcl--) {
			if (m_clalloc(1, M_WAIT) == 0)
				printf("m_clalloc failed even in process context!\n");
		}
	}
}

static struct proc *mclallocproc;
static struct kproc_desc mclalloc_kp = {
	"mclalloc",
	kproc_mclalloc,
	&mclallocproc
};
SYSINIT_KT(mclallocproc, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY, kproc_start,
	   &mclalloc_kp);
#endif

/*
 * Allocate some number of mbuf clusters
 * and place on cluster free list.
 * Must be called at splimp.
 */
/* ARGSUSED */
int
m_clalloc(ncl, how)
	register int ncl;
	int how;
{
	register caddr_t p;
	register int i;
	int npg;

	/*
	 * Once we run out of map space, it will be impossible
	 * to get any more (nothing is ever freed back to the
	 * map).
	 */
	if (mb_map_full) {
		mbstat.m_drops++;
		return (0);
	}

#if MCLBYTES > PAGE_SIZE
	if (how != M_WAIT) {
		i_want_my_mcl += ncl;
		wakeup(&i_want_my_mcl);
		mbstat.m_wait++;
		p = 0;
	} else {
		p = contigmalloc1(MCLBYTES * ncl, M_DEVBUF, M_WAITOK, 0ul,
				  ~0ul, PAGE_SIZE, 0, mb_map);
	}
#else
	npg = ncl;
	p = (caddr_t)kmem_malloc(mb_map, ctob(npg),
				 how != M_WAIT ? M_NOWAIT : M_WAITOK);
	ncl = ncl * PAGE_SIZE / MCLBYTES;
#endif
	/*
	 * Either the map is now full, or `how' is M_NOWAIT and there
	 * are no pages left.
	 */
	if (p == NULL) {
		mbstat.m_drops++;
		return (0);
	}

	for (i = 0; i < ncl; i++) {
		((union mcluster *)p)->mcl_next = mclfree;
		mclfree = (union mcluster *)p;
		p += MCLBYTES;
		mbstat.m_clfree++;
	}
	mbstat.m_clusters += ncl;
	return (1);
}
#endif /* !OSKIT */

/*
 * When MGET fails, ask protocols to free space when short of memory,
 * then re-attempt to allocate an mbuf.
 */
struct mbuf *
m_retry(i, t)
	int i, t;
{
	register struct mbuf *m;

	/*
	 * Must only do the reclaim if not in an interrupt context.
	 */
	if (i == M_WAIT)
		m_reclaim();
#define m_retry(i, t)	(struct mbuf *)0
	MGET(m, i, t);
#undef m_retry
	if (m != NULL) {
		mbstat.m_wait++;
	} else {
		if (i == M_DONTWAIT)
			mbstat.m_drops++;
		else
			panic("Out of mbuf clusters");
	}
	return (m);
}

/*
 * As above; retry an MGETHDR.
 */
struct mbuf *
m_retryhdr(i, t)
	int i, t;
{
	register struct mbuf *m;

	/*
	 * Must only do the reclaim if not in an interrupt context.
	 */
	if (i == M_WAIT)
		m_reclaim();
#define m_retryhdr(i, t) (struct mbuf *)0
	MGETHDR(m, i, t);
#undef m_retryhdr
	if (m != NULL) {
		mbstat.m_wait++;
	} else {
		if (i == M_DONTWAIT)
			mbstat.m_drops++;
		else
			panic("Out of mbuf clusters");
	}
	return (m);
}

static void
m_reclaim()
{
	register struct domain *dp;
	register struct protosw *pr;
	int s = splimp();

	for (dp = domains; dp; dp = dp->dom_next)
		for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
			if (pr->pr_drain)
				(*pr->pr_drain)();
	splx(s);
	mbstat.m_drain++;
}

/*
 * Space allocation routines.
 * These are also available as macros
 * for critical paths.
 */
struct mbuf *
m_get(how, type)
	int how, type;
{
	register struct mbuf *m;

	MGET(m, how, type);
	return (m);
}

struct mbuf *
m_gethdr(how, type)
	int how, type;
{
	register struct mbuf *m;

	MGETHDR(m, how, type);
	return (m);
}

struct mbuf *
m_getclr(how, type)
	int how, type;
{
	register struct mbuf *m;

	MGET(m, how, type);
	if (m == 0)
		return (0);
	bzero(mtod(m, caddr_t), MLEN);
	return (m);
}

struct mbuf *
m_free(m)
	struct mbuf *m;
{
	register struct mbuf *n;

	MFREE(m, n);
	return (n);
}

void
m_freem(m)
	register struct mbuf *m;
{
	register struct mbuf *n;

	if (m == NULL)
		return;
	do {
		MFREE(m, n);
		m = n;
	} while (m);
}

/*
 * Mbuffer utility routines.
 */

/*
 * Lesser-used path for M_PREPEND:
 * allocate new mbuf to prepend to chain,
 * copy junk along.
 */
struct mbuf *
m_prepend(m, len, how)
	register struct mbuf *m;
	int len, how;
{
	struct mbuf *mn;

	MGET(mn, how, m->m_type);
	if (mn == (struct mbuf *)NULL) {
		m_freem(m);
		return ((struct mbuf *)NULL);
	}
	if (m->m_flags & M_PKTHDR) {
		M_COPY_PKTHDR(mn, m);
		m->m_flags &= ~M_PKTHDR;
	}
	mn->m_next = m;
	m = mn;
	if (len < MHLEN)
		MH_ALIGN(m, len);
	m->m_len = len;
	return (m);
}

/*
 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
 * continuing for "len" bytes.  If len is M_COPYALL, copy to end of mbuf.
 * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller.
 */
#define MCFail (mbstat.m_mcfail)

struct mbuf *
m_copym(m, off0, len, wait)
	register struct mbuf *m;
	int off0, wait;
	register int len;
{
	register struct mbuf *n, **np;
	register int off = off0;
	struct mbuf *top;
	int copyhdr = 0;

	if (off < 0 || len < 0)
		panic("m_copym");
	if (off == 0 && m->m_flags & M_PKTHDR)
		copyhdr = 1;
	while (off > 0) {
		if (m == 0)
			panic("m_copym");
		if (off < m->m_len)
			break;
		off -= m->m_len;
		m = m->m_next;
	}
	np = &top;
	top = 0;
	while (len > 0) {
		if (m == 0) {
			if (len != M_COPYALL)
				panic("m_copym");
			break;
		}
		MGET(n, wait, m->m_type);
		*np = n;
		if (n == 0)
			goto nospace;
		if (copyhdr) {
			M_COPY_PKTHDR(n, m);
			if (len == M_COPYALL)
				n->m_pkthdr.len -= off0;
			else
				n->m_pkthdr.len = len;
			copyhdr = 0;
		}
		n->m_len = min(len, m->m_len - off);
		if (m->m_flags & M_EXT) {
			n->m_data = m->m_data + off;
#ifdef OSKIT
			oskit_bufio_addref(m->m_ext.ext_bufio);
#else /* !OSKIT */
			if(!m->m_ext.ext_ref)
				mclrefcnt[mtocl(m->m_ext.ext_buf)]++;
			else
				(*(m->m_ext.ext_ref))(m->m_ext.ext_buf,
							m->m_ext.ext_size);
#endif /* !OSKIT */