4.3BSD/usr/src/sys/sys/uipc_mbuf.c
/*
* Copyright (c) 1982, 1986 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*
* @(#)uipc_mbuf.c 7.1 (Berkeley) 6/5/86
*/
#include "../machine/pte.h"
#include "param.h"
#include "dir.h"
#include "user.h"
#include "proc.h"
#include "cmap.h"
#include "map.h"
#include "mbuf.h"
#include "vm.h"
#include "kernel.h"
mbinit()
{
int s;
s = splimp();
if (m_clalloc(4096/CLBYTES, MPG_MBUFS, M_DONTWAIT) == 0)
goto bad;
if (m_clalloc(4096/CLBYTES, MPG_CLUSTERS, M_DONTWAIT) == 0)
goto bad;
splx(s);
return;
bad:
panic("mbinit");
}
/*
* Must be called at splimp.
*/
caddr_t
m_clalloc(ncl, how, canwait)
register int ncl;
int how;
{
int npg, mbx;
register struct mbuf *m;
register int i;
npg = ncl * CLSIZE;
mbx = rmalloc(mbmap, (long)npg);
if (mbx == 0) {
if (canwait == M_WAIT)
panic("out of mbufs: map full");
return (0);
}
m = cltom(mbx / CLSIZE);
if (memall(&Mbmap[mbx], npg, proc, CSYS) == 0) {
rmfree(mbmap, (long)npg, (long)mbx);
return (0);
}
vmaccess(&Mbmap[mbx], (caddr_t)m, npg);
switch (how) {
case MPG_CLUSTERS:
for (i = 0; i < ncl; i++) {
m->m_off = 0;
m->m_next = mclfree;
mclfree = m;
m += CLBYTES / sizeof (*m);
mbstat.m_clfree++;
}
mbstat.m_clusters += ncl;
break;
case MPG_MBUFS:
for (i = ncl * CLBYTES / sizeof (*m); i > 0; i--) {
m->m_off = 0;
m->m_type = MT_DATA;
mbstat.m_mtypes[MT_DATA]++;
mbstat.m_mbufs++;
(void) m_free(m);
m++;
}
break;
}
return ((caddr_t)m);
}
m_pgfree(addr, n)
caddr_t addr;
int n;
{
#ifdef lint
addr = addr; n = n;
#endif
}
/*
* Must be called at splimp.
*/
m_expand(canwait)
int canwait;
{
if (m_clalloc(1, MPG_MBUFS, canwait) == 0)
goto steal;
return (1);
steal:
/* should ask protocols to free code */
return (0);
}
/* NEED SOME WAY TO RELEASE SPACE */
/*
* Space allocation routines.
* These are also available as macros
* for critical paths.
*/
struct mbuf *
m_get(canwait, type)
int canwait, type;
{
register struct mbuf *m;
MGET(m, canwait, type);
return (m);
}
struct mbuf *
m_getclr(canwait, type)
int canwait, type;
{
register struct mbuf *m;
MGET(m, canwait, 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);
}
/*
* Get more mbufs; called from MGET macro if mfree list is empty.
* Must be called at splimp.
*/
/*ARGSUSED*/
struct mbuf *
m_more(canwait, type)
int canwait, type;
{
register struct mbuf *m;
while (m_expand(canwait) == 0) {
if (canwait == M_WAIT) {
m_want++;
sleep((caddr_t)&mfree, PZERO - 1);
} else {
mbstat.m_drops++;
return (NULL);
}
}
#define m_more(x,y) (panic("m_more"), (struct mbuf *)0)
MGET(m, canwait, type);
#undef m_more
return (m);
}
m_freem(m)
register struct mbuf *m;
{
register struct mbuf *n;
register int s;
if (m == NULL)
return;
s = splimp();
do {
MFREE(m, n);
} while (m = n);
splx(s);
}
/*
* Mbuffer utility routines.
*/
/*
* Make a copy of an mbuf chain starting "off" bytes from the beginning,
* continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
* Should get M_WAIT/M_DONTWAIT from caller.
*/
struct mbuf *
m_copy(m, off, len)
register struct mbuf *m;
int off;
register int len;
{
register struct mbuf *n, **np;
struct mbuf *top, *p;
if (len == 0)
return (0);
if (off < 0 || len < 0)
panic("m_copy");
while (off > 0) {
if (m == 0)
panic("m_copy");
if (off < m->m_len)
break;
off -= m->m_len;
m = m->m_next;
}
np = ⊤
top = 0;
while (len > 0) {
if (m == 0) {
if (len != M_COPYALL)
panic("m_copy");
break;
}
MGET(n, M_DONTWAIT, m->m_type);
*np = n;
if (n == 0)
goto nospace;
n->m_len = MIN(len, m->m_len - off);
if (m->m_off > MMAXOFF) {
p = mtod(m, struct mbuf *);
n->m_off = ((int)p - (int)n) + off;
mclrefcnt[mtocl(p)]++;
} else
bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
(unsigned)n->m_len);
if (len != M_COPYALL)
len -= n->m_len;
off = 0;
m = m->m_next;
np = &n->m_next;
}
return (top);
nospace:
m_freem(top);
return (0);
}
m_cat(m, n)
register struct mbuf *m, *n;
{
while (m->m_next)
m = m->m_next;
while (n) {
if (m->m_off >= MMAXOFF ||
m->m_off + m->m_len + n->m_len > MMAXOFF) {
/* just join the two chains */
m->m_next = n;
return;
}
/* splat the data from one into the other */
bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
(u_int)n->m_len);
m->m_len += n->m_len;
n = m_free(n);
}
}
m_adj(mp, len)
struct mbuf *mp;
register int len;
{
register struct mbuf *m;
register count;
if ((m = mp) == NULL)
return;
if (len >= 0) {
while (m != NULL && len > 0) {
if (m->m_len <= len) {
len -= m->m_len;
m->m_len = 0;
m = m->m_next;
} else {
m->m_len -= len;
m->m_off += len;
break;
}
}
} else {
/*
* Trim from tail. Scan the mbuf chain,
* calculating its length and finding the last mbuf.
* If the adjustment only affects this mbuf, then just
* adjust and return. Otherwise, rescan and truncate
* after the remaining size.
*/
len = -len;
count = 0;
for (;;) {
count += m->m_len;
if (m->m_next == (struct mbuf *)0)
break;
m = m->m_next;
}
if (m->m_len >= len) {
m->m_len -= len;
return;
}
count -= len;
/*
* Correct length for chain is "count".
* Find the mbuf with last data, adjust its length,
* and toss data from remaining mbufs on chain.
*/
for (m = mp; m; m = m->m_next) {
if (m->m_len >= count) {
m->m_len = count;
break;
}
count -= m->m_len;
}
while (m = m->m_next)
m->m_len = 0;
}
}
/*
* Rearange an mbuf chain so that len bytes are contiguous
* and in the data area of an mbuf (so that mtod and dtom
* will work for a structure of size len). Returns the resulting
* mbuf chain on success, frees it and returns null on failure.
* If there is room, it will add up to MPULL_EXTRA bytes to the
* contiguous region in an attempt to avoid being called next time.
*/
struct mbuf *
m_pullup(n, len)
register struct mbuf *n;
int len;
{
register struct mbuf *m;
register int count;
int space;
if (n->m_off + len <= MMAXOFF && n->m_next) {
m = n;
n = n->m_next;
len -= m->m_len;
} else {
if (len > MLEN)
goto bad;
MGET(m, M_DONTWAIT, n->m_type);
if (m == 0)
goto bad;
m->m_len = 0;
}
space = MMAXOFF - m->m_off;
do {
count = MIN(MIN(space - m->m_len, len + MPULL_EXTRA), n->m_len);
bcopy(mtod(n, caddr_t), mtod(m, caddr_t)+m->m_len,
(unsigned)count);
len -= count;
m->m_len += count;
n->m_len -= count;
if (n->m_len)
n->m_off += count;
else
n = m_free(n);
} while (len > 0 && n);
if (len > 0) {
(void) m_free(m);
goto bad;
}
m->m_next = n;
return (m);
bad:
m_freem(n);
return (0);
}