lint

[unix-history] / usr / src / sys / kern / uipc_mbuf.c

/*      uipc_mbuf.c     1.32    82/03/13        */

#include "../h/param.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/proc.h"
#include "../h/pte.h"
#include "../h/cmap.h"
#include "../h/map.h"
#include "../h/mbuf.h"
#include "../net/in_systm.h"            /* XXX */
#include "../h/vm.h"

mbinit()
{

COUNT(MBINIT);
       if (m_reserve(32) == 0)
               goto bad;
       if (m_clalloc(4, MPG_MBUFS) == 0)
               goto bad;
       if (m_clalloc(32, MPG_CLUSTERS) == 0)
               goto bad;
       return;
bad:
       panic("mbinit");
}

caddr_t
m_clalloc(ncl, how)
       register int ncl;
       int how;
{
       int npg, mbx;
       register struct mbuf *m;
       register int i;
       int s;

COUNT(M_CLALLOC);
       npg = ncl * CLSIZE;
       s = splimp();           /* careful: rmalloc isn't reentrant */
       mbx = rmalloc(mbmap, npg);
       splx(s);
       if (mbx == 0)
               return (0);
       m = cltom(mbx / CLSIZE);
       if (memall(&Mbmap[mbx], ncl * CLSIZE, proc, CSYS) == 0)
               return (0);
       vmaccess(&Mbmap[mbx], (caddr_t)m, npg);
       switch (how) {

       case MPG_CLUSTERS:
               s = splimp();
               for (i = 0; i < ncl; i++) {
                       m->m_off = 0;
                       m->m_next = mclfree;
                       mclfree = m;
                       m += CLBYTES / sizeof (*m);
                       nmclfree++;
               }
               mbstat.m_clusters += ncl;
               splx(s);
               break;

       case MPG_MBUFS:
               for (i = ncl * CLBYTES / sizeof (*m); i > 0; i--) {
                       m->m_off = 0;
                       m->m_free = 0;
                       (void) m_free(m);
                       m++;
               }
               mbstat.m_clusters += ncl;
               break;
       }
       return ((caddr_t)m);
}

m_pgfree(addr, n)
       caddr_t addr;
       int n;
{

COUNT(M_PGFREE);
#ifdef lint
       addr = addr; n = n;
#endif
}

m_expand()
{

COUNT(M_EXPAND);
       if (mbstat.m_bufs >= mbstat.m_hiwat)
               return (0);
       if (m_clalloc(1, MPG_MBUFS) == 0)
               goto steal;
       return (1);
steal:
       /* should ask protocols to free code */
       return (0);
}

/* NEED SOME WAY TO RELEASE SPACE */

/*
* Space reservation routines
*/
m_reserve(mbufs)
       int mbufs;
{

       if (mbstat.m_lowat + (mbufs>>1) > (NMBCLUSTERS-32) * CLBYTES) 
               return (0);
       mbstat.m_hiwat += mbufs;
       mbstat.m_lowat = mbstat.m_hiwat >> 1;
       return (1);
}

m_release(mbufs)
       int mbufs;
{

       mbstat.m_hiwat -= mbufs;
       mbstat.m_lowat = mbstat.m_hiwat >> 1;
}

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

COUNT(M_GET);
       MGET(m, canwait);
       return (m);
}

struct mbuf *
m_getclr(canwait)
       int canwait;
{
       register struct mbuf *m;

COUNT(M_GETCLR);
       m = m_get(canwait);
       if (m == 0)
               return (0);
       m->m_off = MMINOFF;
       bzero(mtod(m, caddr_t), MLEN);
       return (m);
}

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

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

/*ARGSUSED*/
struct mbuf *
m_more(type)
       int type;
{
       register struct mbuf *m;

COUNT(M_MORE);
       if (!m_expand()) {
               mbstat.m_drops++;
               return (NULL);
       }
#define m_more(x) (panic("m_more"), (struct mbuf *)0)
       MGET(m, type);
#undef m_more
       return (m);
}

m_freem(m)
       register struct mbuf *m;
{
       register struct mbuf *n;
       register int s;

COUNT(M_FREEM);
       if (m == NULL)
               return;
       s = splimp();
       do {
               MFREE(m, n);
       } while (m = n);
       splx(s);
}

/*
* Mbuffer utility routines.
*/
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;
COUNT(M_COPY);

       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;
       top = 0;
       while (len > 0) {
               if (m == 0) {
                       if (len != M_COPYALL)
                               panic("m_copy");
                       break;
               }
               MGET(n, 1);
               *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 {
                       n->m_off = MMINOFF;
                       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, *n;

COUNT(M_ADJ);
       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 {
               /* a 2 pass algorithm might be better */
               len = -len;
               while (len > 0 && m->m_len != 0) {
                       while (m != NULL && m->m_len != 0) {
                               n = m;
                               m = m->m_next;
                       }
                       if (n->m_len <= len) {
                               len -= n->m_len;
                               n->m_len = 0;
                               m = mp;
                       } else {
                               n->m_len -= len;
                               break;
                       }
               }
       }
}

struct mbuf *
m_pullup(m0, len)
       struct mbuf *m0;
       int len;
{
       register struct mbuf *m, *n;
       int count;

       n = m0;
       if (len > MLEN)
               goto bad;
       MGET(m, 0);
       if (m == 0)
               goto bad;
       m->m_off = MMINOFF;
       m->m_len = 0;
       do {
               count = MIN(MLEN - m->m_len, len);
               if (count > n->m_len)
                       count = 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_off += count;
               n->m_len -= count;
               if (n->m_len)
                       break;
               n = m_free(n);
       } while (n);
       if (len) {
               (void) m_free(m);
               goto bad;
       }
       m->m_next = n;
       return (m);
bad:
       m_freem(n);
       return (0);
}