implement M_WAIT; reduce redundant splimp's

SCCS-vsn: sys/kern/uipc_mbuf.c 6.4

diff --git a/usr/src/sys/kern/uipc_mbuf.c b/usr/src/sys/kern/uipc_mbuf.c
index 4d3b56b..c8c2e17 100644 (file)
--- a/usr/src/sys/kern/uipc_mbuf.c
+++ b/usr/src/sys/kern/uipc_mbuf.c
@@ -1,4 +1,4 @@
-/*     uipc_mbuf.c     6.3     84/08/29        */
+/*     uipc_mbuf.c     6.4     85/05/27        */

 
 #include "../machine/pte.h"
 
 
 #include "../machine/pte.h"
 


@@ -14,44 +14,47 @@
 
 mbinit()
 {
 
 mbinit()
 {

+       int s;

 
 

-       if (m_clalloc(4096/CLBYTES, MPG_MBUFS) == 0)
+       s = splimp();
+       if (m_clalloc(4096/CLBYTES, MPG_MBUFS, M_DONTWAIT) == 0)

                goto bad;
                goto bad;

-       if (m_clalloc(8*4096/CLBYTES, MPG_CLUSTERS) == 0)
+       if (m_clalloc(8*4096/CLBYTES, MPG_CLUSTERS, M_DONTWAIT) == 0)

                goto bad;
                goto bad;

+       splx(s);

        return;
 bad:
        panic("mbinit");
 }
 
        return;
 bad:
        panic("mbinit");
 }
 

+/*
+ * Must be called at splimp.
+ */

 caddr_t
 caddr_t

-m_clalloc(ncl, how)
+m_clalloc(ncl, how, canwait)

        register int ncl;
        int how;
 {
        int npg, mbx;
        register struct mbuf *m;
        register int i;
        register int ncl;
        int how;
 {
        int npg, mbx;
        register struct mbuf *m;
        register int i;

-       int s;

 
        npg = ncl * CLSIZE;
 
        npg = ncl * CLSIZE;

-       s = splimp();           /* careful: rmalloc isn't reentrant */

        mbx = rmalloc(mbmap, (long)npg);
        mbx = rmalloc(mbmap, (long)npg);

-       splx(s);
-       if (mbx == 0)
+       if (mbx == 0) {
+               if (canwait == M_WAIT)
+                       panic("out of mbuf map");

                return (0);
                return (0);

+       }

        m = cltom(mbx / CLSIZE);
        if (memall(&Mbmap[mbx], npg, proc, CSYS) == 0) {
        m = cltom(mbx / CLSIZE);
        if (memall(&Mbmap[mbx], npg, proc, CSYS) == 0) {

-               s = splimp();

                rmfree(mbmap, (long)npg, (long)mbx);
                rmfree(mbmap, (long)npg, (long)mbx);

-               splx(s);

                return (0);
        }
        vmaccess(&Mbmap[mbx], (caddr_t)m, npg);
        switch (how) {
 
        case MPG_CLUSTERS:
                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;
                for (i = 0; i < ncl; i++) {
                        m->m_off = 0;
                        m->m_next = mclfree;


@@ -60,7 +63,6 @@ m_clalloc(ncl, how)
                        mbstat.m_clfree++;
                }
                mbstat.m_clusters += ncl;
                        mbstat.m_clfree++;
                }
                mbstat.m_clusters += ncl;

-               splx(s);

                break;
 
        case MPG_MBUFS:
                break;
 
        case MPG_MBUFS:


@@ -87,10 +89,14 @@ m_pgfree(addr, n)
 #endif
 }
 
 #endif
 }
 

-m_expand()
+/*
+ * Must be called at splimp.
+ */
+m_expand(canwait)
+       int canwait;

 {
 
 {
 

-       if (m_clalloc(1, MPG_MBUFS) == 0)
+       if (m_clalloc(1, MPG_MBUFS, canwait) == 0)

                goto steal;
        return (1);
 steal:
                goto steal;
        return (1);
 steal:


@@ -121,7 +127,7 @@ m_getclr(canwait, type)
 {
        register struct mbuf *m;
 
 {
        register struct mbuf *m;
 

-       m = m_get(canwait, type);
+       MGET(m, canwait, type);

        if (m == 0)
                return (0);
        bzero(mtod(m, caddr_t), MLEN);
        if (m == 0)
                return (0);
        bzero(mtod(m, caddr_t), MLEN);


@@ -138,6 +144,10 @@ m_free(m)
        return (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)
 /*ARGSUSED*/
 struct mbuf *
 m_more(canwait, type)


@@ -145,9 +155,14 @@ m_more(canwait, type)
 {
        register struct mbuf *m;
 
 {
        register struct mbuf *m;
 

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


@@ -173,6 +188,12 @@ m_freem(m)
 /*
  * Mbuffer utility routines.
  */
 /*
  * 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;
 struct mbuf *
 m_copy(m, off, len)
        register struct mbuf *m;


@@ -202,7 +223,7 @@ m_copy(m, off, len)
                                panic("m_copy");
                        break;
                }
                                panic("m_copy");
                        break;
                }

-               MGET(n, M_WAIT, m->m_type);
+               MGET(n, M_DONTWAIT, m->m_type);

                *np = n;
                if (n == 0)
                        goto nospace;
                *np = n;
                if (n == 0)
                        goto nospace;