Patch from Eric Norum <eric@pollux.usask.ca> to eliminate a panic when the

network stack runs out of mbufs.

9 files changed, 264 insertions, 441 deletions

diff --git a/c/src/exec/libnetworking/kern/uipc_mbuf.c b/c/src/exec/libnetworking/kern/uipc_mbuf.c
index d6b51e3d95..17d2be6b26 100644
--- a/c/src/exec/libnetworking/kern/uipc_mbuf.c
+++ b/c/src/exec/libnetworking/kern/uipc_mbuf.c
@@ -63,114 +63,11 @@ int	max_protohdr;
 int	max_hdr;
 int	max_datalen;
 
-static void	m_reclaim __P((void));
-
 /* "number of clusters of pages" */
 #define NCL_INIT	1
 
 #define NMB_INIT	16
 
-/* ARGSUSED*/
-static void
-mbinit(dummy)
-	void *dummy;
-{
-	int s;
-
-	mmbfree = NULL; mclfree = NULL;
-	s = splimp();
-	if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0)
-		goto bad;
-	if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0)
-		goto bad;
-	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, nowait)
-	register int nmb;
-	int nowait;
-{
-	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, nowait ? M_NOWAIT : M_WAITOK);
-	/*
-	 * Either the map is now full, or this is 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);
-}
-
-/*
- * Allocate some number of mbuf clusters
- * and place on cluster free list.
- * Must be called at splimp.
- */
-/* ARGSUSED */
-int
-m_clalloc(ncl, nowait)
-	register int ncl;
-	int nowait;
-{
-	register caddr_t p;
-	register int i;
-
-	/*
-	 * 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)
-		return (0);
-
-	p = (caddr_t)kmem_malloc(mb_map, ncl*MCLBYTES,
-				 nowait ? M_NOWAIT : M_WAITOK);
-	/*
-	 * Either the map is now full, or this is nowait and there
-	 * are no pages left.
-	 */
-	if (p == NULL)
-		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);
-}
-
 /*
  * When MGET failes, ask protocols to free space when short of memory,
  * then re-attempt to allocate an mbuf.
@@ -212,8 +109,8 @@ m_retryhdr(i, t)
 	return (m);
 }
 
-static void
-m_reclaim()
+void
+m_reclaim(void)
 {
 	register struct domain *dp;
 	register struct protosw *pr;
diff --git a/c/src/exec/libnetworking/rtems/rtems_glue.c b/c/src/exec/libnetworking/rtems/rtems_glue.c
index d8ec0a1ec4..8ef1626906 100644
--- a/c/src/exec/libnetworking/rtems/rtems_glue.c
+++ b/c/src/exec/libnetworking/rtems/rtems_glue.c
@@ -126,25 +126,47 @@ rtems_bsdnet_free (void *addr, int type)
 
 /*
  * Do the initializations required by the BSD code
- * FIXME: Maybe we should use a different memory allocation scheme that
- * would let us share space between mbufs and mbuf clusters.
- * For now, we'll just take the easy way out!
  */
 static void
 bsd_init ()
 {
+	int i;
+	char *p;
+
 	/*
-	 * Set up mbuf data strutures
-	 * Cluster allocation *must* come first -- see comment on kmem_malloc().
+	 * Set up mbuf cluster data strutures
 	 */
-	m_clalloc (nmbclusters, M_DONTWAIT);
+	p = malloc ((nmbclusters*MCLBYTES)+MCLBYTES-1);
+	p = (char *)(((unsigned long)p + (MCLBYTES-1)) & ~(MCLBYTES-1));
+	if (p == NULL)
+		rtems_panic ("Can't get network cluster memory.");
+	mbutl = (struct mbuf *)p;
+	for (i = 0; i < nmbclusters; i++) {
+		((union mcluster *)p)->mcl_next = mclfree;
+		mclfree = (union mcluster *)p;
+		p += MCLBYTES;
+		mbstat.m_clfree++;
+	}
+	mbstat.m_clusters = nmbclusters;
 	mclrefcnt = malloc (nmbclusters);
 	if (mclrefcnt == NULL)
-		rtems_panic ("No memory for mbuf cluster reference counts.");
+		rtems_panic ("Can't get mbuf cluster reference counts memory.");
 	memset (mclrefcnt, '\0', nmbclusters);
-	m_mballoc (nmbuf, M_DONTWAIT);
-	mbstat.m_mtypes[MT_FREE] = nmbuf;
 
+	/*
+	 * Set up mbuf data structures
+	 */
+
+	p = malloc(nmbuf * MSIZE);
+	if (p == NULL)
+		rtems_panic ("Can't get network memory.");
+	for (i = 0; i < nmbuf; i++) {
+		((struct mbuf *)p)->m_next = mmbfree;
+		mmbfree = (struct mbuf *)p;
+		p += MSIZE;
+	}
+	mbstat.m_mbufs = nmbuf;
+	mbstat.m_mtypes[MT_FREE] = nmbuf;
 
 	/*
 	 * Set up domains
@@ -663,41 +685,8 @@ rtems_bsdnet_log (int priority, const char *fmt, ...)
 }
 
 /*
- * Hack alert: kmem_malloc `knows' that its
- * first invocation is to get mbuf clusters!
- */
-int mb_map_full;
-vm_map_t mb_map;
-vm_offset_t
-kmem_malloc (vm_map_t *map, vm_size_t size, boolean_t waitflag)
-{
-	void *p;
-	
-	/*
-	 * Can't get memory if we're already running.
-	 */
-	if (networkDaemonTid) {
-		if (waitflag == M_WAITOK)
-			rtems_panic (
-"Network mbuf space can not be enlarged after rtems_bsdnet_initialize() has\n"
-"returned.  Enlarge the initial mbuf/cluster size in rtems_bsdnet_config.");
-		return 0;
-	}
-
-#define ROUNDSIZE 2048
-	p = malloc (size+ROUNDSIZE);
-	p = (void *)((unsigned long)p & ~(ROUNDSIZE-1));
-	if ((p == NULL) && (waitflag == M_WAITOK))
-		rtems_panic ("Can't get initial network memory!");
-	if (mbutl == NULL)
-		mbutl = p;
-	return (vm_offset_t)p;
-}
-
-/*
  * IP header checksum routine for processors which don't have an inline version
  */
-
 u_int
 in_cksum_hdr (const void *ip)
 {
@@ -926,3 +915,57 @@ rtems_bsdnet_parse_driver_name (const struct rtems_bsdnet_ifconfig *config, char
 	printf ("Bad network driver name `%s'", config->name);
 	return -1;
 }
+
+/*
+ * Handle requests for more network memory
+ * XXX: Another possibility would be to use a semaphore here with
+ *      a release in the mbuf free macro.  I have chosen this `polling'
+ *      approach because:
+ *      1) It is simpler.
+ *      2) It adds no complexity to the free macro.
+ *      3) Running out of mbufs should be a rare
+ *         condition -- predeployment testing of
+ *         an application should indicate the
+ *         required mbuf pool size.
+ * XXX: Should there be a panic if a task is stuck in the loop for
+ *      more than a minute or so?
+ */
+int
+m_mballoc (int nmb, int nowait)
+{
+	if (nowait)
+		return 0;
+	m_reclaim ();
+	if (mmbfree == NULL) {
+		mbstat.m_wait++;
+		do {
+			rtems_bsdnet_semaphore_release ();
+			rtems_task_wake_after (1);
+			rtems_bsdnet_semaphore_obtain ();
+		} while (mmbfree == NULL);
+	}
+	else {
+		mbstat.m_drops++;
+	}
+	return 1;
+}
+
+int
+m_clalloc(ncl, nowait)
+{
+	if (nowait)
+		return 0;
+	m_reclaim ();
+	if (mclfree == NULL) {
+		mbstat.m_wait++;
+		do {
+			rtems_bsdnet_semaphore_release ();
+			rtems_task_wake_after (1);
+			rtems_bsdnet_semaphore_obtain ();
+		} while (mclfree == NULL);
+	}
+	else {
+		mbstat.m_drops++;
+	}
+	return 1;
+}
diff --git a/c/src/exec/libnetworking/sys/mbuf.h b/c/src/exec/libnetworking/sys/mbuf.h
index b380b3fca3..00f8a13a5c 100644
--- a/c/src/exec/libnetworking/sys/mbuf.h
+++ b/c/src/exec/libnetworking/sys/mbuf.h
@@ -410,6 +410,7 @@ int	m_clalloc __P((int, int));
 void	m_copyback __P((struct mbuf *, int, int, caddr_t));
 void	m_copydata __P((struct mbuf *,int,int,caddr_t));
 void	m_freem __P((struct mbuf *));
+void	m_reclaim __P((void));
 
 #ifdef MBTYPES
 int mbtypes[] = {				/* XXX */
diff --git a/c/src/lib/libnetworking/kern/uipc_mbuf.c b/c/src/lib/libnetworking/kern/uipc_mbuf.c
index d6b51e3d95..17d2be6b26 100644
--- a/c/src/lib/libnetworking/kern/uipc_mbuf.c
+++ b/c/src/lib/libnetworking/kern/uipc_mbuf.c
@@ -63,114 +63,11 @@ int	max_protohdr;
 int	max_hdr;
 int	max_datalen;
 
-static void	m_reclaim __P((void));
-
 /* "number of clusters of pages" */
 #define NCL_INIT	1
 
 #define NMB_INIT	16
 
-/* ARGSUSED*/
-static void
-mbinit(dummy)
-	void *dummy;
-{
-	int s;
-
-	mmbfree = NULL; mclfree = NULL;
-	s = splimp();
-	if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0)
-		goto bad;
-	if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0)
-		goto bad;
-	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, nowait)
-	register int nmb;
-	int nowait;
-{
-	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, nowait ? M_NOWAIT : M_WAITOK);
-	/*
-	 * Either the map is now full, or this is 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);
-}
-
-/*
- * Allocate some number of mbuf clusters
- * and place on cluster free list.
- * Must be called at splimp.
- */
-/* ARGSUSED */
-int
-m_clalloc(ncl, nowait)
-	register int ncl;
-	int nowait;
-{
-	register caddr_t p;
-	register int i;
-
-	/*
-	 * 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)
-		return (0);
-
-	p = (caddr_t)kmem_malloc(mb_map, ncl*MCLBYTES,
-				 nowait ? M_NOWAIT : M_WAITOK);
-	/*
-	 * Either the map is now full, or this is nowait and there
-	 * are no pages left.
-	 */
-	if (p == NULL)
-		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);
-}
-
 /*
  * When MGET failes, ask protocols to free space when short of memory,
  * then re-attempt to allocate an mbuf.
@@ -212,8 +109,8 @@ m_retryhdr(i, t)
 	return (m);
 }
 
-static void
-m_reclaim()
+void
+m_reclaim(void)
 {
 	register struct domain *dp;
 	register struct protosw *pr;
diff --git a/c/src/lib/libnetworking/rtems/rtems_glue.c b/c/src/lib/libnetworking/rtems/rtems_glue.c
index d8ec0a1ec4..8ef1626906 100644
--- a/c/src/lib/libnetworking/rtems/rtems_glue.c
+++ b/c/src/lib/libnetworking/rtems/rtems_glue.c
@@ -126,25 +126,47 @@ rtems_bsdnet_free (void *addr, int type)
 
 /*
  * Do the initializations required by the BSD code
- * FIXME: Maybe we should use a different memory allocation scheme that
- * would let us share space between mbufs and mbuf clusters.
- * For now, we'll just take the easy way out!
  */
 static void
 bsd_init ()
 {
+	int i;
+	char *p;
+
 	/*
-	 * Set up mbuf data strutures
-	 * Cluster allocation *must* come first -- see comment on kmem_malloc().
+	 * Set up mbuf cluster data strutures
 	 */
-	m_clalloc (nmbclusters, M_DONTWAIT);
+	p = malloc ((nmbclusters*MCLBYTES)+MCLBYTES-1);
+	p = (char *)(((unsigned long)p + (MCLBYTES-1)) & ~(MCLBYTES-1));
+	if (p == NULL)
+		rtems_panic ("Can't get network cluster memory.");
+	mbutl = (struct mbuf *)p;
+	for (i = 0; i < nmbclusters; i++) {
+		((union mcluster *)p)->mcl_next = mclfree;
+		mclfree = (union mcluster *)p;
+		p += MCLBYTES;
+		mbstat.m_clfree++;
+	}
+	mbstat.m_clusters = nmbclusters;
 	mclrefcnt = malloc (nmbclusters);
 	if (mclrefcnt == NULL)
-		rtems_panic ("No memory for mbuf cluster reference counts.");
+		rtems_panic ("Can't get mbuf cluster reference counts memory.");
 	memset (mclrefcnt, '\0', nmbclusters);
-	m_mballoc (nmbuf, M_DONTWAIT);
-	mbstat.m_mtypes[MT_FREE] = nmbuf;
 
+	/*
+	 * Set up mbuf data structures
+	 */
+
+	p = malloc(nmbuf * MSIZE);
+	if (p == NULL)
+		rtems_panic ("Can't get network memory.");
+	for (i = 0; i < nmbuf; i++) {
+		((struct mbuf *)p)->m_next = mmbfree;
+		mmbfree = (struct mbuf *)p;
+		p += MSIZE;
+	}
+	mbstat.m_mbufs = nmbuf;
+	mbstat.m_mtypes[MT_FREE] = nmbuf;
 
 	/*
 	 * Set up domains
@@ -663,41 +685,8 @@ rtems_bsdnet_log (int priority, const char *fmt, ...)
 }
 
 /*
- * Hack alert: kmem_malloc `knows' that its
- * first invocation is to get mbuf clusters!
- */
-int mb_map_full;
-vm_map_t mb_map;
-vm_offset_t
-kmem_malloc (vm_map_t *map, vm_size_t size, boolean_t waitflag)
-{
-	void *p;
-	
-	/*
-	 * Can't get memory if we're already running.
-	 */
-	if (networkDaemonTid) {
-		if (waitflag == M_WAITOK)
-			rtems_panic (
-"Network mbuf space can not be enlarged after rtems_bsdnet_initialize() has\n"
-"returned.  Enlarge the initial mbuf/cluster size in rtems_bsdnet_config.");
-		return 0;
-	}
-
-#define ROUNDSIZE 2048
-	p = malloc (size+ROUNDSIZE);
-	p = (void *)((unsigned long)p & ~(ROUNDSIZE-1));
-	if ((p == NULL) && (waitflag == M_WAITOK))
-		rtems_panic ("Can't get initial network memory!");
-	if (mbutl == NULL)
-		mbutl = p;
-	return (vm_offset_t)p;
-}
-
-/*
  * IP header checksum routine for processors which don't have an inline version
  */
-
 u_int
 in_cksum_hdr (const void *ip)
 {
@@ -926,3 +915,57 @@ rtems_bsdnet_parse_driver_name (const struct rtems_bsdnet_ifconfig *config, char
 	printf ("Bad network driver name `%s'", config->name);
 	return -1;
 }
+
+/*
+ * Handle requests for more network memory
+ * XXX: Another possibility would be to use a semaphore here with
+ *      a release in the mbuf free macro.  I have chosen this `polling'
+ *      approach because:
+ *      1) It is simpler.
+ *      2) It adds no complexity to the free macro.
+ *      3) Running out of mbufs should be a rare
+ *         condition -- predeployment testing of
+ *         an application should indicate the
+ *         required mbuf pool size.
+ * XXX: Should there be a panic if a task is stuck in the loop for
+ *      more than a minute or so?
+ */
+int
+m_mballoc (int nmb, int nowait)
+{
+	if (nowait)
+		return 0;
+	m_reclaim ();
+	if (mmbfree == NULL) {
+		mbstat.m_wait++;
+		do {
+			rtems_bsdnet_semaphore_release ();
+			rtems_task_wake_after (1);
+			rtems_bsdnet_semaphore_obtain ();
+		} while (mmbfree == NULL);
+	}
+	else {
+		mbstat.m_drops++;
+	}
+	return 1;
+}
+
+int
+m_clalloc(ncl, nowait)
+{
+	if (nowait)
+		return 0;
+	m_reclaim ();
+	if (mclfree == NULL) {
+		mbstat.m_wait++;
+		do {
+			rtems_bsdnet_semaphore_release ();
+			rtems_task_wake_after (1);
+			rtems_bsdnet_semaphore_obtain ();
+		} while (mclfree == NULL);
+	}
+	else {
+		mbstat.m_drops++;
+	}
+	return 1;
+}
diff --git a/c/src/lib/libnetworking/sys/mbuf.h b/c/src/lib/libnetworking/sys/mbuf.h
index b380b3fca3..00f8a13a5c 100644
--- a/c/src/lib/libnetworking/sys/mbuf.h
+++ b/c/src/lib/libnetworking/sys/mbuf.h
@@ -410,6 +410,7 @@ int	m_clalloc __P((int, int));
 void	m_copyback __P((struct mbuf *, int, int, caddr_t));
 void	m_copydata __P((struct mbuf *,int,int,caddr_t));
 void	m_freem __P((struct mbuf *));
+void	m_reclaim __P((void));
 
 #ifdef MBTYPES
 int mbtypes[] = {				/* XXX */
diff --git a/c/src/libnetworking/kern/uipc_mbuf.c b/c/src/libnetworking/kern/uipc_mbuf.c
index d6b51e3d95..17d2be6b26 100644
--- a/c/src/libnetworking/kern/uipc_mbuf.c
+++ b/c/src/libnetworking/kern/uipc_mbuf.c
@@ -63,114 +63,11 @@ int	max_protohdr;
 int	max_hdr;
 int	max_datalen;
 
-static void	m_reclaim __P((void));
-
 /* "number of clusters of pages" */
 #define NCL_INIT	1
 
 #define NMB_INIT	16
 
-/* ARGSUSED*/
-static void
-mbinit(dummy)
-	void *dummy;
-{
-	int s;
-
-	mmbfree = NULL; mclfree = NULL;
-	s = splimp();
-	if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0)
-		goto bad;
-	if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0)
-		goto bad;
-	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, nowait)
-	register int nmb;
-	int nowait;
-{
-	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, nowait ? M_NOWAIT : M_WAITOK);
-	/*
-	 * Either the map is now full, or this is 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);
-}
-
-/*
- * Allocate some number of mbuf clusters
- * and place on cluster free list.
- * Must be called at splimp.
- */
-/* ARGSUSED */
-int
-m_clalloc(ncl, nowait)
-	register int ncl;
-	int nowait;
-{
-	register caddr_t p;
-	register int i;
-
-	/*
-	 * 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)
-		return (0);
-
-	p = (caddr_t)kmem_malloc(mb_map, ncl*MCLBYTES,
-				 nowait ? M_NOWAIT : M_WAITOK);
-	/*
-	 * Either the map is now full, or this is nowait and there
-	 * are no pages left.
-	 */
-	if (p == NULL)
-		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);
-}
-
 /*
  * When MGET failes, ask protocols to free space when short of memory,
  * then re-attempt to allocate an mbuf.
@@ -212,8 +109,8 @@ m_retryhdr(i, t)
 	return (m);
 }
 
-static void
-m_reclaim()
+void
+m_reclaim(void)
 {
 	register struct domain *dp;
 	register struct protosw *pr;
diff --git a/c/src/libnetworking/rtems/rtems_glue.c b/c/src/libnetworking/rtems/rtems_glue.c
index d8ec0a1ec4..8ef1626906 100644
--- a/c/src/libnetworking/rtems/rtems_glue.c
+++ b/c/src/libnetworking/rtems/rtems_glue.c
@@ -126,25 +126,47 @@ rtems_bsdnet_free (void *addr, int type)
 
 /*
  * Do the initializations required by the BSD code
- * FIXME: Maybe we should use a different memory allocation scheme that
- * would let us share space between mbufs and mbuf clusters.
- * For now, we'll just take the easy way out!
  */
 static void
 bsd_init ()
 {
+	int i;
+	char *p;
+
 	/*
-	 * Set up mbuf data strutures
-	 * Cluster allocation *must* come first -- see comment on kmem_malloc().
+	 * Set up mbuf cluster data strutures
 	 */
-	m_clalloc (nmbclusters, M_DONTWAIT);
+	p = malloc ((nmbclusters*MCLBYTES)+MCLBYTES-1);
+	p = (char *)(((unsigned long)p + (MCLBYTES-1)) & ~(MCLBYTES-1));
+	if (p == NULL)
+		rtems_panic ("Can't get network cluster memory.");
+	mbutl = (struct mbuf *)p;
+	for (i = 0; i < nmbclusters; i++) {
+		((union mcluster *)p)->mcl_next = mclfree;
+		mclfree = (union mcluster *)p;
+		p += MCLBYTES;
+		mbstat.m_clfree++;
+	}
+	mbstat.m_clusters = nmbclusters;
 	mclrefcnt = malloc (nmbclusters);
 	if (mclrefcnt == NULL)
-		rtems_panic ("No memory for mbuf cluster reference counts.");
+		rtems_panic ("Can't get mbuf cluster reference counts memory.");
 	memset (mclrefcnt, '\0', nmbclusters);
-	m_mballoc (nmbuf, M_DONTWAIT);
-	mbstat.m_mtypes[MT_FREE] = nmbuf;
 
+	/*
+	 * Set up mbuf data structures
+	 */
+
+	p = malloc(nmbuf * MSIZE);
+	if (p == NULL)
+		rtems_panic ("Can't get network memory.");
+	for (i = 0; i < nmbuf; i++) {
+		((struct mbuf *)p)->m_next = mmbfree;
+		mmbfree = (struct mbuf *)p;
+		p += MSIZE;
+	}
+	mbstat.m_mbufs = nmbuf;
+	mbstat.m_mtypes[MT_FREE] = nmbuf;
 
 	/*
 	 * Set up domains
@@ -663,41 +685,8 @@ rtems_bsdnet_log (int priority, const char *fmt, ...)
 }
 
 /*
- * Hack alert: kmem_malloc `knows' that its
- * first invocation is to get mbuf clusters!
- */
-int mb_map_full;
-vm_map_t mb_map;
-vm_offset_t
-kmem_malloc (vm_map_t *map, vm_size_t size, boolean_t waitflag)
-{
-	void *p;
-	
-	/*
-	 * Can't get memory if we're already running.
-	 */
-	if (networkDaemonTid) {
-		if (waitflag == M_WAITOK)
-			rtems_panic (
-"Network mbuf space can not be enlarged after rtems_bsdnet_initialize() has\n"
-"returned.  Enlarge the initial mbuf/cluster size in rtems_bsdnet_config.");
-		return 0;
-	}
-
-#define ROUNDSIZE 2048
-	p = malloc (size+ROUNDSIZE);
-	p = (void *)((unsigned long)p & ~(ROUNDSIZE-1));
-	if ((p == NULL) && (waitflag == M_WAITOK))
-		rtems_panic ("Can't get initial network memory!");
-	if (mbutl == NULL)
-		mbutl = p;
-	return (vm_offset_t)p;
-}
-
-/*
  * IP header checksum routine for processors which don't have an inline version
  */
-
 u_int
 in_cksum_hdr (const void *ip)
 {
@@ -926,3 +915,57 @@ rtems_bsdnet_parse_driver_name (const struct rtems_bsdnet_ifconfig *config, char
 	printf ("Bad network driver name `%s'", config->name);
 	return -1;
 }
+
+/*
+ * Handle requests for more network memory
+ * XXX: Another possibility would be to use a semaphore here with
+ *      a release in the mbuf free macro.  I have chosen this `polling'
+ *      approach because:
+ *      1) It is simpler.
+ *      2) It adds no complexity to the free macro.
+ *      3) Running out of mbufs should be a rare
+ *         condition -- predeployment testing of
+ *         an application should indicate the
+ *         required mbuf pool size.
+ * XXX: Should there be a panic if a task is stuck in the loop for
+ *      more than a minute or so?
+ */
+int
+m_mballoc (int nmb, int nowait)
+{
+	if (nowait)
+		return 0;
+	m_reclaim ();
+	if (mmbfree == NULL) {
+		mbstat.m_wait++;
+		do {
+			rtems_bsdnet_semaphore_release ();
+			rtems_task_wake_after (1);
+			rtems_bsdnet_semaphore_obtain ();
+		} while (mmbfree == NULL);
+	}
+	else {
+		mbstat.m_drops++;
+	}
+	return 1;
+}
+
+int
+m_clalloc(ncl, nowait)
+{
+	if (nowait)
+		return 0;
+	m_reclaim ();
+	if (mclfree == NULL) {
+		mbstat.m_wait++;
+		do {
+			rtems_bsdnet_semaphore_release ();
+			rtems_task_wake_after (1);
+			rtems_bsdnet_semaphore_obtain ();
+		} while (mclfree == NULL);
+	}
+	else {
+		mbstat.m_drops++;
+	}
+	return 1;
+}
diff --git a/c/src/libnetworking/sys/mbuf.h b/c/src/libnetworking/sys/mbuf.h
index b380b3fca3..00f8a13a5c 100644
--- a/c/src/libnetworking/sys/mbuf.h
+++ b/c/src/libnetworking/sys/mbuf.h
@@ -410,6 +410,7 @@ int	m_clalloc __P((int, int));
 void	m_copyback __P((struct mbuf *, int, int, caddr_t));
 void	m_copydata __P((struct mbuf *,int,int,caddr_t));
 void	m_freem __P((struct mbuf *));
+void	m_reclaim __P((void));
 
 #ifdef MBTYPES
 int mbtypes[] = {				/* XXX */