--- a/usr/src/Makefile.lint	Sat Oct 11 18:43:57 2008 -0700
+++ b/usr/src/Makefile.lint	Sun Oct 12 13:47:48 2008 -0700
@@ -461,6 +461,7 @@
 	cmd/prtfru \
 	cmd/sckmd \
 	cmd/vntsd \
+	lib/libds \
 	lib/libdscp \
 	lib/libpri \
 	lib/libpcp \

--- a/usr/src/lib/libds/Makefile.com	Sat Oct 11 18:43:57 2008 -0700
+++ b/usr/src/lib/libds/Makefile.com	Sun Oct 12 13:47:48 2008 -0700
@@ -44,11 +44,11 @@
 LDLIBS += -lsysevent -lnvpair -lc
 
 LINTFLAGS = -msux
-LINTFLAGS64 = -msux -Xarch=$(MACH64:sparcv9=v9)
+LINTFLAGS64 = -msux -m64
 
 $(LINTLIB) := SRCS = $(LINTSRC:%=$(SRCDIR)/%)
 $(LINTLIB) := LINTFLAGS = -nsvx -I$(ROOT)/usr/platform/sun4v/include
-$(LINTLIB) := LINTFLAGS64 = -nsvx -Xarch=$(MACH64:sparcv9=v9) \
+$(LINTLIB) := LINTFLAGS64 = -nsvx -m64 \
 	-I$(ROOT)/usr/platform/sun4v/include
 
 .KEEP_STATE:

--- a/usr/src/lib/libds/common/libds.c	Sat Oct 11 18:43:57 2008 -0700
+++ b/usr/src/lib/libds/common/libds.c	Sun Oct 12 13:47:48 2008 -0700
@@ -43,10 +43,14 @@
 typedef struct dslibentry {
 	ds_hdl_t dsl_hdl;
 	uint32_t dsl_flags;
+	uint32_t dsl_tflags;
 	char *dsl_service;
 	ds_ops_t dsl_ops;
 } dslibentry_t;
 
+/* dsl_tflags */
+#define	DSL_ENTRY_INUSE		0x0001	/* handle is currently active */
+
 #define	MIN_DSLIB_ENTRIES	64
 static dslibentry_t *dslibtab;
 static int ndslib;
@@ -69,6 +73,8 @@
  * Static functions internal to dslib.
  */
 static dslibentry_t *ds_hdl_to_dslibentry(ds_hdl_t hdl);
+static dslibentry_t *ds_new_dslibentry(void);
+static uint_t ds_service_count(char *service, boolean_t is_client);
 static dslibentry_t *ds_lookup_dslibentry(char *service, boolean_t is_client);
 static dslibentry_t *ds_register_dslibentry(ds_hdl_t hdl, char *service,
     boolean_t is_client);
@@ -110,6 +116,24 @@
 	return (dsp);
 }
 
+static uint_t
+ds_service_count(char *service, boolean_t is_client)
+{
+	int i;
+	dslibentry_t *dsp;
+	uint_t is_client_flag = is_client ? VLDS_REG_CLIENT : 0;
+	uint_t count = 0;
+
+	for (i = 0, dsp = dslibtab; i < ndslib; i++, dsp++) {
+		if (dsp->dsl_hdl != NULL &&
+		    strcmp(dsp->dsl_service, service) == 0 &&
+		    (dsp->dsl_flags & VLDS_REG_CLIENT) == is_client_flag) {
+			count++;
+		}
+	}
+	return (count);
+}
+
 static dslibentry_t *
 ds_lookup_dslibentry(char *service, boolean_t is_client)
 {
@@ -131,36 +155,29 @@
 ds_register_dslibentry(ds_hdl_t hdl, char *service, boolean_t is_client)
 {
 	dslibentry_t *dsp, *orig_dsp;
-	uint_t nhdls;
 
-	if ((dsp = ds_hdl_to_dslibentry(hdl)) != NULL)
+	if ((dsp = ds_hdl_to_dslibentry(hdl)) != NULL) {
+		dsp->dsl_tflags |= DSL_ENTRY_INUSE;
 		return (dsp);
+	}
 
 	if ((orig_dsp = ds_lookup_dslibentry(service, is_client)) == NULL) {
 		return (NULL);
 	}
 
-	/*
-	 * Find out if we have 1 or 2 or more handles.  Having one implies
-	 * that we can reuse the current one handle for this service.
-	 * Having two or more implies we need to allocate a new handle.
-	 */
-	if (ds_hdl_lookup(service, is_client, NULL, 2, &nhdls) != 0)
+	if ((orig_dsp->dsl_tflags & DSL_ENTRY_INUSE) == 0) {
+		/* use the original structure entry */
+		orig_dsp->dsl_tflags |= DSL_ENTRY_INUSE;
+		orig_dsp->dsl_hdl = hdl;
+		return (orig_dsp);
+	}
+
+	/* allocate a new structure entry */
+	if ((dsp = ds_new_dslibentry()) == NULL)
 		return (NULL);
 
-	if (nhdls == 1) {
-		/* reuse the original structure entry */
-		dsp = orig_dsp;
-	} else if (nhdls == 2) {
-		/* allocate a new structure entry */
-		if ((dsp = ds_new_dslibentry()) == NULL)
-			return (NULL);
-		*dsp = *orig_dsp;
-		dsp->dsl_service = strdup(orig_dsp->dsl_service);
-	} else {
-		/* can't happen... */
-		return (NULL);
-	}
+	*dsp = *orig_dsp;
+	dsp->dsl_service = strdup(orig_dsp->dsl_service);
 	dsp->dsl_hdl = hdl;
 	return (dsp);
 }
@@ -175,22 +192,22 @@
 	uint_t nhdls;
 
 	/*
-	 * Find out if we have 1 or 2 or more handles.  Having one implies
-	 * that we want to leave the entry alone unless this is a ds_unreg_hdl
+	 * Find out if we have 1 or 2 or more handles for the given
+	 * service.  Having one implies that we want to leave the entry
+	 * intact but marked as not in use unless this is a ds_unreg_hdl
 	 * (force_unreg is true).
 	 */
-	if (ds_hdl_lookup(dsp->dsl_service,
-	    (dsp->dsl_flags & VLDS_REG_CLIENT) != 0, NULL, 2, &nhdls) != 0) {
-		/* should never happen */
-		return;
-	}
+	nhdls = ds_service_count(dsp->dsl_service,
+	    (dsp->dsl_flags & VLDS_REG_CLIENT) != 0);
 
-	if ((nhdls == 1 && force_unreg) || nhdls == 2) {
+	if ((nhdls == 1 && force_unreg) || nhdls >= 2) {
 		dsp->dsl_hdl = NULL;
 		if (dsp->dsl_service) {
 			free(dsp->dsl_service);
 		}
 		(void) memset(dsp, 0, sizeof (dslibentry_t));
+	} else if (nhdls == 1) {
+		dsp->dsl_tflags &= ~DSL_ENTRY_INUSE;
 	}
 }
 
@@ -316,7 +333,8 @@
 		return (errno);
 
 	if (dslibtab == NULL) {
-		if ((dslibtab = malloc(sizeof (dslibentry_t) * ndslib)) == NULL)
+		dslibtab = malloc(sizeof (dslibentry_t) * MIN_DSLIB_ENTRIES);
+		if (dslibtab == NULL)
 			return (errno = ENOMEM);
 		ndslib = MIN_DSLIB_ENTRIES;
 		(void) memset(dslibtab, 0, sizeof (dslibentry_t) * ndslib);
@@ -415,6 +433,7 @@
 	 */
 	dsp->dsl_hdl = hdl;
 	dsp->dsl_flags = flags;
+	dsp->dsl_tflags = 0;
 	dsp->dsl_service = strdup(cap->svc_id);
 	dsp->dsl_ops = *ops;
 	(void) mutex_unlock(&dslib_lock);

--- a/usr/src/uts/sun4v/io/vlds.c	Sat Oct 11 18:43:57 2008 -0700
+++ b/usr/src/uts/sun4v/io/vlds.c	Sun Oct 12 13:47:48 2008 -0700
@@ -77,6 +77,7 @@
 	vlds_recv_hdr_t	*recv_headp;	/* ptr to head of recv queue */
 	vlds_recv_hdr_t	*recv_tailp;	/* ptr to tail of recv queue */
 	size_t		recv_size;	/* no. of bytes in recv queue */
+	uint_t		recv_cnt;	/* no of messages in recv queue */
 	kmutex_t	recv_lock;	/* lock for recv queue */
 	kcondvar_t	recv_cv;	/* condition variable for recv queue */
 	int		recv_nreaders;	/* no of currently waiting readers */
@@ -84,6 +85,7 @@
 
 #define	VLDS_RECV_OK		1
 #define	VLDS_RECV_UNREG_PENDING	2
+#define	VLDS_RECV_OVERFLOW	3
 
 static int vlds_ports_inited = 0;
 
@@ -179,6 +181,9 @@
 	NULL				/* ds_ucap_init will fill in */
 };
 
+static size_t vlds_recvq_maxsize = DS_STREAM_MTU * 8;
+static uint_t vlds_recvq_maxmsg = 16;
+
 #define	VLDS_MINOR_MAX			SHRT_MAX
 
 /* Definitions for binding handle array */
@@ -1393,6 +1398,7 @@
 	dpsp->recv_headp = NULL;
 	dpsp->recv_tailp = NULL;
 	dpsp->recv_size = 0;
+	dpsp->recv_cnt = 0;
 }
 
 static void
@@ -1400,6 +1406,7 @@
 {
 	ASSERT(dpsp->state == VLDS_RECV_UNREG_PENDING);
 	ASSERT(dpsp->recv_size == 0);
+	ASSERT(dpsp->recv_cnt == 0);
 	ASSERT(dpsp->recv_headp == NULL);
 	ASSERT(dpsp->recv_tailp == NULL);
 
@@ -1418,8 +1425,17 @@
 
 	mutex_enter(&dpsp->recv_lock);
 	while (dpsp->recv_size == 0) {
+		ASSERT(dpsp->recv_cnt == 0);
 		if (dpsp->state == VLDS_RECV_UNREG_PENDING)
 			break;
+
+		if (dpsp->state == VLDS_RECV_OVERFLOW) {
+			DS_DBG_RCVQ(CE_NOTE, "%s: user data queue overflow",
+			    __func__);
+			dpsp->state = VLDS_RECV_OK;
+			mutex_exit(&dpsp->recv_lock);
+			return (ENOBUFS);
+		}
 		/*
 		 * Passing in a buflen of 0 allows user to poll for msgs.
 		 */
@@ -1462,7 +1478,9 @@
 		dpsp->recv_headp = rhp->next;
 		ASSERT(dpsp->recv_headp != NULL);
 	}
+	ASSERT(dpsp->recv_cnt > 0);
 	dpsp->recv_size -= rhp->datasz;
+	dpsp->recv_cnt -= 1;
 	mutex_exit(&dpsp->recv_lock);
 
 	msglen = rhp->datasz;
@@ -1503,6 +1521,7 @@
 	dpsp->recv_headp = NULL;
 	dpsp->recv_tailp = NULL;
 	dpsp->recv_size = 0;
+	dpsp->recv_cnt = 0;
 
 	/*
 	 * Make sure other readers have exited.
@@ -1524,6 +1543,26 @@
 
 	mutex_enter(&dpsp->recv_lock);
 	if (dpsp->state != VLDS_RECV_UNREG_PENDING) {
+		/*
+		 * If we've already encountered an overflow, or there
+		 * are pending messages and either queue size and
+		 * message limits will be exceeded with this message,
+		 * we mark the recvq as overflowed and return an ENOBUFS
+		 * error.  This allows the enqueuing of one big message
+		 * or several little messages.
+		 */
+		if ((dpsp->state == VLDS_RECV_OVERFLOW) ||
+		    ((dpsp->recv_cnt != 0) &&
+		    ((dpsp->recv_size + buflen) > vlds_recvq_maxsize) ||
+		    ((dpsp->recv_cnt + 1) > vlds_recvq_maxmsg))) {
+			DS_DBG_RCVQ(CE_NOTE, "%s: user data queue overflow",
+			    __func__);
+			dpsp->state = VLDS_RECV_OVERFLOW;
+			cv_broadcast(&dpsp->recv_cv);
+			mutex_exit(&dpsp->recv_lock);
+			return (ENOBUFS);
+		}
+
 		DS_DBG_RCVQ(CE_NOTE, "%s: user data enqueued msglen: %ld",
 		    __func__, buflen);
 		DS_DUMP_MSG(DS_DBG_FLAG_RCVQ, buf, buflen);
@@ -1540,6 +1579,7 @@
 			dpsp->recv_tailp = rhp;
 		}
 		dpsp->recv_size += rhp->datasz;
+		dpsp->recv_cnt += 1;
 		cv_broadcast(&dpsp->recv_cv);
 	}
 	mutex_exit(&dpsp->recv_lock);