* Rename M_WAIT mbuf subsystem flag to M_TRYWAIT.

  This is because calls with M_WAIT (now M_TRYWAIT) may not wait
  forever when nothing is available for allocation, and may end up
  returning NULL. Hopefully we now communicate more of the right thing
  to developers and make it very clear that it's necessary to check whether
  calls with M_(TRY)WAIT also resulted in a failed allocation.
  M_TRYWAIT basically means "try harder, block if necessary, but don't
  necessarily wait forever." The time spent blocking is tunable with
  the kern.ipc.mbuf_wait sysctl.
  M_WAIT is now deprecated but still defined for the next little while.

* Fix a typo in a comment in mbuf.h

* Fix some code that was actually passing the mbuf subsystem's M_WAIT to
  malloc(). Made it pass M_WAITOK instead. If we were ever to redefine the
  value of the M_WAIT flag, this could have became a big problem.

51 files changed, 198 insertions, 197 deletions

diff --git a/sys/dev/musycc/musycc.c b/sys/dev/musycc/musycc.c
index 85ec6e0..98d5334 100644
--- a/sys/dev/musycc/musycc.c
+++ b/sys/dev/musycc/musycc.c
@@ -1207,8 +1207,8 @@ musycc_connect(hook_p hook)
 		sc->mdt[ch][i].m = NULL;
 		sc->mdt[ch][i].data = 0;
 
-		MGETHDR(m, M_WAIT, MT_DATA);
-		MCLGET(m, M_WAIT);
+		MGETHDR(m, M_TRYWAIT, MT_DATA);
+		MCLGET(m, M_TRYWAIT);
 		sc->mdr[ch][i].m = m;
 		sc->mdr[ch][i].data = vtophys(m->m_data);
 		sc->mdr[ch][i].status = 1600; /* MTU */
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index 2c52f78..d8cc445 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -206,8 +206,8 @@ m_alloc_ref(nmb, how)
 	nbytes = round_page(nmb * sizeof(union mext_refcnt));
 	mtx_exit(&mcntfree.m_mtx, MTX_DEF);
 	mtx_enter(&Giant, MTX_DEF);
-	if ((p = (caddr_t)kmem_malloc(mb_map, nbytes, how == M_WAIT ? M_WAIT :
-	    M_NOWAIT)) == NULL) {
+	if ((p = (caddr_t)kmem_malloc(mb_map, nbytes, how == M_TRYWAIT ?
+	    M_WAITOK : M_NOWAIT)) == NULL) {
 		mtx_exit(&Giant, MTX_DEF);
 		mtx_enter(&mcntfree.m_mtx, MTX_DEF); /* XXX: We must be	holding
 						             it going out. */
@@ -265,11 +265,11 @@ m_mballoc(nmb, how)
 	nbytes = round_page(nmb * MSIZE);
 
 	/* XXX: The letting go of the mmbfree lock here may eventually
-	   be moved to only be done for M_WAIT calls to kmem_malloc() */
+	   be moved to only be done for M_TRYWAIT calls to kmem_malloc() */
 	mtx_exit(&mmbfree.m_mtx, MTX_DEF);
 	mtx_enter(&Giant, MTX_DEF);
 	p = (caddr_t)kmem_malloc(mb_map, nbytes, M_NOWAIT);
-	if (p == 0 && how == M_WAIT) {
+	if (p == 0 && how == M_TRYWAIT) {
 		atomic_add_long(&mbstat.m_wait, 1);
 		p = (caddr_t)kmem_malloc(mb_map, nbytes, M_WAITOK);
 	}
@@ -302,8 +302,8 @@ m_mballoc(nmb, how)
 
 /*
  * Once the mb_map has been exhausted and if the call to the allocation macros
- * (or, in some cases, functions) is with M_WAIT, then it is necessary to rely
- * solely on reclaimed mbufs.
+ * (or, in some cases, functions) is with M_TRYWAIT, then it is necessary to
+ * rely solely on reclaimed mbufs.
  *
  * Here we request for the protocols to free up some resources and, if we
  * still cannot get anything, then we wait for an mbuf to be freed for a 
@@ -385,7 +385,7 @@ m_clalloc(ncl, how)
 	mtx_exit(&mclfree.m_mtx, MTX_DEF);
 	mtx_enter(&Giant, MTX_DEF);
 	p = (caddr_t)kmem_malloc(mb_map, ctob(npg),
-				 how != M_WAIT ? M_NOWAIT : M_WAITOK);
+				 how == M_TRYWAIT ? M_WAITOK : M_NOWAIT);
 	mtx_exit(&Giant, MTX_DEF);
 	ncl = ncl * PAGE_SIZE / MCLBYTES;
 	mtx_enter(&mclfree.m_mtx, MTX_DEF);
@@ -414,7 +414,7 @@ m_clalloc(ncl, how)
 
 /*
  * Once the mb_map submap has been exhausted and the allocation is called with
- * M_WAIT, we rely on the mclfree list. If nothing is free, we will
+ * M_TRYWAIT, we rely on the mclfree list. If nothing is free, we will
  * sleep for a designated amount of time (mbuf_wait) or until we're woken up
  * due to sudden mcluster availability.
  *
@@ -578,7 +578,7 @@ m_prepend(m, len, how)
 /*
  * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
  * continuing for "len" bytes.  If len is M_COPYALL, copy to end of mbuf.
- * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller.
+ * The wait parameter is a choice of M_TRYWAIT/M_DONTWAIT from caller.
  * Note that the copy is read-only, because clusters are not copied,
  * only their reference counts are incremented.
  */
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index a93ee50..fe78205 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -558,7 +558,7 @@ restart:
 				top->m_flags |= M_EOR;
 		    } else do {
 			if (top == 0) {
-				MGETHDR(m, M_WAIT, MT_DATA);
+				MGETHDR(m, M_TRYWAIT, MT_DATA);
 				if (m == NULL) {
 					error = ENOBUFS;
 					goto release;
@@ -567,7 +567,7 @@ restart:
 				m->m_pkthdr.len = 0;
 				m->m_pkthdr.rcvif = (struct ifnet *)0;
 			} else {
-				MGET(m, M_WAIT, MT_DATA);
+				MGET(m, M_TRYWAIT, MT_DATA);
 				if (m == NULL) {
 					error = ENOBUFS;
 					goto release;
@@ -575,7 +575,7 @@ restart:
 				mlen = MLEN;
 			}
 			if (resid >= MINCLSIZE) {
-				MCLGET(m, M_WAIT);
+				MCLGET(m, M_TRYWAIT);
 				if ((m->m_flags & M_EXT) == 0)
 					goto nopages;
 				mlen = MCLBYTES;
@@ -695,7 +695,7 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
 	else
 		flags = 0;
 	if (flags & MSG_OOB) {
-		m = m_get(M_WAIT, MT_DATA);
+		m = m_get(M_TRYWAIT, MT_DATA);
 		if (m == NULL)
 			return (ENOBUFS);
 		error = (*pr->pr_usrreqs->pru_rcvoob)(so, m, flags & MSG_PEEK);
@@ -887,7 +887,7 @@ dontblock:
 				moff += len;
 			else {
 				if (mp)
-					*mp = m_copym(m, 0, len, M_WAIT);
+					*mp = m_copym(m, 0, len, M_TRYWAIT);
 				m->m_data += len;
 				m->m_len -= len;
 				so->so_rcv.sb_cc -= len;
@@ -1390,11 +1390,11 @@ soopt_getm(struct sockopt *sopt, struct mbuf **mp)
 	struct mbuf *m, *m_prev;
 	int sopt_size = sopt->sopt_valsize;
 
-	MGET(m, sopt->sopt_p ? M_WAIT : M_DONTWAIT, MT_DATA);
+	MGET(m, sopt->sopt_p ? M_TRYWAIT : M_DONTWAIT, MT_DATA);
 	if (m == 0)
 		return ENOBUFS;
 	if (sopt_size > MLEN) {
-		MCLGET(m, sopt->sopt_p ? M_WAIT : M_DONTWAIT);
+		MCLGET(m, sopt->sopt_p ? M_TRYWAIT : M_DONTWAIT);
 		if ((m->m_flags & M_EXT) == 0) {
 			m_free(m);
 			return ENOBUFS;
@@ -1408,13 +1408,13 @@ soopt_getm(struct sockopt *sopt, struct mbuf **mp)
 	m_prev = m;
 
 	while (sopt_size) {
-		MGET(m, sopt->sopt_p ? M_WAIT : M_DONTWAIT, MT_DATA);
+		MGET(m, sopt->sopt_p ? M_TRYWAIT : M_DONTWAIT, MT_DATA);
 		if (m == 0) {
 			m_freem(*mp);
 			return ENOBUFS;
 		}
 		if (sopt_size > MLEN) {
-			MCLGET(m, sopt->sopt_p ? M_WAIT : M_DONTWAIT);
+			MCLGET(m, sopt->sopt_p ? M_TRYWAIT : M_DONTWAIT);
 			if ((m->m_flags & M_EXT) == 0) {
 				m_freem(*mp);
 				return ENOBUFS;
diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index d5b8ec5..812764f 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -548,7 +548,7 @@ sendit(p, s, mp, flags)
 		if (mp->msg_flags == MSG_COMPAT) {
 			register struct cmsghdr *cm;
 
-			M_PREPEND(control, sizeof(*cm), M_WAIT);
+			M_PREPEND(control, sizeof(*cm), M_TRYWAIT);
 			if (control == 0) {
 				error = ENOBUFS;
 				goto bad;
@@ -1331,7 +1331,7 @@ sockargs(mp, buf, buflen, type)
 #endif
 		return (EINVAL);
 	}
-	m = m_get(M_WAIT, type);
+	m = m_get(M_TRYWAIT, type);
 	if (m == NULL)
 		return (ENOBUFS);
 	m->m_len = buflen;
@@ -1702,7 +1702,7 @@ retry_lookup:
 		/*
 		 * Get an mbuf header and set it up as having external storage.
 		 */
-		MGETHDR(m, M_WAIT, MT_DATA);
+		MGETHDR(m, M_TRYWAIT, MT_DATA);
 		if (m == NULL) {
 			error = ENOBUFS;
 			sf_buf_free((void *)sf->kva, NULL);
diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
index d77b67b..79477c9 100644
--- a/sys/kern/uipc_usrreq.c
+++ b/sys/kern/uipc_usrreq.c
@@ -1017,7 +1017,7 @@ unp_internalize(control, p)
 	if (newlen - control->m_len > M_TRAILINGSPACE(control)) {
 		if (control->m_flags & M_EXT)
 			return (E2BIG);
-		MCLGET(control, M_WAIT);
+		MCLGET(control, M_TRYWAIT);
 		if ((control->m_flags & M_EXT) == 0)
 			return (ENOBUFS);
 
diff --git a/sys/net/bpf.c b/sys/net/bpf.c
index 12e375e..21eeff3 100644
--- a/sys/net/bpf.c
+++ b/sys/net/bpf.c
@@ -231,12 +231,12 @@ bpf_movein(uio, linktype, mp, sockp, datlen)
 	if ((unsigned)len > MCLBYTES)
 		return (EIO);
 
-	MGETHDR(m, M_WAIT, MT_DATA);
+	MGETHDR(m, M_TRYWAIT, MT_DATA);
 	if (m == 0)
 		return (ENOBUFS);
 	if (len > MHLEN) {
 #if BSD >= 199103
-		MCLGET(m, M_WAIT);
+		MCLGET(m, M_TRYWAIT);
 		if ((m->m_flags & M_EXT) == 0) {
 #else
 		MCLGET(m);
diff --git a/sys/net/bpf_compat.h b/sys/net/bpf_compat.h
index 0936b84..8ccaa23 100644
--- a/sys/net/bpf_compat.h
+++ b/sys/net/bpf_compat.h
@@ -46,7 +46,7 @@
  */
 #define malloc(size, type, canwait) bpf_alloc(size, canwait)
 #define free(cp, type) m_free(*(struct mbuf **)(cp - 8))
-#define M_WAITOK M_WAIT
+#define M_WAITOK M_TRYWAIT
 
 /* This mapping works for our purposes. */
 #define ERESTART EINTR
diff --git a/sys/net/if_ef.c b/sys/net/if_ef.c
index 4554a29..f11fa70 100644
--- a/sys/net/if_ef.c
+++ b/sys/net/if_ef.c
@@ -439,7 +439,7 @@ ef_output(struct ifnet *ifp, struct mbuf **mp, struct sockaddr *dst, short *tp,
 		type = htons(m->m_pkthdr.len);
 		break;
 	    case ETHER_FT_8022:
-		M_PREPEND(m, ETHER_HDR_LEN + 3, M_WAIT);
+		M_PREPEND(m, ETHER_HDR_LEN + 3, M_TRYWAIT);
 		if (m == NULL) {
 			*mp = NULL;
 			return ENOBUFS;
@@ -462,7 +462,7 @@ ef_output(struct ifnet *ifp, struct mbuf **mp, struct sockaddr *dst, short *tp,
 		*hlen += 3;
 		break;
 	    case ETHER_FT_SNAP:
-		M_PREPEND(m, 8, M_WAIT);
+		M_PREPEND(m, 8, M_TRYWAIT);
 		if (m == NULL) {
 			*mp = NULL;
 			return ENOBUFS;
diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index cfca498..ebd4b37 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -221,7 +221,7 @@ ether_output(ifp, m, dst, rt0)
 	    if ( aa->aa_flags & AFA_PHASE2 ) {
 		struct llc llc;
 
-		M_PREPEND(m, sizeof(struct llc), M_WAIT);
+		M_PREPEND(m, sizeof(struct llc), M_TRYWAIT);
 		llc.llc_dsap = llc.llc_ssap = LLC_SNAP_LSAP;
 		llc.llc_control = LLC_UI;
 		bcopy(at_org_code, llc.llc_snap_org_code, sizeof(at_org_code));
@@ -246,7 +246,7 @@ ether_output(ifp, m, dst, rt0)
 			type = htons( m->m_pkthdr.len);
 			break;
 		case 0xe0e0: /* Novell 802.2 and Token-Ring */
-			M_PREPEND(m, 3, M_WAIT);
+			M_PREPEND(m, 3, M_TRYWAIT);
 			type = htons( m->m_pkthdr.len);
 			cp = mtod(m, u_char *);
 			*cp++ = 0xE0;
diff --git a/sys/net/if_fddisubr.c b/sys/net/if_fddisubr.c
index 186fec5..b93414a 100644
--- a/sys/net/if_fddisubr.c
+++ b/sys/net/if_fddisubr.c
@@ -213,7 +213,7 @@ fddi_output(ifp, m, dst, rt0)
 	    if (aa->aa_flags & AFA_PHASE2) {
 		struct llc llc;
 
-		M_PREPEND(m, sizeof(struct llc), M_WAIT);
+		M_PREPEND(m, sizeof(struct llc), M_TRYWAIT);
 		if (m == 0)
 			senderr(ENOBUFS);
 		llc.llc_dsap = llc.llc_ssap = LLC_SNAP_LSAP;
diff --git a/sys/net/if_gif.c b/sys/net/if_gif.c
index 143f06f..f8af910 100644
--- a/sys/net/if_gif.c
+++ b/sys/net/if_gif.c
@@ -118,7 +118,7 @@ gifattach(dummy)
 	register int i;
 
 	ngif = NGIF;
-	gif = sc = malloc (ngif * sizeof(struct gif_softc), M_DEVBUF, M_WAIT);
+	gif = sc = malloc (ngif * sizeof(struct gif_softc), M_DEVBUF, M_WAITOK);
 	bzero(sc, ngif * sizeof(struct gif_softc));
 	for (i = 0; i < ngif; sc++, i++) {
 		sc->gif_if.if_name = "gif";
diff --git a/sys/net/if_sl.c b/sys/net/if_sl.c
index f7bc1f2..d3f8085 100644
--- a/sys/net/if_sl.c
+++ b/sys/net/if_sl.c
@@ -253,9 +253,9 @@ slcreate()
 
 	MALLOC(sc, struct sl_softc *, sizeof(*sc), M_SL, M_WAITOK | M_ZERO);
 
-	m = m_gethdr(M_WAIT, MT_DATA);
+	m = m_gethdr(M_TRYWAIT, MT_DATA);
 	if (m != NULL) {
-		MCLGET(m, M_WAIT);
+		MCLGET(m, M_TRYWAIT);
 		if ((m->m_flags & M_EXT) == 0) {
 			m_free(m);
 			m = NULL;
diff --git a/sys/net/if_stf.c b/sys/net/if_stf.c
index 8ae33de..769e376 100644
--- a/sys/net/if_stf.c
+++ b/sys/net/if_stf.c
@@ -173,7 +173,7 @@ stfattach(dummy)
 	const struct encaptab *p;
 
 	nstf = NSTF;
-	stf = malloc(nstf * sizeof(struct stf_softc), M_DEVBUF, M_WAIT);
+	stf = malloc(nstf * sizeof(struct stf_softc), M_DEVBUF, M_WAITOK);
 	bzero(stf, nstf * sizeof(struct stf_softc));
 	sc = stf;
 
diff --git a/sys/net/ppp_tty.c b/sys/net/ppp_tty.c
index 16cc009..3a95fdb 100644
--- a/sys/net/ppp_tty.c
+++ b/sys/net/ppp_tty.c
@@ -391,7 +391,7 @@ pppwrite(tp, uio, flag)
 
     s = spltty();
     for (mp = &m0; uio->uio_resid; mp = &m->m_next) {
-	MGET(m, M_WAIT, MT_DATA);
+	MGET(m, M_TRYWAIT, MT_DATA);
 	if ((*mp = m) == NULL) {
 	    m_freem(m0);
 	    splx(s);
diff --git a/sys/netatalk/aarp.c b/sys/netatalk/aarp.c
index e5aa7c6..0493870 100644
--- a/sys/netatalk/aarp.c
+++ b/sys/netatalk/aarp.c
@@ -161,7 +161,7 @@ aarpwhohas( struct arpcom *ac, struct sockaddr_at *sat )
 	bcopy((caddr_t)atmulticastaddr, (caddr_t)eh->ether_dhost,
 		sizeof( eh->ether_dhost ));
 	eh->ether_type = htons(sizeof(struct llc) + sizeof(struct ether_aarp));
-	M_PREPEND( m, sizeof( struct llc ), M_WAIT );
+	M_PREPEND( m, sizeof( struct llc ), M_TRYWAIT );
 	llc = mtod( m, struct llc *);
 	llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
 	llc->llc_control = LLC_UI;
@@ -571,7 +571,7 @@ aarpprobe( void *arg )
 		sizeof( eh->ether_dhost ));
 	eh->ether_type = htons( sizeof( struct llc ) +
 		sizeof( struct ether_aarp ));
-	M_PREPEND( m, sizeof( struct llc ), M_WAIT );
+	M_PREPEND( m, sizeof( struct llc ), M_TRYWAIT );
 	llc = mtod( m, struct llc *);
 	llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
 	llc->llc_control = LLC_UI;
diff --git a/sys/netatalk/ddp_output.c b/sys/netatalk/ddp_output.c
index 66e20df..3d48fd2 100644
--- a/sys/netatalk/ddp_output.c
+++ b/sys/netatalk/ddp_output.c
@@ -48,7 +48,7 @@ ddp_output( struct mbuf *m, struct socket *so)
     struct ddpehdr	*deh;
     struct ddpcb *ddp = sotoddpcb( so );
 
-    M_PREPEND( m, sizeof( struct ddpehdr ), M_WAIT );
+    M_PREPEND( m, sizeof( struct ddpehdr ), M_TRYWAIT );
 
     deh = mtod( m, struct ddpehdr *);
     deh->deh_pad = 0;
@@ -189,7 +189,7 @@ ddp_route( struct mbuf *m, struct route *ro)
      * packets end up poorly aligned due to the three byte elap header.
      */
     if ( !(aa->aa_flags & AFA_PHASE2) ) {
-	MGET( m0, M_WAIT, MT_HEADER );
+	MGET( m0, M_TRYWAIT, MT_HEADER );
 	if ( m0 == 0 ) {
 	    m_freem( m );
 	    printf("ddp_route: no buffers\n");
diff --git a/sys/netatm/port.h b/sys/netatm/port.h
index ca111c7..8ada59f 100644
--- a/sys/netatm/port.h
+++ b/sys/netatm/port.h
@@ -210,7 +210,7 @@
 #include <sys/mbuf.h>
 typedef struct mbuf	KBuffer;
 
-#define	KB_F_WAIT	M_WAIT
+#define	KB_F_WAIT	M_TRYWAIT
 #define	KB_F_NOWAIT	M_DONTWAIT
 
 #define	KB_T_HEADER	MT_HEADER
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 21cdc0c..fb8669c 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -1115,7 +1115,7 @@ ip_ctloutput(so, sopt)
 				error = EMSGSIZE;
 				break;
 			}
-			MGET(m, sopt->sopt_p ? M_WAIT : M_DONTWAIT, MT_HEADER);
+			MGET(m, sopt->sopt_p ? M_TRYWAIT : M_DONTWAIT, MT_HEADER);
 			if (m == 0) {
 				error = ENOBUFS;
 				break;
diff --git a/sys/netinet/raw_ip.c b/sys/netinet/raw_ip.c
index e15ee4e..0342d39 100644
--- a/sys/netinet/raw_ip.c
+++ b/sys/netinet/raw_ip.c
@@ -195,7 +195,7 @@ rip_output(m, so, dst)
 			m_freem(m);
 			return(EMSGSIZE);
 		}
-		M_PREPEND(m, sizeof(struct ip), M_WAIT);
+		M_PREPEND(m, sizeof(struct ip), M_TRYWAIT);
 		ip = mtod(m, struct ip *);
 		ip->ip_tos = 0;
 		ip->ip_off = 0;
diff --git a/sys/netinet6/ip6_fw.c b/sys/netinet6/ip6_fw.c
index f0f710f..6bcef8a 100644
--- a/sys/netinet6/ip6_fw.c
+++ b/sys/netinet6/ip6_fw.c
@@ -1045,11 +1045,11 @@ ip6_fw_ctl(int stage, struct mbuf **mm)
 
 	if (stage == IPV6_FW_GET) {
 		struct ip6_fw_chain *fcp = ip6_fw_chain.lh_first;
-		*mm = m = m_get(M_WAIT, MT_DATA); /* XXX */
+		*mm = m = m_get(M_TRYWAIT, MT_DATA); /* XXX */
 		if (!m)
 			return(ENOBUFS);
 		if (sizeof *(fcp->rule) > MLEN) {
-			MCLGET(m, M_WAIT);
+			MCLGET(m, M_TRYWAIT);
 			if ((m->m_flags & M_EXT) == 0) {
 				m_free(m);
 				return(ENOBUFS);
@@ -1058,14 +1058,14 @@ ip6_fw_ctl(int stage, struct mbuf **mm)
 		for (; fcp; fcp = fcp->chain.le_next) {
 			memcpy(m->m_data, fcp->rule, sizeof *(fcp->rule));
 			m->m_len = sizeof *(fcp->rule);
-			m->m_next = m_get(M_WAIT, MT_DATA); /* XXX */
+			m->m_next = m_get(M_TRYWAIT, MT_DATA); /* XXX */
 			if (!m->m_next) {
 				m_freem(*mm);
 				return(ENOBUFS);
 			}
 			m = m->m_next;
 			if (sizeof *(fcp->rule) > MLEN) {
-				MCLGET(m, M_WAIT);
+				MCLGET(m, M_TRYWAIT);
 				if ((m->m_flags & M_EXT) == 0) {
 					m_freem(*mm);
 					return(ENOBUFS);
diff --git a/sys/netinet6/ip6_output.c b/sys/netinet6/ip6_output.c
index f990d44..a898cf2 100644
--- a/sys/netinet6/ip6_output.c
+++ b/sys/netinet6/ip6_output.c
@@ -1330,7 +1330,7 @@ ip6_ctloutput(so, sopt)
 					break;
 				}
 				/* XXX */
-				MGET(m, sopt->sopt_p ? M_WAIT : M_DONTWAIT, MT_HEADER);
+				MGET(m, sopt->sopt_p ? M_TRYWAIT : M_DONTWAIT, MT_HEADER);
 				if (m == 0) {
 					error = ENOBUFS;
 					break;
@@ -1920,7 +1920,7 @@ ip6_getmoptions(optname, im6o, mp)
 {
 	u_int *hlim, *loop, *ifindex;
 
-	*mp = m_get(M_WAIT, MT_HEADER);		/*XXX*/
+	*mp = m_get(M_TRYWAIT, MT_HEADER);		/*XXX*/
 
 	switch (optname) {
 
diff --git a/sys/netinet6/raw_ip6.c b/sys/netinet6/raw_ip6.c
index 95c7d20..42f38fd 100644
--- a/sys/netinet6/raw_ip6.c
+++ b/sys/netinet6/raw_ip6.c
@@ -333,7 +333,7 @@ rip6_output(m, va_alist)
 		code = icmp6->icmp6_code;
 	}
 
-	M_PREPEND(m, sizeof(*ip6), M_WAIT);
+	M_PREPEND(m, sizeof(*ip6), M_TRYWAIT);
 	ip6 = mtod(m, struct ip6_hdr *);
 
 	/*
diff --git a/sys/netipx/spx_usrreq.c b/sys/netipx/spx_usrreq.c
index eef2445..b77b1b3 100644
--- a/sys/netipx/spx_usrreq.c
+++ b/sys/netipx/spx_usrreq.c
@@ -751,7 +751,7 @@ spx_output(cb, m0)
 					 * from usrreq(), so it is OK to
 					 * block.
 					 */
-					m = m_copym(m0, 0, mtu, M_WAIT);
+					m = m_copym(m0, 0, mtu, M_TRYWAIT);
 					if (cb->s_flags & SF_NEWCALL) {
 					    struct mbuf *mm = m;
 					    spx_newchecks[7]++;
diff --git a/sys/netncp/ncp_rq.c b/sys/netncp/ncp_rq.c
index 8cef7d2..e661f5e 100644
--- a/sys/netncp/ncp_rq.c
+++ b/sys/netncp/ncp_rq.c
@@ -60,9 +60,9 @@ ncp_rq_head(struct ncp_rq *rqp, u_int32_t ptype, u_int8_t fn,struct proc *p,
 	bzero(rqp, sizeof(*rqp));
 	rqp->p = p;
 	rqp->cred = cred;
-	m = m_gethdr(M_WAIT, MT_DATA);
+	m = m_gethdr(M_TRYWAIT, MT_DATA);
 	if (m == NULL) 
-		return ENOBUFS;		/* if M_WAIT ? */
+		return ENOBUFS;		/* if M_TRYWAIT ? */
 	m->m_pkthdr.rcvif = NULL;
 	rqp->rq = rqp->mrq = m;
 	rqp->rp = NULL;
@@ -106,9 +106,9 @@ m_getm(struct mbuf *top, int len) {
 	mp = top;
 	while (rest > 0) {
 /*	NCPSDEBUG("%d\n",rest);*/
-		m = m_get(M_WAIT, MT_DATA);
+		m = m_get(M_TRYWAIT, MT_DATA);
 		if (rest > MINCLSIZE) {
-			MCLGET(m,M_WAIT);
+			MCLGET(m,M_TRYWAIT);
 			mlen = ( (m->m_flags & M_EXT) == 0) ? MLEN : MCLBYTES;
 		} else { 
 			mlen = MLEN;
@@ -135,7 +135,7 @@ ncp_mchecksize(struct ncp_rq *rqp, int size) {
 		panic("ncp_mchecksize\n");
 	if (M_TRAILINGSPACE(rqp->mrq)<(size)) {
 		struct mbuf *m;
-		m = m_get(M_WAIT, MT_DATA);
+		m = m_get(M_TRYWAIT, MT_DATA);
 		m->m_len = 0;
 		rqp->bpos = mtod(m, caddr_t);
 		rqp->mrq->m_next = m;
@@ -435,7 +435,7 @@ ncp_rp_mbuf(struct ncp_rq *rqp, int size) {
 	register struct mbuf *m=rqp->mrp, *rm;
 	register unsigned count;
 	
-	rm = m_copym(m, rqp->bpos - mtod(m,caddr_t), size, M_WAIT);
+	rm = m_copym(m, rqp->bpos - mtod(m,caddr_t), size, M_TRYWAIT);
 	while (size > 0) {
 		if (m == 0) {
 			printf("ncp_rp_mbuf: can't advance\n");
@@ -555,9 +555,9 @@ nwfs_uiotombuf(uiop, mq, siz, bpos)
 		while (left > 0) {
 			mlen = M_TRAILINGSPACE(mp);
 			if (mlen == 0) {
-				MGET(mp, M_WAIT, MT_DATA);
+				MGET(mp, M_TRYWAIT, MT_DATA);
 				if (clflg)
-					MCLGET(mp, M_WAIT);
+					MCLGET(mp, M_TRYWAIT);
 				mp->m_len = 0;
 				mp2->m_next = mp;
 				mp2 = mp;
diff --git a/sys/netncp/ncp_sock.c b/sys/netncp/ncp_sock.c
index 238f0ae..206c341 100644
--- a/sys/netncp/ncp_sock.c
+++ b/sys/netncp/ncp_sock.c
@@ -171,7 +171,7 @@ ncp_sock_send(struct socket *so, struct mbuf *top, struct ncp_rq *rqp)
 	int sendwait;
 
 	for(;;) {
-		m = m_copym(top, 0, M_COPYALL, M_WAIT);
+		m = m_copym(top, 0, M_COPYALL, M_TRYWAIT);
 /*		NCPDDEBUG(m);*/
 		error = so->so_proto->pr_usrreqs->pru_sosend(so, to, 0, m, 0, flags, p);
 		if (error == 0 || error == EINTR || error == ENETDOWN)
diff --git a/sys/netns/spp_usrreq.c b/sys/netns/spp_usrreq.c
index 4ab74ce..8a14ff0 100644
--- a/sys/netns/spp_usrreq.c
+++ b/sys/netns/spp_usrreq.c
@@ -743,7 +743,7 @@ spp_output(cb, m0)
 					 * from usrreq(), so it is OK to
 					 * block.
 					 */
-					m = m_copym(m0, 0, mtu, M_WAIT);
+					m = m_copym(m0, 0, mtu, M_TRYWAIT);
 					if (cb->s_flags & SF_NEWCALL) {
 					    struct mbuf *mm = m;
 					    spp_newchecks[7]++;
diff --git a/sys/nfs/bootp_subr.c b/sys/nfs/bootp_subr.c
index 80375d7..9101ba7 100644
--- a/sys/nfs/bootp_subr.c
+++ b/sys/nfs/bootp_subr.c
@@ -1755,7 +1755,7 @@ md_lookup_swap(struct sockaddr_in *mdsin,	/* mountd server address */
 		u_int32_t v3[21];
 	} fattribs;
 	
-	m = m_get(M_WAIT,MT_DATA);
+	m = m_get(M_TRYWAIT,MT_DATA);
 	if (m == NULL)
 	  	return ENOBUFS;
 	
diff --git a/sys/nfs/krpc_subr.c b/sys/nfs/krpc_subr.c
index 054a278..b7b1d2c 100644
--- a/sys/nfs/krpc_subr.c
+++ b/sys/nfs/krpc_subr.c
@@ -149,7 +149,7 @@ krpc_portmap(sin,  prog, vers, portp, procp)
 		return 0;
 	}
 
-	m = m_get(M_WAIT, MT_DATA);
+	m = m_get(M_TRYWAIT, MT_DATA);
 	if (m == NULL)
 		return ENOBUFS;
 	sdata = mtod(m, struct sdata *);
@@ -275,7 +275,7 @@ krpc_call(sa, prog, vers, func, data, from_p, procp)
 	/*
 	 * Prepend RPC message header.
 	 */
-	mhead = m_gethdr(M_WAIT, MT_DATA);
+	mhead = m_gethdr(M_TRYWAIT, MT_DATA);
 	mhead->m_next = *data;
 	call = mtod(mhead, struct rpc_call *);
 	mhead->m_len = sizeof(*call);
@@ -315,7 +315,7 @@ krpc_call(sa, prog, vers, func, data, from_p, procp)
 	timo = 0;
 	for (;;) {
 		/* Send RPC request (or re-send). */
-		m = m_copym(mhead, 0, M_COPYALL, M_WAIT);
+		m = m_copym(mhead, 0, M_COPYALL, M_TRYWAIT);
 		if (m == NULL) {
 			error = ENOBUFS;
 			goto out;
@@ -471,9 +471,9 @@ xdr_string_encode(str, len)
 	if (mlen > MCLBYTES)		/* If too big, we just can't do it. */
 		return (NULL);
 
-	m = m_get(M_WAIT, MT_DATA);
+	m = m_get(M_TRYWAIT, MT_DATA);
 	if (mlen > MLEN) {
-		MCLGET(m, M_WAIT);
+		MCLGET(m, M_TRYWAIT);
 		if ((m->m_flags & M_EXT) == 0) {
 			(void) m_free(m);	/* There can be only one. */
 			return (NULL);
diff --git a/sys/nfs/nfs_common.c b/sys/nfs/nfs_common.c
index 95138c3..c7e6917 100644
--- a/sys/nfs/nfs_common.c
+++ b/sys/nfs/nfs_common.c
@@ -588,9 +588,9 @@ nfsm_reqh(vp, procid, hsiz, bposp)
 	struct nfsmount *nmp;
 	int nqflag;
 
-	MGET(mb, M_WAIT, MT_DATA);
+	MGET(mb, M_TRYWAIT, MT_DATA);
 	if (hsiz >= MINCLSIZE)
-		MCLGET(mb, M_WAIT);
+		MCLGET(mb, M_TRYWAIT);
 	mb->m_len = 0;
 	bpos = mtod(mb, caddr_t);
 
@@ -646,9 +646,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 	int siz, grpsiz, authsiz;
 
 	authsiz = nfsm_rndup(auth_len);
-	MGETHDR(mb, M_WAIT, MT_DATA);
+	MGETHDR(mb, M_TRYWAIT, MT_DATA);
 	if ((authsiz + 10 * NFSX_UNSIGNED) >= MINCLSIZE) {
-		MCLGET(mb, M_WAIT);
+		MCLGET(mb, M_TRYWAIT);
 	} else if ((authsiz + 10 * NFSX_UNSIGNED) < MHLEN) {
 		MH_ALIGN(mb, authsiz + 10 * NFSX_UNSIGNED);
 	} else {
@@ -711,9 +711,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 		siz = auth_len;
 		while (siz > 0) {
 			if (M_TRAILINGSPACE(mb) == 0) {
-				MGET(mb2, M_WAIT, MT_DATA);
+				MGET(mb2, M_TRYWAIT, MT_DATA);
 				if (siz >= MINCLSIZE)
-					MCLGET(mb2, M_WAIT);
+					MCLGET(mb2, M_TRYWAIT);
 				mb->m_next = mb2;
 				mb = mb2;
 				mb->m_len = 0;
@@ -744,9 +744,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 		siz = verf_len;
 		while (siz > 0) {
 			if (M_TRAILINGSPACE(mb) == 0) {
-				MGET(mb2, M_WAIT, MT_DATA);
+				MGET(mb2, M_TRYWAIT, MT_DATA);
 				if (siz >= MINCLSIZE)
-					MCLGET(mb2, M_WAIT);
+					MCLGET(mb2, M_TRYWAIT);
 				mb->m_next = mb2;
 				mb = mb2;
 				mb->m_len = 0;
@@ -887,9 +887,9 @@ nfsm_uiotombuf(uiop, mq, siz, bpos)
 		while (left > 0) {
 			mlen = M_TRAILINGSPACE(mp);
 			if (mlen == 0) {
-				MGET(mp, M_WAIT, MT_DATA);
+				MGET(mp, M_TRYWAIT, MT_DATA);
 				if (clflg)
-					MCLGET(mp, M_WAIT);
+					MCLGET(mp, M_TRYWAIT);
 				mp->m_len = 0;
 				mp2->m_next = mp;
 				mp2 = mp;
@@ -919,7 +919,7 @@ nfsm_uiotombuf(uiop, mq, siz, bpos)
 	}
 	if (rem > 0) {
 		if (rem > M_TRAILINGSPACE(mp)) {
-			MGET(mp, M_WAIT, MT_DATA);
+			MGET(mp, M_TRYWAIT, MT_DATA);
 			mp->m_len = 0;
 			mp2->m_next = mp;
 		}
@@ -968,7 +968,7 @@ nfsm_disct(mdp, dposp, siz, left, cp2)
 	} else if (siz > MHLEN) {
 		panic("nfs S too big");
 	} else {
-		MGET(mp2, M_WAIT, MT_DATA);
+		MGET(mp2, M_TRYWAIT, MT_DATA);
 		mp2->m_next = mp->m_next;
 		mp->m_next = mp2;
 		mp->m_len -= left;
@@ -1061,9 +1061,9 @@ nfsm_strtmbuf(mb, bpos, cp, siz)
 	}
 	/* Loop around adding mbufs */
 	while (siz > 0) {
-		MGET(m1, M_WAIT, MT_DATA);
+		MGET(m1, M_TRYWAIT, MT_DATA);
 		if (siz > MLEN)
-			MCLGET(m1, M_WAIT);
+			MCLGET(m1, M_TRYWAIT);
 		m1->m_len = NFSMSIZ(m1);
 		m2->m_next = m1;
 		m2 = m1;
diff --git a/sys/nfs/nfs_common.h b/sys/nfs/nfs_common.h
index 0990fe4..d58ef15 100644
--- a/sys/nfs/nfs_common.h
+++ b/sys/nfs/nfs_common.h
@@ -94,7 +94,7 @@ struct mbuf *nfsm_rpchead __P((struct ucred *cr, int nmflag, int procid,
 #define	nfsm_build(a,c,s) \
 	do { \
 		if ((s) > M_TRAILINGSPACE(mb)) { \
-			MGET(mb2, M_WAIT, MT_DATA); \
+			MGET(mb2, M_TRYWAIT, MT_DATA); \
 			if ((s) > MLEN) \
 				panic("build > MLEN"); \
 			mb->m_next = mb2; \
@@ -491,8 +491,8 @@ struct mbuf *nfsm_rpchead __P((struct ucred *cr, int nmflag, int procid,
 		if (bp >= be) { \
 			if (mp == mb) \
 				mp->m_len += bp-bpos; \
-			MGET(mp, M_WAIT, MT_DATA); \
-			MCLGET(mp, M_WAIT); \
+			MGET(mp, M_TRYWAIT, MT_DATA); \
+			MCLGET(mp, M_TRYWAIT); \
 			mp->m_len = NFSMSIZ(mp); \
 			mp2->m_next = mp; \
 			mp2 = mp; \
diff --git a/sys/nfs/nfs_nqlease.c b/sys/nfs/nfs_nqlease.c
index 6669010..379db2c 100644
--- a/sys/nfs/nfs_nqlease.c
+++ b/sys/nfs/nfs_nqlease.c
@@ -554,7 +554,7 @@ nqsrv_send_eviction(vp, lp, slp, nam, cred)
 			 * Record Mark.
 			 */
 			if (sotype == SOCK_STREAM) {
-				M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
+				M_PREPEND(m, NFSX_UNSIGNED, M_TRYWAIT);
 				*mtod(m, u_int32_t *) = htonl(0x80000000 |
 					(m->m_pkthdr.len - NFSX_UNSIGNED));
 			}
@@ -932,7 +932,7 @@ nqnfs_vacated(vp, cred)
 		RPCAUTH_UNIX, 5 * NFSX_UNSIGNED, (char *)0,
 		0, (char *)NULL, mreq, i, &mheadend, &xid);
 	if (nmp->nm_sotype == SOCK_STREAM) {
-		M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
+		M_PREPEND(m, NFSX_UNSIGNED, M_TRYWAIT);
 		*mtod(m, u_int32_t *) = htonl(0x80000000 | (m->m_pkthdr.len -
 			NFSX_UNSIGNED));
 	}
diff --git a/sys/nfs/nfs_serv.c b/sys/nfs/nfs_serv.c
index 0334f74..648384e 100644
--- a/sys/nfs/nfs_serv.c
+++ b/sys/nfs/nfs_serv.c
@@ -689,8 +689,8 @@ nfsrv_readlink(nfsd, slp, procp, mrq)
 	len = 0;
 	i = 0;
 	while (len < NFS_MAXPATHLEN) {
-		MGET(mp, M_WAIT, MT_DATA);
-		MCLGET(mp, M_WAIT);
+		MGET(mp, M_TRYWAIT, MT_DATA);
+		MCLGET(mp, M_TRYWAIT);
 		mp->m_len = NFSMSIZ(mp);
 		if (len == 0)
 			mp3 = mp2 = mp;
@@ -940,8 +940,8 @@ nfsrv_read(nfsd, slp, procp, mrq)
 				i++;
 			}
 			if (left > 0) {
-				MGET(m, M_WAIT, MT_DATA);
-				MCLGET(m, M_WAIT);
+				MGET(m, M_TRYWAIT, MT_DATA);
+				MCLGET(m, M_TRYWAIT);
 				m->m_len = 0;
 				m2->m_next = m;
 				m2 = m;
diff --git a/sys/nfs/nfs_socket.c b/sys/nfs/nfs_socket.c
index f1ace4e..fefeea8 100644
--- a/sys/nfs/nfs_socket.c
+++ b/sys/nfs/nfs_socket.c
@@ -590,7 +590,7 @@ tryagain:
 			goto tryagain;
 		}
 		while (rep->r_flags & R_MUSTRESEND) {
-			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_WAIT);
+			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_TRYWAIT);
 			nfsstats.rpcretries++;
 			error = nfs_send(so, rep->r_nmp->nm_nam, m, rep);
 			if (error) {
@@ -1014,7 +1014,7 @@ kerbauth:
 	 * For stream protocols, insert a Sun RPC Record Mark.
 	 */
 	if (nmp->nm_sotype == SOCK_STREAM) {
-		M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
+		M_PREPEND(m, NFSX_UNSIGNED, M_TRYWAIT);
 		*mtod(m, u_int32_t *) = htonl(0x80000000 |
 			 (m->m_pkthdr.len - NFSX_UNSIGNED));
 	}
@@ -1058,7 +1058,7 @@ tryagain:
 		if (nmp->nm_soflags & PR_CONNREQUIRED)
 			error = nfs_sndlock(rep);
 		if (!error) {
-			m2 = m_copym(m, 0, M_COPYALL, M_WAIT);
+			m2 = m_copym(m, 0, M_COPYALL, M_TRYWAIT);
 			error = nfs_send(nmp->nm_so, nmp->nm_nam, m2, rep);
 			if (nmp->nm_soflags & PR_CONNREQUIRED)
 				nfs_sndunlock(rep);
@@ -1237,7 +1237,7 @@ nfs_rephead(siz, nd, slp, err, cache, frev, mrq, mbp, bposp)
 	caddr_t bpos;
 	struct mbuf *mb, *mb2;
 
-	MGETHDR(mreq, M_WAIT, MT_DATA);
+	MGETHDR(mreq, M_TRYWAIT, MT_DATA);
 	mb = mreq;
 	/*
 	 * If this is a big reply, use a cluster else
@@ -1245,7 +1245,7 @@ nfs_rephead(siz, nd, slp, err, cache, frev, mrq, mbp, bposp)
 	 */
 	siz += RPC_REPLYSIZ;
 	if ((max_hdr + siz) >= MINCLSIZE) {
-		MCLGET(mreq, M_WAIT);
+		MCLGET(mreq, M_TRYWAIT);
 	} else
 		mreq->m_data += max_hdr;
 	tl = mtod(mreq, u_int32_t *);
@@ -1686,9 +1686,9 @@ nfs_realign(pm, hsiz)
 
 	while ((m = *pm) != NULL) {
 		if ((m->m_len & 0x3) || (mtod(m, intptr_t) & 0x3)) {
-			MGET(n, M_WAIT, MT_DATA);
+			MGET(n, M_TRYWAIT, MT_DATA);
 			if (m->m_len >= MINCLSIZE) {
-				MCLGET(n, M_WAIT);
+				MCLGET(n, M_TRYWAIT);
 			}
 			n->m_len = 0;
 			break;
@@ -1978,7 +1978,7 @@ nfs_msg(p, server, msg)
  * Socket upcall routine for the nfsd sockets.
  * The caddr_t arg is a pointer to the "struct nfssvc_sock".
  * Essentially do as much as possible non-blocking, else punt and it will
- * be called with M_WAIT from an nfsd.
+ * be called with M_TRYWAIT from an nfsd.
  */
 void
 nfsrv_rcv(so, arg, waitflag)
diff --git a/sys/nfs/nfs_srvcache.c b/sys/nfs/nfs_srvcache.c
index 99fae0e..e7b10dd 100644
--- a/sys/nfs/nfs_srvcache.c
+++ b/sys/nfs/nfs_srvcache.c
@@ -201,7 +201,7 @@ loop:
 			} else if (rp->rc_flag & RC_REPMBUF) {
 				nfsstats.srvcache_nonidemdonehits++;
 				*repp = m_copym(rp->rc_reply, 0, M_COPYALL,
-						M_WAIT);
+						M_TRYWAIT);
 				ret = RC_REPLY;
 			} else {
 				nfsstats.srvcache_idemdonehits++;
@@ -313,7 +313,7 @@ loop:
 					rp->rc_flag |= RC_REPSTATUS;
 				} else {
 					rp->rc_reply = m_copym(repmbuf,
-						0, M_COPYALL, M_WAIT);
+						0, M_COPYALL, M_TRYWAIT);
 					rp->rc_flag |= RC_REPMBUF;
 				}
 			}
diff --git a/sys/nfs/nfs_subs.c b/sys/nfs/nfs_subs.c
index 95138c3..c7e6917 100644
--- a/sys/nfs/nfs_subs.c
+++ b/sys/nfs/nfs_subs.c
@@ -588,9 +588,9 @@ nfsm_reqh(vp, procid, hsiz, bposp)
 	struct nfsmount *nmp;
 	int nqflag;
 
-	MGET(mb, M_WAIT, MT_DATA);
+	MGET(mb, M_TRYWAIT, MT_DATA);
 	if (hsiz >= MINCLSIZE)
-		MCLGET(mb, M_WAIT);
+		MCLGET(mb, M_TRYWAIT);
 	mb->m_len = 0;
 	bpos = mtod(mb, caddr_t);
 
@@ -646,9 +646,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 	int siz, grpsiz, authsiz;
 
 	authsiz = nfsm_rndup(auth_len);
-	MGETHDR(mb, M_WAIT, MT_DATA);
+	MGETHDR(mb, M_TRYWAIT, MT_DATA);
 	if ((authsiz + 10 * NFSX_UNSIGNED) >= MINCLSIZE) {
-		MCLGET(mb, M_WAIT);
+		MCLGET(mb, M_TRYWAIT);
 	} else if ((authsiz + 10 * NFSX_UNSIGNED) < MHLEN) {
 		MH_ALIGN(mb, authsiz + 10 * NFSX_UNSIGNED);
 	} else {
@@ -711,9 +711,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 		siz = auth_len;
 		while (siz > 0) {
 			if (M_TRAILINGSPACE(mb) == 0) {
-				MGET(mb2, M_WAIT, MT_DATA);
+				MGET(mb2, M_TRYWAIT, MT_DATA);
 				if (siz >= MINCLSIZE)
-					MCLGET(mb2, M_WAIT);
+					MCLGET(mb2, M_TRYWAIT);
 				mb->m_next = mb2;
 				mb = mb2;
 				mb->m_len = 0;
@@ -744,9 +744,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 		siz = verf_len;
 		while (siz > 0) {
 			if (M_TRAILINGSPACE(mb) == 0) {
-				MGET(mb2, M_WAIT, MT_DATA);
+				MGET(mb2, M_TRYWAIT, MT_DATA);
 				if (siz >= MINCLSIZE)
-					MCLGET(mb2, M_WAIT);
+					MCLGET(mb2, M_TRYWAIT);
 				mb->m_next = mb2;
 				mb = mb2;
 				mb->m_len = 0;
@@ -887,9 +887,9 @@ nfsm_uiotombuf(uiop, mq, siz, bpos)
 		while (left > 0) {
 			mlen = M_TRAILINGSPACE(mp);
 			if (mlen == 0) {
-				MGET(mp, M_WAIT, MT_DATA);
+				MGET(mp, M_TRYWAIT, MT_DATA);
 				if (clflg)
-					MCLGET(mp, M_WAIT);
+					MCLGET(mp, M_TRYWAIT);
 				mp->m_len = 0;
 				mp2->m_next = mp;
 				mp2 = mp;
@@ -919,7 +919,7 @@ nfsm_uiotombuf(uiop, mq, siz, bpos)
 	}
 	if (rem > 0) {
 		if (rem > M_TRAILINGSPACE(mp)) {
-			MGET(mp, M_WAIT, MT_DATA);
+			MGET(mp, M_TRYWAIT, MT_DATA);
 			mp->m_len = 0;
 			mp2->m_next = mp;
 		}
@@ -968,7 +968,7 @@ nfsm_disct(mdp, dposp, siz, left, cp2)
 	} else if (siz > MHLEN) {
 		panic("nfs S too big");
 	} else {
-		MGET(mp2, M_WAIT, MT_DATA);
+		MGET(mp2, M_TRYWAIT, MT_DATA);
 		mp2->m_next = mp->m_next;
 		mp->m_next = mp2;
 		mp->m_len -= left;
@@ -1061,9 +1061,9 @@ nfsm_strtmbuf(mb, bpos, cp, siz)
 	}
 	/* Loop around adding mbufs */
 	while (siz > 0) {
-		MGET(m1, M_WAIT, MT_DATA);
+		MGET(m1, M_TRYWAIT, MT_DATA);
 		if (siz > MLEN)
-			MCLGET(m1, M_WAIT);
+			MCLGET(m1, M_TRYWAIT);
 		m1->m_len = NFSMSIZ(m1);
 		m2->m_next = m1;
 		m2 = m1;
diff --git a/sys/nfs/nfs_syscalls.c b/sys/nfs/nfs_syscalls.c
index d1a8ead..4eb5c86 100644
--- a/sys/nfs/nfs_syscalls.c
+++ b/sys/nfs/nfs_syscalls.c
@@ -480,7 +480,7 @@ nfssvc_nfsd(nsd, argp, p)
 					slp->ns_flag &= ~SLP_NEEDQ;
 					(void) nfs_slplock(slp, 1);
 					nfsrv_rcv(slp->ns_so, (caddr_t)slp,
-						M_WAIT);
+						M_TRYWAIT);
 					nfs_slpunlock(slp);
 				}
 				error = nfsrv_dorec(slp, nfsd, &nd);
@@ -632,7 +632,7 @@ nfssvc_nfsd(nsd, argp, p)
 			 * Record Mark.
 			 */
 			if (sotype == SOCK_STREAM) {
-				M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
+				M_PREPEND(m, NFSX_UNSIGNED, M_TRYWAIT);
 				*mtod(m, u_int32_t *) = htonl(0x80000000 | siz);
 			}
 			if (slp->ns_so->so_proto->pr_flags & PR_CONNREQUIRED)
diff --git a/sys/nfs/nfsm_subs.h b/sys/nfs/nfsm_subs.h
index 0990fe4..d58ef15 100644
--- a/sys/nfs/nfsm_subs.h
+++ b/sys/nfs/nfsm_subs.h
@@ -94,7 +94,7 @@ struct mbuf *nfsm_rpchead __P((struct ucred *cr, int nmflag, int procid,
 #define	nfsm_build(a,c,s) \
 	do { \
 		if ((s) > M_TRAILINGSPACE(mb)) { \
-			MGET(mb2, M_WAIT, MT_DATA); \
+			MGET(mb2, M_TRYWAIT, MT_DATA); \
 			if ((s) > MLEN) \
 				panic("build > MLEN"); \
 			mb->m_next = mb2; \
@@ -491,8 +491,8 @@ struct mbuf *nfsm_rpchead __P((struct ucred *cr, int nmflag, int procid,
 		if (bp >= be) { \
 			if (mp == mb) \
 				mp->m_len += bp-bpos; \
-			MGET(mp, M_WAIT, MT_DATA); \
-			MCLGET(mp, M_WAIT); \
+			MGET(mp, M_TRYWAIT, MT_DATA); \
+			MCLGET(mp, M_TRYWAIT); \
 			mp->m_len = NFSMSIZ(mp); \
 			mp2->m_next = mp; \
 			mp2 = mp; \
diff --git a/sys/nfsclient/bootp_subr.c b/sys/nfsclient/bootp_subr.c
index 80375d7..9101ba7 100644
--- a/sys/nfsclient/bootp_subr.c
+++ b/sys/nfsclient/bootp_subr.c
@@ -1755,7 +1755,7 @@ md_lookup_swap(struct sockaddr_in *mdsin,	/* mountd server address */
 		u_int32_t v3[21];
 	} fattribs;
 	
-	m = m_get(M_WAIT,MT_DATA);
+	m = m_get(M_TRYWAIT,MT_DATA);
 	if (m == NULL)
 	  	return ENOBUFS;
 	
diff --git a/sys/nfsclient/krpc_subr.c b/sys/nfsclient/krpc_subr.c
index 054a278..b7b1d2c 100644
--- a/sys/nfsclient/krpc_subr.c
+++ b/sys/nfsclient/krpc_subr.c
@@ -149,7 +149,7 @@ krpc_portmap(sin,  prog, vers, portp, procp)
 		return 0;
 	}
 
-	m = m_get(M_WAIT, MT_DATA);
+	m = m_get(M_TRYWAIT, MT_DATA);
 	if (m == NULL)
 		return ENOBUFS;
 	sdata = mtod(m, struct sdata *);
@@ -275,7 +275,7 @@ krpc_call(sa, prog, vers, func, data, from_p, procp)
 	/*
 	 * Prepend RPC message header.
 	 */
-	mhead = m_gethdr(M_WAIT, MT_DATA);
+	mhead = m_gethdr(M_TRYWAIT, MT_DATA);
 	mhead->m_next = *data;
 	call = mtod(mhead, struct rpc_call *);
 	mhead->m_len = sizeof(*call);
@@ -315,7 +315,7 @@ krpc_call(sa, prog, vers, func, data, from_p, procp)
 	timo = 0;
 	for (;;) {
 		/* Send RPC request (or re-send). */
-		m = m_copym(mhead, 0, M_COPYALL, M_WAIT);
+		m = m_copym(mhead, 0, M_COPYALL, M_TRYWAIT);
 		if (m == NULL) {
 			error = ENOBUFS;
 			goto out;
@@ -471,9 +471,9 @@ xdr_string_encode(str, len)
 	if (mlen > MCLBYTES)		/* If too big, we just can't do it. */
 		return (NULL);
 
-	m = m_get(M_WAIT, MT_DATA);
+	m = m_get(M_TRYWAIT, MT_DATA);
 	if (mlen > MLEN) {
-		MCLGET(m, M_WAIT);
+		MCLGET(m, M_TRYWAIT);
 		if ((m->m_flags & M_EXT) == 0) {
 			(void) m_free(m);	/* There can be only one. */
 			return (NULL);
diff --git a/sys/nfsclient/nfs_nfsiod.c b/sys/nfsclient/nfs_nfsiod.c
index d1a8ead..4eb5c86 100644
--- a/sys/nfsclient/nfs_nfsiod.c
+++ b/sys/nfsclient/nfs_nfsiod.c
@@ -480,7 +480,7 @@ nfssvc_nfsd(nsd, argp, p)
 					slp->ns_flag &= ~SLP_NEEDQ;
 					(void) nfs_slplock(slp, 1);
 					nfsrv_rcv(slp->ns_so, (caddr_t)slp,
-						M_WAIT);
+						M_TRYWAIT);
 					nfs_slpunlock(slp);
 				}
 				error = nfsrv_dorec(slp, nfsd, &nd);
@@ -632,7 +632,7 @@ nfssvc_nfsd(nsd, argp, p)
 			 * Record Mark.
 			 */
 			if (sotype == SOCK_STREAM) {
-				M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
+				M_PREPEND(m, NFSX_UNSIGNED, M_TRYWAIT);
 				*mtod(m, u_int32_t *) = htonl(0x80000000 | siz);
 			}
 			if (slp->ns_so->so_proto->pr_flags & PR_CONNREQUIRED)
diff --git a/sys/nfsclient/nfs_socket.c b/sys/nfsclient/nfs_socket.c
index f1ace4e..fefeea8 100644
--- a/sys/nfsclient/nfs_socket.c
+++ b/sys/nfsclient/nfs_socket.c
@@ -590,7 +590,7 @@ tryagain:
 			goto tryagain;
 		}
 		while (rep->r_flags & R_MUSTRESEND) {
-			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_WAIT);
+			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_TRYWAIT);
 			nfsstats.rpcretries++;
 			error = nfs_send(so, rep->r_nmp->nm_nam, m, rep);
 			if (error) {
@@ -1014,7 +1014,7 @@ kerbauth:
 	 * For stream protocols, insert a Sun RPC Record Mark.
 	 */
 	if (nmp->nm_sotype == SOCK_STREAM) {
-		M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
+		M_PREPEND(m, NFSX_UNSIGNED, M_TRYWAIT);
 		*mtod(m, u_int32_t *) = htonl(0x80000000 |
 			 (m->m_pkthdr.len - NFSX_UNSIGNED));
 	}
@@ -1058,7 +1058,7 @@ tryagain:
 		if (nmp->nm_soflags & PR_CONNREQUIRED)
 			error = nfs_sndlock(rep);
 		if (!error) {
-			m2 = m_copym(m, 0, M_COPYALL, M_WAIT);
+			m2 = m_copym(m, 0, M_COPYALL, M_TRYWAIT);
 			error = nfs_send(nmp->nm_so, nmp->nm_nam, m2, rep);
 			if (nmp->nm_soflags & PR_CONNREQUIRED)
 				nfs_sndunlock(rep);
@@ -1237,7 +1237,7 @@ nfs_rephead(siz, nd, slp, err, cache, frev, mrq, mbp, bposp)
 	caddr_t bpos;
 	struct mbuf *mb, *mb2;
 
-	MGETHDR(mreq, M_WAIT, MT_DATA);
+	MGETHDR(mreq, M_TRYWAIT, MT_DATA);
 	mb = mreq;
 	/*
 	 * If this is a big reply, use a cluster else
@@ -1245,7 +1245,7 @@ nfs_rephead(siz, nd, slp, err, cache, frev, mrq, mbp, bposp)
 	 */
 	siz += RPC_REPLYSIZ;
 	if ((max_hdr + siz) >= MINCLSIZE) {
-		MCLGET(mreq, M_WAIT);
+		MCLGET(mreq, M_TRYWAIT);
 	} else
 		mreq->m_data += max_hdr;
 	tl = mtod(mreq, u_int32_t *);
@@ -1686,9 +1686,9 @@ nfs_realign(pm, hsiz)
 
 	while ((m = *pm) != NULL) {
 		if ((m->m_len & 0x3) || (mtod(m, intptr_t) & 0x3)) {
-			MGET(n, M_WAIT, MT_DATA);
+			MGET(n, M_TRYWAIT, MT_DATA);
 			if (m->m_len >= MINCLSIZE) {
-				MCLGET(n, M_WAIT);
+				MCLGET(n, M_TRYWAIT);
 			}
 			n->m_len = 0;
 			break;
@@ -1978,7 +1978,7 @@ nfs_msg(p, server, msg)
  * Socket upcall routine for the nfsd sockets.
  * The caddr_t arg is a pointer to the "struct nfssvc_sock".
  * Essentially do as much as possible non-blocking, else punt and it will
- * be called with M_WAIT from an nfsd.
+ * be called with M_TRYWAIT from an nfsd.
  */
 void
 nfsrv_rcv(so, arg, waitflag)
diff --git a/sys/nfsclient/nfs_subs.c b/sys/nfsclient/nfs_subs.c
index 95138c3..c7e6917 100644
--- a/sys/nfsclient/nfs_subs.c
+++ b/sys/nfsclient/nfs_subs.c
@@ -588,9 +588,9 @@ nfsm_reqh(vp, procid, hsiz, bposp)
 	struct nfsmount *nmp;
 	int nqflag;
 
-	MGET(mb, M_WAIT, MT_DATA);
+	MGET(mb, M_TRYWAIT, MT_DATA);
 	if (hsiz >= MINCLSIZE)
-		MCLGET(mb, M_WAIT);
+		MCLGET(mb, M_TRYWAIT);
 	mb->m_len = 0;
 	bpos = mtod(mb, caddr_t);
 
@@ -646,9 +646,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 	int siz, grpsiz, authsiz;
 
 	authsiz = nfsm_rndup(auth_len);
-	MGETHDR(mb, M_WAIT, MT_DATA);
+	MGETHDR(mb, M_TRYWAIT, MT_DATA);
 	if ((authsiz + 10 * NFSX_UNSIGNED) >= MINCLSIZE) {
-		MCLGET(mb, M_WAIT);
+		MCLGET(mb, M_TRYWAIT);
 	} else if ((authsiz + 10 * NFSX_UNSIGNED) < MHLEN) {
 		MH_ALIGN(mb, authsiz + 10 * NFSX_UNSIGNED);
 	} else {
@@ -711,9 +711,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 		siz = auth_len;
 		while (siz > 0) {
 			if (M_TRAILINGSPACE(mb) == 0) {
-				MGET(mb2, M_WAIT, MT_DATA);
+				MGET(mb2, M_TRYWAIT, MT_DATA);
 				if (siz >= MINCLSIZE)
-					MCLGET(mb2, M_WAIT);
+					MCLGET(mb2, M_TRYWAIT);
 				mb->m_next = mb2;
 				mb = mb2;
 				mb->m_len = 0;
@@ -744,9 +744,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 		siz = verf_len;
 		while (siz > 0) {
 			if (M_TRAILINGSPACE(mb) == 0) {
-				MGET(mb2, M_WAIT, MT_DATA);
+				MGET(mb2, M_TRYWAIT, MT_DATA);
 				if (siz >= MINCLSIZE)
-					MCLGET(mb2, M_WAIT);
+					MCLGET(mb2, M_TRYWAIT);
 				mb->m_next = mb2;
 				mb = mb2;
 				mb->m_len = 0;
@@ -887,9 +887,9 @@ nfsm_uiotombuf(uiop, mq, siz, bpos)
 		while (left > 0) {
 			mlen = M_TRAILINGSPACE(mp);
 			if (mlen == 0) {
-				MGET(mp, M_WAIT, MT_DATA);
+				MGET(mp, M_TRYWAIT, MT_DATA);
 				if (clflg)
-					MCLGET(mp, M_WAIT);
+					MCLGET(mp, M_TRYWAIT);
 				mp->m_len = 0;
 				mp2->m_next = mp;
 				mp2 = mp;
@@ -919,7 +919,7 @@ nfsm_uiotombuf(uiop, mq, siz, bpos)
 	}
 	if (rem > 0) {
 		if (rem > M_TRAILINGSPACE(mp)) {
-			MGET(mp, M_WAIT, MT_DATA);
+			MGET(mp, M_TRYWAIT, MT_DATA);
 			mp->m_len = 0;
 			mp2->m_next = mp;
 		}
@@ -968,7 +968,7 @@ nfsm_disct(mdp, dposp, siz, left, cp2)
 	} else if (siz > MHLEN) {
 		panic("nfs S too big");
 	} else {
-		MGET(mp2, M_WAIT, MT_DATA);
+		MGET(mp2, M_TRYWAIT, MT_DATA);
 		mp2->m_next = mp->m_next;
 		mp->m_next = mp2;
 		mp->m_len -= left;
@@ -1061,9 +1061,9 @@ nfsm_strtmbuf(mb, bpos, cp, siz)
 	}
 	/* Loop around adding mbufs */
 	while (siz > 0) {
-		MGET(m1, M_WAIT, MT_DATA);
+		MGET(m1, M_TRYWAIT, MT_DATA);
 		if (siz > MLEN)
-			MCLGET(m1, M_WAIT);
+			MCLGET(m1, M_TRYWAIT);
 		m1->m_len = NFSMSIZ(m1);
 		m2->m_next = m1;
 		m2 = m1;
diff --git a/sys/nfsclient/nfsm_subs.h b/sys/nfsclient/nfsm_subs.h
index 0990fe4..d58ef15 100644
--- a/sys/nfsclient/nfsm_subs.h
+++ b/sys/nfsclient/nfsm_subs.h
@@ -94,7 +94,7 @@ struct mbuf *nfsm_rpchead __P((struct ucred *cr, int nmflag, int procid,
 #define	nfsm_build(a,c,s) \
 	do { \
 		if ((s) > M_TRAILINGSPACE(mb)) { \
-			MGET(mb2, M_WAIT, MT_DATA); \
+			MGET(mb2, M_TRYWAIT, MT_DATA); \
 			if ((s) > MLEN) \
 				panic("build > MLEN"); \
 			mb->m_next = mb2; \
@@ -491,8 +491,8 @@ struct mbuf *nfsm_rpchead __P((struct ucred *cr, int nmflag, int procid,
 		if (bp >= be) { \
 			if (mp == mb) \
 				mp->m_len += bp-bpos; \
-			MGET(mp, M_WAIT, MT_DATA); \
-			MCLGET(mp, M_WAIT); \
+			MGET(mp, M_TRYWAIT, MT_DATA); \
+			MCLGET(mp, M_TRYWAIT); \
 			mp->m_len = NFSMSIZ(mp); \
 			mp2->m_next = mp; \
 			mp2 = mp; \
diff --git a/sys/nfsserver/nfs_serv.c b/sys/nfsserver/nfs_serv.c
index 0334f74..648384e 100644
--- a/sys/nfsserver/nfs_serv.c
+++ b/sys/nfsserver/nfs_serv.c
@@ -689,8 +689,8 @@ nfsrv_readlink(nfsd, slp, procp, mrq)
 	len = 0;
 	i = 0;
 	while (len < NFS_MAXPATHLEN) {
-		MGET(mp, M_WAIT, MT_DATA);
-		MCLGET(mp, M_WAIT);
+		MGET(mp, M_TRYWAIT, MT_DATA);
+		MCLGET(mp, M_TRYWAIT);
 		mp->m_len = NFSMSIZ(mp);
 		if (len == 0)
 			mp3 = mp2 = mp;
@@ -940,8 +940,8 @@ nfsrv_read(nfsd, slp, procp, mrq)
 				i++;
 			}
 			if (left > 0) {
-				MGET(m, M_WAIT, MT_DATA);
-				MCLGET(m, M_WAIT);
+				MGET(m, M_TRYWAIT, MT_DATA);
+				MCLGET(m, M_TRYWAIT);
 				m->m_len = 0;
 				m2->m_next = m;
 				m2 = m;
diff --git a/sys/nfsserver/nfs_srvcache.c b/sys/nfsserver/nfs_srvcache.c
index 99fae0e..e7b10dd 100644
--- a/sys/nfsserver/nfs_srvcache.c
+++ b/sys/nfsserver/nfs_srvcache.c
@@ -201,7 +201,7 @@ loop:
 			} else if (rp->rc_flag & RC_REPMBUF) {
 				nfsstats.srvcache_nonidemdonehits++;
 				*repp = m_copym(rp->rc_reply, 0, M_COPYALL,
-						M_WAIT);
+						M_TRYWAIT);
 				ret = RC_REPLY;
 			} else {
 				nfsstats.srvcache_idemdonehits++;
@@ -313,7 +313,7 @@ loop:
 					rp->rc_flag |= RC_REPSTATUS;
 				} else {
 					rp->rc_reply = m_copym(repmbuf,
-						0, M_COPYALL, M_WAIT);
+						0, M_COPYALL, M_TRYWAIT);
 					rp->rc_flag |= RC_REPMBUF;
 				}
 			}
diff --git a/sys/nfsserver/nfs_srvsock.c b/sys/nfsserver/nfs_srvsock.c
index f1ace4e..fefeea8 100644
--- a/sys/nfsserver/nfs_srvsock.c
+++ b/sys/nfsserver/nfs_srvsock.c
@@ -590,7 +590,7 @@ tryagain:
 			goto tryagain;
 		}
 		while (rep->r_flags & R_MUSTRESEND) {
-			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_WAIT);
+			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_TRYWAIT);
 			nfsstats.rpcretries++;
 			error = nfs_send(so, rep->r_nmp->nm_nam, m, rep);
 			if (error) {
@@ -1014,7 +1014,7 @@ kerbauth:
 	 * For stream protocols, insert a Sun RPC Record Mark.
 	 */
 	if (nmp->nm_sotype == SOCK_STREAM) {
-		M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
+		M_PREPEND(m, NFSX_UNSIGNED, M_TRYWAIT);
 		*mtod(m, u_int32_t *) = htonl(0x80000000 |
 			 (m->m_pkthdr.len - NFSX_UNSIGNED));
 	}
@@ -1058,7 +1058,7 @@ tryagain:
 		if (nmp->nm_soflags & PR_CONNREQUIRED)
 			error = nfs_sndlock(rep);
 		if (!error) {
-			m2 = m_copym(m, 0, M_COPYALL, M_WAIT);
+			m2 = m_copym(m, 0, M_COPYALL, M_TRYWAIT);
 			error = nfs_send(nmp->nm_so, nmp->nm_nam, m2, rep);
 			if (nmp->nm_soflags & PR_CONNREQUIRED)
 				nfs_sndunlock(rep);
@@ -1237,7 +1237,7 @@ nfs_rephead(siz, nd, slp, err, cache, frev, mrq, mbp, bposp)
 	caddr_t bpos;
 	struct mbuf *mb, *mb2;
 
-	MGETHDR(mreq, M_WAIT, MT_DATA);
+	MGETHDR(mreq, M_TRYWAIT, MT_DATA);
 	mb = mreq;
 	/*
 	 * If this is a big reply, use a cluster else
@@ -1245,7 +1245,7 @@ nfs_rephead(siz, nd, slp, err, cache, frev, mrq, mbp, bposp)
 	 */
 	siz += RPC_REPLYSIZ;
 	if ((max_hdr + siz) >= MINCLSIZE) {
-		MCLGET(mreq, M_WAIT);
+		MCLGET(mreq, M_TRYWAIT);
 	} else
 		mreq->m_data += max_hdr;
 	tl = mtod(mreq, u_int32_t *);
@@ -1686,9 +1686,9 @@ nfs_realign(pm, hsiz)
 
 	while ((m = *pm) != NULL) {
 		if ((m->m_len & 0x3) || (mtod(m, intptr_t) & 0x3)) {
-			MGET(n, M_WAIT, MT_DATA);
+			MGET(n, M_TRYWAIT, MT_DATA);
 			if (m->m_len >= MINCLSIZE) {
-				MCLGET(n, M_WAIT);
+				MCLGET(n, M_TRYWAIT);
 			}
 			n->m_len = 0;
 			break;
@@ -1978,7 +1978,7 @@ nfs_msg(p, server, msg)
  * Socket upcall routine for the nfsd sockets.
  * The caddr_t arg is a pointer to the "struct nfssvc_sock".
  * Essentially do as much as possible non-blocking, else punt and it will
- * be called with M_WAIT from an nfsd.
+ * be called with M_TRYWAIT from an nfsd.
  */
 void
 nfsrv_rcv(so, arg, waitflag)
diff --git a/sys/nfsserver/nfs_srvsubs.c b/sys/nfsserver/nfs_srvsubs.c
index 95138c3..c7e6917 100644
--- a/sys/nfsserver/nfs_srvsubs.c
+++ b/sys/nfsserver/nfs_srvsubs.c
@@ -588,9 +588,9 @@ nfsm_reqh(vp, procid, hsiz, bposp)
 	struct nfsmount *nmp;
 	int nqflag;
 
-	MGET(mb, M_WAIT, MT_DATA);
+	MGET(mb, M_TRYWAIT, MT_DATA);
 	if (hsiz >= MINCLSIZE)
-		MCLGET(mb, M_WAIT);
+		MCLGET(mb, M_TRYWAIT);
 	mb->m_len = 0;
 	bpos = mtod(mb, caddr_t);
 
@@ -646,9 +646,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 	int siz, grpsiz, authsiz;
 
 	authsiz = nfsm_rndup(auth_len);
-	MGETHDR(mb, M_WAIT, MT_DATA);
+	MGETHDR(mb, M_TRYWAIT, MT_DATA);
 	if ((authsiz + 10 * NFSX_UNSIGNED) >= MINCLSIZE) {
-		MCLGET(mb, M_WAIT);
+		MCLGET(mb, M_TRYWAIT);
 	} else if ((authsiz + 10 * NFSX_UNSIGNED) < MHLEN) {
 		MH_ALIGN(mb, authsiz + 10 * NFSX_UNSIGNED);
 	} else {
@@ -711,9 +711,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 		siz = auth_len;
 		while (siz > 0) {
 			if (M_TRAILINGSPACE(mb) == 0) {
-				MGET(mb2, M_WAIT, MT_DATA);
+				MGET(mb2, M_TRYWAIT, MT_DATA);
 				if (siz >= MINCLSIZE)
-					MCLGET(mb2, M_WAIT);
+					MCLGET(mb2, M_TRYWAIT);
 				mb->m_next = mb2;
 				mb = mb2;
 				mb->m_len = 0;
@@ -744,9 +744,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 		siz = verf_len;
 		while (siz > 0) {
 			if (M_TRAILINGSPACE(mb) == 0) {
-				MGET(mb2, M_WAIT, MT_DATA);
+				MGET(mb2, M_TRYWAIT, MT_DATA);
 				if (siz >= MINCLSIZE)
-					MCLGET(mb2, M_WAIT);
+					MCLGET(mb2, M_TRYWAIT);
 				mb->m_next = mb2;
 				mb = mb2;
 				mb->m_len = 0;
@@ -887,9 +887,9 @@ nfsm_uiotombuf(uiop, mq, siz, bpos)
 		while (left > 0) {
 			mlen = M_TRAILINGSPACE(mp);
 			if (mlen == 0) {
-				MGET(mp, M_WAIT, MT_DATA);
+				MGET(mp, M_TRYWAIT, MT_DATA);
 				if (clflg)
-					MCLGET(mp, M_WAIT);
+					MCLGET(mp, M_TRYWAIT);
 				mp->m_len = 0;
 				mp2->m_next = mp;
 				mp2 = mp;
@@ -919,7 +919,7 @@ nfsm_uiotombuf(uiop, mq, siz, bpos)
 	}
 	if (rem > 0) {
 		if (rem > M_TRAILINGSPACE(mp)) {
-			MGET(mp, M_WAIT, MT_DATA);
+			MGET(mp, M_TRYWAIT, MT_DATA);
 			mp->m_len = 0;
 			mp2->m_next = mp;
 		}
@@ -968,7 +968,7 @@ nfsm_disct(mdp, dposp, siz, left, cp2)
 	} else if (siz > MHLEN) {
 		panic("nfs S too big");
 	} else {
-		MGET(mp2, M_WAIT, MT_DATA);
+		MGET(mp2, M_TRYWAIT, MT_DATA);
 		mp2->m_next = mp->m_next;
 		mp->m_next = mp2;
 		mp->m_len -= left;
@@ -1061,9 +1061,9 @@ nfsm_strtmbuf(mb, bpos, cp, siz)
 	}
 	/* Loop around adding mbufs */
 	while (siz > 0) {
-		MGET(m1, M_WAIT, MT_DATA);
+		MGET(m1, M_TRYWAIT, MT_DATA);
 		if (siz > MLEN)
-			MCLGET(m1, M_WAIT);
+			MCLGET(m1, M_TRYWAIT);
 		m1->m_len = NFSMSIZ(m1);
 		m2->m_next = m1;
 		m2 = m1;
diff --git a/sys/nfsserver/nfs_syscalls.c b/sys/nfsserver/nfs_syscalls.c
index d1a8ead..4eb5c86 100644
--- a/sys/nfsserver/nfs_syscalls.c
+++ b/sys/nfsserver/nfs_syscalls.c
@@ -480,7 +480,7 @@ nfssvc_nfsd(nsd, argp, p)
 					slp->ns_flag &= ~SLP_NEEDQ;
 					(void) nfs_slplock(slp, 1);
 					nfsrv_rcv(slp->ns_so, (caddr_t)slp,
-						M_WAIT);
+						M_TRYWAIT);
 					nfs_slpunlock(slp);
 				}
 				error = nfsrv_dorec(slp, nfsd, &nd);
@@ -632,7 +632,7 @@ nfssvc_nfsd(nsd, argp, p)
 			 * Record Mark.
 			 */
 			if (sotype == SOCK_STREAM) {
-				M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
+				M_PREPEND(m, NFSX_UNSIGNED, M_TRYWAIT);
 				*mtod(m, u_int32_t *) = htonl(0x80000000 | siz);
 			}
 			if (slp->ns_so->so_proto->pr_flags & PR_CONNREQUIRED)
diff --git a/sys/nfsserver/nfsm_subs.h b/sys/nfsserver/nfsm_subs.h
index 0990fe4..d58ef15 100644
--- a/sys/nfsserver/nfsm_subs.h
+++ b/sys/nfsserver/nfsm_subs.h
@@ -94,7 +94,7 @@ struct mbuf *nfsm_rpchead __P((struct ucred *cr, int nmflag, int procid,
 #define	nfsm_build(a,c,s) \
 	do { \
 		if ((s) > M_TRAILINGSPACE(mb)) { \
-			MGET(mb2, M_WAIT, MT_DATA); \
+			MGET(mb2, M_TRYWAIT, MT_DATA); \
 			if ((s) > MLEN) \
 				panic("build > MLEN"); \
 			mb->m_next = mb2; \
@@ -491,8 +491,8 @@ struct mbuf *nfsm_rpchead __P((struct ucred *cr, int nmflag, int procid,
 		if (bp >= be) { \
 			if (mp == mb) \
 				mp->m_len += bp-bpos; \
-			MGET(mp, M_WAIT, MT_DATA); \
-			MCLGET(mp, M_WAIT); \
+			MGET(mp, M_TRYWAIT, MT_DATA); \
+			MCLGET(mp, M_TRYWAIT); \
 			mp->m_len = NFSMSIZ(mp); \
 			mp2->m_next = mp; \
 			mp2 = mp; \
diff --git a/sys/pci/if_mn.c b/sys/pci/if_mn.c
index 8028389..e3af171 100644
--- a/sys/pci/if_mn.c
+++ b/sys/pci/if_mn.c
@@ -615,7 +615,7 @@ ngmn_connect(hook_p hook)
 	/* Setup a transmit chain with one descriptor */
 	/* XXX: we actually send a 1 byte packet */
 	dp = mn_alloc_desc();
-	MGETHDR(m, M_WAIT, MT_DATA);
+	MGETHDR(m, M_TRYWAIT, MT_DATA);
 	if (m == NULL)
 		return ENOBUFS;
 	m->m_pkthdr.len = 0;
@@ -632,12 +632,12 @@ ngmn_connect(hook_p hook)
 
 	dp = mn_alloc_desc();
 	m = NULL;
-	MGETHDR(m, M_WAIT, MT_DATA);
+	MGETHDR(m, M_TRYWAIT, MT_DATA);
 	if (m == NULL) {
 		mn_free_desc(dp);
 		return (ENOBUFS);
 	}
-	MCLGET(m, M_WAIT);
+	MCLGET(m, M_TRYWAIT);
 	if ((m->m_flags & M_EXT) == 0) {
 		mn_free_desc(dp);
 		m_freem(m);
@@ -655,13 +655,13 @@ ngmn_connect(hook_p hook)
 		dp2 = dp;
 		dp = mn_alloc_desc();
 		m = NULL;
-		MGETHDR(m, M_WAIT, MT_DATA);
+		MGETHDR(m, M_TRYWAIT, MT_DATA);
 		if (m == NULL) {
 			mn_free_desc(dp);
 			m_freem(m);
 			return (ENOBUFS);
 		}
-		MCLGET(m, M_WAIT);
+		MCLGET(m, M_TRYWAIT);
 		if ((m->m_flags & M_EXT) == 0) {
 			mn_free_desc(dp);
 			m_freem(m);
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index f6cf06e..1643404 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -227,7 +227,8 @@ struct mbstat {
 
 /* flags to m_get/MGET */
 #define	M_DONTWAIT	1
-#define	M_WAIT		0
+#define	M_TRYWAIT	0
+#define	M_WAIT		M_TRYWAIT	/* XXX: Deprecated. */
 
 /*
  * Normal mbuf clusters are normally treated as character arrays
@@ -362,7 +363,7 @@ struct mcntfree_lst {
 		mmbfree.m_head = (m_mget)->m_next;			\
 		mbtypes[MT_FREE]--;					\
 	} else {							\
-		if ((m_get_how) == M_WAIT)				\
+		if ((m_get_how) == M_TRYWAIT)				\
 			(m_mget) = m_mballoc_wait();			\
 	}								\
 } while (0)
@@ -429,7 +430,7 @@ struct mcntfree_lst {
 		mbstat.m_clfree--;					\
 		mclfree.m_head = ((union mcluster *)_mp)->mcl_next;	\
 	} else {							\
-		if (_mhow == M_WAIT)					\
+		if (_mhow == M_TRYWAIT)					\
 			_mp = m_clalloc_wait();				\
 	}								\
 	(p) = _mp;							\
@@ -460,7 +461,7 @@ struct mcntfree_lst {
 #define MEXTADD(m, buf, size, free, args, flags, type) do {		\
 	struct mbuf *_mm = (m);						\
 									\
-	MEXT_INIT_REF(_mm, M_WAIT);					\
+	MEXT_INIT_REF(_mm, M_TRYWAIT);					\
 	if (_mm->m_ext.ref_cnt != NULL) {				\
 		_mm->m_flags |= (M_EXT | (flags));			\
 		_mm->m_ext.ext_buf = (caddr_t)(buf);			\
@@ -588,8 +589,8 @@ struct mcntfree_lst {
 /*
  * Arrange to prepend space of size plen to mbuf m.
  * If a new mbuf must be allocated, how specifies whether to wait.
- * If how is M_DONTWAIT and allocation fails, the original mbuf chain
- * is freed and m is set to NULL.
+ * If the allocation fails, the original mbuf chain is freed and m is
+ * set to NULL.
  */
 #define	M_PREPEND(m, plen, how) do {					\
 	struct mbuf **_mmp = &(m);					\