Introduce an M_ASSERTPKTHDR() macro which performs the very common task

of asserting that an mbuf has a packet header.  Use it instead of hand-
rolled versions wherever applicable.

Submitted by:	Hiten Pandya <hiten@unixdaemons.com>

31 files changed, 52 insertions, 66 deletions

diff --git a/sys/alpha/alpha/busdma_machdep.c b/sys/alpha/alpha/busdma_machdep.c
index 0b9ed6d..e2000cb 100644
--- a/sys/alpha/alpha/busdma_machdep.c
+++ b/sys/alpha/alpha/busdma_machdep.c
@@ -667,8 +667,7 @@ bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 
 	KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 		("bus_dmamap_load_mbuf: No support for bounce pages!"));
-	KASSERT(m0->m_flags & M_PKTHDR,
-		("bus_dmamap_load_mbuf: no packet header"));
+	M_ASSERTPKTHDR(m0);
 
 	nsegs = 0;
 	error = 0;
diff --git a/sys/dev/snc/dp83932.c b/sys/dev/snc/dp83932.c
index f0ebae1..58966ea 100644
--- a/sys/dev/snc/dp83932.c
+++ b/sys/dev/snc/dp83932.c
@@ -345,9 +345,7 @@ outloop:
 		return;
 
 	/* We need the header for m_pkthdr.len. */
-	if ((m->m_flags & M_PKTHDR) == 0)
-		panic("%s: sncstart: no header mbuf",
-		      device_get_nameunit(sc->sc_dev));
+	M_ASSERTPKTHDR(m);
 
 	/*
 	 * If bpf is listening on this interface, let it
diff --git a/sys/dev/vx/if_vx.c b/sys/dev/vx/if_vx.c
index 143a821..3106de0 100644
--- a/sys/dev/vx/if_vx.c
+++ b/sys/dev/vx/if_vx.c
@@ -400,12 +400,9 @@ vxstart(ifp)
 startagain:
     /* Sneak a peek at the next packet */
     m = ifp->if_snd.ifq_head;
-    if (m == NULL) {
-	return;
-    }
+    
     /* We need to use m->m_pkthdr.len, so require the header */
-    if ((m->m_flags & M_PKTHDR) == 0)
-	panic("vxstart: no header mbuf");
+    M_ASSERTPKTHDR(m);
     len = m->m_pkthdr.len;
 
     pad = (4 - len) & 3;
diff --git a/sys/ia64/ia64/busdma_machdep.c b/sys/ia64/ia64/busdma_machdep.c
index 3feacca..d9c24dd 100644
--- a/sys/ia64/ia64/busdma_machdep.c
+++ b/sys/ia64/ia64/busdma_machdep.c
@@ -643,8 +643,7 @@ bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 
 	KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 		("bus_dmamap_load_mbuf: No support for bounce pages!"));
-	KASSERT(m0->m_flags & M_PKTHDR,
-		("bus_dmamap_load_mbuf: no packet header"));
+	M_ASSERTPKTHDR(m0);
 
 	nsegs = 0;
 	error = 0;
diff --git a/sys/kern/kern_mac.c b/sys/kern/kern_mac.c
index 17b37d8..38f7e9b 100644
--- a/sys/kern/kern_mac.c
+++ b/sys/kern/kern_mac.c
@@ -721,7 +721,7 @@ mac_init_mbuf(struct mbuf *m, int flag)
 {
 	int error;
 
-	KASSERT(m->m_flags & M_PKTHDR, ("mac_init_mbuf on non-header mbuf"));
+	M_ASSERTPKTHDR(m);
 
 	mac_init_label(&m->m_pkthdr.label);
 
@@ -2270,7 +2270,7 @@ mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
 	if (!mac_enforce_network)
 		return (0);
 
-	KASSERT(mbuf->m_flags & M_PKTHDR, ("packet has no pkthdr"));
+	M_ASSERTPKTHDR(mbuf);
 	if (!(mbuf->m_pkthdr.label.l_flags & MAC_FLAG_INITIALIZED))
 		if_printf(ifnet, "not initialized\n");
 
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index c6ada18..9caeed9 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -87,8 +87,7 @@ m_move_pkthdr(struct mbuf *to, struct mbuf *from)
 
 #if 0
 	/* see below for why these are not enabled */
-	KASSERT(to->m_flags & M_PKTHDR,
-	    ("m_move_pkthdr: called on non-header"));
+	M_ASSERTPKTHDR(to);
 	KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags),
 	    ("m_move_pkthdr: to has tags"));
 #endif
@@ -125,7 +124,7 @@ m_dup_pkthdr(struct mbuf *to, struct mbuf *from, int how)
 	 * smash the pkthdr as needed causing these
 	 * assertions to trip.  For now just disable them.
 	 */
-	KASSERT(to->m_flags & M_PKTHDR, ("m_dup_pkthdr: called on non-header"));
+	M_ASSERTPKTHDR(to);
 	KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags"));
 #endif
 #ifdef MAC
@@ -349,7 +348,7 @@ m_dup(struct mbuf *m, int how)
 	/* Sanity check */
 	if (m == NULL)
 		return (NULL);
-	KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __func__));
+	M_ASSERTPKTHDR(m);
 
 	/* While there's more data, get a new mbuf, tack it on, and fill it */
 	remain = m->m_pkthdr.len;
diff --git a/sys/net/if_disc.c b/sys/net/if_disc.c
index 79775f1..cfc0432 100644
--- a/sys/net/if_disc.c
+++ b/sys/net/if_disc.c
@@ -155,8 +155,7 @@ static int
 discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
     struct rtentry *rt)
 {
-	if ((m->m_flags & M_PKTHDR) == 0)
-		panic("discoutput no HDR");
+	M_ASSERTPKTHDR(m);
 	/* BPF write needs to be handled specially */
 	if (dst->sa_family == AF_UNSPEC) {
 		dst->sa_family = *(mtod(m, int *));
diff --git a/sys/net/if_faith.c b/sys/net/if_faith.c
index 372786a..761f151 100644
--- a/sys/net/if_faith.c
+++ b/sys/net/if_faith.c
@@ -203,8 +203,7 @@ faithoutput(ifp, m, dst, rt)
 {
 	int isr;
 
-	if ((m->m_flags & M_PKTHDR) == 0)
-		panic("faithoutput no HDR");
+	M_ASSERTPKTHDR(m);
 
 	/* BPF write needs to be handled specially */
 	if (dst->sa_family == AF_UNSPEC) {
diff --git a/sys/net/if_loop.c b/sys/net/if_loop.c
index 92add8a..09ba6a3 100644
--- a/sys/net/if_loop.c
+++ b/sys/net/if_loop.c
@@ -192,8 +192,8 @@ looutput(ifp, m, dst, rt)
 	struct sockaddr *dst;
 	register struct rtentry *rt;
 {
-	if ((m->m_flags & M_PKTHDR) == 0)
-		panic("looutput no HDR");
+
+	M_ASSERTPKTHDR(m); /* check if we have the packet header */
 
 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
 		m_freem(m);
@@ -276,7 +276,7 @@ if_simloop(ifp, m, af, hlen)
 {
 	int isr;
 
-	KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR"));
+	M_ASSERTPKTHDR(m);
 	m->m_pkthdr.rcvif = ifp;
 
 	/* BPF write needs to be handled specially */
diff --git a/sys/netgraph/bluetooth/socket/ng_btsocket_hci_raw.c b/sys/netgraph/bluetooth/socket/ng_btsocket_hci_raw.c
index 2221f44..d8da877 100644
--- a/sys/netgraph/bluetooth/socket/ng_btsocket_hci_raw.c
+++ b/sys/netgraph/bluetooth/socket/ng_btsocket_hci_raw.c
@@ -451,8 +451,7 @@ ng_btsocket_hci_raw_data_input(struct mbuf *nam)
 
 	KASSERT((nam->m_type == MT_SONAME),
 		("%s: m_type=%d\n", __func__, nam->m_type));
-	KASSERT((m0->m_flags & M_PKTHDR),
-		("%s: m_flags=%#x\n", __func__, m0->m_flags));
+	M_ASSERTPKTHDR(m0);
 
 	sa = mtod(nam, struct sockaddr_hci *);
 
@@ -614,8 +613,7 @@ ng_btsocket_hci_raw_output(node_p node, hook_p hook, void *arg1, int arg2)
 
 	KASSERT((nam->m_type == MT_SONAME),
 		("%s: m_type=%d\n", __func__, nam->m_type));
-	KASSERT((m->m_flags & M_PKTHDR),
-		("%s: m_flags=%#x\n", __func__, m->m_flags));
+	M_ASSERTPKTHDR(m);
 
 	sa = mtod(nam, struct sockaddr_hci *);
 
diff --git a/sys/netgraph/ng_base.c b/sys/netgraph/ng_base.c
index efa0e03..786eecd 100644
--- a/sys/netgraph/ng_base.c
+++ b/sys/netgraph/ng_base.c
@@ -335,8 +335,7 @@ static	ng_ID_t nextID = 1;
 		struct mbuf *n;						\
 		int total;						\
 									\
-		if (((m)->m_flags & M_PKTHDR) == 0)			\
-			panic("%s: !PKTHDR", __func__);		\
+		M_ASSERTPKTHDR(m);					\
 		for (total = 0, n = (m); n != NULL; n = n->m_next)	\
 			total += n->m_len;				\
 		if ((m)->m_pkthdr.len != total) {			\
diff --git a/sys/netgraph/ng_iface.c b/sys/netgraph/ng_iface.c
index 07968ff..3aa34f2 100644
--- a/sys/netgraph/ng_iface.c
+++ b/sys/netgraph/ng_iface.c
@@ -739,7 +739,7 @@ ng_iface_rcvdata(hook_p hook, item_p item)
 	NG_FREE_ITEM(item);
 	/* Sanity checks */
 	KASSERT(iffam != NULL, ("%s: iffam", __func__));
-	KASSERT(m->m_flags & M_PKTHDR, ("%s: not pkthdr", __func__));
+	M_ASSERTPKTHDR(m);
 	if (m == NULL)
 		return (EINVAL);
 	if ((ifp->if_flags & IFF_UP) == 0) {
diff --git a/sys/netinet/ip_divert.c b/sys/netinet/ip_divert.c
index 162d7f7..d10ed97 100644
--- a/sys/netinet/ip_divert.c
+++ b/sys/netinet/ip_divert.c
@@ -180,7 +180,7 @@ divert_packet(struct mbuf *m, int incoming, int port, int rule)
 		struct ifaddr *ifa;
 
 		/* Sanity check */
-		KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __func__));
+		M_ASSERTPKTHDR(m);
 
 		/* Find IP address for receive interface */
 		TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index e26cc8d..5cf4ff4 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -334,8 +334,7 @@ ip_input(struct mbuf *m)
 		}
 	}
 
-	KASSERT(m != NULL && (m->m_flags & M_PKTHDR) != 0,
-	    ("ip_input: no HDR"));
+	M_ASSERTPKTHDR(m);
 
 	if (args.rule) {	/* dummynet already filtered us */
 		ip = mtod(m, struct ip *);
diff --git a/sys/netinet/ip_mroute.c b/sys/netinet/ip_mroute.c
index 8c7d890..5abf2ee 100644
--- a/sys/netinet/ip_mroute.c
+++ b/sys/netinet/ip_mroute.c
@@ -1827,8 +1827,7 @@ X_rsvp_input(struct mbuf *m, int off)
 	printf("rsvp_input: check vifs\n");
 
 #ifdef DIAGNOSTIC
-    if (!(m->m_flags & M_PKTHDR))
-	panic("rsvp_input no hdr");
+    M_ASSERTPKTHDR(m);
 #endif
 
     ifp = m->m_pkthdr.rcvif;
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 478a0d5..c303c93 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -199,7 +199,7 @@ ip_output(m0, opt, ro, flags, imo, inp)
 	}
 	m = m0;
 
-	KASSERT(!m || (m->m_flags & M_PKTHDR) != 0, ("ip_output: no HDR"));
+	M_ASSERTPKTHDR(m);
 #ifndef FAST_IPSEC
 	KASSERT(ro != NULL, ("ip_output: no route, proto %d",
 	    mtod(m, struct ip *)->ip_p));
diff --git a/sys/netipsec/keysock.c b/sys/netipsec/keysock.c
index d61c15b..4b587f4 100644
--- a/sys/netipsec/keysock.c
+++ b/sys/netipsec/keysock.c
@@ -114,8 +114,7 @@ key_output(m, va_alist)
 		}
 	}
 
-	if ((m->m_flags & M_PKTHDR) == 0)
-		panic("key_output: not M_PKTHDR ??");
+	M_ASSERTPKTHDR(m);
 
 	KEYDEBUG(KEYDEBUG_KEY_DUMP, kdebug_mbuf(m));
 
diff --git a/sys/netkey/keysock.c b/sys/netkey/keysock.c
index dbc48a8..5cf0924 100644
--- a/sys/netkey/keysock.c
+++ b/sys/netkey/keysock.c
@@ -110,8 +110,7 @@ key_output(m, va_alist)
 		}
 	}
 
-	if ((m->m_flags & M_PKTHDR) == 0)
-		panic("key_output: not M_PKTHDR ??");
+	M_ASSERTPKTHDR(m);
 
 	KEYDEBUG(KEYDEBUG_KEY_DUMP, kdebug_mbuf(m));
 
diff --git a/sys/netnatm/natm.c b/sys/netnatm/natm.c
index 2df3c22..87269fe 100644
--- a/sys/netnatm/natm.c
+++ b/sys/netnatm/natm.c
@@ -705,8 +705,7 @@ natmintr(struct mbuf *m)
   struct natmpcb *npcb;
 
 #ifdef DIAGNOSTIC
-  if ((m->m_flags & M_PKTHDR) == 0)
-    panic("natmintr no HDR");
+  M_ASSERTPKTHDR(m);
 #endif
 
   npcb = (struct natmpcb *) m->m_pkthdr.rcvif; /* XXX: overloaded */
diff --git a/sys/powerpc/powerpc/busdma_machdep.c b/sys/powerpc/powerpc/busdma_machdep.c
index 7401e27..9e4727f 100644
--- a/sys/powerpc/powerpc/busdma_machdep.c
+++ b/sys/powerpc/powerpc/busdma_machdep.c
@@ -417,8 +417,7 @@ bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map, struct mbuf *m0,
 #endif
 	int nsegs = 0, error = 0;
 
-	KASSERT(m0->m_flags & M_PKTHDR,
-	    ("bus_dmamap_load_mbuf: no packet header"));
+	M_ASSERTPKTHDR(m0);
 
 	if (m0->m_pkthdr.len <= dmat->maxsize) {
 		int first = 1;
diff --git a/sys/security/mac/mac_framework.c b/sys/security/mac/mac_framework.c
index 17b37d8..38f7e9b 100644
--- a/sys/security/mac/mac_framework.c
+++ b/sys/security/mac/mac_framework.c
@@ -721,7 +721,7 @@ mac_init_mbuf(struct mbuf *m, int flag)
 {
 	int error;
 
-	KASSERT(m->m_flags & M_PKTHDR, ("mac_init_mbuf on non-header mbuf"));
+	M_ASSERTPKTHDR(m);
 
 	mac_init_label(&m->m_pkthdr.label);
 
@@ -2270,7 +2270,7 @@ mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
 	if (!mac_enforce_network)
 		return (0);
 
-	KASSERT(mbuf->m_flags & M_PKTHDR, ("packet has no pkthdr"));
+	M_ASSERTPKTHDR(mbuf);
 	if (!(mbuf->m_pkthdr.label.l_flags & MAC_FLAG_INITIALIZED))
 		if_printf(ifnet, "not initialized\n");
 
diff --git a/sys/security/mac/mac_internal.h b/sys/security/mac/mac_internal.h
index 17b37d8..38f7e9b 100644
--- a/sys/security/mac/mac_internal.h
+++ b/sys/security/mac/mac_internal.h
@@ -721,7 +721,7 @@ mac_init_mbuf(struct mbuf *m, int flag)
 {
 	int error;
 
-	KASSERT(m->m_flags & M_PKTHDR, ("mac_init_mbuf on non-header mbuf"));
+	M_ASSERTPKTHDR(m);
 
 	mac_init_label(&m->m_pkthdr.label);
 
@@ -2270,7 +2270,7 @@ mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
 	if (!mac_enforce_network)
 		return (0);
 
-	KASSERT(mbuf->m_flags & M_PKTHDR, ("packet has no pkthdr"));
+	M_ASSERTPKTHDR(mbuf);
 	if (!(mbuf->m_pkthdr.label.l_flags & MAC_FLAG_INITIALIZED))
 		if_printf(ifnet, "not initialized\n");
 
diff --git a/sys/security/mac/mac_net.c b/sys/security/mac/mac_net.c
index 17b37d8..38f7e9b 100644
--- a/sys/security/mac/mac_net.c
+++ b/sys/security/mac/mac_net.c
@@ -721,7 +721,7 @@ mac_init_mbuf(struct mbuf *m, int flag)
 {
 	int error;
 
-	KASSERT(m->m_flags & M_PKTHDR, ("mac_init_mbuf on non-header mbuf"));
+	M_ASSERTPKTHDR(m);
 
 	mac_init_label(&m->m_pkthdr.label);
 
@@ -2270,7 +2270,7 @@ mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
 	if (!mac_enforce_network)
 		return (0);
 
-	KASSERT(mbuf->m_flags & M_PKTHDR, ("packet has no pkthdr"));
+	M_ASSERTPKTHDR(mbuf);
 	if (!(mbuf->m_pkthdr.label.l_flags & MAC_FLAG_INITIALIZED))
 		if_printf(ifnet, "not initialized\n");
 
diff --git a/sys/security/mac/mac_pipe.c b/sys/security/mac/mac_pipe.c
index 17b37d8..38f7e9b 100644
--- a/sys/security/mac/mac_pipe.c
+++ b/sys/security/mac/mac_pipe.c
@@ -721,7 +721,7 @@ mac_init_mbuf(struct mbuf *m, int flag)
 {
 	int error;
 
-	KASSERT(m->m_flags & M_PKTHDR, ("mac_init_mbuf on non-header mbuf"));
+	M_ASSERTPKTHDR(m);
 
 	mac_init_label(&m->m_pkthdr.label);
 
@@ -2270,7 +2270,7 @@ mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
 	if (!mac_enforce_network)
 		return (0);
 
-	KASSERT(mbuf->m_flags & M_PKTHDR, ("packet has no pkthdr"));
+	M_ASSERTPKTHDR(mbuf);
 	if (!(mbuf->m_pkthdr.label.l_flags & MAC_FLAG_INITIALIZED))
 		if_printf(ifnet, "not initialized\n");
 
diff --git a/sys/security/mac/mac_process.c b/sys/security/mac/mac_process.c
index 17b37d8..38f7e9b 100644
--- a/sys/security/mac/mac_process.c
+++ b/sys/security/mac/mac_process.c
@@ -721,7 +721,7 @@ mac_init_mbuf(struct mbuf *m, int flag)
 {
 	int error;
 
-	KASSERT(m->m_flags & M_PKTHDR, ("mac_init_mbuf on non-header mbuf"));
+	M_ASSERTPKTHDR(m);
 
 	mac_init_label(&m->m_pkthdr.label);
 
@@ -2270,7 +2270,7 @@ mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
 	if (!mac_enforce_network)
 		return (0);
 
-	KASSERT(mbuf->m_flags & M_PKTHDR, ("packet has no pkthdr"));
+	M_ASSERTPKTHDR(mbuf);
 	if (!(mbuf->m_pkthdr.label.l_flags & MAC_FLAG_INITIALIZED))
 		if_printf(ifnet, "not initialized\n");
 
diff --git a/sys/security/mac/mac_syscalls.c b/sys/security/mac/mac_syscalls.c
index 17b37d8..38f7e9b 100644
--- a/sys/security/mac/mac_syscalls.c
+++ b/sys/security/mac/mac_syscalls.c
@@ -721,7 +721,7 @@ mac_init_mbuf(struct mbuf *m, int flag)
 {
 	int error;
 
-	KASSERT(m->m_flags & M_PKTHDR, ("mac_init_mbuf on non-header mbuf"));
+	M_ASSERTPKTHDR(m);
 
 	mac_init_label(&m->m_pkthdr.label);
 
@@ -2270,7 +2270,7 @@ mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
 	if (!mac_enforce_network)
 		return (0);
 
-	KASSERT(mbuf->m_flags & M_PKTHDR, ("packet has no pkthdr"));
+	M_ASSERTPKTHDR(mbuf);
 	if (!(mbuf->m_pkthdr.label.l_flags & MAC_FLAG_INITIALIZED))
 		if_printf(ifnet, "not initialized\n");
 
diff --git a/sys/security/mac/mac_system.c b/sys/security/mac/mac_system.c
index 17b37d8..38f7e9b 100644
--- a/sys/security/mac/mac_system.c
+++ b/sys/security/mac/mac_system.c
@@ -721,7 +721,7 @@ mac_init_mbuf(struct mbuf *m, int flag)
 {
 	int error;
 
-	KASSERT(m->m_flags & M_PKTHDR, ("mac_init_mbuf on non-header mbuf"));
+	M_ASSERTPKTHDR(m);
 
 	mac_init_label(&m->m_pkthdr.label);
 
@@ -2270,7 +2270,7 @@ mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
 	if (!mac_enforce_network)
 		return (0);
 
-	KASSERT(mbuf->m_flags & M_PKTHDR, ("packet has no pkthdr"));
+	M_ASSERTPKTHDR(mbuf);
 	if (!(mbuf->m_pkthdr.label.l_flags & MAC_FLAG_INITIALIZED))
 		if_printf(ifnet, "not initialized\n");
 
diff --git a/sys/security/mac/mac_vfs.c b/sys/security/mac/mac_vfs.c
index 17b37d8..38f7e9b 100644
--- a/sys/security/mac/mac_vfs.c
+++ b/sys/security/mac/mac_vfs.c
@@ -721,7 +721,7 @@ mac_init_mbuf(struct mbuf *m, int flag)
 {
 	int error;
 
-	KASSERT(m->m_flags & M_PKTHDR, ("mac_init_mbuf on non-header mbuf"));
+	M_ASSERTPKTHDR(m);
 
 	mac_init_label(&m->m_pkthdr.label);
 
@@ -2270,7 +2270,7 @@ mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
 	if (!mac_enforce_network)
 		return (0);
 
-	KASSERT(mbuf->m_flags & M_PKTHDR, ("packet has no pkthdr"));
+	M_ASSERTPKTHDR(mbuf);
 	if (!(mbuf->m_pkthdr.label.l_flags & MAC_FLAG_INITIALIZED))
 		if_printf(ifnet, "not initialized\n");
 
diff --git a/sys/sparc64/sparc64/bus_machdep.c b/sys/sparc64/sparc64/bus_machdep.c
index 1b97419..2b3ddc87 100644
--- a/sys/sparc64/sparc64/bus_machdep.c
+++ b/sys/sparc64/sparc64/bus_machdep.c
@@ -446,8 +446,7 @@ nexus_dmamap_load_mbuf(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat,
 #endif
 	int nsegs, error;
 
-	KASSERT(m0->m_flags & M_PKTHDR,
-		("nexus_dmamap_load_mbuf: no packet header"));
+	M_ASSERTPKTHDR(m0);
 
 	nsegs = 0;
 	error = 0;
diff --git a/sys/sparc64/sparc64/iommu.c b/sys/sparc64/sparc64/iommu.c
index 8eccb04..9dc8d96 100644
--- a/sys/sparc64/sparc64/iommu.c
+++ b/sys/sparc64/sparc64/iommu.c
@@ -906,8 +906,7 @@ iommu_dvmamap_load_mbuf(bus_dma_tag_t pt, bus_dma_tag_t dt,
 	struct mbuf *m;
 	int error = 0, first = 1, nsegs = -1;
 
-	KASSERT(m0->m_flags & M_PKTHDR,
-	    ("iommu_dvmamap_load_mbuf: no packet header"));
+	M_ASSERTPKTHDR(m0);
 
 	if (map->dm_loaded) {
 #ifdef DIAGNOSTIC
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index ae8025a..dd21312 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -334,6 +334,13 @@ struct mbstat {
 			    & M_EXT) || !MEXT_IS_REF(m)))
 
 /*
+ * Check if the supplied mbuf has a packet header, or else panic.
+ */
+#define M_ASSERTPKTHDR(m)				\
+	KASSERT(m != NULL && m->m_flags & M_PKTHDR,	\
+		("%s: no mbuf packet header!", __func__))
+
+/*
  * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
  * an object of the specified size at the end of the mbuf, longword aligned.
  */