Change m_devget()'s outdated and unused "offset" argument: It is

now the offset into the first mbuf of the target chain before copying
the source data over.  From FreeBSD.

Convert drivers' use of m_devget().  Mostly from thib@.

Update mbuf(9) man page.

ok claudio@, thib@

16 files changed, 87 insertions, 113 deletions

diff --git a/sys/arch/sparc/dev/hme.c b/sys/arch/sparc/dev/hme.c
index a9984cb6b21..ef974a765cd 100644
--- a/sys/arch/sparc/dev/hme.c
+++ b/sys/arch/sparc/dev/hme.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: hme.c,v 1.56 2008/10/02 20:21:13 brad Exp $	*/
+/*	$OpenBSD: hme.c,v 1.57 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  * Copyright (c) 1998 Jason L. Wright (jason@thought.net)
@@ -953,13 +953,12 @@ hme_read(sc, idx, len, flags)
 	}
 
 	/* Pull packet off interface. */
-	m = m_devget(sc->sc_bufs->rx_buf[idx], len + HME_RX_OFFSET, 0,
-	    &sc->sc_arpcom.ac_if, NULL);
+	m = m_devget(sc->sc_bufs->rx_buf[idx] + HME_RX_OFFSET, len,
+	    HME_RX_OFFSET, &sc->sc_arpcom.ac_if, NULL);
 	if (m == NULL) {
 		ifp->if_ierrors++;
 		return;
 	}
-	m_adj(m, HME_RX_OFFSET);
 
 	ifp->if_ipackets++;
 	hme_rxcksum(m, flags);
diff --git a/sys/dev/ic/dc.c b/sys/dev/ic/dc.c
index 1f6be3b776e..232494a990b 100644
--- a/sys/dev/ic/dc.c
+++ b/sys/dev/ic/dc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dc.c,v 1.104 2008/10/02 20:21:13 brad Exp $	*/
+/*	$OpenBSD: dc.c,v 1.105 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  * Copyright (c) 1997, 1998, 1999
@@ -2183,15 +2183,14 @@ dc_rxeof(struct dc_softc *sc)
 		total_len -= ETHER_CRC_LEN;
 
 		m->m_pkthdr.rcvif = ifp;
-		m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
-		    total_len + ETHER_ALIGN, 0, ifp, NULL);
+		m0 = m_devget(mtod(m, char *), total_len, ETHER_ALIGN,
+		    ifp, NULL);
 		dc_newbuf(sc, i, m);
 		DC_INC(i, DC_RX_LIST_CNT);
 		if (m0 == NULL) {
 			ifp->if_ierrors++;
 			continue;
 		}
-		m_adj(m0, ETHER_ALIGN);
 		m = m0;
 
 		ifp->if_ipackets++;
diff --git a/sys/dev/ic/mtd8xx.c b/sys/dev/ic/mtd8xx.c
index 0256e67a490..3fa3f8daa8b 100644
--- a/sys/dev/ic/mtd8xx.c
+++ b/sys/dev/ic/mtd8xx.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mtd8xx.c,v 1.14 2008/10/02 20:21:13 brad Exp $	*/
+/*	$OpenBSD: mtd8xx.c,v 1.15 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  * Copyright (c) 2003 Oleg Safiullin <form@pdp11.org.ru>
@@ -945,15 +945,14 @@ mtd_rxeof(struct mtd_softc *sc)
 		    0, sc->mtd_cdata.mtd_rx_chain[i].sd_map->dm_mapsize,
 		    BUS_DMASYNC_POSTREAD);
 
-		m0 = m_devget(mtod(m, char *) - ETHER_ALIGN, total_len + ETHER_ALIGN,
-		    0, ifp, NULL);
+		m0 = m_devget(mtod(m, char *), total_len,  ETHER_ALIGN,
+		    ifp, NULL);
 		mtd_newbuf(sc, i, m);
 		i = (i + 1) % MTD_RX_LIST_CNT;
 		if (m0 == NULL) {
 			ifp->if_ierrors++;
 			continue;
 		}
-		m_adj(m0, ETHER_ALIGN);
 		m = m0;
 
 		ifp->if_ipackets++;
diff --git a/sys/dev/ic/rtl81x9.c b/sys/dev/ic/rtl81x9.c
index f7e9c98f9d9..3a0256f699e 100644
--- a/sys/dev/ic/rtl81x9.c
+++ b/sys/dev/ic/rtl81x9.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtl81x9.c,v 1.60 2008/10/02 20:21:13 brad Exp $ */
+/*	$OpenBSD: rtl81x9.c,v 1.61 2008/10/14 18:01:53 naddy Exp $ */
 
 /*
  * Copyright (c) 1997, 1998
@@ -676,27 +676,22 @@ rl_rxeof(sc)
 		wrap = (sc->rl_cdata.rl_rx_buf + RL_RXBUFLEN) - rxbufpos;
 
 		if (total_len > wrap) {
-			m = m_devget(rxbufpos - ETHER_ALIGN,
-			    wrap + ETHER_ALIGN, 0, ifp, NULL);
+			m = m_devget(rxbufpos, wrap, ETHER_ALIGN, ifp, NULL);
 			if (m == NULL)
 				ifp->if_ierrors++;
 			else {
-				m_copyback(m, wrap + ETHER_ALIGN,
-				     total_len - wrap, sc->rl_cdata.rl_rx_buf);
-				m = m_pullup(m, sizeof(struct ip) +ETHER_ALIGN);
+				m_copyback(m, wrap, total_len - wrap,
+				    sc->rl_cdata.rl_rx_buf);
+				m = m_pullup(m, sizeof(struct ip));
 				if (m == NULL)
 					ifp->if_ierrors++;
-				else
-					m_adj(m, ETHER_ALIGN);
 			}
 			cur_rx = (total_len - wrap + ETHER_CRC_LEN);
 		} else {
-			m = m_devget(rxbufpos - ETHER_ALIGN,
-			    total_len + ETHER_ALIGN, 0, ifp, NULL);
+			m = m_devget(rxbufpos, total_len, ETHER_ALIGN, ifp,
+			    NULL);
 			if (m == NULL)
 				ifp->if_ierrors++;
-			else
-				m_adj(m, ETHER_ALIGN);
 			cur_rx += total_len + 4 + ETHER_CRC_LEN;
 		}
 
diff --git a/sys/dev/pci/if_bge.c b/sys/dev/pci/if_bge.c
index 539479badda..7ef02187d77 100644
--- a/sys/dev/pci/if_bge.c
+++ b/sys/dev/pci/if_bge.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_bge.c,v 1.246 2008/10/02 20:21:14 brad Exp $	*/
+/*	$OpenBSD: if_bge.c,v 1.247 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  * Copyright (c) 2001 Wind River Systems
@@ -2468,15 +2468,14 @@ bge_rxeof(struct bge_softc *sc)
 			if (bge_newbuf_jumbo(sc, sc->bge_jumbo, NULL)
 			    == ENOBUFS) {
 				struct mbuf             *m0;
-				m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
-				    cur_rx->bge_len - ETHER_CRC_LEN +
-				    ETHER_ALIGN, 0, ifp, NULL);
+				m0 = m_devget(mtod(m, char *),
+				    cur_rx->bge_len - ETHER_CRC_LEN,
+				    ETHER_ALIGN, ifp, NULL);
 				bge_newbuf_jumbo(sc, sc->bge_jumbo, m);
 				if (m0 == NULL) {
 					ifp->if_ierrors++;
 					continue;
 				}
-				m_adj(m0, ETHER_ALIGN);
 				m = m0;
 			}
 		} else {
diff --git a/sys/dev/pci/if_cas.c b/sys/dev/pci/if_cas.c
index a6cfd556c05..4c42eb8bbe0 100644
--- a/sys/dev/pci/if_cas.c
+++ b/sys/dev/pci/if_cas.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_cas.c,v 1.22 2008/10/02 20:21:14 brad Exp $	*/
+/*	$OpenBSD: if_cas.c,v 1.23 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  *
@@ -1205,14 +1205,13 @@ cas_rint(struct cas_softc *sc)
 			bus_dmamap_sync(sc->sc_dmatag, rxs->rxs_dmamap, 0,
 			    rxs->rxs_dmamap->dm_mapsize, BUS_DMASYNC_POSTREAD);
 
-			cp = rxs->rxs_kva + off * 256;
-			m = m_devget(cp, len + ETHER_ALIGN, 0, ifp, NULL);
+			cp = rxs->rxs_kva + off * 256 + ETHER_ALIGN;
+			m = m_devget(cp, len, ETHER_ALIGN, ifp, NULL);
 			
 			if (word[0] & CAS_RC0_RELEASE_HDR)
 				cas_add_rxbuf(sc, idx);
 
 			if (m != NULL) {
-				m_adj(m, ETHER_ALIGN);
 
 #if NBPFILTER > 0
 				/*
@@ -1242,15 +1241,13 @@ cas_rint(struct cas_softc *sc)
 			    rxs->rxs_dmamap->dm_mapsize, BUS_DMASYNC_POSTREAD);
 
 			/* XXX We should not be copying the packet here. */
-			cp = rxs->rxs_kva + off;
-			m = m_devget(cp, len + ETHER_ALIGN, 0, ifp, NULL);
+			cp = rxs->rxs_kva + off + ETHER_ALIGN;
+			m = m_devget(cp, len, ETHER_ALIGN, ifp, NULL);
 
 			if (word[0] & CAS_RC0_RELEASE_DATA)
 				cas_add_rxbuf(sc, idx);
 
 			if (m != NULL) {
-				m_adj(m, ETHER_ALIGN);
-
 #if NBPFILTER > 0
 				/*
 				 * Pass this up to any BPF listeners, but only
diff --git a/sys/dev/pci/if_msk.c b/sys/dev/pci/if_msk.c
index 489ef5e9b96..ad9c0958fad 100644
--- a/sys/dev/pci/if_msk.c
+++ b/sys/dev/pci/if_msk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_msk.c,v 1.66 2008/10/02 20:21:14 brad Exp $	*/
+/*	$OpenBSD: if_msk.c,v 1.67 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  * Copyright (c) 1997, 1998, 1999, 2000
@@ -1702,14 +1702,13 @@ msk_rxeof(struct sk_if_softc *sc_if, u_int16_t len, u_int32_t rxstat)
 	 */
 	if (msk_newbuf(sc_if, cur, NULL, dmamap) == ENOBUFS) {
 		struct mbuf		*m0;
-		m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
-		    total_len + ETHER_ALIGN, 0, ifp, NULL);
+		m0 = m_devget(mtod(m, char *), total_len, ETHER_ALIGN,
+		    ifp, NULL);
 		msk_newbuf(sc_if, cur, m, dmamap);
 		if (m0 == NULL) {
 			ifp->if_ierrors++;
 			return;
 		}
-		m_adj(m0, ETHER_ALIGN);
 		m = m0;
 	} else {
 		m->m_pkthdr.rcvif = ifp;
diff --git a/sys/dev/pci/if_sis.c b/sys/dev/pci/if_sis.c
index 34fd7dac425..d1d94d5b1fc 100644
--- a/sys/dev/pci/if_sis.c
+++ b/sys/dev/pci/if_sis.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_sis.c,v 1.82 2008/10/02 20:21:14 brad Exp $ */
+/*	$OpenBSD: if_sis.c,v 1.83 2008/10/14 18:01:53 naddy Exp $ */
 /*
  * Copyright (c) 1997, 1998, 1999
  *	Bill Paul <wpaul@ctr.columbia.edu>.  All rights reserved.
@@ -1344,14 +1344,13 @@ sis_rxeof(struct sis_softc *sc)
 #endif
 		{
 			struct mbuf *m0;
-			m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
-			    total_len + ETHER_ALIGN, 0, ifp, NULL);
+			m0 = m_devget(mtod(m, char *), total_len, ETHER_ALIGN,
+			    ifp, NULL);
 			sis_newbuf(sc, cur_rx, m);
 			if (m0 == NULL) {
 				ifp->if_ierrors++;
 				continue;
 			}
-			m_adj(m0, ETHER_ALIGN);
 			m = m0;
 		}
 
diff --git a/sys/dev/pci/if_sk.c b/sys/dev/pci/if_sk.c
index 13c3b8b0e4c..40466aa83f7 100644
--- a/sys/dev/pci/if_sk.c
+++ b/sys/dev/pci/if_sk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_sk.c,v 1.148 2008/10/02 20:21:14 brad Exp $	*/
+/*	$OpenBSD: if_sk.c,v 1.149 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  * Copyright (c) 1997, 1998, 1999, 2000
@@ -1777,14 +1777,13 @@ sk_rxeof(struct sk_if_softc *sc_if)
 		 */
 		if (sk_newbuf(sc_if, cur, NULL, dmamap) == ENOBUFS) {
 			struct mbuf		*m0;
-			m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
-			    total_len + ETHER_ALIGN, 0, ifp, NULL);
+			m0 = m_devget(mtod(m, char *), total_len, ETHER_ALIGN,
+			    ifp, NULL);
 			sk_newbuf(sc_if, cur, m, dmamap);
 			if (m0 == NULL) {
 				ifp->if_ierrors++;
 				continue;
 			}
-			m_adj(m0, ETHER_ALIGN);
 			m = m0;
 		} else {
 			m->m_pkthdr.rcvif = ifp;
diff --git a/sys/dev/pci/if_ti.c b/sys/dev/pci/if_ti.c
index a0045948c75..4520179b368 100644
--- a/sys/dev/pci/if_ti.c
+++ b/sys/dev/pci/if_ti.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ti.c,v 1.88 2008/10/02 20:21:14 brad Exp $	*/
+/*	$OpenBSD: if_ti.c,v 1.89 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  * Copyright (c) 1997, 1998, 1999
@@ -1787,14 +1787,13 @@ ti_rxeof(struct ti_softc *sc)
 			if (ti_newbuf_jumbo(sc, sc->ti_jumbo, NULL)
 			    == ENOBUFS) {
 				struct mbuf             *m0;
-				m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
-				    cur_rx->ti_len + ETHER_ALIGN, 0, ifp, NULL);
+				m0 = m_devget(mtod(m, char *), cur_rx->ti_len,
+				    ETHER_ALIGN, ifp, NULL);
 				ti_newbuf_jumbo(sc, sc->ti_jumbo, m);
 				if (m0 == NULL) {
 					ifp->if_ierrors++;
 					continue;
 				}
-				m_adj(m0, ETHER_ALIGN);
 				m = m0;
 			}
 		} else if (cur_rx->ti_flags & TI_BDFLAG_MINI_RING) {
diff --git a/sys/dev/pci/if_vge.c b/sys/dev/pci/if_vge.c
index 8259c41a1bf..1c1de93f34c 100644
--- a/sys/dev/pci/if_vge.c
+++ b/sys/dev/pci/if_vge.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_vge.c,v 1.39 2008/10/02 20:21:14 brad Exp $	*/
+/*	$OpenBSD: if_vge.c,v 1.40 2008/10/14 18:01:53 naddy Exp $	*/
 /*	$FreeBSD: if_vge.c,v 1.3 2004/09/11 22:13:25 wpaul Exp $	*/
 /*
  * Copyright (c) 2004
@@ -1031,15 +1031,13 @@ vge_rxeof(struct vge_softc *sc)
 				sc->vge_head = sc->vge_tail = NULL;
 			}
 
-			m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
-			    total_len - ETHER_CRC_LEN + ETHER_ALIGN,
-			    0, ifp, NULL);
+			m0 = m_devget(mtod(m, char *),
+			    total_len - ETHER_CRC_LEN, ETHER_ALIGN, ifp, NULL);
 			vge_newbuf(sc, i, m);
 			if (m0 == NULL) {
 				ifp->if_ierrors++;
 				continue;
 			}
-			m_adj(m0, ETHER_ALIGN);
 			m = m0;
 
 			VGE_RX_DESC_INC(i);
diff --git a/sys/dev/pci/if_vr.c b/sys/dev/pci/if_vr.c
index e4def20edf5..90d0d884645 100644
--- a/sys/dev/pci/if_vr.c
+++ b/sys/dev/pci/if_vr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_vr.c,v 1.78 2008/10/02 20:21:14 brad Exp $	*/
+/*	$OpenBSD: if_vr.c,v 1.79 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  * Copyright (c) 1997, 1998
@@ -806,14 +806,13 @@ vr_rxeof(struct vr_softc *sc)
 		} else
 #endif
 		{
-			m0 = m_devget(mtod(m, caddr_t) - ETHER_ALIGN,
-			    total_len + ETHER_ALIGN, 0, ifp, NULL);
+			m0 = m_devget(mtod(m, caddr_t), total_len,
+			    ETHER_ALIGN, ifp, NULL);
 			vr_alloc_mbuf(sc, cur_rx, m);
 			if (m0 == NULL) {
 				ifp->if_ierrors++;
 				continue;
 			}
-			m_adj(m0, ETHER_ALIGN);
 			m = m0;
 		}
 
diff --git a/sys/dev/pci/if_wb.c b/sys/dev/pci/if_wb.c
index e94485747a7..4b3d36dc0e4 100644
--- a/sys/dev/pci/if_wb.c
+++ b/sys/dev/pci/if_wb.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_wb.c,v 1.40 2008/10/02 20:21:14 brad Exp $	*/
+/*	$OpenBSD: if_wb.c,v 1.41 2008/10/14 18:01:53 naddy Exp $	*/
 
 /*
  * Copyright (c) 1997, 1998
@@ -1050,14 +1050,13 @@ void wb_rxeof(sc)
 		 */
 		total_len -= ETHER_CRC_LEN;
 
-		m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
-		    total_len + ETHER_ALIGN, 0, ifp, NULL);
+		m0 = m_devget(mtod(m, char *), total_len, ETHER_ALIGN,
+		    ifp, NULL);
 		wb_newbuf(sc, cur_rx, m);
 		if (m0 == NULL) {
 			ifp->if_ierrors++;
 			break;
 		}
-		m_adj(m0, ETHER_ALIGN);
 		m = m0;
 
 		ifp->if_ipackets++;
diff --git a/sys/dev/pcmcia/if_malo.c b/sys/dev/pcmcia/if_malo.c
index d8ff907f818..ba2395d7a66 100644
--- a/sys/dev/pcmcia/if_malo.c
+++ b/sys/dev/pcmcia/if_malo.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: if_malo.c,v 1.63 2008/07/29 10:05:38 thib Exp $ */
+/*      $OpenBSD: if_malo.c,v 1.64 2008/10/14 18:01:53 naddy Exp $ */
 
 /*
  * Copyright (c) 2007 Marcus Glocker <mglocker@openbsd.org>
@@ -927,14 +927,13 @@ cmalo_rx(struct malo_softc *sc)
 	rxdesc->pkglen -= sizeof(struct llc);
 
 	/* prepare mbuf */
-	m = m_devget(sc->sc_data + rxdesc->pkgoffset - ETHER_ALIGN,
-	    rxdesc->pkglen + ETHER_ALIGN, 0, ifp, NULL);
+	m = m_devget(sc->sc_data + rxdesc->pkgoffset,
+	    rxdesc->pkglen, ETHER_ALIGN, ifp, NULL);
 	if (m == NULL) {
 		DPRINTF(1, "RX m_devget failed!\n");
 		ifp->if_ierrors++;
 		return;
 	}
-	m_adj(m, ETHER_ALIGN);
 
 #if NBPFILTER > 0
 	if (ifp->if_bpf)
diff --git a/sys/dev/usb/if_upgt.c b/sys/dev/usb/if_upgt.c
index a7496e3319f..3981c81c901 100644
--- a/sys/dev/usb/if_upgt.c
+++ b/sys/dev/usb/if_upgt.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_upgt.c,v 1.38 2008/08/27 10:34:24 damien Exp $ */
+/*	$OpenBSD: if_upgt.c,v 1.39 2008/10/14 18:01:53 naddy Exp $ */
 
 /*
  * Copyright (c) 2007 Marcus Glocker <mglocker@openbsd.org>
@@ -1780,14 +1780,12 @@ upgt_rx(struct upgt_softc *sc, uint8_t *data, int pkglen)
 	rxdesc = (struct upgt_lmac_rx_desc *)data;
 
 	/* create mbuf which is suitable for strict alignment archs */
-	m = m_devget(rxdesc->data - ETHER_ALIGN, pkglen + ETHER_ALIGN, 0, ifp,
-	    NULL);
+	m = m_devget(rxdesc->data, pkglen, ETHER_ALIGN, ifp, NULL);
 	if (m == NULL) {
 		DPRINTF(1, "%s: could not create RX mbuf!\n", sc->sc_dev.dv_xname);
 		ifp->if_ierrors++;
 		return;
 	}
-	m_adj(m, ETHER_ALIGN);
 
 	s = splnet();
 
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index 7c46413419f..7db45a81cff 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_mbuf.c,v 1.93 2008/09/28 14:08:51 naddy Exp $	*/
+/*	$OpenBSD: uipc_mbuf.c,v 1.94 2008/10/14 18:01:53 naddy Exp $	*/
 /*	$NetBSD: uipc_mbuf.c,v 1.15.4.1 1996/06/13 17:11:44 cgd Exp $	*/
 
 /*
@@ -922,28 +922,24 @@ struct mbuf *
 m_devget(char *buf, int totlen, int off, struct ifnet *ifp,
     void (*copy)(const void *, void *, size_t))
 {
-	struct mbuf *m;
-	struct mbuf *top = NULL, **mp = &top;
-	int len;
-	char *cp;
-	char *epkt;
-
-	cp = buf;
-	epkt = cp + totlen;
-	if (off) {
-		/*
-		 * If 'off' is non-zero, packet is trailer-encapsulated,
-		 * so we have to skip the type and length fields.
-		 */
-		cp += off + 2 * sizeof(u_int16_t);
-		totlen -= 2 * sizeof(u_int16_t);
-	}
+	struct mbuf	*m;
+	struct mbuf	*top, **mp;
+	int		 len;
+
+	top = NULL;
+	mp = &top;
+
+	if (off < 0 || off > MHLEN)
+		return (NULL);
+
 	MGETHDR(m, M_DONTWAIT, MT_DATA);
 	if (m == NULL)
 		return (NULL);
+
 	m->m_pkthdr.rcvif = ifp;
 	m->m_pkthdr.len = totlen;
-	m->m_len = MHLEN;
+
+	len = MHLEN;
 
 	while (totlen > 0) {
 		if (top != NULL) {
@@ -952,37 +948,38 @@ m_devget(char *buf, int totlen, int off, struct ifnet *ifp,
 				m_freem(top);
 				return (NULL);
 			}
-			m->m_len = MLEN;
+			len = MLEN;
 		}
-		len = min(totlen, epkt - cp);
-		if (len >= MINCLSIZE) {
+
+		if (totlen + off >= MINCLSIZE) {
 			MCLGET(m, M_DONTWAIT);
 			if (m->m_flags & M_EXT)
-				m->m_len = len = min(len, MCLBYTES);
-			else
-				len = m->m_len;
+				len = MCLBYTES;
 		} else {
-			/*
-			 * Place initial small packet/header at end of mbuf.
-			 */
-			if (len < m->m_len) {
-				if (top == NULL &&
-				    len + max_linkhdr <= m->m_len)
-					m->m_data += max_linkhdr;
-				m->m_len = len;
-			} else
-				len = m->m_len;
+			/* Place initial small packet/header at end of mbuf. */
+			if (top == NULL && totlen + off + max_linkhdr <= len) {
+				m->m_data += max_linkhdr;
+				len -= max_linkhdr;
+			}
+		}
+
+		if (off) {
+			m->m_data += off;
+			len -= off;
+			off = 0;
 		}
+
+		m->m_len = len = min(totlen, len);
+
 		if (copy)
-			copy(cp, mtod(m, caddr_t), (size_t)len);
+			copy(buf, mtod(m, caddr_t), (size_t)len);
 		else
-			bcopy(cp, mtod(m, caddr_t), (size_t)len);
-		cp += len;
+			bcopy(buf, mtod(m, caddr_t), (size_t)len);
+
+		buf += len;
 		*mp = m;
 		mp = &m->m_next;
 		totlen -= len;
-		if (cp == epkt)
-			cp = buf;
 	}
 	return (top);
 }