ip: always pass a single block to Medium.bwrite(), avoid concatblock() calls in Dev.bwrite()

the convention for Dev.bwrite() is that it accepts a *single* block,
and not a block chain. so we never have concatblock here.

to keep stuff consistent, we also guarantee thet Medium.bwrite()
will get a *single* block passed as well, as the callers are
few in number.

7 files changed, 5 insertions, 13 deletions

diff --git a/sys/src/9/ip/arp.c b/sys/src/9/ip/arp.c
index 43d8de43b..9d650a978 100644
--- a/sys/src/9/ip/arp.c
+++ b/sys/src/9/ip/arp.c
@@ -375,7 +375,7 @@ arpenter(Fs *fs, int version, uchar *ip, uchar *mac, int n, int refresh)
 				}
 				rlock(ifc);
 				if(ifc->m != nil)
-					ifc->m->bwrite(ifc, bp, version, ip);
+					ifc->m->bwrite(ifc, concatblock(bp), version, ip);
 				else
 					freeblist(bp);
 				runlock(ifc);
diff --git a/sys/src/9/ip/devip.c b/sys/src/9/ip/devip.c
index c784f73a0..2f39a6535 100644
--- a/sys/src/9/ip/devip.c
+++ b/sys/src/9/ip/devip.c
@@ -1195,9 +1195,6 @@ ipbwrite(Chan* ch, Block* bp, ulong offset)
 		if(c->wq == nil)
 			error(Eperm);
 
-		if(bp->next)
-			bp = concatblock(bp);
-		
 		return qbwrite(c->wq, bp);
 	default:
 		return devbwrite(ch, bp, offset);
diff --git a/sys/src/9/ip/ethermedium.c b/sys/src/9/ip/ethermedium.c
index f5b4e855d..5853ceec0 100644
--- a/sys/src/9/ip/ethermedium.c
+++ b/sys/src/9/ip/ethermedium.c
@@ -298,8 +298,6 @@ etherbwrite(Ipifc *ifc, Block *bp, int version, uchar *ip)
 
 	/* make it a single block with space for the ether header */
 	bp = padblock(bp, ifc->m->hsize);
-	if(bp->next)
-		bp = concatblock(bp);
 	if(BLEN(bp) < ifc->mintu)
 		bp = adjustblock(bp, ifc->mintu);
 	eh = (Etherhdr*)bp->rp;
diff --git a/sys/src/9/ip/ip.c b/sys/src/9/ip/ip.c
index 0a8863e77..ef8a7e19c 100644
--- a/sys/src/9/ip/ip.c
+++ b/sys/src/9/ip/ip.c
@@ -208,7 +208,7 @@ ipoput4(Fs *f, Block *bp, int gating, int ttl, int tos, Conv *c)
 		eh->cksum[0] = 0;
 		eh->cksum[1] = 0;
 		hnputs(eh->cksum, ipcsum(&eh->vihl));
-		ifc->m->bwrite(ifc, bp, V4, gate);
+		ifc->m->bwrite(ifc, concatblock(bp), V4, gate);
 		runlock(ifc);
 		poperror();
 		return 0;
@@ -240,7 +240,7 @@ if((eh->frag[0] & (IP_DF>>8)) && !gating) print("%V: DF set\n", eh->dst);
 		lid = incref(&ip->id4);
 
 	offset = IP4HDR;
-	while(xp != nil && offset && offset >= BLEN(xp)) {
+	while(offset && offset >= BLEN(xp)) {
 		offset -= BLEN(xp);
 		xp = xp->next;
 	}
diff --git a/sys/src/9/ip/ipv6.c b/sys/src/9/ip/ipv6.c
index 606f638e9..8b50706f4 100644
--- a/sys/src/9/ip/ipv6.c
+++ b/sys/src/9/ip/ipv6.c
@@ -118,7 +118,7 @@ ipoput6(Fs *f, Block *bp, int gating, int ttl, int tos, Conv *c)
 	medialen = ifc->maxtu - ifc->m->hsize;
 	if(len <= medialen) {
 		hnputs(eh->ploadlen, len - IP6HDR);
-		ifc->m->bwrite(ifc, bp, V6, gate);
+		ifc->m->bwrite(ifc, concatblock(bp), V6, gate);
 		runlock(ifc);
 		poperror();
 		return 0;
@@ -161,7 +161,7 @@ ipoput6(Fs *f, Block *bp, int gating, int ttl, int tos, Conv *c)
 
 	xp = bp;
 	offset = uflen;
-	while (xp && offset && offset >= BLEN(xp)) {
+	while (offset && offset >= BLEN(xp)) {
 		offset -= BLEN(xp);
 		xp = xp->next;
 	}
diff --git a/sys/src/9/ip/netdevmedium.c b/sys/src/9/ip/netdevmedium.c
index bcbdeeda2..74d47290c 100644
--- a/sys/src/9/ip/netdevmedium.c
+++ b/sys/src/9/ip/netdevmedium.c
@@ -86,8 +86,6 @@ netdevbwrite(Ipifc *ifc, Block *bp, int, uchar*)
 {
 	Netdevrock *er = ifc->arg;
 
-	if(bp->next)
-		bp = concatblock(bp);
 	if(BLEN(bp) < ifc->mintu)
 		bp = adjustblock(bp, ifc->mintu);
 
diff --git a/sys/src/9/ip/pktmedium.c b/sys/src/9/ip/pktmedium.c
index 81feb3dfb..d978289c4 100644
--- a/sys/src/9/ip/pktmedium.c
+++ b/sys/src/9/ip/pktmedium.c
@@ -51,7 +51,6 @@ static void
 pktbwrite(Ipifc *ifc, Block *bp, int, uchar*)
 {
 	/* enqueue onto the conversation's rq */
-	bp = concatblock(bp);
 	if(ifc->conv->snoopers.ref > 0)
 		qpass(ifc->conv->sq, copyblock(bp, BLEN(bp)));
 	qpass(ifc->conv->rq, bp);