Merge branch 'sunvnet-jumbograms'

David L Stevens says:

====================
sunvnet: add jumbo frames support

This patch set updates the sunvnet driver to version 1.6 of the VIO protocol
to support per-port exchange of MTU information and allow non-standard MTU
sizes, including jumbo frames.

Using large MTUs shows a nearly 5X throughput improvement Linux-Solaris
and > 10X throughput improvement Linux-Linux.

Changes from v8:
	-add a short timeout to free pending skbs if a new transmit doesn't
	 do it first per Dave Miller <davem@davemloft.net>
Changes from v7:
	-handle skb allocation failures in vnet_skb_shape()
	 per Dave Miller <davem@davemloft.net>
Changes from v6:
	-made kernel transmit path zero-copy to remove memory n^2 scaling issue
	 raised by Raghuram Kothakota <Raghuram.Kothakota@oracle.com>
Changes from v5:
	- fixed comment per Sowmini Varadhan <sowmini.varadhan@oracle.com>
Changes from v4:
	- changed VNET_MAXPACKET per David Laight <David.Laight@ACULAB.COM>
	- added cookies to support non-contiguous buffers of max size
Changes from v3:
	- added version functions per Dave Miller <davem@davemloft.net>
	- moved rmtu to vnet_port per Dave Miller <davem@davemloft.net>
	- explicitly set options bits and capability flags to 0 per
		Raghuram Kothakota <Raghuram.Kothakota@oracle.com>
Changes from v2:
	- make checkpatch clean
Changes from v1:
	- fix brace formatting per Dave Miller <davem@davemloft.net>
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/vio.h

@@ -65,6 +65,7 @@ struct vio_dring_register {
 	u16			options;
 #define VIO_TX_DRING		0x0001
 #define VIO_RX_DRING		0x0002
+#define VIO_RX_DRING_DATA	0x0004
 	u16			resv;
 	u32			num_cookies;
 	struct ldc_trans_cookie	cookies[0];
@@ -80,6 +81,8 @@ struct vio_dring_unregister {
 #define VIO_PKT_MODE		0x01 /* Packet based transfer	*/
 #define VIO_DESC_MODE		0x02 /* In-band descriptors	*/
 #define VIO_DRING_MODE		0x03 /* Descriptor rings	*/
+/* in vers >= 1.2, VIO_DRING_MODE is 0x04 and transfer mode is a bitmask */
+#define VIO_NEW_DRING_MODE	0x04
 
 struct vio_dring_data {
 	struct vio_msg_tag	tag;
@@ -205,10 +208,20 @@ struct vio_net_attr_info {
 	u8			addr_type;
 #define VNET_ADDR_ETHERMAC	0x01
 	u16			ack_freq;
-	u32			resv1;
+	u8			plnk_updt;
+#define PHYSLINK_UPDATE_NONE		0x00
+#define PHYSLINK_UPDATE_STATE		0x01
+#define PHYSLINK_UPDATE_STATE_ACK	0x02
+#define PHYSLINK_UPDATE_STATE_NACK	0x03
+	u8			options;
+	u16			resv1;
 	u64			addr;
 	u64			mtu;
-	u64			resv2[3];
+	u16			cflags;
+#define VNET_LSO_IPV4_CAPAB		0x0001
+	u16			ipv4_lso_maxlen;
+	u32			resv2;
+	u64			resv3[2];
 };
 
 #define VNET_NUM_MCAST		7
@@ -366,6 +379,33 @@ struct vio_driver_state {
 	struct vio_driver_ops	*ops;
 };
 
+static inline bool vio_version_before(struct vio_driver_state *vio,
+				      u16 major, u16 minor)
+{
+	u32 have = (u32)vio->ver.major << 16 | vio->ver.minor;
+	u32 want = (u32)major << 16 | minor;
+
+	return have < want;
+}
+
+static inline bool vio_version_after(struct vio_driver_state *vio,
+				      u16 major, u16 minor)
+{
+	u32 have = (u32)vio->ver.major << 16 | vio->ver.minor;
+	u32 want = (u32)major << 16 | minor;
+
+	return have > want;
+}
+
+static inline bool vio_version_after_eq(struct vio_driver_state *vio,
+					u16 major, u16 minor)
+{
+	u32 have = (u32)vio->ver.major << 16 | vio->ver.minor;
+	u32 want = (u32)major << 16 | minor;
+
+	return have >= want;
+}
+
 #define viodbg(TYPE, f, a...) \
 do {	if (vio->debug & VIO_DEBUG_##TYPE) \
 		printk(KERN_INFO "vio: ID[%lu] " f, \

arch/sparc/kernel/ldc.c

@@ -2159,7 +2159,7 @@ int ldc_map_single(struct ldc_channel *lp,
 	state.pte_idx = (base - iommu->page_table);
 	state.nc = 0;
 	fill_cookies(&state, (pa & PAGE_MASK), (pa & ~PAGE_MASK), len);
-	BUG_ON(state.nc != 1);
+	BUG_ON(state.nc > ncookies);
 
 	return state.nc;
 }

arch/sparc/kernel/viohs.c

@@ -426,6 +426,13 @@ static int process_dreg_info(struct vio_driver_state *vio,
 	if (vio->dr_state & VIO_DR_STATE_RXREG)
 		goto send_nack;
 
+	/* v1.6 and higher, ACK with desired, supported mode, or NACK */
+	if (vio_version_after_eq(vio, 1, 6)) {
+		if (!(pkt->options & VIO_TX_DRING))
+			goto send_nack;
+		pkt->options = VIO_TX_DRING;
+	}
+
 	BUG_ON(vio->desc_buf);
 
 	vio->desc_buf = kzalloc(pkt->descr_size, GFP_ATOMIC);
@@ -453,8 +460,11 @@ static int process_dreg_info(struct vio_driver_state *vio,
 	pkt->tag.stype = VIO_SUBTYPE_ACK;
 	pkt->dring_ident = ++dr->ident;
 
-	viodbg(HS, "SEND DRING_REG ACK ident[%llx]\n",
-	       (unsigned long long) pkt->dring_ident);
+	viodbg(HS, "SEND DRING_REG ACK ident[%llx] "
+	       "ndesc[%u] dsz[%u] opt[0x%x] ncookies[%u]\n",
+	       (unsigned long long) pkt->dring_ident,
+	       pkt->num_descr, pkt->descr_size, pkt->options,
+	       pkt->num_cookies);
 
 	len = (sizeof(*pkt) +
 	       (dr->ncookies * sizeof(struct ldc_trans_cookie)));

drivers/net/ethernet/sun/sunvnet.c

@@ -15,6 +15,14 @@
 #include <linux/ethtool.h>
 #include <linux/etherdevice.h>
 #include <linux/mutex.h>
+#include <linux/if_vlan.h>
+
+#if IS_ENABLED(CONFIG_IPV6)
+#include <linux/icmpv6.h>
+#endif
+
+#include <net/icmp.h>
+#include <net/route.h>
 
 #include <asm/vio.h>
 #include <asm/ldc.h>
@@ -41,6 +49,7 @@ static int __vnet_tx_trigger(struct vnet_port *port, u32 start);
 
 /* Ordered from largest major to lowest */
 static struct vio_version vnet_versions[] = {
+	{ .major = 1, .minor = 6 },
 	{ .major = 1, .minor = 0 },
 };
 
@@ -67,6 +76,7 @@ static int vnet_send_attr(struct vio_driver_state *vio)
 	struct vnet_port *port = to_vnet_port(vio);
 	struct net_device *dev = port->vp->dev;
 	struct vio_net_attr_info pkt;
+	int framelen = ETH_FRAME_LEN;
 	int i;
 
 	memset(&pkt, 0, sizeof(pkt));
@@ -74,19 +84,41 @@ static int vnet_send_attr(struct vio_driver_state *vio)
 	pkt.tag.stype = VIO_SUBTYPE_INFO;
 	pkt.tag.stype_env = VIO_ATTR_INFO;
 	pkt.tag.sid = vio_send_sid(vio);
+	if (vio_version_before(vio, 1, 2))
 		pkt.xfer_mode = VIO_DRING_MODE;
+	else
+		pkt.xfer_mode = VIO_NEW_DRING_MODE;
 	pkt.addr_type = VNET_ADDR_ETHERMAC;
 	pkt.ack_freq = 0;
 	for (i = 0; i < 6; i++)
 		pkt.addr |= (u64)dev->dev_addr[i] << ((5 - i) * 8);
-	pkt.mtu = ETH_FRAME_LEN;
+	if (vio_version_after(vio, 1, 3)) {
+		if (port->rmtu) {
+			port->rmtu = min(VNET_MAXPACKET, port->rmtu);
+			pkt.mtu = port->rmtu;
+		} else {
+			port->rmtu = VNET_MAXPACKET;
+			pkt.mtu = port->rmtu;
+		}
+		if (vio_version_after_eq(vio, 1, 6))
+			pkt.options = VIO_TX_DRING;
+	} else if (vio_version_before(vio, 1, 3)) {
+		pkt.mtu = framelen;
+	} else { /* v1.3 */
+		pkt.mtu = framelen + VLAN_HLEN;
+	}
+
+	pkt.plnk_updt = PHYSLINK_UPDATE_NONE;
+	pkt.cflags = 0;
 
 	viodbg(HS, "SEND NET ATTR xmode[0x%x] atype[0x%x] addr[%llx] "
-	       "ackfreq[%u] mtu[%llu]\n",
+	       "ackfreq[%u] plnk_updt[0x%02x] opts[0x%02x] mtu[%llu] "
+	       "cflags[0x%04x] lso_max[%u]\n",
 	       pkt.xfer_mode, pkt.addr_type,
-	       (unsigned long long) pkt.addr,
-	       pkt.ack_freq,
-	       (unsigned long long) pkt.mtu);
+	       (unsigned long long)pkt.addr,
+	       pkt.ack_freq, pkt.plnk_updt, pkt.options,
+	       (unsigned long long)pkt.mtu, pkt.cflags, pkt.ipv4_lso_maxlen);
+
 
 	return vio_ldc_send(vio, &pkt, sizeof(pkt));
 }
@@ -94,18 +126,52 @@ static int vnet_send_attr(struct vio_driver_state *vio)
 static int handle_attr_info(struct vio_driver_state *vio,
 			    struct vio_net_attr_info *pkt)
 {
-	viodbg(HS, "GOT NET ATTR INFO xmode[0x%x] atype[0x%x] addr[%llx] "
-	       "ackfreq[%u] mtu[%llu]\n",
+	struct vnet_port *port = to_vnet_port(vio);
+	u64	localmtu;
+	u8	xfer_mode;
+
+	viodbg(HS, "GOT NET ATTR xmode[0x%x] atype[0x%x] addr[%llx] "
+	       "ackfreq[%u] plnk_updt[0x%02x] opts[0x%02x] mtu[%llu] "
+	       " (rmtu[%llu]) cflags[0x%04x] lso_max[%u]\n",
 	       pkt->xfer_mode, pkt->addr_type,
-	       (unsigned long long) pkt->addr,
-	       pkt->ack_freq,
-	       (unsigned long long) pkt->mtu);
+	       (unsigned long long)pkt->addr,
+	       pkt->ack_freq, pkt->plnk_updt, pkt->options,
+	       (unsigned long long)pkt->mtu, port->rmtu, pkt->cflags,
+	       pkt->ipv4_lso_maxlen);
 
 	pkt->tag.sid = vio_send_sid(vio);
 
-	if (pkt->xfer_mode != VIO_DRING_MODE ||
+	xfer_mode = pkt->xfer_mode;
+	/* for version < 1.2, VIO_DRING_MODE = 0x3 and no bitmask */
+	if (vio_version_before(vio, 1, 2) && xfer_mode == VIO_DRING_MODE)
+		xfer_mode = VIO_NEW_DRING_MODE;
+
+	/* MTU negotiation:
+	 *	< v1.3 - ETH_FRAME_LEN exactly
+	 *	> v1.3 - MIN(pkt.mtu, VNET_MAXPACKET, port->rmtu) and change
+	 *			pkt->mtu for ACK
+	 *	= v1.3 - ETH_FRAME_LEN + VLAN_HLEN exactly
+	 */
+	if (vio_version_before(vio, 1, 3)) {
+		localmtu = ETH_FRAME_LEN;
+	} else if (vio_version_after(vio, 1, 3)) {
+		localmtu = port->rmtu ? port->rmtu : VNET_MAXPACKET;
+		localmtu = min(pkt->mtu, localmtu);
+		pkt->mtu = localmtu;
+	} else { /* v1.3 */
+		localmtu = ETH_FRAME_LEN + VLAN_HLEN;
+	}
+	port->rmtu = localmtu;
+
+	/* for version >= 1.6, ACK packet mode we support */
+	if (vio_version_after_eq(vio, 1, 6)) {
+		pkt->xfer_mode = VIO_NEW_DRING_MODE;
+		pkt->options = VIO_TX_DRING;
+	}
+
+	if (!(xfer_mode | VIO_NEW_DRING_MODE) ||
 	    pkt->addr_type != VNET_ADDR_ETHERMAC ||
-	    pkt->mtu != ETH_FRAME_LEN) {
+	    pkt->mtu != localmtu) {
 		viodbg(HS, "SEND NET ATTR NACK\n");
 
 		pkt->tag.stype = VIO_SUBTYPE_NACK;
@@ -114,7 +180,14 @@ static int handle_attr_info(struct vio_driver_state *vio,
 
 		return -ECONNRESET;
 	} else {
-		viodbg(HS, "SEND NET ATTR ACK\n");
+		viodbg(HS, "SEND NET ATTR ACK xmode[0x%x] atype[0x%x] "
+		       "addr[%llx] ackfreq[%u] plnk_updt[0x%02x] opts[0x%02x] "
+		       "mtu[%llu] (rmtu[%llu]) cflags[0x%04x] lso_max[%u]\n",
+		       pkt->xfer_mode, pkt->addr_type,
+		       (unsigned long long)pkt->addr,
+		       pkt->ack_freq, pkt->plnk_updt, pkt->options,
+		       (unsigned long long)pkt->mtu, port->rmtu, pkt->cflags,
+		       pkt->ipv4_lso_maxlen);
 
 		pkt->tag.stype = VIO_SUBTYPE_ACK;
 
@@ -210,7 +283,7 @@ static int vnet_rx_one(struct vnet_port *port, unsigned int len,
 	int err;
 
 	err = -EMSGSIZE;
-	if (unlikely(len < ETH_ZLEN || len > ETH_FRAME_LEN)) {
+	if (unlikely(len < ETH_ZLEN || len > port->rmtu)) {
 		dev->stats.rx_length_errors++;
 		goto out_dropped;
 	}
@@ -558,8 +631,10 @@ static void vnet_event(void *arg, int event)
 		vio_link_state_change(vio, event);
 		spin_unlock_irqrestore(&vio->lock, flags);
 
-		if (event == LDC_EVENT_RESET)
+		if (event == LDC_EVENT_RESET) {
+			port->rmtu = 0;
 			vio_port_up(vio);
+		}
 		return;
 	}
 
@@ -712,6 +787,117 @@ struct vnet_port *tx_port_find(struct vnet *vp, struct sk_buff *skb)
 	return ret;
 }
 
+static struct sk_buff *vnet_clean_tx_ring(struct vnet_port *port,
+					  unsigned *pending)
+{
+	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+	struct sk_buff *skb = NULL;
+	int i, txi;
+
+	*pending = 0;
+
+	txi = dr->prod-1;
+	if (txi < 0)
+		txi = VNET_TX_RING_SIZE-1;
+
+	for (i = 0; i < VNET_TX_RING_SIZE; ++i) {
+		struct vio_net_desc *d;
+
+		d = vio_dring_entry(dr, txi);
+
+		if (d->hdr.state == VIO_DESC_DONE) {
+			if (port->tx_bufs[txi].skb) {
+				BUG_ON(port->tx_bufs[txi].skb->next);
+
+				port->tx_bufs[txi].skb->next = skb;
+				skb = port->tx_bufs[txi].skb;
+				port->tx_bufs[txi].skb = NULL;
+
+				ldc_unmap(port->vio.lp,
+					  port->tx_bufs[txi].cookies,
+					  port->tx_bufs[txi].ncookies);
+			}
+			d->hdr.state = VIO_DESC_FREE;
+		} else if (d->hdr.state == VIO_DESC_READY) {
+			(*pending)++;
+		} else if (d->hdr.state == VIO_DESC_FREE) {
+			break;
+		}
+		--txi;
+		if (txi < 0)
+			txi = VNET_TX_RING_SIZE-1;
+	}
+	return skb;
+}
+
+static inline void vnet_free_skbs(struct sk_buff *skb)
+{
+	struct sk_buff *next;
+
+	while (skb) {
+		next = skb->next;
+		skb->next = NULL;
+		dev_kfree_skb(skb);
+		skb = next;
+	}
+}
+
+static void vnet_clean_timer_expire(unsigned long port0)
+{
+	struct vnet_port *port = (struct vnet_port *)port0;
+	struct sk_buff *freeskbs;
+	unsigned pending;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->vio.lock, flags);
+	freeskbs = vnet_clean_tx_ring(port, &pending);
+	spin_unlock_irqrestore(&port->vio.lock, flags);
+
+	vnet_free_skbs(freeskbs);
+
+	if (pending)
+		(void)mod_timer(&port->clean_timer,
+				jiffies + VNET_CLEAN_TIMEOUT);
+	 else
+		del_timer(&port->clean_timer);
+}
+
+static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, void **pstart,
+					     int *plen)
+{
+	struct sk_buff *nskb;
+	int len, pad;
+
+	len = skb->len;
+	pad = 0;
+	if (len < ETH_ZLEN) {
+		pad += ETH_ZLEN - skb->len;
+		len += pad;
+	}
+	len += VNET_PACKET_SKIP;
+	pad += 8 - (len & 7);
+	len += 8 - (len & 7);
+
+	if (((unsigned long)skb->data & 7) != VNET_PACKET_SKIP ||
+	    skb_tailroom(skb) < pad ||
+	    skb_headroom(skb) < VNET_PACKET_SKIP) {
+		nskb = alloc_and_align_skb(skb->dev, skb->len);
+		skb_reserve(nskb, VNET_PACKET_SKIP);
+		if (skb_copy_bits(skb, 0, nskb->data, skb->len)) {
+			dev_kfree_skb(nskb);
+			dev_kfree_skb(skb);
+			return NULL;
+		}
+		(void)skb_put(nskb, skb->len);
+		dev_kfree_skb(skb);
+		skb = nskb;
+	}
+
+	*pstart = skb->data - VNET_PACKET_SKIP;
+	*plen = len;
+	return skb;
+}
+
 static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct vnet *vp = netdev_priv(dev);
@@ -720,12 +906,51 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct vio_net_desc *d;
 	unsigned long flags;
 	unsigned int len;
-	void *tx_buf;
-	int i, err;
+	struct sk_buff *freeskbs = NULL;
+	int i, err, txi;
+	void *start = NULL;
+	int nlen = 0;
+	unsigned pending = 0;
 
 	if (unlikely(!port))
 		goto out_dropped;
 
+	skb = vnet_skb_shape(skb, &start, &nlen);
+
+	if (unlikely(!skb))
+		goto out_dropped;
+
+	if (skb->len > port->rmtu) {
+		unsigned long localmtu = port->rmtu - ETH_HLEN;
+
+		if (vio_version_after_eq(&port->vio, 1, 3))
+			localmtu -= VLAN_HLEN;
+
+		if (skb->protocol == htons(ETH_P_IP)) {
+			struct flowi4 fl4;
+			struct rtable *rt = NULL;
+
+			memset(&fl4, 0, sizeof(fl4));
+			fl4.flowi4_oif = dev->ifindex;
+			fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
+			fl4.daddr = ip_hdr(skb)->daddr;
+			fl4.saddr = ip_hdr(skb)->saddr;
+
+			rt = ip_route_output_key(dev_net(dev), &fl4);
+			if (!IS_ERR(rt)) {
+				skb_dst_set(skb, &rt->dst);
+				icmp_send(skb, ICMP_DEST_UNREACH,
+					  ICMP_FRAG_NEEDED,
+					  htonl(localmtu));
+			}
+		}
+#if IS_ENABLED(CONFIG_IPV6)
+		else if (skb->protocol == htons(ETH_P_IPV6))
+			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, localmtu);
+#endif
+		goto out_dropped;
+	}
+
 	spin_lock_irqsave(&port->vio.lock, flags);
 
 	dr = &port->vio.drings[VIO_DRIVER_TX_RING];
@@ -743,14 +968,27 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	d = vio_dring_cur(dr);
 
-	tx_buf = port->tx_bufs[dr->prod].buf;
-	skb_copy_from_linear_data(skb, tx_buf + VNET_PACKET_SKIP, skb->len);
+	txi = dr->prod;
+
+	freeskbs = vnet_clean_tx_ring(port, &pending);
+
+	BUG_ON(port->tx_bufs[txi].skb);
 
 	len = skb->len;
-	if (len < ETH_ZLEN) {
+	if (len < ETH_ZLEN)
 		len = ETH_ZLEN;
-		memset(tx_buf+VNET_PACKET_SKIP+skb->len, 0, len - skb->len);
+
+	port->tx_bufs[txi].skb = skb;
+	skb = NULL;
+
+	err = ldc_map_single(port->vio.lp, start, nlen,
+			     port->tx_bufs[txi].cookies, VNET_MAXCOOKIES,
+			     (LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_RW));
+	if (err < 0) {
+		netdev_info(dev, "tx buffer map error %d\n", err);
+		goto out_dropped_unlock;
 	}
+	port->tx_bufs[txi].ncookies = err;
 
 	/* We don't rely on the ACKs to free the skb in vnet_start_xmit(),
 	 * thus it is safe to not set VIO_ACK_ENABLE for each transmission:
@@ -762,9 +1000,9 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	 */
 	d->hdr.ack = VIO_ACK_DISABLE;
 	d->size = len;
-	d->ncookies = port->tx_bufs[dr->prod].ncookies;
+	d->ncookies = port->tx_bufs[txi].ncookies;
 	for (i = 0; i < d->ncookies; i++)
-		d->cookies[i] = port->tx_bufs[dr->prod].cookies[i];
+		d->cookies[i] = port->tx_bufs[txi].cookies[i];
 
 	/* This has to be a non-SMP write barrier because we are writing
 	 * to memory which is shared with the peer LDOM.
@@ -808,7 +1046,7 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	port->start_cons = false;
 
 	dev->stats.tx_packets++;
-	dev->stats.tx_bytes += skb->len;
+	dev->stats.tx_bytes += port->tx_bufs[txi].skb->len;
 
 	dr->prod = (dr->prod + 1) & (VNET_TX_RING_SIZE - 1);
 	if (unlikely(vnet_tx_dring_avail(dr) < 2)) {
@@ -819,7 +1057,9 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	spin_unlock_irqrestore(&port->vio.lock, flags);
 
-	dev_kfree_skb(skb);
+	vnet_free_skbs(freeskbs);
+
+	(void)mod_timer(&port->clean_timer, jiffies + VNET_CLEAN_TIMEOUT);
 
 	return NETDEV_TX_OK;
 
@@ -827,7 +1067,14 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	spin_unlock_irqrestore(&port->vio.lock, flags);
 
 out_dropped:
+	if (skb)
 		dev_kfree_skb(skb);
+	vnet_free_skbs(freeskbs);
+	if (pending)
+		(void)mod_timer(&port->clean_timer,
+				jiffies + VNET_CLEAN_TIMEOUT);
+	else
+		del_timer(&port->clean_timer);
 	dev->stats.tx_dropped++;
 	return NETDEV_TX_OK;
 }
@@ -973,7 +1220,7 @@ static void vnet_set_rx_mode(struct net_device *dev)
 
 static int vnet_change_mtu(struct net_device *dev, int new_mtu)
 {
-	if (new_mtu != ETH_DATA_LEN)
+	if (new_mtu < 68 || new_mtu > 65535)
 		return -EINVAL;
 
 	dev->mtu = new_mtu;
@@ -1029,17 +1276,22 @@ static void vnet_port_free_tx_bufs(struct vnet_port *port)
 	}
 
 	for (i = 0; i < VNET_TX_RING_SIZE; i++) {
-		void *buf = port->tx_bufs[i].buf;
+		struct vio_net_desc *d;
+		void *skb = port->tx_bufs[i].skb;
 
-		if (!buf)
+		if (!skb)
 			continue;
 
+		d = vio_dring_entry(dr, i);
+		if (d->hdr.state == VIO_DESC_READY)
+			pr_warn("active transmit buffers freed\n");
+
 		ldc_unmap(port->vio.lp,
 			  port->tx_bufs[i].cookies,
 			  port->tx_bufs[i].ncookies);
-
-		kfree(buf);
-		port->tx_bufs[i].buf = NULL;
+		dev_kfree_skb(skb);
+		port->tx_bufs[i].skb = NULL;
+		d->hdr.state = VIO_DESC_FREE;
 	}
 }
 
@@ -1050,34 +1302,6 @@ static int vnet_port_alloc_tx_bufs(struct vnet_port *port)
 	int i, err, ncookies;
 	void *dring;
 
-	for (i = 0; i < VNET_TX_RING_SIZE; i++) {
-		void *buf = kzalloc(ETH_FRAME_LEN + 8, GFP_KERNEL);
-		int map_len = (ETH_FRAME_LEN + 7) & ~7;
-
-		err = -ENOMEM;
-		if (!buf)
-			goto err_out;
-
-		err = -EFAULT;
-		if ((unsigned long)buf & (8UL - 1)) {
-			pr_err("TX buffer misaligned\n");
-			kfree(buf);
-			goto err_out;
-		}
-
-		err = ldc_map_single(port->vio.lp, buf, map_len,
-				     port->tx_bufs[i].cookies, 2,
-				     (LDC_MAP_SHADOW |
-				      LDC_MAP_DIRECT |
-				      LDC_MAP_RW));
-		if (err < 0) {
-			kfree(buf);
-			goto err_out;
-		}
-		port->tx_bufs[i].buf = buf;
-		port->tx_bufs[i].ncookies = err;
-	}
-
 	dr = &port->vio.drings[VIO_DRIVER_TX_RING];
 
 	len = (VNET_TX_RING_SIZE *
@@ -1104,6 +1328,12 @@ static int vnet_port_alloc_tx_bufs(struct vnet_port *port)
 	dr->pending = VNET_TX_RING_SIZE;
 	dr->ncookies = ncookies;
 
+	for (i = 0; i < VNET_TX_RING_SIZE; ++i) {
+		struct vio_net_desc *d;
+
+		d = vio_dring_entry(dr, i);
+		d->hdr.state = VIO_DESC_FREE;
+	}
 	return 0;
 
 err_out:
@@ -1135,6 +1365,8 @@ static struct vnet *vnet_new(const u64 *local_mac)
 	dev = alloc_etherdev(sizeof(*vp));
 	if (!dev)
 		return ERR_PTR(-ENOMEM);
+	dev->needed_headroom = VNET_PACKET_SKIP + 8;
+	dev->needed_tailroom = 8;
 
 	for (i = 0; i < ETH_ALEN; i++)
 		dev->dev_addr[i] = (*local_mac >> (5 - i) * 8) & 0xff;
@@ -1329,6 +1561,9 @@ static int vnet_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 	pr_info("%s: PORT ( remote-mac %pM%s )\n",
 		vp->dev->name, port->raddr, switch_port ? " switch-port" : "");
 
+	setup_timer(&port->clean_timer, vnet_clean_timer_expire,
+		    (unsigned long)port);
+
 	vio_port_up(&port->vio);
 
 	mdesc_release(hp);
@@ -1355,6 +1590,7 @@ static int vnet_port_remove(struct vio_dev *vdev)
 		unsigned long flags;
 
 		del_timer_sync(&port->vio.timer);
+		del_timer_sync(&port->clean_timer);
 
 		spin_lock_irqsave(&vp->lock, flags);
 		list_del(&port->list);

drivers/net/ethernet/sun/sunvnet.h

@@ -11,6 +11,12 @@
  */
 #define VNET_TX_TIMEOUT			(5 * HZ)
 
+/* length of time (or less) we expect pending descriptors to be marked
+ * as VIO_DESC_DONE and skbs ready to be freed
+ */
+#define	VNET_CLEAN_TIMEOUT		((HZ/100)+1)
+
+#define VNET_MAXPACKET			(65535ULL + ETH_HLEN + VLAN_HLEN)
 #define VNET_TX_RING_SIZE		512
 #define VNET_TX_WAKEUP_THRESH(dr)	((dr)->pending / 4)
 
@@ -20,10 +26,12 @@
  */
 #define VNET_PACKET_SKIP		6
 
+#define VNET_MAXCOOKIES			(VNET_MAXPACKET/PAGE_SIZE + 1)
+
 struct vnet_tx_entry {
-	void			*buf;
+	struct sk_buff		*skb;
 	unsigned int		ncookies;
-	struct ldc_trans_cookie	cookies[2];
+	struct ldc_trans_cookie	cookies[VNET_MAXCOOKIES];
 };
 
 struct vnet;
@@ -44,6 +52,10 @@ struct vnet_port {
 	u32			stop_rx_idx;
 	bool			stop_rx;
 	bool			start_cons;
+
+	struct timer_list	clean_timer;
+
+	u64			rmtu;
 };
 
 static inline struct vnet_port *to_vnet_port(struct vio_driver_state *vio)