# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID aecdb4c52fa78dc2824f6be011689a2c4de4de11
# Parent 50db8c95e65d6bf08ba0107399654439ee05b8fc
[NET] front: Transmit SG packets if supported
This patch adds scatter-and-gather transmission support to the frontend.
This allows the MTU to be raised right now and the potential for TSO in
future.
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
---
linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c | 171 +++++++++++++++----
xen/include/public/io/ring.h | 6
2 files changed, 147 insertions(+), 30 deletions(-)
diff -r 50db8c95e65d -r aecdb4c52fa7
linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c
--- a/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c Mon Jun 05
16:13:47 2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c Mon Jun 05
16:33:49 2006 +0100
@@ -45,6 +45,7 @@
#include <linux/bitops.h>
#include <linux/ethtool.h>
#include <linux/in.h>
+#include <linux/if_ether.h>
#include <net/sock.h>
#include <net/pkt_sched.h>
#include <net/arp.h>
@@ -173,6 +174,11 @@ static void xennet_sysfs_delif(struct ne
#define xennet_sysfs_delif(dev) do { } while(0)
#endif
+static inline int xennet_can_sg(struct net_device *dev)
+{
+ return dev->features & NETIF_F_SG;
+}
+
/**
* Entry point to this code when a new device is created. Allocate the basic
* structures and the ring buffers for communication with the backend, and
@@ -307,8 +313,6 @@ again:
goto destroy_ring;
}
- xenbus_switch_state(dev, XenbusStateConnected);
-
return 0;
abort_transaction:
@@ -370,12 +374,9 @@ static int setup_device(struct xenbus_de
goto fail;
memcpy(netdev->dev_addr, info->mac, ETH_ALEN);
- network_connect(netdev);
info->irq = bind_evtchn_to_irqhandler(
info->evtchn, netif_int, SA_SAMPLE_RANDOM, netdev->name,
netdev);
- (void)send_fake_arp(netdev);
- show_device(info);
return 0;
@@ -391,15 +392,24 @@ static void backend_changed(struct xenbu
static void backend_changed(struct xenbus_device *dev,
enum xenbus_state backend_state)
{
+ struct netfront_info *np = dev->data;
+ struct net_device *netdev = np->netdev;
+
DPRINTK("\n");
switch (backend_state) {
case XenbusStateInitialising:
- case XenbusStateInitWait:
case XenbusStateInitialised:
case XenbusStateConnected:
case XenbusStateUnknown:
case XenbusStateClosed:
+ break;
+
+ case XenbusStateInitWait:
+ network_connect(netdev);
+ xenbus_switch_state(dev, XenbusStateConnected);
+ (void)send_fake_arp(netdev);
+ show_device(np);
break;
case XenbusStateClosing:
@@ -452,13 +462,17 @@ static int network_open(struct net_devic
return 0;
}
+static inline int netfront_tx_slot_available(struct netfront_info *np)
+{
+ return RING_FREE_REQUESTS(&np->tx) >= MAX_SKB_FRAGS + 1;
+}
+
static inline void network_maybe_wake_tx(struct net_device *dev)
{
struct netfront_info *np = netdev_priv(dev);
if (unlikely(netif_queue_stopped(dev)) &&
- !RING_FULL(&np->tx) &&
- !gnttab_empty_grant_references(&np->gref_tx_head) &&
+ netfront_tx_slot_available(np) &&
likely(netif_running(dev)))
netif_wake_queue(dev);
}
@@ -638,36 +652,95 @@ static void network_alloc_rx_buffers(str
RING_PUSH_REQUESTS(&np->rx);
}
+static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
+ struct netif_tx_request *tx)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ char *data = skb->data;
+ unsigned long mfn;
+ RING_IDX prod = np->tx.req_prod_pvt;
+ int frags = skb_shinfo(skb)->nr_frags;
+ unsigned int offset = offset_in_page(data);
+ unsigned int len = skb_headlen(skb);
+ unsigned int id;
+ grant_ref_t ref;
+ int i;
+
+ while (len > PAGE_SIZE - offset) {
+ tx->size = PAGE_SIZE - offset;
+ tx->flags |= NETTXF_more_data;
+ len -= tx->size;
+ data += tx->size;
+ offset = 0;
+
+ id = get_id_from_freelist(np->tx_skbs);
+ np->tx_skbs[id] = skb_get(skb);
+ tx = RING_GET_REQUEST(&np->tx, prod++);
+ tx->id = id;
+ ref = gnttab_claim_grant_reference(&np->gref_tx_head);
+ BUG_ON((signed short)ref < 0);
+
+ mfn = virt_to_mfn(data);
+ gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
+ mfn, GNTMAP_readonly);
+
+ tx->gref = np->grant_tx_ref[id] = ref;
+ tx->offset = offset;
+ tx->size = len;
+ tx->flags = 0;
+ }
+
+ for (i = 0; i < frags; i++) {
+ skb_frag_t *frag = skb_shinfo(skb)->frags + i;
+
+ tx->flags |= NETTXF_more_data;
+
+ id = get_id_from_freelist(np->tx_skbs);
+ np->tx_skbs[id] = skb_get(skb);
+ tx = RING_GET_REQUEST(&np->tx, prod++);
+ tx->id = id;
+ ref = gnttab_claim_grant_reference(&np->gref_tx_head);
+ BUG_ON((signed short)ref < 0);
+
+ mfn = pfn_to_mfn(page_to_pfn(frag->page));
+ gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
+ mfn, GNTMAP_readonly);
+
+ tx->gref = np->grant_tx_ref[id] = ref;
+ tx->offset = frag->page_offset;
+ tx->size = frag->size;
+ tx->flags = 0;
+ }
+
+ np->tx.req_prod_pvt = prod;
+}
static int network_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
unsigned short id;
struct netfront_info *np = netdev_priv(dev);
struct netif_tx_request *tx;
+ char *data = skb->data;
RING_IDX i;
grant_ref_t ref;
unsigned long mfn;
int notify;
-
- if (unlikely((((unsigned long)skb->data & ~PAGE_MASK) + skb->len) >=
- PAGE_SIZE)) {
- struct sk_buff *nskb;
- nskb = __dev_alloc_skb(skb->len, GFP_ATOMIC|__GFP_NOWARN);
- if (unlikely(nskb == NULL))
- goto drop;
- skb_put(nskb, skb->len);
- memcpy(nskb->data, skb->data, skb->len);
- /* Copy only the header fields we use in this driver. */
- nskb->dev = skb->dev;
- nskb->ip_summed = skb->ip_summed;
- nskb->proto_data_valid = skb->proto_data_valid;
- dev_kfree_skb(skb);
- skb = nskb;
+ int frags = skb_shinfo(skb)->nr_frags;
+ unsigned int offset = offset_in_page(data);
+ unsigned int len = skb_headlen(skb);
+
+ frags += (offset + len + PAGE_SIZE - 1) / PAGE_SIZE;
+ if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
+ printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
+ frags);
+ dump_stack();
+ goto drop;
}
spin_lock_irq(&np->tx_lock);
- if (unlikely(!netif_carrier_ok(dev))) {
+ if (unlikely(!netif_carrier_ok(dev) ||
+ (frags > 1 && !xennet_can_sg(dev)))) {
spin_unlock_irq(&np->tx_lock);
goto drop;
}
@@ -682,12 +755,12 @@ static int network_start_xmit(struct sk_
tx->id = id;
ref = gnttab_claim_grant_reference(&np->gref_tx_head);
BUG_ON((signed short)ref < 0);
- mfn = virt_to_mfn(skb->data);
+ mfn = virt_to_mfn(data);
gnttab_grant_foreign_access_ref(
ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
tx->gref = np->grant_tx_ref[id] = ref;
- tx->offset = (unsigned long)skb->data & ~PAGE_MASK;
- tx->size = skb->len;
+ tx->offset = offset;
+ tx->size = len;
tx->flags = 0;
if (skb->ip_summed == CHECKSUM_HW) /* local packet? */
@@ -696,14 +769,17 @@ static int network_start_xmit(struct sk_
tx->flags |= NETTXF_data_validated;
np->tx.req_prod_pvt = i + 1;
+
+ xennet_make_frags(skb, dev, tx);
+ tx->size = skb->len;
+
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
if (notify)
notify_remote_via_irq(np->irq);
network_tx_buf_gc(dev);
- if (RING_FULL(&np->tx) ||
- gnttab_empty_grant_references(&np->gref_tx_head))
+ if (!netfront_tx_slot_available(np))
netif_stop_queue(dev);
spin_unlock_irq(&np->tx_lock);
@@ -963,12 +1039,46 @@ static struct net_device_stats *network_
return &np->stats;
}
+static int xennet_change_mtu(struct net_device *dev, int mtu)
+{
+ int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN;
+
+ if (mtu > max)
+ return -EINVAL;
+ dev->mtu = mtu;
+ return 0;
+}
+
+static int xennet_set_sg(struct net_device *dev, u32 data)
+{
+ if (data) {
+ struct netfront_info *np = netdev_priv(dev);
+ int val;
+
+ if (xenbus_scanf(XBT_NULL, np->xbdev->otherend, "feature-sg",
+ "%d", &val) < 0)
+ val = 0;
+ if (!val)
+ return -ENOSYS;
+ } else if (dev->mtu > ETH_DATA_LEN)
+ dev->mtu = ETH_DATA_LEN;
+
+ return ethtool_op_set_sg(dev, data);
+}
+
+static void xennet_set_features(struct net_device *dev)
+{
+ xennet_set_sg(dev, 1);
+}
+
static void network_connect(struct net_device *dev)
{
struct netfront_info *np;
int i, requeue_idx;
struct netif_tx_request *tx;
struct sk_buff *skb;
+
+ xennet_set_features(dev);
np = netdev_priv(dev);
spin_lock_irq(&np->tx_lock);
@@ -1081,6 +1191,8 @@ static struct ethtool_ops network_ethtoo
{
.get_tx_csum = ethtool_op_get_tx_csum,
.set_tx_csum = ethtool_op_set_tx_csum,
+ .get_sg = ethtool_op_get_sg,
+ .set_sg = xennet_set_sg,
};
#ifdef CONFIG_SYSFS
@@ -1297,6 +1409,7 @@ static struct net_device * __devinit cre
netdev->poll = netif_poll;
netdev->set_multicast_list = network_set_multicast_list;
netdev->uninit = netif_uninit;
+ netdev->change_mtu = xennet_change_mtu;
netdev->weight = 64;
netdev->features = NETIF_F_IP_CSUM;
diff -r 50db8c95e65d -r aecdb4c52fa7 xen/include/public/io/ring.h
--- a/xen/include/public/io/ring.h Mon Jun 05 16:13:47 2006 +0100
+++ b/xen/include/public/io/ring.h Mon Jun 05 16:33:49 2006 +0100
@@ -151,11 +151,15 @@ typedef struct __name##_back_ring __name
#define RING_SIZE(_r) \
((_r)->nr_ents)
+/* Number of free requests (for use on front side only). */
+#define RING_FREE_REQUESTS(_r) \
+ (RING_SIZE(_r) - ((_r)->req_prod_pvt - (_r)->rsp_cons))
+
/* Test if there is an empty slot available on the front ring.
* (This is only meaningful from the front. )
*/
#define RING_FULL(_r) \
- (((_r)->req_prod_pvt - (_r)->rsp_cons) == RING_SIZE(_r))
+ (RING_FREE_REQUESTS(_r) == 0)
/* Test if there are outstanding messages to be processed on a ring. */
#define RING_HAS_UNCONSUMED_RESPONSES(_r) \
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