sunvnet: add scatter/gather support

This patch adds scatter/gather support to the sunvnet driver.

Signed-off-by: David L Stevens <david.stevens@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c
index 7a8da56..b6a5336 100644 (file)
--- a/drivers/net/ethernet/sun/sunvnet.c
+++ b/drivers/net/ethernet/sun/sunvnet.c
@@ -15,6 +15,7 @@
 #include <linux/ethtool.h>
 #include <linux/etherdevice.h>
 #include <linux/mutex.h>
+#include <linux/highmem.h>
 #include <linux/if_vlan.h>
 
 #if IS_ENABLED(CONFIG_IPV6)
@@ -978,11 +979,54 @@ static void vnet_clean_timer_expire(unsigned long port0)
                del_timer(&port->clean_timer);
 }
 
-static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, void **pstart,
-                                            int *plen)
+static inline int vnet_skb_map(struct ldc_channel *lp, struct sk_buff *skb,
+                              struct ldc_trans_cookie *cookies, int ncookies,
+                              unsigned int map_perm)
+{
+       int i, nc, err, blen;
+
+       /* header */
+       blen = skb_headlen(skb);
+       if (blen < ETH_ZLEN)
+               blen = ETH_ZLEN;
+       blen += VNET_PACKET_SKIP;
+       blen += 8 - (blen & 7);
+
+       err = ldc_map_single(lp, skb->data-VNET_PACKET_SKIP, blen, cookies,
+                            ncookies, map_perm);
+       if (err < 0)
+               return err;
+       nc = err;
+
+       for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+               skb_frag_t *f = &skb_shinfo(skb)->frags[i];
+               u8 *vaddr;
+
+               if (nc < ncookies) {
+                       vaddr = kmap_atomic(skb_frag_page(f));
+                       blen = skb_frag_size(f);
+                       blen += 8 - (blen & 7);
+                       err = ldc_map_single(lp, vaddr + f->page_offset,
+                                            blen, cookies + nc, ncookies - nc,
+                                            map_perm);
+                       kunmap_atomic(vaddr);
+               } else {
+                       err = -EMSGSIZE;
+               }
+
+               if (err < 0) {
+                       ldc_unmap(lp, cookies, nc);
+                       return err;
+               }
+               nc += err;
+       }
+       return nc;
+}
+
+static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, int ncookies)
 {
        struct sk_buff *nskb;
-       int len, pad;
+       int i, len, pad, docopy;
 
        len = skb->len;
        pad = 0;
@@ -992,14 +1036,25 @@ static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, void **pstart,
        }
        len += VNET_PACKET_SKIP;
        pad += 8 - (len & 7);
-       len += 8 - (len & 7);
 
+       /* make sure we have enough cookies and alignment in every frag */
+       docopy = skb_shinfo(skb)->nr_frags >= ncookies;
+       for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+               skb_frag_t *f = &skb_shinfo(skb)->frags[i];
+
+               docopy |= f->page_offset & 7;
+       }
        if (((unsigned long)skb->data & 7) != VNET_PACKET_SKIP ||
            skb_tailroom(skb) < pad ||
-           skb_headroom(skb) < VNET_PACKET_SKIP) {
+           skb_headroom(skb) < VNET_PACKET_SKIP || docopy) {
                int offset;
 
-               nskb = alloc_and_align_skb(skb->dev, skb->len);
+               len = skb->len > ETH_ZLEN ? skb->len : ETH_ZLEN;
+               nskb = alloc_and_align_skb(skb->dev, len);
+               if (nskb == NULL) {
+                       dev_kfree_skb(skb);
+                       return NULL;
+               }
                skb_reserve(nskb, VNET_PACKET_SKIP);
 
                nskb->protocol = skb->protocol;
@@ -1022,9 +1077,6 @@ static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, void **pstart,
                dev_kfree_skb(skb);
                skb = nskb;
        }
-
-       *pstart = skb->data - VNET_PACKET_SKIP;
-       *plen = len;
        return skb;
 }
 
@@ -1049,15 +1101,9 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
        unsigned int len;
        struct sk_buff *freeskbs = NULL;
        int i, err, txi;
-       void *start = NULL;
-       int nlen = 0;
        unsigned pending = 0;
        struct netdev_queue *txq;
 
-       skb = vnet_skb_shape(skb, &start, &nlen);
-       if (unlikely(!skb))
-               goto out_dropped;
-
        rcu_read_lock();
        port = __tx_port_find(vp, skb);
        if (unlikely(!port)) {
@@ -1097,6 +1143,13 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
                goto out_dropped;
        }
 
+       skb = vnet_skb_shape(skb, 2);
+
+       if (unlikely(!skb)) {
+               rcu_read_unlock();
+               goto out_dropped;
+       }
+
        dr = &port->vio.drings[VIO_DRIVER_TX_RING];
        i = skb_get_queue_mapping(skb);
        txq = netdev_get_tx_queue(dev, i);
@@ -1124,16 +1177,15 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
        if (len < ETH_ZLEN)
                len = ETH_ZLEN;
 
-       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));
+       err = vnet_skb_map(port->vio.lp, skb, port->tx_bufs[txi].cookies, 2,
+                          (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;
        }
+
+       port->tx_bufs[txi].skb = skb;
+       skb = NULL;
        port->tx_bufs[txi].ncookies = err;
 
        /* We don't rely on the ACKs to free the skb in vnet_start_xmit(),
@@ -1559,6 +1611,9 @@ static struct vnet *vnet_new(const u64 *local_mac)
        dev->ethtool_ops = &vnet_ethtool_ops;
        dev->watchdog_timeo = VNET_TX_TIMEOUT;
 
+       dev->hw_features = NETIF_F_SG;
+       dev->features = dev->hw_features;
+
        err = register_netdev(dev);
        if (err) {
                pr_err("Cannot register net device, aborting\n");