net: Support GRO/GSO fraglist chaining.

This patch adds the core functions to chain/unchain
GSO skbs at the frag_list pointer. This also adds
a new GSO type SKB_GSO_FRAGLIST and a is_flist
flag to napi_gro_cb which indicates that this
flow will be GROed by fraglist chaining.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index fcc76b8..20445f9 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2326,7 +2326,8 @@ struct napi_gro_cb {
        /* Number of gro_receive callbacks this packet already went through */
        u8 recursion_counter:4;
 
-       /* 1 bit hole */
+       /* GRO is done by frag_list pointer chaining. */
+       u8      is_flist:1;
 
        /* used to support CHECKSUM_COMPLETE for tunneling protocols */
        __wsum  csum;
@@ -2694,6 +2695,7 @@ struct net_device *dev_get_by_napi_id(unsigned int napi_id);
 int netdev_get_name(struct net *net, char *name, int ifindex);
 int dev_restart(struct net_device *dev);
 int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb);
+int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb);
 
 static inline unsigned int skb_gro_offset(const struct sk_buff *skb)
 {

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 23aaaf0..3d13a4b 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3535,6 +3535,8 @@ void skb_scrub_packet(struct sk_buff *skb, bool xnet);
 bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu);
 bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len);
 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
+struct sk_buff *skb_segment_list(struct sk_buff *skb, netdev_features_t features,
+                                unsigned int offset);
 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
 int skb_ensure_writable(struct sk_buff *skb, int write_len);
 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);

diff --git a/net/core/dev.c b/net/core/dev.c
index a3b154a..ce8900d 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3249,7 +3249,7 @@ struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
 
        segs = skb_mac_gso_segment(skb, features);
 
-       if (unlikely(skb_needs_check(skb, tx_path) && !IS_ERR(segs)))
+       if (segs != skb && unlikely(skb_needs_check(skb, tx_path) && !IS_ERR(segs)))
                skb_warn_bad_offload(skb);
 
        return segs;

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 48a7029..864cb9e 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3639,6 +3639,97 @@ static inline skb_frag_t skb_head_frag_to_page_desc(struct sk_buff *frag_skb)
        return head_frag;
 }
 
+struct sk_buff *skb_segment_list(struct sk_buff *skb,
+                                netdev_features_t features,
+                                unsigned int offset)
+{
+       struct sk_buff *list_skb = skb_shinfo(skb)->frag_list;
+       unsigned int tnl_hlen = skb_tnl_header_len(skb);
+       unsigned int delta_truesize = 0;
+       unsigned int delta_len = 0;
+       struct sk_buff *tail = NULL;
+       struct sk_buff *nskb;
+
+       skb_push(skb, -skb_network_offset(skb) + offset);
+
+       skb_shinfo(skb)->frag_list = NULL;
+
+       do {
+               nskb = list_skb;
+               list_skb = list_skb->next;
+
+               if (!tail)
+                       skb->next = nskb;
+               else
+                       tail->next = nskb;
+
+               tail = nskb;
+
+               delta_len += nskb->len;
+               delta_truesize += nskb->truesize;
+
+               skb_push(nskb, -skb_network_offset(nskb) + offset);
+
+                __copy_skb_header(nskb, skb);
+
+               skb_headers_offset_update(nskb, skb_headroom(nskb) - skb_headroom(skb));
+               skb_copy_from_linear_data_offset(skb, -tnl_hlen,
+                                                nskb->data - tnl_hlen,
+                                                offset + tnl_hlen);
+
+               if (skb_needs_linearize(nskb, features) &&
+                   __skb_linearize(nskb))
+                       goto err_linearize;
+
+       } while (list_skb);
+
+       skb->truesize = skb->truesize - delta_truesize;
+       skb->data_len = skb->data_len - delta_len;
+       skb->len = skb->len - delta_len;
+
+       skb_gso_reset(skb);
+
+       skb->prev = tail;
+
+       if (skb_needs_linearize(skb, features) &&
+           __skb_linearize(skb))
+               goto err_linearize;
+
+       skb_get(skb);
+
+       return skb;
+
+err_linearize:
+       kfree_skb_list(skb->next);
+       skb->next = NULL;
+       return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(skb_segment_list);
+
+int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
+{
+       if (unlikely(p->len + skb->len >= 65536))
+               return -E2BIG;
+
+       if (NAPI_GRO_CB(p)->last == p)
+               skb_shinfo(p)->frag_list = skb;
+       else
+               NAPI_GRO_CB(p)->last->next = skb;
+
+       skb_pull(skb, skb_gro_offset(skb));
+
+       NAPI_GRO_CB(p)->last = skb;
+       NAPI_GRO_CB(p)->count++;
+       p->data_len += skb->len;
+       p->truesize += skb->truesize;
+       p->len += skb->len;
+
+       NAPI_GRO_CB(skb)->same_flow = 1;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(skb_gro_receive_list);
+
 /**
  *     skb_segment - Perform protocol segmentation on skb.
  *     @head_skb: buffer to segment