gso: Support partial splitting at the frag_list pointer
Since commit 8a29111c7 ("net: gro: allow to build full sized skb")
gro may build buffers with a frag_list. This can hurt forwarding
because most NICs can't offload such packets, they need to be
segmented in software. This patch splits buffers with a frag_list
at the frag_list pointer into buffers that can be TSO offloaded.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 1e329d4..7bf82a2 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3097,11 +3097,31 @@
sg = !!(features & NETIF_F_SG);
csum = !!can_checksum_protocol(features, proto);
- /* GSO partial only requires that we trim off any excess that
- * doesn't fit into an MSS sized block, so take care of that
- * now.
- */
- if (sg && csum && (features & NETIF_F_GSO_PARTIAL)) {
+ if (sg && csum && (mss != GSO_BY_FRAGS)) {
+ if (!(features & NETIF_F_GSO_PARTIAL)) {
+ struct sk_buff *iter;
+
+ if (!list_skb ||
+ !net_gso_ok(features, skb_shinfo(head_skb)->gso_type))
+ goto normal;
+
+ /* Split the buffer at the frag_list pointer.
+ * This is based on the assumption that all
+ * buffers in the chain excluding the last
+ * containing the same amount of data.
+ */
+ skb_walk_frags(head_skb, iter) {
+ if (skb_headlen(iter))
+ goto normal;
+
+ len -= iter->len;
+ }
+ }
+
+ /* GSO partial only requires that we trim off any excess that
+ * doesn't fit into an MSS sized block, so take care of that
+ * now.
+ */
partial_segs = len / mss;
if (partial_segs > 1)
mss *= partial_segs;
@@ -3109,6 +3129,7 @@
partial_segs = 0;
}
+normal:
headroom = skb_headroom(head_skb);
pos = skb_headlen(head_skb);
@@ -3300,21 +3321,29 @@
*/
segs->prev = tail;
- /* Update GSO info on first skb in partial sequence. */
if (partial_segs) {
+ struct sk_buff *iter;
int type = skb_shinfo(head_skb)->gso_type;
+ unsigned short gso_size = skb_shinfo(head_skb)->gso_size;
/* Update type to add partial and then remove dodgy if set */
- type |= SKB_GSO_PARTIAL;
+ type |= (features & NETIF_F_GSO_PARTIAL) / NETIF_F_GSO_PARTIAL * SKB_GSO_PARTIAL;
type &= ~SKB_GSO_DODGY;
/* Update GSO info and prepare to start updating headers on
* our way back down the stack of protocols.
*/
- skb_shinfo(segs)->gso_size = skb_shinfo(head_skb)->gso_size;
- skb_shinfo(segs)->gso_segs = partial_segs;
- skb_shinfo(segs)->gso_type = type;
- SKB_GSO_CB(segs)->data_offset = skb_headroom(segs) + doffset;
+ for (iter = segs; iter; iter = iter->next) {
+ skb_shinfo(iter)->gso_size = gso_size;
+ skb_shinfo(iter)->gso_segs = partial_segs;
+ skb_shinfo(iter)->gso_type = type;
+ SKB_GSO_CB(iter)->data_offset = skb_headroom(iter) + doffset;
+ }
+
+ if (tail->len - doffset <= gso_size)
+ skb_shinfo(tail)->gso_size = 0;
+ else if (tail != segs)
+ skb_shinfo(tail)->gso_segs = DIV_ROUND_UP(tail->len - doffset, gso_size);
}
/* Following permits correct backpressure, for protocols