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Message-ID: <20160823052030.GI3735@gauss.secunet.com>
Date: Tue, 23 Aug 2016 07:20:30 +0200
From: Steffen Klassert <steffen.klassert@...unet.com>
To: <netdev@...r.kernel.org>
CC: Eric Dumazet <eric.dumazet@...il.com>,
Alexander Duyck <alexander.h.duyck@...el.com>
Subject: [PATCH net-next v1] 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@...unet.com>
---
net/core/skbuff.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++-
net/ipv4/af_inet.c | 7 ++--
net/ipv4/gre_offload.c | 7 +++-
net/ipv4/tcp_offload.c | 3 ++
net/ipv4/udp_offload.c | 9 +++--
net/ipv6/ip6_offload.c | 6 +++-
6 files changed, 114 insertions(+), 7 deletions(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 3864b4b6..a614e9d 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3078,6 +3078,92 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
sg = !!(features & NETIF_F_SG);
csum = !!can_checksum_protocol(features, proto);
+ headroom = skb_headroom(head_skb);
+
+ if (list_skb && net_gso_ok(features, skb_shinfo(head_skb)->gso_type) &&
+ csum && sg && (mss != GSO_BY_FRAGS) &&
+ !(features & NETIF_F_GSO_PARTIAL)) {
+ unsigned int lskb_segs;
+ unsigned int delta_segs, delta_len, delta_truesize;
+ struct sk_buff *nskb;
+ delta_segs = delta_len = delta_truesize = 0;
+
+ segs = __alloc_skb(skb_headlen(head_skb) + headroom,
+ GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
+ NUMA_NO_NODE);
+ if (unlikely(!segs))
+ return ERR_PTR(-ENOMEM);
+
+ skb_reserve(segs, headroom);
+ skb_put(segs, skb_headlen(head_skb));
+ skb_copy_from_linear_data(head_skb, segs->data, segs->len);
+ copy_skb_header(segs, head_skb);
+
+ if (skb_shinfo(head_skb)->nr_frags) {
+ int i;
+
+ if (skb_orphan_frags(head_skb, GFP_ATOMIC))
+ goto err;
+
+ for (i = 0; i < skb_shinfo(head_skb)->nr_frags; i++) {
+ skb_shinfo(segs)->frags[i] = skb_shinfo(head_skb)->frags[i];
+ skb_frag_ref(head_skb, i);
+ }
+ skb_shinfo(segs)->nr_frags = i;
+ }
+
+ do {
+ nskb = skb_clone(list_skb, GFP_ATOMIC);
+ if (unlikely(!nskb))
+ goto err;
+
+ list_skb = list_skb->next;
+
+ if (!tail)
+ segs->next = nskb;
+ else
+ tail->next = nskb;
+
+ tail = nskb;
+
+ if (skb_cow_head(nskb, doffset + headroom))
+ goto err;
+
+ lskb_segs = nskb->len / mss;
+
+ skb_shinfo(nskb)->gso_size = mss;
+ skb_shinfo(nskb)->gso_type = skb_shinfo(head_skb)->gso_type;
+ skb_shinfo(nskb)->gso_segs = lskb_segs;
+
+
+ delta_segs += lskb_segs;
+ delta_len += nskb->len;
+ delta_truesize += nskb->truesize;
+
+ __skb_push(nskb, doffset);
+
+ skb_release_head_state(nskb);
+ __copy_skb_header(nskb, head_skb);
+
+ skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
+ skb_reset_mac_len(nskb);
+
+ skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
+ nskb->data - tnl_hlen,
+ doffset + tnl_hlen);
+
+ } while (list_skb);
+
+ skb_shinfo(segs)->gso_segs -= delta_segs;
+ segs->len = head_skb->len - delta_len;
+ segs->data_len = head_skb->data_len - delta_len;
+ segs->truesize += head_skb->data_len - delta_truesize;
+
+ segs->prev = tail;
+
+ goto out;
+ }
+
/* 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.
@@ -3090,7 +3176,6 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
partial_segs = 0;
}
- headroom = skb_headroom(head_skb);
pos = skb_headlen(head_skb);
do {
@@ -3307,6 +3392,8 @@ perform_csum_check:
swap(tail->destructor, head_skb->destructor);
swap(tail->sk, head_skb->sk);
}
+
+out:
return segs;
err:
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 55513e6..c814afa 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1195,7 +1195,7 @@ EXPORT_SYMBOL(inet_sk_rebuild_header);
struct sk_buff *inet_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
- bool udpfrag = false, fixedid = false, encap;
+ bool udpfrag = false, fixedid = false, gso_partial = false, encap;
struct sk_buff *segs = ERR_PTR(-EINVAL);
const struct net_offload *ops;
unsigned int offset = 0;
@@ -1248,6 +1248,9 @@ struct sk_buff *inet_gso_segment(struct sk_buff *skb,
if (IS_ERR_OR_NULL(segs))
goto out;
+ if (skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL)
+ gso_partial = true;
+
skb = segs;
do {
iph = (struct iphdr *)(skb_mac_header(skb) + nhoff);
@@ -1257,7 +1260,7 @@ struct sk_buff *inet_gso_segment(struct sk_buff *skb,
iph->frag_off |= htons(IP_MF);
offset += skb->len - nhoff - ihl;
tot_len = skb->len - nhoff;
- } else if (skb_is_gso(skb)) {
+ } else if (skb_is_gso(skb) && gso_partial) {
if (!fixedid) {
iph->id = htons(id);
id += skb_shinfo(skb)->gso_segs;
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index ecd1e09..cf82e28 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -24,7 +24,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
__be16 protocol = skb->protocol;
u16 mac_len = skb->mac_len;
int gre_offset, outer_hlen;
- bool need_csum, ufo;
+ bool need_csum, ufo, gso_partial;
if (!skb->encapsulation)
goto out;
@@ -69,6 +69,11 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
goto out;
}
+ if (skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL)
+ gso_partial = true;
+ else
+ gso_partial = false;
+
outer_hlen = skb_tnl_header_len(skb);
gre_offset = outer_hlen - tnl_hlen;
skb = segs;
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 5c59649..dddd227 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -107,6 +107,9 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
/* Only first segment might have ooo_okay set */
segs->ooo_okay = ooo_okay;
+ if (skb_is_gso(segs) && !(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL))
+ mss = (skb_tail_pointer(segs) - skb_transport_header(segs)) +
+ segs->data_len - thlen;
delta = htonl(oldlen + (thlen + mss));
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 81f253b..dfb6a2c 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -21,7 +21,7 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
__be16 new_protocol, bool is_ipv6)
{
int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
- bool remcsum, need_csum, offload_csum, ufo;
+ bool remcsum, need_csum, offload_csum, ufo, gso_partial;
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct udphdr *uh = udp_hdr(skb);
u16 mac_offset = skb->mac_header;
@@ -88,6 +88,11 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
goto out;
}
+ if (skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL)
+ gso_partial = true;
+ else
+ gso_partial = false;
+
outer_hlen = skb_tnl_header_len(skb);
udp_offset = outer_hlen - tnl_hlen;
skb = segs;
@@ -117,7 +122,7 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
* will be using a length value equal to only one MSS sized
* segment instead of the entire frame.
*/
- if (skb_is_gso(skb)) {
+ if (skb_is_gso(skb) && gso_partial) {
uh->len = htons(skb_shinfo(skb)->gso_size +
SKB_GSO_CB(skb)->data_offset +
skb->head - (unsigned char *)uh);
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index 22e90e5..0ec16ba 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -69,6 +69,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
int offset = 0;
bool encap, udpfrag;
int nhoff;
+ bool gso_partial = false;
skb_reset_network_header(skb);
nhoff = skb_network_header(skb) - skb_mac_header(skb);
@@ -101,9 +102,12 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
if (IS_ERR(segs))
goto out;
+ if (skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL)
+ gso_partial = true;
+
for (skb = segs; skb; skb = skb->next) {
ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
- if (skb_is_gso(skb))
+ if (skb_is_gso(skb) && gso_partial)
payload_len = skb_shinfo(skb)->gso_size +
SKB_GSO_CB(skb)->data_offset +
skb->head - (unsigned char *)(ipv6h + 1);
--
1.9.1
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