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net: gro: skb_gro_header helper function
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Introduce a simple helper function to replace a common pattern.
When accessing the GRO header, we fetch the pointer from frag0,
then test its validity and fetch it from the skb when necessary.

This leads to the pattern
skb_gro_header_fast -> skb_gro_header_hard -> skb_gro_header_slow
recurring many times throughout GRO code.

This patch replaces these patterns with a single inlined function
call, improving code readability.

Signed-off-by: Richard Gobert <richardbgobert@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220823071034.GA56142@debian
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Richard Gobert authored and Paolo Abeni committed Aug 25, 2022
1 parent 77a70f9 commit 35ffb66
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Showing 10 changed files with 45 additions and 69 deletions.
9 changes: 3 additions & 6 deletions drivers/net/geneve.c
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Original file line number Diff line number Diff line change
Expand Up @@ -503,12 +503,9 @@ static struct sk_buff *geneve_gro_receive(struct sock *sk,

off_gnv = skb_gro_offset(skb);
hlen = off_gnv + sizeof(*gh);
gh = skb_gro_header_fast(skb, off_gnv);
if (skb_gro_header_hard(skb, hlen)) {
gh = skb_gro_header_slow(skb, hlen, off_gnv);
if (unlikely(!gh))
goto out;
}
gh = skb_gro_header(skb, hlen, off_gnv);
if (unlikely(!gh))
goto out;

if (gh->ver != GENEVE_VER || gh->oam)
goto out;
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9 changes: 3 additions & 6 deletions drivers/net/vxlan/vxlan_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -713,12 +713,9 @@ static struct sk_buff *vxlan_gro_receive(struct sock *sk,

off_vx = skb_gro_offset(skb);
hlen = off_vx + sizeof(*vh);
vh = skb_gro_header_fast(skb, off_vx);
if (skb_gro_header_hard(skb, hlen)) {
vh = skb_gro_header_slow(skb, hlen, off_vx);
if (unlikely(!vh))
goto out;
}
vh = skb_gro_header(skb, hlen, off_vx);
if (unlikely(!vh))
goto out;

skb_gro_postpull_rcsum(skb, vh, sizeof(struct vxlanhdr));

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33 changes: 18 additions & 15 deletions include/net/gro.h
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Original file line number Diff line number Diff line change
Expand Up @@ -160,6 +160,17 @@ static inline void *skb_gro_header_slow(struct sk_buff *skb, unsigned int hlen,
return skb->data + offset;
}

static inline void *skb_gro_header(struct sk_buff *skb,
unsigned int hlen, unsigned int offset)
{
void *ptr;

ptr = skb_gro_header_fast(skb, offset);
if (skb_gro_header_hard(skb, hlen))
ptr = skb_gro_header_slow(skb, hlen, offset);
return ptr;
}

static inline void *skb_gro_network_header(struct sk_buff *skb)
{
return (NAPI_GRO_CB(skb)->frag0 ?: skb->data) +
Expand Down Expand Up @@ -301,12 +312,9 @@ static inline void *skb_gro_remcsum_process(struct sk_buff *skb, void *ptr,
return ptr;
}

ptr = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, off + plen)) {
ptr = skb_gro_header_slow(skb, off + plen, off);
if (!ptr)
return NULL;
}
ptr = skb_gro_header(skb, off + plen, off);
if (!ptr)
return NULL;

delta = remcsum_adjust(ptr + hdrlen, NAPI_GRO_CB(skb)->csum,
start, offset);
Expand All @@ -329,12 +337,9 @@ static inline void skb_gro_remcsum_cleanup(struct sk_buff *skb,
if (!grc->delta)
return;

ptr = skb_gro_header_fast(skb, grc->offset);
if (skb_gro_header_hard(skb, grc->offset + sizeof(u16))) {
ptr = skb_gro_header_slow(skb, plen, grc->offset);
if (!ptr)
return;
}
ptr = skb_gro_header(skb, plen, grc->offset);
if (!ptr)
return;

remcsum_unadjust((__sum16 *)ptr, grc->delta);
}
Expand Down Expand Up @@ -405,9 +410,7 @@ static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)

off = skb_gro_offset(skb);
hlen = off + sizeof(*uh);
uh = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, hlen))
uh = skb_gro_header_slow(skb, hlen, off);
uh = skb_gro_header(skb, hlen, off);

return uh;
}
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9 changes: 3 additions & 6 deletions net/8021q/vlan_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -467,12 +467,9 @@ static struct sk_buff *vlan_gro_receive(struct list_head *head,

off_vlan = skb_gro_offset(skb);
hlen = off_vlan + sizeof(*vhdr);
vhdr = skb_gro_header_fast(skb, off_vlan);
if (skb_gro_header_hard(skb, hlen)) {
vhdr = skb_gro_header_slow(skb, hlen, off_vlan);
if (unlikely(!vhdr))
goto out;
}
vhdr = skb_gro_header(skb, hlen, off_vlan);
if (unlikely(!vhdr))
goto out;

type = vhdr->h_vlan_encapsulated_proto;

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9 changes: 3 additions & 6 deletions net/ethernet/eth.c
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Original file line number Diff line number Diff line change
Expand Up @@ -414,12 +414,9 @@ struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)

off_eth = skb_gro_offset(skb);
hlen = off_eth + sizeof(*eh);
eh = skb_gro_header_fast(skb, off_eth);
if (skb_gro_header_hard(skb, hlen)) {
eh = skb_gro_header_slow(skb, hlen, off_eth);
if (unlikely(!eh))
goto out;
}
eh = skb_gro_header(skb, hlen, off_eth);
if (unlikely(!eh))
goto out;

flush = 0;

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9 changes: 3 additions & 6 deletions net/ipv4/af_inet.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1464,12 +1464,9 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb)

off = skb_gro_offset(skb);
hlen = off + sizeof(*iph);
iph = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, hlen)) {
iph = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!iph))
goto out;
}
iph = skb_gro_header(skb, hlen, off);
if (unlikely(!iph))
goto out;

proto = iph->protocol;

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9 changes: 3 additions & 6 deletions net/ipv4/fou.c
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Original file line number Diff line number Diff line change
Expand Up @@ -323,12 +323,9 @@ static struct sk_buff *gue_gro_receive(struct sock *sk,
off = skb_gro_offset(skb);
len = off + sizeof(*guehdr);

guehdr = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, len)) {
guehdr = skb_gro_header_slow(skb, len, off);
if (unlikely(!guehdr))
goto out;
}
guehdr = skb_gro_header(skb, len, off);
if (unlikely(!guehdr))
goto out;

switch (guehdr->version) {
case 0:
Expand Down
9 changes: 3 additions & 6 deletions net/ipv4/gre_offload.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -137,12 +137,9 @@ static struct sk_buff *gre_gro_receive(struct list_head *head,

off = skb_gro_offset(skb);
hlen = off + sizeof(*greh);
greh = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, hlen)) {
greh = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!greh))
goto out;
}
greh = skb_gro_header(skb, hlen, off);
if (unlikely(!greh))
goto out;

/* Only support version 0 and K (key), C (csum) flags. Note that
* although the support for the S (seq#) flag can be added easily
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9 changes: 3 additions & 6 deletions net/ipv4/tcp_offload.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -195,12 +195,9 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)

off = skb_gro_offset(skb);
hlen = off + sizeof(*th);
th = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, hlen)) {
th = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!th))
goto out;
}
th = skb_gro_header(skb, hlen, off);
if (unlikely(!th))
goto out;

thlen = th->doff * 4;
if (thlen < sizeof(*th))
Expand Down
9 changes: 3 additions & 6 deletions net/ipv6/ip6_offload.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -219,12 +219,9 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,

off = skb_gro_offset(skb);
hlen = off + sizeof(*iph);
iph = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, hlen)) {
iph = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!iph))
goto out;
}
iph = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!iph))
goto out;

skb_set_network_header(skb, off);
skb_gro_pull(skb, sizeof(*iph));
Expand Down

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