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net: move make_writable helper into common code
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note that skb_make_writable already exists in net/netfilter/core.c
but does something slightly different.

Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jiri Pirko authored and David S. Miller committed Nov 21, 2014
1 parent 15255a4 commit e219512
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Showing 3 changed files with 27 additions and 25 deletions.
1 change: 1 addition & 0 deletions include/linux/skbuff.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2678,6 +2678,7 @@ void skb_scrub_packet(struct sk_buff *skb, bool xnet);
unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
int skb_ensure_writable(struct sk_buff *skb, int write_len);

struct skb_checksum_ops {
__wsum (*update)(const void *mem, int len, __wsum wsum);
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12 changes: 12 additions & 0 deletions net/core/skbuff.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4151,6 +4151,18 @@ struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
}
EXPORT_SYMBOL(skb_vlan_untag);

int skb_ensure_writable(struct sk_buff *skb, int write_len)
{
if (!pskb_may_pull(skb, write_len))
return -ENOMEM;

if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
return 0;

return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
}
EXPORT_SYMBOL(skb_ensure_writable);

/**
* alloc_skb_with_frags - allocate skb with page frags
*
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39 changes: 14 additions & 25 deletions net/openvswitch/actions.c
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Original file line number Diff line number Diff line change
Expand Up @@ -119,17 +119,6 @@ static bool is_flow_key_valid(const struct sw_flow_key *key)
return !!key->eth.type;
}

static int make_writable(struct sk_buff *skb, int write_len)
{
if (!pskb_may_pull(skb, write_len))
return -ENOMEM;

if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
return 0;

return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
}

static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
const struct ovs_action_push_mpls *mpls)
{
Expand Down Expand Up @@ -171,7 +160,7 @@ static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
struct ethhdr *hdr;
int err;

err = make_writable(skb, skb->mac_len + MPLS_HLEN);
err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
if (unlikely(err))
return err;

Expand Down Expand Up @@ -201,7 +190,7 @@ static int set_mpls(struct sk_buff *skb, struct sw_flow_key *key,
__be32 *stack;
int err;

err = make_writable(skb, skb->mac_len + MPLS_HLEN);
err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
if (unlikely(err))
return err;

Expand All @@ -223,7 +212,7 @@ static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
struct vlan_hdr *vhdr;
int err;

err = make_writable(skb, VLAN_ETH_HLEN);
err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
if (unlikely(err))
return err;

Expand Down Expand Up @@ -310,7 +299,7 @@ static int set_eth_addr(struct sk_buff *skb, struct sw_flow_key *key,
const struct ovs_key_ethernet *eth_key)
{
int err;
err = make_writable(skb, ETH_HLEN);
err = skb_ensure_writable(skb, ETH_HLEN);
if (unlikely(err))
return err;

Expand Down Expand Up @@ -412,8 +401,8 @@ static int set_ipv4(struct sk_buff *skb, struct sw_flow_key *key,
struct iphdr *nh;
int err;

err = make_writable(skb, skb_network_offset(skb) +
sizeof(struct iphdr));
err = skb_ensure_writable(skb, skb_network_offset(skb) +
sizeof(struct iphdr));
if (unlikely(err))
return err;

Expand Down Expand Up @@ -450,8 +439,8 @@ static int set_ipv6(struct sk_buff *skb, struct sw_flow_key *key,
__be32 *saddr;
__be32 *daddr;

err = make_writable(skb, skb_network_offset(skb) +
sizeof(struct ipv6hdr));
err = skb_ensure_writable(skb, skb_network_offset(skb) +
sizeof(struct ipv6hdr));
if (unlikely(err))
return err;

Expand Down Expand Up @@ -493,7 +482,7 @@ static int set_ipv6(struct sk_buff *skb, struct sw_flow_key *key,
return 0;
}

/* Must follow make_writable() since that can move the skb data. */
/* Must follow skb_ensure_writable() since that can move the skb data. */
static void set_tp_port(struct sk_buff *skb, __be16 *port,
__be16 new_port, __sum16 *check)
{
Expand Down Expand Up @@ -523,8 +512,8 @@ static int set_udp(struct sk_buff *skb, struct sw_flow_key *key,
struct udphdr *uh;
int err;

err = make_writable(skb, skb_transport_offset(skb) +
sizeof(struct udphdr));
err = skb_ensure_writable(skb, skb_transport_offset(skb) +
sizeof(struct udphdr));
if (unlikely(err))
return err;

Expand All @@ -548,8 +537,8 @@ static int set_tcp(struct sk_buff *skb, struct sw_flow_key *key,
struct tcphdr *th;
int err;

err = make_writable(skb, skb_transport_offset(skb) +
sizeof(struct tcphdr));
err = skb_ensure_writable(skb, skb_transport_offset(skb) +
sizeof(struct tcphdr));
if (unlikely(err))
return err;

Expand All @@ -574,7 +563,7 @@ static int set_sctp(struct sk_buff *skb, struct sw_flow_key *key,
int err;
unsigned int sctphoff = skb_transport_offset(skb);

err = make_writable(skb, sctphoff + sizeof(struct sctphdr));
err = skb_ensure_writable(skb, sctphoff + sizeof(struct sctphdr));
if (unlikely(err))
return err;

Expand Down

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