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net: Add skb_unclone() helper function.
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This function will be used in next GRE_GSO patch. This patch does
not change any functionality.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Eric Dumazet <edumazet@google.com>
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Pravin B Shelar authored and David S. Miller committed Feb 15, 2013
1 parent d887199 commit 14bbd6a
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Showing 13 changed files with 23 additions and 21 deletions.
3 changes: 1 addition & 2 deletions drivers/net/ppp/ppp_generic.c
Original file line number Diff line number Diff line change
Expand Up @@ -1805,8 +1805,7 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
/* the filter instructions are constructed assuming
a four-byte PPP header on each packet */
if (ppp->pass_filter || ppp->active_filter) {
if (skb_cloned(skb) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
if (skb_unclone(skb, GFP_ATOMIC))
goto err;

*skb_push(skb, 2) = 0;
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10 changes: 10 additions & 0 deletions include/linux/skbuff.h
Original file line number Diff line number Diff line change
Expand Up @@ -804,6 +804,16 @@ static inline int skb_cloned(const struct sk_buff *skb)
(atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
}

static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
{
might_sleep_if(pri & __GFP_WAIT);

if (skb_cloned(skb))
return pskb_expand_head(skb, 0, 0, pri);

return 0;
}

/**
* skb_header_cloned - is the header a clone
* @skb: buffer to check
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3 changes: 1 addition & 2 deletions net/ipv4/ah4.c
Original file line number Diff line number Diff line change
Expand Up @@ -321,8 +321,7 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)

/* We are going to _remove_ AH header to keep sockets happy,
* so... Later this can change. */
if (skb_cloned(skb) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
if (skb_unclone(skb, GFP_ATOMIC))
goto out;

skb->ip_summed = CHECKSUM_NONE;
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2 changes: 1 addition & 1 deletion net/ipv4/ip_fragment.c
Original file line number Diff line number Diff line change
Expand Up @@ -590,7 +590,7 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
goto out_oversize;

/* Head of list must not be cloned. */
if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
if (skb_unclone(head, GFP_ATOMIC))
goto out_nomem;

/* If the first fragment is fragmented itself, we split
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2 changes: 1 addition & 1 deletion net/ipv4/tcp_output.c
Original file line number Diff line number Diff line change
Expand Up @@ -1331,7 +1331,7 @@ static void __pskb_trim_head(struct sk_buff *skb, int len)
/* Remove acked data from a packet in the transmit queue. */
int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
{
if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
if (skb_unclone(skb, GFP_ATOMIC))
return -ENOMEM;

__pskb_trim_head(skb, len);
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2 changes: 1 addition & 1 deletion net/ipv4/xfrm4_input.c
Original file line number Diff line number Diff line change
Expand Up @@ -132,7 +132,7 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
* header and optional ESP marker bytes) and then modify the
* protocol to ESP, and then call into the transform receiver.
*/
if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
if (skb_unclone(skb, GFP_ATOMIC))
goto drop;

/* Now we can update and verify the packet length... */
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3 changes: 1 addition & 2 deletions net/ipv4/xfrm4_mode_tunnel.c
Original file line number Diff line number Diff line change
Expand Up @@ -142,8 +142,7 @@ static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
for_each_input_rcu(rcv_notify_handlers, handler)
handler->handler(skb);

if (skb_cloned(skb) &&
(err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
if (err = skb_unclone(skb, GFP_ATOMIC))
goto out;

if (x->props.flags & XFRM_STATE_DECAP_DSCP)
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3 changes: 1 addition & 2 deletions net/ipv6/ah6.c
Original file line number Diff line number Diff line change
Expand Up @@ -521,8 +521,7 @@ static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)

/* We are going to _remove_ AH header to keep sockets happy,
* so... Later this can change. */
if (skb_cloned(skb) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
if (skb_unclone(skb, GFP_ATOMIC))
goto out;

skb->ip_summed = CHECKSUM_NONE;
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2 changes: 1 addition & 1 deletion net/ipv6/netfilter/nf_conntrack_reasm.c
Original file line number Diff line number Diff line change
Expand Up @@ -368,7 +368,7 @@ nf_ct_frag6_reasm(struct frag_queue *fq, struct net_device *dev)
}

/* Head of list must not be cloned. */
if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) {
if (skb_unclone(head, GFP_ATOMIC)) {
pr_debug("skb is cloned but can't expand head");
goto out_oom;
}
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2 changes: 1 addition & 1 deletion net/ipv6/reassembly.c
Original file line number Diff line number Diff line change
Expand Up @@ -404,7 +404,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
goto out_oversize;

/* Head of list must not be cloned. */
if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
if (skb_unclone(head, GFP_ATOMIC))
goto out_oom;

/* If the first fragment is fragmented itself, we split
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3 changes: 1 addition & 2 deletions net/ipv6/xfrm6_mode_tunnel.c
Original file line number Diff line number Diff line change
Expand Up @@ -69,8 +69,7 @@ static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
goto out;

if (skb_cloned(skb) &&
(err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
if (err = skb_unclone(skb, GFP_ATOMIC))
goto out;

if (x->props.flags & XFRM_STATE_DECAP_DSCP)
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6 changes: 2 additions & 4 deletions net/sched/act_ipt.c
Original file line number Diff line number Diff line change
Expand Up @@ -207,10 +207,8 @@ static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
struct tcf_ipt *ipt = a->priv;
struct xt_action_param par;

if (skb_cloned(skb)) {
if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
return TC_ACT_UNSPEC;
}
if (skb_unclone(skb, GFP_ATOMIC))
return TC_ACT_UNSPEC;

spin_lock(&ipt->tcf_lock);

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3 changes: 1 addition & 2 deletions net/sched/act_pedit.c
Original file line number Diff line number Diff line change
Expand Up @@ -131,8 +131,7 @@ static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
int i, munged = 0;
unsigned int off;

if (skb_cloned(skb) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
if (skb_unclone(skb, GFP_ATOMIC))
return p->tcf_action;

off = skb_network_offset(skb);
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