Patchwork [1/2] net: Add skb_unclone() helper function.

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Submitter Pravin B Shelar
Date Jan. 24, 2013, 10:16 p.m.
Message ID <1359065787-1763-1-git-send-email-pshelar@nicira.com>
Download mbox | patch
Permalink /patch/215503/
State Changes Requested
Delegated to: David Miller
Headers show

Comments

Pravin B Shelar - Jan. 24, 2013, 10:16 p.m.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
---
 drivers/net/ppp/ppp_generic.c           |    3 +--
 include/linux/skbuff.h                  |   13 +++++++++++++
 net/ipv4/ah4.c                          |    3 +--
 net/ipv4/ip_fragment.c                  |    2 +-
 net/ipv4/tcp_output.c                   |    2 +-
 net/ipv4/xfrm4_input.c                  |    2 +-
 net/ipv4/xfrm4_mode_tunnel.c            |    3 +--
 net/ipv6/ah6.c                          |    3 +--
 net/ipv6/netfilter/nf_conntrack_reasm.c |    2 +-
 net/ipv6/reassembly.c                   |    2 +-
 net/ipv6/xfrm6_mode_tunnel.c            |    3 +--
 net/sched/act_ipt.c                     |    6 ++----
 net/sched/act_pedit.c                   |    3 +--
 13 files changed, 26 insertions(+), 21 deletions(-)
Eric Dumazet - Jan. 25, 2013, 1:13 a.m.
On Thu, 2013-01-24 at 14:16 -0800, Pravin B Shelar wrote:
> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>


>  
>  /**
> + *	skb_unclone - creates separate copy if skb is cloned.
> + */

A proper kernel doc comment is not really needed, or must be complete
 * @skb: ...
 * @pri: ...

> +static inline bool 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;

	return false;

> +}
> +

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=?ISO-8859-2?Q?Micha=B3_Miros=B3aw?= - Jan. 25, 2013, 1:21 a.m.
2013/1/24 Pravin B Shelar <pshelar@nicira.com>:
[...]
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -798,6 +798,19 @@ static inline int skb_cloned(const struct sk_buff *skb)
>  }
>
>  /**
> + *     skb_unclone - creates separate copy if skb is cloned.
> + */
> +static inline bool 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;
> +}

This should return int. pskb_expand_head() returns 0 or -ENOMEM.

[...]
> diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
> index ddee0a0..c1f00ef 100644
> --- a/net/ipv4/xfrm4_mode_tunnel.c
> +++ b/net/ipv4/xfrm4_mode_tunnel.c
> @@ -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 (skb_unclone(skb, GFP_ATOMIC))
>                 goto out;

And here return -ENOMEM is replaced with return -EINVAL because of this.

Best Regards,
Michał Mirosław
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Pravin B Shelar - Jan. 25, 2013, 1:36 a.m.
On Thu, Jan 24, 2013 at 5:21 PM, Michał Mirosław <mirqus@gmail.com> wrote:
> 2013/1/24 Pravin B Shelar <pshelar@nicira.com>:
> [...]
>> --- a/include/linux/skbuff.h
>> +++ b/include/linux/skbuff.h
>> @@ -798,6 +798,19 @@ static inline int skb_cloned(const struct sk_buff *skb)
>>  }
>>
>>  /**
>> + *     skb_unclone - creates separate copy if skb is cloned.
>> + */
>> +static inline bool 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;
>> +}
>
> This should return int. pskb_expand_head() returns 0 or -ENOMEM.
>
> [...]
>> diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
>> index ddee0a0..c1f00ef 100644
>> --- a/net/ipv4/xfrm4_mode_tunnel.c
>> +++ b/net/ipv4/xfrm4_mode_tunnel.c
>> @@ -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 (skb_unclone(skb, GFP_ATOMIC))
>>                 goto out;
>
> And here return -ENOMEM is replaced with return -EINVAL because of this.
>
ok, I will change skb_unclone return to int.

Thanks.
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Patch

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 0b2706a..4fd754e 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -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;
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 8b2256e..7c00664 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -798,6 +798,19 @@  static inline int skb_cloned(const struct sk_buff *skb)
 }
 
 /**
+ *	skb_unclone - creates separate copy if skb is cloned.
+ */
+static inline bool 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
  *
diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index a0d8392..396c823 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -317,8 +317,7 @@  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;
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index f55a4e6..411ef7c 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -594,7 +594,7 @@  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
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 667a6ad..0ecc187 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -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);
diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index 06814b6..1f12c8b 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -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... */
diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
index ddee0a0..c1f00ef 100644
--- a/net/ipv4/xfrm4_mode_tunnel.c
+++ b/net/ipv4/xfrm4_mode_tunnel.c
@@ -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 (skb_unclone(skb, GFP_ATOMIC))
 		goto out;
 
 	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index ecc35b9..afcf8ee 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -518,8 +518,7 @@  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;
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 3dacecc..4e941dc 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -369,7 +369,7 @@  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;
 	}
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index e5253ec..c9d5d3ddfc 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -406,7 +406,7 @@  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
diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
index 9f2095b..4b04f4e 100644
--- a/net/ipv6/xfrm6_mode_tunnel.c
+++ b/net/ipv6/xfrm6_mode_tunnel.c
@@ -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 (skb_unclone(skb, GFP_ATOMIC))
 		goto out;
 
 	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index 0fb9e3f..e0f6de6 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -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);
 
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index 0c3fadd..7ed78c9 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -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);