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Date: Wed, 12 Jun 2013 22:40:11 +1000
From: Dave Wiltshire <david.wiltshire@....com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
nsujir@...adcom.com, mchan@...adcom.com, rmody@...cade.com,
jcliburn@...il.com, chris.snook@...il.com,
jeffrey.t.kirsher@...el.com, bruce.w.allan@...el.com,
alexander.h.duyck@...el.com, cooldavid@...ldavid.org,
linux-driver@...gic.com, linux-wimax@...el.com,
wimax@...uxwimax.org, linux-wireless@...r.kernel.org,
viro@...iv.linux.org.uk, eparis@...hat.com, edumazet@...gle.com,
dev@...nvswitch.org, jhs@...atatu.com,
Dave Wiltshire <david.wiltshire@....com>
Subject: [PATCH 3/3] skbuff: Added new helper function skb_cow_clone_head.
In a few different drivers there is a check of (skb_cloned &&
!skb_clone_writable) before then using pskb_expand_head to copy the skb
if that is required. There are already some skb_cow_* functions for
other conditions, so added this one and changed the call sites.
Signed-off-by: Dave Wiltshire <david.wiltshire@....com>
---
include/linux/skbuff.h | 14 ++++++++++++++
net/core/dev.c | 8 ++------
net/openvswitch/actions.c | 22 +++++++---------------
net/sched/act_csum.c | 8 ++------
net/sched/act_nat.c | 18 +++++-------------
5 files changed, 30 insertions(+), 40 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a7393ad..7d18541 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2154,6 +2154,20 @@ static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
}
/**
+ * skb_cow_clone_head
+ * @skb: buffer to cow
+ * @len: length up to which to write
+ *
+ * This function is identical to skb_cow and sb_cow_head except that we
+ * replace the skb_cloned check by skb_cloned && !skb_clone_writable.
+ *
+ */
+static inline int skb_cow_clone_head(struct sk_buff *skb, unsigned int len)
+{
+ return __skb_cow(skb, 0, skb_cloned(skb) && !skb_clone_writable(skb, len));
+}
+
+/**
* skb_padto - pad an skbuff up to a minimal size
* @skb: buffer to pad
* @len: minimal length
diff --git a/net/core/dev.c b/net/core/dev.c
index fa007db..1fb1cf5 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2222,12 +2222,8 @@ int skb_checksum_help(struct sk_buff *skb)
offset += skb->csum_offset;
BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb));
- if (skb_cloned(skb) &&
- !skb_clone_writable(skb, offset + sizeof(__sum16))) {
- ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
- if (ret)
- goto out;
- }
+ if (skb_cow_clone_head(skb, offset + sizeof(__sum16)))
+ goto out;
*(__sum16 *)(skb->data + offset) = csum_fold(csum);
out_set_summed:
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 894b6cb..3d3a9d0 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -38,21 +38,13 @@
static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
const struct nlattr *attr, int len, bool keep_skb);
-static int make_writable(struct sk_buff *skb, int write_len)
-{
- if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
- return 0;
-
- return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
-}
-
/* remove VLAN header from packet and update csum accordingly. */
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_cow_clone_head(skb, VLAN_ETH_HLEN);
if (unlikely(err))
return err;
@@ -126,7 +118,7 @@ static int set_eth_addr(struct sk_buff *skb,
const struct ovs_key_ethernet *eth_key)
{
int err;
- err = make_writable(skb, ETH_HLEN);
+ err = skb_cow_clone_head(skb, ETH_HLEN);
if (unlikely(err))
return err;
@@ -221,7 +213,7 @@ static int set_ipv4(struct sk_buff *skb, const struct ovs_key_ipv4 *ipv4_key)
struct iphdr *nh;
int err;
- err = make_writable(skb, skb_network_offset(skb) +
+ err = skb_cow_clone_head(skb, skb_network_offset(skb) +
sizeof(struct iphdr));
if (unlikely(err))
return err;
@@ -250,7 +242,7 @@ static int set_ipv6(struct sk_buff *skb, const struct ovs_key_ipv6 *ipv6_key)
__be32 *saddr;
__be32 *daddr;
- err = make_writable(skb, skb_network_offset(skb) +
+ err = skb_cow_clone_head(skb, skb_network_offset(skb) +
sizeof(struct ipv6hdr));
if (unlikely(err))
return err;
@@ -284,7 +276,7 @@ static int set_ipv6(struct sk_buff *skb, const struct ovs_key_ipv6 *ipv6_key)
return 0;
}
-/* Must follow make_writable() since that can move the skb data. */
+/* Must follow skb_cow_clone_head() since that can move the skb data. */
static void set_tp_port(struct sk_buff *skb, __be16 *port,
__be16 new_port, __sum16 *check)
{
@@ -313,7 +305,7 @@ static int set_udp(struct sk_buff *skb, const struct ovs_key_udp *udp_port_key)
struct udphdr *uh;
int err;
- err = make_writable(skb, skb_transport_offset(skb) +
+ err = skb_cow_clone_head(skb, skb_transport_offset(skb) +
sizeof(struct udphdr));
if (unlikely(err))
return err;
@@ -333,7 +325,7 @@ static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
struct tcphdr *th;
int err;
- err = make_writable(skb, skb_transport_offset(skb) +
+ err = skb_cow_clone_head(skb, skb_transport_offset(skb) +
sizeof(struct tcphdr));
if (unlikely(err))
return err;
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index 3a4c0ca..e7ff098 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -122,9 +122,7 @@ static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
int hl = ihl + jhl;
if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
- (skb_cloned(skb) &&
- !skb_clone_writable(skb, hl + ntkoff) &&
- pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+ skb_cow_clone_head(skb, hl + ntkoff))
return NULL;
else
return (void *)(skb_network_header(skb) + ihl);
@@ -382,9 +380,7 @@ static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
}
if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
- if (skb_cloned(skb) &&
- !skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
- pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+ if (skb_cow_clone_head(skb, sizeof(*iph) + ntkoff))
goto fail;
ip_send_check(ip_hdr(skb));
diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index 876f0ef..2b5b89c 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -144,9 +144,7 @@ static int tcf_nat(struct sk_buff *skb, const struct tc_action *a,
addr = iph->daddr;
if (!((old_addr ^ addr) & mask)) {
- if (skb_cloned(skb) &&
- !skb_clone_writable(skb, sizeof(*iph) + noff) &&
- pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+ if (skb_cow_clone_head(skb, sizeof(*iph) + noff))
goto drop;
new_addr &= mask;
@@ -174,9 +172,7 @@ static int tcf_nat(struct sk_buff *skb, const struct tc_action *a,
struct tcphdr *tcph;
if (!pskb_may_pull(skb, ihl + sizeof(*tcph) + noff) ||
- (skb_cloned(skb) &&
- !skb_clone_writable(skb, ihl + sizeof(*tcph) + noff) &&
- pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+ skb_cow_clone_head(skb, ihl + sizeof(*tcph) + noff))
goto drop;
tcph = (void *)(skb_network_header(skb) + ihl);
@@ -188,9 +184,7 @@ static int tcf_nat(struct sk_buff *skb, const struct tc_action *a,
struct udphdr *udph;
if (!pskb_may_pull(skb, ihl + sizeof(*udph) + noff) ||
- (skb_cloned(skb) &&
- !skb_clone_writable(skb, ihl + sizeof(*udph) + noff) &&
- pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+ skb_cow_clone_head(skb, ihl + sizeof(*udph) + noff))
goto drop;
udph = (void *)(skb_network_header(skb) + ihl);
@@ -230,10 +224,8 @@ static int tcf_nat(struct sk_buff *skb, const struct tc_action *a,
if ((old_addr ^ addr) & mask)
break;
- if (skb_cloned(skb) &&
- !skb_clone_writable(skb, ihl + sizeof(*icmph) +
- sizeof(*iph) + noff) &&
- pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+ if (skb_cow_clone_head(skb, ihl + sizeof(*icmph) +
+ sizeof(*iph) + noff))
goto drop;
icmph = (void *)(skb_network_header(skb) + ihl);
--
1.7.10.4
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