[PATCH] net: ipv4: inlining ip_send_check()

From: Christophe Leroy
Date: Tue Aug 18 2015 - 08:14:48 EST


ip_send_check() is a function that does nothing but calling
ip_fast_csum() after having zeroed iph->check

We get (on PPC) a quite long function for just that, as it requires
setting the stack frame, saving volatile regs, restoring them after
the call, etc ...

c02d3e3c <ip_send_check>:
c02d3e3c: 7c 08 02 a6 mflr r0
c02d3e40: 94 21 ff f0 stwu r1,-16(r1)
c02d3e44: 39 20 00 00 li r9,0
c02d3e48: 93 e1 00 0c stw r31,12(r1)
c02d3e4c: 90 01 00 14 stw r0,20(r1)
c02d3e50: b1 23 00 0a sth r9,10(r3)
c02d3e54: 88 83 00 00 lbz r4,0(r3)
c02d3e58: 7c 7f 1b 78 mr r31,r3
c02d3e5c: 54 84 07 3e clrlwi r4,r4,28
c02d3e60: 4b d3 ab 7d bl c000e9dc <ip_fast_csum>
c02d3e64: b0 7f 00 0a sth r3,10(r31)
c02d3e68: 80 01 00 14 lwz r0,20(r1)
c02d3e6c: 83 e1 00 0c lwz r31,12(r1)
c02d3e70: 7c 08 03 a6 mtlr r0
c02d3e74: 38 21 00 10 addi r1,r1,16
c02d3e78: 4e 80 00 20 blr

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
include/net/ip.h | 9 ++++++++-
net/ipv4/ip_output.c | 8 --------
2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/include/net/ip.h b/include/net/ip.h
index c0c26c3..b88d592 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -32,6 +32,7 @@
#include <net/snmp.h>
#include <net/flow.h>
#include <net/flow_keys.h>
+#include <net/checksum.h>

struct sock;

@@ -110,7 +111,13 @@ int ip_output(struct sock *sk, struct sk_buff *skb);
int ip_mc_output(struct sock *sk, struct sk_buff *skb);
int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
int ip_do_nat(struct sk_buff *skb);
-void ip_send_check(struct iphdr *ip);
+/* Generate a checksum for an outgoing IP datagram. */
+static inline void ip_send_check(struct iphdr *iph)
+{
+ iph->check = 0;
+ iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
+}
+
int __ip_local_out(struct sk_buff *skb);
int ip_local_out_sk(struct sock *sk, struct sk_buff *skb);
static inline int ip_local_out(struct sk_buff *skb)
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 357c2a9..fa054cf 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -83,14 +83,6 @@
int sysctl_ip_default_ttl __read_mostly = IPDEFTTL;
EXPORT_SYMBOL(sysctl_ip_default_ttl);

-/* Generate a checksum for an outgoing IP datagram. */
-void ip_send_check(struct iphdr *iph)
-{
- iph->check = 0;
- iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
-}
-EXPORT_SYMBOL(ip_send_check);
-
int __ip_local_out(struct sk_buff *skb)
{
struct iphdr *iph = ip_hdr(skb);
--
2.1.0
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