[PATCH net-next v2 3/4] net: use indirect call helpers for dst_mtu

From: Brian Vazquez
Date: Fri Dec 11 2020 - 18:36:25 EST


From: brianvv <brianvv@xxxxxxxxxx>

This patch avoids the indirect call for the common case:
ip6_mtu and ipv4_mtu

Signed-off-by: brianvv <brianvv@xxxxxxxxxx>
---
include/net/dst.h | 4 +++-
net/ipv4/route.c | 6 ++++--
net/ipv6/route.c | 6 ++++--
3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/include/net/dst.h b/include/net/dst.h
index 3932e9931f08..9f474a79ed7d 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -194,9 +194,11 @@ dst_feature(const struct dst_entry *dst, u32 feature)
return dst_metric(dst, RTAX_FEATURES) & feature;
}

+INDIRECT_CALLABLE_DECLARE(unsigned int ip6_mtu(const struct dst_entry *));
+INDIRECT_CALLABLE_DECLARE(unsigned int ipv4_mtu(const struct dst_entry *));
static inline u32 dst_mtu(const struct dst_entry *dst)
{
- return dst->ops->mtu(dst);
+ return INDIRECT_CALL_INET(dst->ops->mtu, ip6_mtu, ipv4_mtu, dst);
}

/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index e26652ff7059..4fac91f8bd6c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -135,7 +135,8 @@ static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;

static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
-static unsigned int ipv4_mtu(const struct dst_entry *dst);
+INDIRECT_CALLABLE_SCOPE
+unsigned int ipv4_mtu(const struct dst_entry *dst);
static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
static void ipv4_link_failure(struct sk_buff *skb);
static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
@@ -1311,7 +1312,7 @@ static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
return min(advmss, IPV4_MAX_PMTU - header_size);
}

-static unsigned int ipv4_mtu(const struct dst_entry *dst)
+INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
{
const struct rtable *rt = (const struct rtable *)dst;
unsigned int mtu = rt->rt_pmtu;
@@ -1333,6 +1334,7 @@ static unsigned int ipv4_mtu(const struct dst_entry *dst)

return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
}
+EXPORT_SYMBOL(ipv4_mtu);

static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
{
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 188e114b29b4..22caee290b6c 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -83,7 +83,8 @@ enum rt6_nud_state {

static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie);
static unsigned int ip6_default_advmss(const struct dst_entry *dst);
-static unsigned int ip6_mtu(const struct dst_entry *dst);
+INDIRECT_CALLABLE_SCOPE
+unsigned int ip6_mtu(const struct dst_entry *dst);
static struct dst_entry *ip6_negative_advice(struct dst_entry *);
static void ip6_dst_destroy(struct dst_entry *);
static void ip6_dst_ifdown(struct dst_entry *,
@@ -3089,7 +3090,7 @@ static unsigned int ip6_default_advmss(const struct dst_entry *dst)
return mtu;
}

-static unsigned int ip6_mtu(const struct dst_entry *dst)
+INDIRECT_CALLABLE_SCOPE unsigned int ip6_mtu(const struct dst_entry *dst)
{
struct inet6_dev *idev;
unsigned int mtu;
@@ -3111,6 +3112,7 @@ static unsigned int ip6_mtu(const struct dst_entry *dst)

return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
}
+EXPORT_SYMBOL(ip6_mtu);

/* MTU selection:
* 1. mtu on route is locked - use it
--
2.29.2.576.ga3fc446d84-goog