[PATCH net-next 1/1] net: neighbour: Simplify ifdefs around neigh_app_ns()

[PATCH net-next 1/1] net: neighbour: Simplify ifdefs around neigh_app_ns()

[Tim Gardner]

Drop a couple of ifdef/endif pairs by moving the ifdef
surrounding neigh_app_ns() to the interior of neigh_app_ns().

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---

This is an admittedly trivial change. I stumbled on it while trying to figure
out why Ubuntu doesn't have CONFIG_ARPD enabled.

 net/core/neighbour.c |    4 ++--
 net/ipv4/arp.c       |    2 --
 net/ipv6/ndisc.c     |    2 --
 3 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 60533db..049dd9e 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2759,13 +2759,13 @@ errout:
 		rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
 }
 
-#ifdef CONFIG_ARPD
 void neigh_app_ns(struct neighbour *n)
 {
+#ifdef CONFIG_ARPD
 	__neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
+#endif /* CONFIG_ARPD */
 }
 EXPORT_SYMBOL(neigh_app_ns);
-#endif /* CONFIG_ARPD */
 
 #ifdef CONFIG_SYSCTL
 static int zero;
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 4429b01..7808093 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -368,9 +368,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
 	} else {
 		probes -= neigh->parms->app_probes;
 		if (probes < 0) {
-#ifdef CONFIG_ARPD
 			neigh_app_ns(neigh);
-#endif
 			return;
 		}
 	}
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 04d31c2..d5693ad 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -663,9 +663,7 @@ static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
 		}
 		ndisc_send_ns(dev, neigh, target, target, saddr);
 	} else if ((probes -= neigh->parms->app_probes) < 0) {
-#ifdef CONFIG_ARPD
 		neigh_app_ns(neigh);
-#endif
 	} else {
 		addrconf_addr_solict_mult(target, &mcaddr);
 		ndisc_send_ns(dev, NULL, target, &mcaddr, saddr);
-- 
1.7.9.5

Re: [PATCH net-next 1/1] net: neighbour: Simplify ifdefs around neigh_app_ns()

[Joe Perches]

On Wed, 2013-08-28 at 12:24 -0600, Tim Gardner wrote:
> Drop a couple of ifdef/endif pairs by moving the ifdef
> surrounding neigh_app_ns() to the interior of neigh_app_ns().
[]
> This is an admittedly trivial change. I stumbled on it while trying to figure
> out why Ubuntu doesn't have CONFIG_ARPD enabled.

I'd be more inclined to make neigh_app_ns static inline
in the .h file and remove the EXPORT_SYMBOL

> diff --git a/net/core/neighbour.c b/net/core/neighbour.c
> index 60533db..049dd9e 100644
> --- a/net/core/neighbour.c
> +++ b/net/core/neighbour.c
> @@ -2759,13 +2759,13 @@ errout:
>  		rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
>  }
>  
> -#ifdef CONFIG_ARPD
>  void neigh_app_ns(struct neighbour *n)
>  {
> +#ifdef CONFIG_ARPD
>  	__neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
> +#endif /* CONFIG_ARPD */
>  }
>  EXPORT_SYMBOL(neigh_app_ns);
> -#endif /* CONFIG_ARPD */
>  
>  #ifdef CONFIG_SYSCTL
>  static int zero;
> diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
> index 4429b01..7808093 100644
> --- a/net/ipv4/arp.c
> +++ b/net/ipv4/arp.c
> @@ -368,9 +368,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
>  	} else {
>  		probes -= neigh->parms->app_probes;
>  		if (probes < 0) {
> -#ifdef CONFIG_ARPD
>  			neigh_app_ns(neigh);
> -#endif
>  			return;
>  		}
>  	}
> diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
> index 04d31c2..d5693ad 100644
> --- a/net/ipv6/ndisc.c
> +++ b/net/ipv6/ndisc.c
> @@ -663,9 +663,7 @@ static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
>  		}
>  		ndisc_send_ns(dev, neigh, target, target, saddr);
>  	} else if ((probes -= neigh->parms->app_probes) < 0) {
> -#ifdef CONFIG_ARPD
>  		neigh_app_ns(neigh);
> -#endif
>  	} else {
>  		addrconf_addr_solict_mult(target, &mcaddr);
>  		ndisc_send_ns(dev, NULL, target, &mcaddr, saddr);

Re: [PATCH net-next 1/1] net: neighbour: Simplify ifdefs around neigh_app_ns()

[Tim Gardner]

On 08/28/2013 12:51 PM, Joe Perches wrote:
> On Wed, 2013-08-28 at 12:24 -0600, Tim Gardner wrote:
>> Drop a couple of ifdef/endif pairs by moving the ifdef
>> surrounding neigh_app_ns() to the interior of neigh_app_ns().
> []
>> This is an admittedly trivial change. I stumbled on it while trying to figure
>> out why Ubuntu doesn't have CONFIG_ARPD enabled.
> 
> I'd be more inclined to make neigh_app_ns static inline
> in the .h file and remove the EXPORT_SYMBOL
> 

I thought about that as well, but then you'd have to extern
__neigh_notify(), which is currently a static function and large enough
to not really be suitable for inlining. Seems like unnecessary churn to me.

rtg
-- 
Tim Gardner tim.gardner@canonical.com

Re: [PATCH net-next 1/1] net: neighbour: Simplify ifdefs around neigh_app_ns()

[Eric W. Biederman]

Tim Gardner <tim.gardner@canonical.com> writes:

> Drop a couple of ifdef/endif pairs by moving the ifdef
> surrounding neigh_app_ns() to the interior of neigh_app_ns().

Can we please just remove the CONFIG_ARPD option entirely.

There really is no savings to keeping this option configurable and the
option only removes a netlink notification.

> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
> Cc: James Morris <jmorris@namei.org>
> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
> Cc: Patrick McHardy <kaber@trash.net>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Gao feng <gaofeng@cn.fujitsu.com>
> Cc: Joe Perches <joe@perches.com>
> Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
> ---
>
> This is an admittedly trivial change. I stumbled on it while trying to figure
> out why Ubuntu doesn't have CONFIG_ARPD enabled.
>
>  net/core/neighbour.c |    4 ++--
>  net/ipv4/arp.c       |    2 --
>  net/ipv6/ndisc.c     |    2 --
>  3 files changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/net/core/neighbour.c b/net/core/neighbour.c
> index 60533db..049dd9e 100644
> --- a/net/core/neighbour.c
> +++ b/net/core/neighbour.c
> @@ -2759,13 +2759,13 @@ errout:
>  		rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
>  }
>  
> -#ifdef CONFIG_ARPD
>  void neigh_app_ns(struct neighbour *n)
>  {
> +#ifdef CONFIG_ARPD
>  	__neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
> +#endif /* CONFIG_ARPD */
>  }
>  EXPORT_SYMBOL(neigh_app_ns);
> -#endif /* CONFIG_ARPD */
>  
>  #ifdef CONFIG_SYSCTL
>  static int zero;
> diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
> index 4429b01..7808093 100644
> --- a/net/ipv4/arp.c
> +++ b/net/ipv4/arp.c
> @@ -368,9 +368,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
>  	} else {
>  		probes -= neigh->parms->app_probes;
>  		if (probes < 0) {
> -#ifdef CONFIG_ARPD
>  			neigh_app_ns(neigh);
> -#endif
>  			return;
>  		}
>  	}
> diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
> index 04d31c2..d5693ad 100644
> --- a/net/ipv6/ndisc.c
> +++ b/net/ipv6/ndisc.c
> @@ -663,9 +663,7 @@ static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
>  		}
>  		ndisc_send_ns(dev, neigh, target, target, saddr);
>  	} else if ((probes -= neigh->parms->app_probes) < 0) {
> -#ifdef CONFIG_ARPD
>  		neigh_app_ns(neigh);
> -#endif
>  	} else {
>  		addrconf_addr_solict_mult(target, &mcaddr);
>  		ndisc_send_ns(dev, NULL, target, &mcaddr, saddr);

Re: [PATCH net-next 1/1] net: neighbour: Simplify ifdefs around neigh_app_ns()

[Joe Perches]

On Wed, 2013-08-28 at 13:09 -0600, Tim Gardner wrote:
> On 08/28/2013 12:51 PM, Joe Perches wrote:
> > On Wed, 2013-08-28 at 12:24 -0600, Tim Gardner wrote:
> >> Drop a couple of ifdef/endif pairs by moving the ifdef
> >> surrounding neigh_app_ns() to the interior of neigh_app_ns().
> > []
> >> This is an admittedly trivial change. I stumbled on it while trying to figure
> >> out why Ubuntu doesn't have CONFIG_ARPD enabled.

> > I'd be more inclined to make neigh_app_ns static inline
> > in the .h file and remove the EXPORT_SYMBOL

> I thought about that as well, but then you'd have to extern
> __neigh_notify(), which is currently a static function and large enough
> to not really be suitable for inlining. Seems like unnecessary churn to me.

Hi Tim.

As is, this makes the call to neight_app_ns
impossible to optimize away.

Perhaps this:

(this does add a possibly unused neigh_notify as a global symbol)

Rename __neigh_notify to neigh_notify and make public
Add static inline neigh_app_ns
Remove #ifdefs around use of neigh_app_ns

---

Compile tested only

 include/net/neighbour.h | 10 +++++++++-
 net/core/neighbour.c    | 15 +++------------
 net/ipv4/arp.c          |  2 --
 net/ipv6/ndisc.c        |  2 --
 4 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 536501a..a08b0a7 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -249,7 +249,15 @@ static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
 	return read_pnet(&pneigh->net);
 }
 
-void neigh_app_ns(struct neighbour *n);
+void neigh_notify(struct neighbour *n, int type, int flags);
+
+static inline void neigh_app_ns(struct neighbour *n)
+{
+#ifdef CONFIG_ARPD
+	neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
+#endif
+}
+
 void neigh_for_each(struct neigh_table *tbl,
 		    void (*cb)(struct neighbour *, void *), void *cookie);
 void __neigh_for_each_release(struct neigh_table *tbl,
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 60533db..6ec5f86 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -50,7 +50,6 @@ do {						\
 #define PNEIGH_HASHMASK		0xF
 
 static void neigh_timer_handler(unsigned long arg);
-static void __neigh_notify(struct neighbour *n, int type, int flags);
 static void neigh_update_notify(struct neighbour *neigh);
 static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 
@@ -103,7 +102,7 @@ static void neigh_cleanup_and_release(struct neighbour *neigh)
 	if (neigh->parms->neigh_cleanup)
 		neigh->parms->neigh_cleanup(neigh);
 
-	__neigh_notify(neigh, RTM_DELNEIGH, 0);
+	neigh_notify(neigh, RTM_DELNEIGH, 0);
 	neigh_release(neigh);
 }
 
@@ -2215,7 +2214,7 @@ nla_put_failure:
 static void neigh_update_notify(struct neighbour *neigh)
 {
 	call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, neigh);
-	__neigh_notify(neigh, RTM_NEWNEIGH, 0);
+	neigh_notify(neigh, RTM_NEWNEIGH, 0);
 }
 
 static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
@@ -2735,7 +2734,7 @@ static inline size_t neigh_nlmsg_size(void)
 	       + nla_total_size(4); /* NDA_PROBES */
 }
 
-static void __neigh_notify(struct neighbour *n, int type, int flags)
+void neigh_notify(struct neighbour *n, int type, int flags)
 {
 	struct net *net = dev_net(n->dev);
 	struct sk_buff *skb;
@@ -2759,14 +2758,6 @@ errout:
 		rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
 }
 
-#ifdef CONFIG_ARPD
-void neigh_app_ns(struct neighbour *n)
-{
-	__neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
-}
-EXPORT_SYMBOL(neigh_app_ns);
-#endif /* CONFIG_ARPD */
-
 #ifdef CONFIG_SYSCTL
 static int zero;
 static int int_max = INT_MAX;
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 4429b01..7808093 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -368,9 +368,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
 	} else {
 		probes -= neigh->parms->app_probes;
 		if (probes < 0) {
-#ifdef CONFIG_ARPD
 			neigh_app_ns(neigh);
-#endif
 			return;
 		}
 	}
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 04d31c2..d5693ad 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -663,9 +663,7 @@ static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
 		}
 		ndisc_send_ns(dev, neigh, target, target, saddr);
 	} else if ((probes -= neigh->parms->app_probes) < 0) {
-#ifdef CONFIG_ARPD
 		neigh_app_ns(neigh);
-#endif
 	} else {
 		addrconf_addr_solict_mult(target, &mcaddr);
 		ndisc_send_ns(dev, NULL, target, &mcaddr, saddr);

Re: [PATCH net-next 1/1] net: neighbour: Simplify ifdefs around neigh_app_ns()

[Eric W. Biederman]

Joe Perches <joe@perches.com> writes:

> On Wed, 2013-08-28 at 13:09 -0600, Tim Gardner wrote:
>> On 08/28/2013 12:51 PM, Joe Perches wrote:
>> > On Wed, 2013-08-28 at 12:24 -0600, Tim Gardner wrote:
>> >> Drop a couple of ifdef/endif pairs by moving the ifdef
>> >> surrounding neigh_app_ns() to the interior of neigh_app_ns().
>> > []
>> >> This is an admittedly trivial change. I stumbled on it while trying to figure
>> >> out why Ubuntu doesn't have CONFIG_ARPD enabled.
>
>> > I'd be more inclined to make neigh_app_ns static inline
>> > in the .h file and remove the EXPORT_SYMBOL
>
>> I thought about that as well, but then you'd have to extern
>> __neigh_notify(), which is currently a static function and large enough
>> to not really be suitable for inlining. Seems like unnecessary churn to me.
>
> Hi Tim.
>
> As is, this makes the call to neight_app_ns
> impossible to optimize away.
>
> Perhaps this:
>
> (this does add a possibly unused neigh_notify as a global symbol)
>
> Rename __neigh_notify to neigh_notify and make public
> Add static inline neigh_app_ns
> Remove #ifdefs around use of neigh_app_ns

Again.  Why not just remove CONFIG_ARPD entirely?  A config option to
compile out a single line of code seems like a real waste.

Eric

> ---
>
> Compile tested only
>
>  include/net/neighbour.h | 10 +++++++++-
>  net/core/neighbour.c    | 15 +++------------
>  net/ipv4/arp.c          |  2 --
>  net/ipv6/ndisc.c        |  2 --
>  4 files changed, 12 insertions(+), 17 deletions(-)
>
> diff --git a/include/net/neighbour.h b/include/net/neighbour.h
> index 536501a..a08b0a7 100644
> --- a/include/net/neighbour.h
> +++ b/include/net/neighbour.h
> @@ -249,7 +249,15 @@ static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
>  	return read_pnet(&pneigh->net);
>  }
>  
> -void neigh_app_ns(struct neighbour *n);
> +void neigh_notify(struct neighbour *n, int type, int flags);
> +
> +static inline void neigh_app_ns(struct neighbour *n)
> +{
> +#ifdef CONFIG_ARPD
> +	neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
> +#endif
> +}
> +
>  void neigh_for_each(struct neigh_table *tbl,
>  		    void (*cb)(struct neighbour *, void *), void *cookie);
>  void __neigh_for_each_release(struct neigh_table *tbl,
> diff --git a/net/core/neighbour.c b/net/core/neighbour.c
> index 60533db..6ec5f86 100644
> --- a/net/core/neighbour.c
> +++ b/net/core/neighbour.c
> @@ -50,7 +50,6 @@ do {						\
>  #define PNEIGH_HASHMASK		0xF
>  
>  static void neigh_timer_handler(unsigned long arg);
> -static void __neigh_notify(struct neighbour *n, int type, int flags);
>  static void neigh_update_notify(struct neighbour *neigh);
>  static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
>  
> @@ -103,7 +102,7 @@ static void neigh_cleanup_and_release(struct neighbour *neigh)
>  	if (neigh->parms->neigh_cleanup)
>  		neigh->parms->neigh_cleanup(neigh);
>  
> -	__neigh_notify(neigh, RTM_DELNEIGH, 0);
> +	neigh_notify(neigh, RTM_DELNEIGH, 0);
>  	neigh_release(neigh);
>  }
>  
> @@ -2215,7 +2214,7 @@ nla_put_failure:
>  static void neigh_update_notify(struct neighbour *neigh)
>  {
>  	call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, neigh);
> -	__neigh_notify(neigh, RTM_NEWNEIGH, 0);
> +	neigh_notify(neigh, RTM_NEWNEIGH, 0);
>  }
>  
>  static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
> @@ -2735,7 +2734,7 @@ static inline size_t neigh_nlmsg_size(void)
>  	       + nla_total_size(4); /* NDA_PROBES */
>  }
>  
> -static void __neigh_notify(struct neighbour *n, int type, int flags)
> +void neigh_notify(struct neighbour *n, int type, int flags)
>  {
>  	struct net *net = dev_net(n->dev);
>  	struct sk_buff *skb;
> @@ -2759,14 +2758,6 @@ errout:
>  		rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
>  }
>  
> -#ifdef CONFIG_ARPD
> -void neigh_app_ns(struct neighbour *n)
> -{
> -	__neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
> -}
> -EXPORT_SYMBOL(neigh_app_ns);
> -#endif /* CONFIG_ARPD */
> -
>  #ifdef CONFIG_SYSCTL
>  static int zero;
>  static int int_max = INT_MAX;
> diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
> index 4429b01..7808093 100644
> --- a/net/ipv4/arp.c
> +++ b/net/ipv4/arp.c
> @@ -368,9 +368,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
>  	} else {
>  		probes -= neigh->parms->app_probes;
>  		if (probes < 0) {
> -#ifdef CONFIG_ARPD
>  			neigh_app_ns(neigh);
> -#endif
>  			return;
>  		}
>  	}
> diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
> index 04d31c2..d5693ad 100644
> --- a/net/ipv6/ndisc.c
> +++ b/net/ipv6/ndisc.c
> @@ -663,9 +663,7 @@ static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
>  		}
>  		ndisc_send_ns(dev, neigh, target, target, saddr);
>  	} else if ((probes -= neigh->parms->app_probes) < 0) {
> -#ifdef CONFIG_ARPD
>  		neigh_app_ns(neigh);
> -#endif
>  	} else {
>  		addrconf_addr_solict_mult(target, &mcaddr);
>  		ndisc_send_ns(dev, NULL, target, &mcaddr, saddr);

[PATCH net-next v2] net: neighbour: Remove CONFIG_ARPD

[Tim Gardner]

This config option is superfluous in that it only guards a call
to neigh_app_ns(). Enabling CONFIG_ARPD by default has no
change in behavior. There will now be call to __neigh_notify()
for each ARP resolution, which has no impact unless there is a
user space daemon waiting to receive the notification, i.e.,
the case for which CONFIG_ARPD was designed anyways.

Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Joe Perches <joe@perches.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---

Eric's suggestion to simply remove the config option makes sense
to me. If acceptable then I'll submit a patch series that also removes
CONFIG_ARPD from the various arch defconfigs.

 net/core/neighbour.c |    2 --
 net/ipv4/Kconfig     |   16 ----------------
 net/ipv4/arp.c       |    2 --
 net/ipv6/ndisc.c     |    2 --
 4 files changed, 22 deletions(-)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 60533db..6072610 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2759,13 +2759,11 @@ errout:
 		rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
 }
 
-#ifdef CONFIG_ARPD
 void neigh_app_ns(struct neighbour *n)
 {
 	__neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
 }
 EXPORT_SYMBOL(neigh_app_ns);
-#endif /* CONFIG_ARPD */
 
 #ifdef CONFIG_SYSCTL
 static int zero;
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 37cf1a6..05c57f0 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -259,22 +259,6 @@ config IP_PIMSM_V2
 	  gated-5). This routing protocol is not used widely, so say N unless
 	  you want to play with it.
 
-config ARPD
-	bool "IP: ARP daemon support"
-	---help---
-	  The kernel maintains an internal cache which maps IP addresses to
-	  hardware addresses on the local network, so that Ethernet
-	  frames are sent to the proper address on the physical networking
-	  layer. Normally, kernel uses the ARP protocol to resolve these
-	  mappings.
-
-	  Saying Y here adds support to have an user space daemon to do this
-	  resolution instead. This is useful for implementing an alternate
-	  address resolution protocol (e.g. NHRP on mGRE tunnels) and also for
-	  testing purposes.
-
-	  If unsure, say N.
-
 config SYN_COOKIES
 	bool "IP: TCP syncookie support"
 	---help---
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 4429b01..7808093 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -368,9 +368,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
 	} else {
 		probes -= neigh->parms->app_probes;
 		if (probes < 0) {
-#ifdef CONFIG_ARPD
 			neigh_app_ns(neigh);
-#endif
 			return;
 		}
 	}
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 04d31c2..d5693ad 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -663,9 +663,7 @@ static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
 		}
 		ndisc_send_ns(dev, neigh, target, target, saddr);
 	} else if ((probes -= neigh->parms->app_probes) < 0) {
-#ifdef CONFIG_ARPD
 		neigh_app_ns(neigh);
-#endif
 	} else {
 		addrconf_addr_solict_mult(target, &mcaddr);
 		ndisc_send_ns(dev, NULL, target, &mcaddr, saddr);
-- 
1.7.9.5

Re: [PATCH net-next v2] net: neighbour: Remove CONFIG_ARPD

[Eric W. Biederman]

Tim Gardner <tim.gardner@canonical.com> writes:

> This config option is superfluous in that it only guards a call
> to neigh_app_ns(). Enabling CONFIG_ARPD by default has no
> change in behavior. There will now be call to __neigh_notify()
> for each ARP resolution, which has no impact unless there is a
> user space daemon waiting to receive the notification, i.e.,
> the case for which CONFIG_ARPD was designed anyways.

This looks good to me, and much less magic to maintain.

Eric


> Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>

> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
> Cc: James Morris <jmorris@namei.org>
> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
> Cc: Patrick McHardy <kaber@trash.net>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Gao feng <gaofeng@cn.fujitsu.com>
> Cc: Joe Perches <joe@perches.com>
> Cc: Veaceslav Falico <vfalico@redhat.com>
> Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
> ---
>
> Eric's suggestion to simply remove the config option makes sense
> to me. If acceptable then I'll submit a patch series that also removes
> CONFIG_ARPD from the various arch defconfigs.
>
>  net/core/neighbour.c |    2 --
>  net/ipv4/Kconfig     |   16 ----------------
>  net/ipv4/arp.c       |    2 --
>  net/ipv6/ndisc.c     |    2 --
>  4 files changed, 22 deletions(-)
>
> diff --git a/net/core/neighbour.c b/net/core/neighbour.c
> index 60533db..6072610 100644
> --- a/net/core/neighbour.c
> +++ b/net/core/neighbour.c
> @@ -2759,13 +2759,11 @@ errout:
>  		rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
>  }
>  
> -#ifdef CONFIG_ARPD
>  void neigh_app_ns(struct neighbour *n)
>  {
>  	__neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
>  }
>  EXPORT_SYMBOL(neigh_app_ns);
> -#endif /* CONFIG_ARPD */
>  
>  #ifdef CONFIG_SYSCTL
>  static int zero;
> diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
> index 37cf1a6..05c57f0 100644
> --- a/net/ipv4/Kconfig
> +++ b/net/ipv4/Kconfig
> @@ -259,22 +259,6 @@ config IP_PIMSM_V2
>  	  gated-5). This routing protocol is not used widely, so say N unless
>  	  you want to play with it.
>  
> -config ARPD
> -	bool "IP: ARP daemon support"
> -	---help---
> -	  The kernel maintains an internal cache which maps IP addresses to
> -	  hardware addresses on the local network, so that Ethernet
> -	  frames are sent to the proper address on the physical networking
> -	  layer. Normally, kernel uses the ARP protocol to resolve these
> -	  mappings.
> -
> -	  Saying Y here adds support to have an user space daemon to do this
> -	  resolution instead. This is useful for implementing an alternate
> -	  address resolution protocol (e.g. NHRP on mGRE tunnels) and also for
> -	  testing purposes.
> -
> -	  If unsure, say N.
> -
>  config SYN_COOKIES
>  	bool "IP: TCP syncookie support"
>  	---help---
> diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
> index 4429b01..7808093 100644
> --- a/net/ipv4/arp.c
> +++ b/net/ipv4/arp.c
> @@ -368,9 +368,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
>  	} else {
>  		probes -= neigh->parms->app_probes;
>  		if (probes < 0) {
> -#ifdef CONFIG_ARPD
>  			neigh_app_ns(neigh);
> -#endif
>  			return;
>  		}
>  	}
> diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
> index 04d31c2..d5693ad 100644
> --- a/net/ipv6/ndisc.c
> +++ b/net/ipv6/ndisc.c
> @@ -663,9 +663,7 @@ static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
>  		}
>  		ndisc_send_ns(dev, neigh, target, target, saddr);
>  	} else if ((probes -= neigh->parms->app_probes) < 0) {
> -#ifdef CONFIG_ARPD
>  		neigh_app_ns(neigh);
> -#endif
>  	} else {
>  		addrconf_addr_solict_mult(target, &mcaddr);
>  		ndisc_send_ns(dev, NULL, target, &mcaddr, saddr);

Re: [PATCH net-next v2] net: neighbour: Remove CONFIG_ARPD

[David Miller]

From: Tim Gardner <tim.gardner@canonical.com>
Date: Thu, 29 Aug 2013 06:38:47 -0600

> This config option is superfluous in that it only guards a call
> to neigh_app_ns(). Enabling CONFIG_ARPD by default has no
> change in behavior. There will now be call to __neigh_notify()
> for each ARP resolution, which has no impact unless there is a
> user space daemon waiting to receive the notification, i.e.,
> the case for which CONFIG_ARPD was designed anyways.
> 
> Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
 ...
> Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

Applied, thanks.