[PATCH v1 net-next 0/2] net: Clean up af_ops->{get_link_af_size,fill_link_af}().

[PATCH v1 net-next 0/2] net: Clean up af_ops->{get_link_af_size,fill_link_af}().

[Kuniyuki Iwashima]

Since commit 5fa85a09390c ("net: core: rcu-ify rtnl af_ops"),
af_ops->{get_link_af_size,fill_link_af}() are called under RCU.

Patch 1 makes the context clear and patch 2 removes unnecessary
rcu_read_lock().


Kuniyuki Iwashima (2):
  ipv4: Use RCU helper in inet_get_link_af_size() and
    inet_fill_link_af().
  net: bridge: Remove rcu_read_lock() in br_get_link_af_size_filtered().

 net/bridge/br_netlink.c | 2 --
 net/ipv4/devinet.c      | 6 ++----
 2 files changed, 2 insertions(+), 6 deletions(-)

-- 
2.30.2

[PATCH v1 net-next 1/2] ipv4: Use RCU helper in inet_get_link_af_size() and inet_fill_link_af().

[Kuniyuki Iwashima]

Since commit 5fa85a09390c ("net: core: rcu-ify rtnl af_ops"),
af_ops->{get_link_af_size,fill_link_af}() are called under RCU.

Instead of using rcu_dereference_rtnl(), let's make the context
clear by using RCU helpers.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv4/devinet.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 61be85154dd1..a4f9822213bf 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1950,9 +1950,7 @@ static void rtmsg_ifa(int event, struct in_ifaddr *ifa, struct nlmsghdr *nlh,
 static size_t inet_get_link_af_size(const struct net_device *dev,
 				    u32 ext_filter_mask)
 {
-	struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);
-
-	if (!in_dev)
+	if (!rcu_access_pointer(dev->ip_ptr))
 		return 0;
 
 	return nla_total_size(IPV4_DEVCONF_MAX * 4); /* IFLA_INET_CONF */
@@ -1961,7 +1959,7 @@ static size_t inet_get_link_af_size(const struct net_device *dev,
 static int inet_fill_link_af(struct sk_buff *skb, const struct net_device *dev,
 			     u32 ext_filter_mask)
 {
-	struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);
+	struct in_device *in_dev = rcu_dereference(dev->ip_ptr);
 	struct nlattr *nla;
 	int i;
 
-- 
2.30.2

[PATCH v1 net-next 2/2] net: bridge: Remove rcu_read_lock() in br_get_link_af_size_filtered().

[Kuniyuki Iwashima]

Since commit 5fa85a09390c ("net: core: rcu-ify rtnl af_ops"),
af_ops->get_link_af_size() is called under RCU.

Let's remove unnecessary rcu_read_lock() in br_get_link_af_size_filtered().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/bridge/br_netlink.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index f17dbac7d828..c386a8ec370f 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -101,7 +101,6 @@ static size_t br_get_link_af_size_filtered(const struct net_device *dev,
 	size_t vinfo_sz = 0;
 	int num_vlan_infos;
 
-	rcu_read_lock();
 	if (netif_is_bridge_port(dev)) {
 		p = br_port_get_check_rcu(dev);
 		if (p)
@@ -111,7 +110,6 @@ static size_t br_get_link_af_size_filtered(const struct net_device *dev,
 		vg = br_vlan_group_rcu(br);
 	}
 	num_vlan_infos = br_get_num_vlan_infos(vg, filter_mask);
-	rcu_read_unlock();
 
 	if (p && (p->flags & BR_VLAN_TUNNEL))
 		vinfo_sz += br_get_vlan_tunnel_info_size(vg);
-- 
2.30.2

Re: [PATCH v1 net-next 0/2] net: Clean up af_ops->{get_link_af_size,fill_link_af}().

[Jakub Kicinski]

On Thu, 15 Aug 2024 14:11:35 -0700 Kuniyuki Iwashima wrote:
> Since commit 5fa85a09390c ("net: core: rcu-ify rtnl af_ops"),
> af_ops->{get_link_af_size,fill_link_af}() are called under RCU.
> 
> Patch 1 makes the context clear and patch 2 removes unnecessary
> rcu_read_lock().

Tests violently disagree.

https://netdev.bots.linux.dev/contest.html?branch=net-next-2024-08-16--00-00&pw-n=0&pass=0
-- 
pw-bot: cr

Re: [PATCH v1 net-next 0/2] net: Clean up af_ops->{get_link_af_size,fill_link_af}().

[Kuniyuki Iwashima]

From: Jakub Kicinski <kuba@kernel.org>
Date: Thu, 15 Aug 2024 18:36:51 -0700
> On Thu, 15 Aug 2024 14:11:35 -0700 Kuniyuki Iwashima wrote:
> > Since commit 5fa85a09390c ("net: core: rcu-ify rtnl af_ops"),
> > af_ops->{get_link_af_size,fill_link_af}() are called under RCU.
> > 
> > Patch 1 makes the context clear and patch 2 removes unnecessary
> > rcu_read_lock().
> 
> Tests violently disagree.
> 
> https://netdev.bots.linux.dev/contest.html?branch=net-next-2024-08-16--00-00&pw-n=0&pass=0

Sorry, I missed the birdge one is called under RTNL.
I'll drop patch 2.