diff mbox series

[v2,net-next,3/4] rtnetlink: Add assertion helpers for per-netns RTNL.

Message ID 20241002151240.49813-4-kuniyu@amazon.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series rtnetlink: Per-netns RTNL. | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 24 this patch: 24
netdev/build_tools success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 4 of 4 maintainers
netdev/build_clang success Errors and warnings before: 67 this patch: 67
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 3559 this patch: 3559
netdev/checkpatch warning WARNING: Argument 'net' is not used in function-like macro
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 7 this patch: 7
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-10-04--18-00 (tests: 773)

Commit Message

Kuniyuki Iwashima Oct. 2, 2024, 3:12 p.m. UTC 
Once an RTNL scope is converted with rtnl_net_lock(), we will replace
RTNL helper functions inside the scope with the following per-netns
alternatives:

  ASSERT_RTNL()           -> ASSERT_RTNL_NET(net)
  rcu_dereference_rtnl(p) -> rcu_dereference_rtnl_net(net, p)

Note that the per-netns helpers are equivalent to the conventional
helpers unless CONFIG_DEBUG_NET_SMALL_RTNL is enabled.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 include/linux/rtnetlink.h | 25 +++++++++++++++++++++++++
 net/core/rtnetlink.c      | 12 ++++++++++++
 2 files changed, 37 insertions(+)

Comments

Eric Dumazet Oct. 4, 2024, 11:10 a.m. UTC | #1 
On Wed, Oct 2, 2024 at 5:14 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote:
>
> Once an RTNL scope is converted with rtnl_net_lock(), we will replace
> RTNL helper functions inside the scope with the following per-netns
> alternatives:
>
>   ASSERT_RTNL()           -> ASSERT_RTNL_NET(net)
>   rcu_dereference_rtnl(p) -> rcu_dereference_rtnl_net(net, p)
>
> Note that the per-netns helpers are equivalent to the conventional
> helpers unless CONFIG_DEBUG_NET_SMALL_RTNL is enabled.
>
> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>

Reviewed-by: Eric Dumazet <edumazet@google.com>
diff mbox series

Patch

diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index f743c4f678bf..ec2fc946cd8a 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -52,11 +52,36 @@  void __rtnl_net_unlock(struct net *net);
 void rtnl_net_lock(struct net *net);
 void rtnl_net_unlock(struct net *net);
 int rtnl_net_lock_cmp_fn(const struct lockdep_map *a, const struct lockdep_map *b);
+
+bool rtnl_net_is_locked(struct net *net);
+
+#define ASSERT_RTNL_NET(net)						\
+	WARN_ONCE(!rtnl_net_is_locked(net),				\
+		  "RTNL_NET: assertion failed at %s (%d)\n",		\
+		  __FILE__,  __LINE__)
+
+bool lockdep_rtnl_net_is_held(struct net *net);
+
+#define rcu_dereference_rtnl_net(net, p)				\
+	rcu_dereference_check(p, lockdep_rtnl_net_is_held(net))
+#define rtnl_net_dereference(net, p)					\
+	rcu_dereference_protected(p, lockdep_rtnl_net_is_held(net))
+#define rcu_replace_pointer_rtnl_net(net, rp, p)			\
+	rcu_replace_pointer(rp, p, lockdep_rtnl_net_is_held(net))
 #else
 #define __rtnl_net_lock(net)
 #define __rtnl_net_unlock(net)
 #define rtnl_net_lock(net) rtnl_lock()
 #define rtnl_net_unlock(net) rtnl_unlock()
+
+#define ASSERT_RTNL_NET(net)	ASSERT_RTNL()
+
+#define rcu_dereference_rtnl_net(net, p)		\
+	rcu_dereference_rtnl(p)
+#define rtnl_net_dereference(net, p)			\
+	rtnl_dereference(p)
+#define rcu_replace_pointer_rtnl_net(net, rp, p)	\
+	rcu_replace_pointer_rtnl(rp, p)
 #endif
 
 extern wait_queue_head_t netdev_unregistering_wq;
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index edf530441b65..2b44ec690780 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -235,6 +235,18 @@  int rtnl_net_lock_cmp_fn(const struct lockdep_map *a, const struct lockdep_map *
 
 	return rtnl_net_cmp_locks(net_a, net_b);
 }
+
+bool rtnl_net_is_locked(struct net *net)
+{
+	return rtnl_is_locked() && mutex_is_locked(&net->rtnl_mutex);
+}
+EXPORT_SYMBOL(rtnl_net_is_locked);
+
+bool lockdep_rtnl_net_is_held(struct net *net)
+{
+	return lockdep_rtnl_is_held() && lockdep_is_held(&net->rtnl_mutex);
+}
+EXPORT_SYMBOL(lockdep_rtnl_net_is_held);
 #endif
 
 static struct rtnl_link __rcu *__rcu *rtnl_msg_handlers[RTNL_FAMILY_MAX + 1];