diff mbox series

[net-next,v3,1/7] net: treat possible_net_t net pointer as an RCU one and add read_pnet_rcu()

Message ID 20231013121029.353351-2-jiri@resnulli.us (mailing list archive)
State Accepted
Commit 2034d90ae41ae93e30d492ebcf1f06f97a9cfba6
Delegated to: Netdev Maintainers
Headers show
Series devlink: fix a deadlock when taking devlink instance lock while holding RTNL lock | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
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: 5692 this patch: 5692
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 1692 this patch: 1692
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: 6062 this patch: 6062
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 33 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Jiri Pirko Oct. 13, 2023, 12:10 p.m. UTC 
From: Jiri Pirko <jiri@nvidia.com>

Make the net pointer stored in possible_net_t structure annotated as
an RCU pointer. Change the access helpers to treat it as such.
Introduce read_pnet_rcu() helper to allow caller to dereference
the net pointer under RCU read lock.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
v1->v2:
- new patch
---
 include/net/net_namespace.h | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

Comments

Simon Horman Oct. 17, 2023, 8:49 a.m. UTC | #1 
On Fri, Oct 13, 2023 at 02:10:23PM +0200, Jiri Pirko wrote:
> From: Jiri Pirko <jiri@nvidia.com>
> 
> Make the net pointer stored in possible_net_t structure annotated as
> an RCU pointer. Change the access helpers to treat it as such.
> Introduce read_pnet_rcu() helper to allow caller to dereference
> the net pointer under RCU read lock.
> 
> Signed-off-by: Jiri Pirko <jiri@nvidia.com>

Reviewed-by: Simon Horman <horms@kernel.org>
diff mbox series

Patch

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index eb6cd43b1746..13b3a4e29fdb 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -368,21 +368,30 @@  static inline void put_net_track(struct net *net, netns_tracker *tracker)
 
 typedef struct {
 #ifdef CONFIG_NET_NS
-	struct net *net;
+	struct net __rcu *net;
 #endif
 } possible_net_t;
 
 static inline void write_pnet(possible_net_t *pnet, struct net *net)
 {
 #ifdef CONFIG_NET_NS
-	pnet->net = net;
+	rcu_assign_pointer(pnet->net, net);
 #endif
 }
 
 static inline struct net *read_pnet(const possible_net_t *pnet)
 {
 #ifdef CONFIG_NET_NS
-	return pnet->net;
+	return rcu_dereference_protected(pnet->net, true);
+#else
+	return &init_net;
+#endif
+}
+
+static inline struct net *read_pnet_rcu(possible_net_t *pnet)
+{
+#ifdef CONFIG_NET_NS
+	return rcu_dereference(pnet->net);
 #else
 	return &init_net;
 #endif