[PATCH ipsec-next v4 1/5] xfrm: add missing __rcu annotation to nlsk

[Antony Antony]

The nlsk field in struct netns_xfrm is RCU-protected, as seen by
the use of rcu_assign_pointer() and RCU_INIT_POINTER() when updating
it.
However, the field lacks the __rcu annotation, and most read-side
accesses don't use rcu_dereference().

Add the missing __rcu annotation and convert all read-side accesses to
use rcu_dereference() for correctness and to silence sparse warnings.

Sparse warning reported by NIPA allmodconfig test when modifying
net/xfrm/xfrm_user.c. The warning is a pre-existing issue in
xfrm_nlmsg_multicast(). This series added a new call to this function
and NIPA testing reported a new warning was added by this series.

To reproduce (requires sparse):
make C=2 net/xfrm/
net/xfrm/xfrm_user.c:1574:29: error: incompatible types in comparison
expression (different address spaces):
net/xfrm/xfrm_user.c:1574:29:    struct sock [noderef] __rcu *
net/xfrm/xfrm_user.c:1574:29:    struct sock *

Signed-off-by: Antony Antony <antony.antony@xxxxxxxxxxx>
---
 include/net/netns/xfrm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h
index 23dd647fe024..ed8eee81bbb0 100644
--- a/include/net/netns/xfrm.h
+++ b/include/net/netns/xfrm.h
@@ -59,7 +59,7 @@ struct netns_xfrm {
 	struct list_head	inexact_bins;


-	struct sock		*nlsk;
+	struct sock __rcu	*nlsk;
 	struct sock		*nlsk_stash;

 	u32			sysctl_aevent_etime;
--
2.39.5