[PATCH net 1/2] netpoll: Use rcu_access_pointer() in __netpoll_setup

[Breno Leitao <leitao@debian.org>]

The ndev->npinfo pointer in __netpoll_setup() is RCU-protected but is being
accessed directly for a NULL check. While no RCU read lock is held in this
context, we should still use proper RCU primitives for consistency and
correctness.

Replace the direct NULL check with rcu_access_pointer(), which is the
appropriate primitive when only checking for NULL without dereferencing
the pointer. This function provides the necessary ordering guarantees
without requiring RCU read-side protection.

Signed-off-by: Breno Leitao <leitao@debian.org>
Fixes: 8fdd95ec162a ("netpoll: Allow netpoll_setup/cleanup recursion")
---
 net/core/netpoll.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index aa49b92e9194babab17b2e039daf092a524c5b88..45fb60bc4803958eb07d4038028269fc0c19622e 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -626,7 +626,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 		goto out;
 	}
 
-	if (!ndev->npinfo) {
+	if (!rcu_access_pointer(ndev->npinfo)) {
 		npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 		if (!npinfo) {
 			err = -ENOMEM;

-- 
2.43.5