linux-kernel - [PATCH net-next 2/2] net: netpoll: use synchronize_net() instead of synchronize

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Message-Id: <20250918-netpoll_jv-v1-2-67d50eeb2c26@debian.org>
Date: Thu, 18 Sep 2025 05:25:58 -0700
From: Breno Leitao <leitao@...ian.org>
To: "David S. Miller" <davem@...emloft.net>, 
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
 Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Breno Leitao <leitao@...ian.org>, efault@....de, jv@...sburgh.net, 
 kernel-team@...a.com, calvin@...nvd.org
Subject: [PATCH net-next 2/2] net: netpoll: use synchronize_net() instead
 of synchronize_rcu()

Replace synchronize_rcu() with synchronize_net() in __netpoll_free().

synchronize_net() is RTNL-aware and will use the more efficient
synchronize_rcu_expedited() when called under RTNL lock, avoiding
the potentially expensive synchronize_rcu() in RTNL critical sections.

Since __netpoll_free() is called with RTNL held (as indicated by
ASSERT_RTNL()), this change improves performance by reducing the
time spent in the RTNL critical section.

Signed-off-by: Breno Leitao <leitao@...ian.org>
---
 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 c58faa7471650..60a05d3b7c249 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -834,7 +834,7 @@ void __netpoll_free(struct netpoll *np)
 	ASSERT_RTNL();

 	/* Wait for transmitting packets to finish before freeing. */
-	synchronize_rcu();
+	synchronize_net();
 	__netpoll_cleanup(np);
 	kfree(np);
 }

-- 
2.47.3