netdev - [PATCH net-next v5 02/10] net: free_netdev: exit earlier if dummy

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Message-ID: <20240410131407.3897251-3-leitao@debian.org>
Date: Wed, 10 Apr 2024 06:13:43 -0700
From: Breno Leitao <leitao@...ian.org>
To: aleksander.lobakin@...el.com,
	kuba@...nel.org,
	davem@...emloft.net,
	pabeni@...hat.com,
	edumazet@...gle.com,
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	nbd@....name,
	sean.wang@...iatek.com,
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	ath10k@...ts.infradead.org,
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Cc: quic_jjohnson@...cinc.com,
	leon@...nel.org,
	dennis.dalessandro@...nelisnetworks.com,
	linux-kernel@...r.kernel.org,
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	leitao@...ian.org,
	Jiri Pirko <jiri@...nulli.us>,
	Simon Horman <horms@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH net-next v5 02/10] net: free_netdev: exit earlier if dummy

For dummy devices, exit earlier at free_netdev() instead of executing
the whole function. This is necessary, because dummy devices are
special, and shouldn't have the second part of the function executed.

Otherwise reg_state, which is NETREG_DUMMY, will be overwritten and
there will be no way to identify that this is a dummy device. Also, this
device do not need the final put_device(), since dummy devices are not
registered (through register_netdevice()), where the device reference is
increased (at netdev_register_kobject()/device_add()).

Suggested-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Breno Leitao <leitao@...ian.org>
---
 net/core/dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 987039ffa63c..c74b42bc6888 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -11060,7 +11060,8 @@ void free_netdev(struct net_device *dev)
 	phy_link_topo_destroy(dev->link_topo);
 
 	/*  Compatibility with error handling in drivers */
-	if (dev->reg_state == NETREG_UNINITIALIZED) {
+	if (dev->reg_state == NETREG_UNINITIALIZED ||
+	    dev->reg_state == NETREG_DUMMY) {
 		netdev_freemem(dev);
 		return;
 	}
-- 
2.43.0