[PATCH net-next] vrf: use dev_replace_track() for better tracking

[PATCH net-next] vrf: use dev_replace_track() for better tracking

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

vrf_rt6_release() and vrf_rtable_release() changes dst->dev

Instead of

dev_hold(ndev);
dev_put(odev);

We should use

dev_replace_track(odev, ndev, &dst->dev_tracker, GFP_KERNEL);

If we do not transfer dst->dev_tracker to the new device,
we will get warnings from ref_tracker_dir_exit() when odev
is finally dismantled.

Fixes: 9038c320001d ("net: dst: add net device refcount tracking to dst_entry")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 drivers/net/vrf.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 131c745dc7010b1653b937e87c7f7f5a67e3460d..dbfa124d1c1c03c768ddeae6f2fc7a06166a20d4 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -814,9 +814,9 @@ static void vrf_rt6_release(struct net_device *dev, struct net_vrf *vrf)
 	 */
 	if (rt6) {
 		dst = &rt6->dst;
-		dev_put(dst->dev);
+		dev_replace_track(dst->dev, net->loopback_dev,
+				  &dst->dev_tracker, GFP_KERNEL);
 		dst->dev = net->loopback_dev;
-		dev_hold(dst->dev);
 		dst_release(dst);
 	}
 }
@@ -1061,9 +1061,9 @@ static void vrf_rtable_release(struct net_device *dev, struct net_vrf *vrf)
 	 */
 	if (rth) {
 		dst = &rth->dst;
-		dev_put(dst->dev);
+		dev_replace_track(dst->dev, net->loopback_dev,
+				  &dst->dev_tracker, GFP_KERNEL);
 		dst->dev = net->loopback_dev;
-		dev_hold(dst->dev);
 		dst_release(dst);
 	}
 }
-- 
2.34.1.400.ga245620fadb-goog

Re: [PATCH net-next] vrf: use dev_replace_track() for better tracking

[David Ahern]

On 12/6/21 10:56 PM, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> vrf_rt6_release() and vrf_rtable_release() changes dst->dev
> 
> Instead of
> 
> dev_hold(ndev);
> dev_put(odev);
> 
> We should use
> 
> dev_replace_track(odev, ndev, &dst->dev_tracker, GFP_KERNEL);
> 
> If we do not transfer dst->dev_tracker to the new device,
> we will get warnings from ref_tracker_dir_exit() when odev
> is finally dismantled.
> 
> Fixes: 9038c320001d ("net: dst: add net device refcount tracking to dst_entry")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
>  drivers/net/vrf.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 


Reviewed-by: David Ahern <dsahern@kernel.org>

Re: [PATCH net-next] vrf: use dev_replace_track() for better tracking

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Mon,  6 Dec 2021 21:56:03 -0800 you wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> vrf_rt6_release() and vrf_rtable_release() changes dst->dev
> 
> Instead of
> 
> dev_hold(ndev);
> dev_put(odev);
> 
> [...]

Here is the summary with links:
  - [net-next] vrf: use dev_replace_track() for better tracking
    https://git.kernel.org/netdev/net-next/c/c0e5e11af12b

You are awesome, thank you!
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