6.17-stable review patch. If anyone has any objections, please let me know.
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From: Breno Leitao leitao@debian.org
[ Upstream commit 1a8fed52f7be14e45785e8e54d0d0b50fc17dbd8 ]
Bringing a linked netdevsim device down and then up causes communication failure because both interfaces lack carrier. Basically a ifdown/ifup on the interface make the link broken.
Commit 3762ec05a9fbda ("netdevsim: add NAPI support") added supported for NAPI, calling netif_carrier_off() in nsim_stop(). This patch re-enables the carrier symmetrically on nsim_open(), in case the device is linked and the peer is up.
Signed-off-by: Breno Leitao leitao@debian.org Fixes: 3762ec05a9fbda ("netdevsim: add NAPI support") Reviewed-by: Andrew Lunn andrew@lunn.ch Link: https://patch.msgid.link/20251014-netdevsim_fix-v2-1-53b40590dae1@debian.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/netdevsim/netdev.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c index 0178219f0db53..d7938e11f24de 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -528,6 +528,7 @@ static void nsim_enable_napi(struct netdevsim *ns) static int nsim_open(struct net_device *dev) { struct netdevsim *ns = netdev_priv(dev); + struct netdevsim *peer; int err;
netdev_assert_locked(dev); @@ -538,6 +539,12 @@ static int nsim_open(struct net_device *dev)
nsim_enable_napi(ns);
+ peer = rtnl_dereference(ns->peer); + if (peer && netif_running(peer->netdev)) { + netif_carrier_on(dev); + netif_carrier_on(peer->netdev); + } + return 0; }