From: Marek Marczykowski-Górecki marmarek@invisiblethingslab.com
stable inclusion from stable-v5.10.106 commit 8c0c50e9fcff7db3257721537d52575a1a636dc2 bugzilla: https://gitee.com/openeuler/kernel/issues/I573US
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit e8240addd0a3919e0fd7436416afe9aa6429c484 ]
This reverts commit 2afeec08ab5c86ae21952151f726bfe184f6b23d.
The reasoning in the commit was wrong - the code expected to setup the watch even if 'hotplug-status' didn't exist. In fact, it relied on the watch being fired the first time - to check if maybe 'hotplug-status' is already set to 'connected'. Not registering a watch for non-existing path (which is the case if hotplug script hasn't been executed yet), made the backend not waiting for the hotplug script to execute. This in turns, made the netfront think the interface is fully operational, while in fact it was not (the vif interface on xen-netback side might not be configured yet).
This was a workaround for 'hotplug-status' erroneously being removed. But since that is reverted now, the workaround is not necessary either.
More discussion at https://lore.kernel.org/xen-devel/afedd7cb-a291-e773-8b0d-4db9b291fa98@ipxe....
Signed-off-by: Marek Marczykowski-Górecki marmarek@invisiblethingslab.com Reviewed-by: Paul Durrant paul@xen.org Reviewed-by: Michael Brown mbrown@fensystems.co.uk Link: https://lore.kernel.org/r/20220222001817.2264967-2-marmarek@invisiblethingsl... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yu Liao liaoyu15@huawei.com Reviewed-by: Wei Li liwei391@huawei.com --- drivers/net/xen-netback/xenbus.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c index 7acf3940dc1f..ca261e0fc9c9 100644 --- a/drivers/net/xen-netback/xenbus.c +++ b/drivers/net/xen-netback/xenbus.c @@ -824,15 +824,11 @@ static void connect(struct backend_info *be) xenvif_carrier_on(be->vif);
unregister_hotplug_status_watch(be); - if (xenbus_exists(XBT_NIL, dev->nodename, "hotplug-status")) { - err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, - NULL, hotplug_status_changed, - "%s/%s", dev->nodename, - "hotplug-status"); - if (err) - goto err; + err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, NULL, + hotplug_status_changed, + "%s/%s", dev->nodename, "hotplug-status"); + if (!err) be->have_hotplug_status_watch = 1; - }
netif_tx_wake_all_queues(be->vif->dev);