From: Pratyush Yadav ptyadav@amazon.de
The removal of "hotplug-status" has moved around a bit. First it was moved from netback_remove() to hotplug_status_changed() in upstream commit 1f2565780e9b ("xen-netback: remove 'hotplug-status' once it has served its purpose"). Then the change was reverted in upstream commit 0f4558ae9187 ("Revert "xen-netback: remove 'hotplug-status' once it has served its purpose""), but it moved the removal to backend_disconnect(). Then the upstream commit c55f34b6aec2 ("xen-netback: only remove 'hotplug-status' when the vif is actually destroyed") moved it finally back to netback_remove(). The thing to note being it is removed unconditionally this time around.
The story on v5.4.y adds to this confusion. Commit 60e4e3198ce8 ("Revert "xen-netback: remove 'hotplug-status' once it has served its purpose"") is backported to v5.4.y but the original commit that it tries to revert was never present on 5.4. So the backport incorrectly ends up just adding another xenbus_rm() of "hotplug-status" in backend_disconnect().
Now in v5.4.y it is removed in both backend_disconnect() and netback_remove(). But it should only be removed in netback_remove(), as the upstream version does.
Removing "hotplug-status" in backend_disconnect() causes problems when the frontend unilaterally disconnects, as explained in c55f34b6aec2 ("xen-netback: only remove 'hotplug-status' when the vif is actually destroyed").
Remove "hotplug-status" in the same place as it is done on the upstream version to ensure unilateral re-connection of frontend continues to work.
Fixes: 60e4e3198ce8 ("Revert "xen-netback: remove 'hotplug-status' once it has served its purpose"") Signed-off-by: Pratyush Yadav ptyadav@amazon.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/xen-netback/xenbus.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/drivers/net/xen-netback/xenbus.c +++ b/drivers/net/xen-netback/xenbus.c @@ -202,10 +202,10 @@ static int netback_remove(struct xenbus_ set_backend_state(be, XenbusStateClosed);
unregister_hotplug_status_watch(be); + xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); if (be->vif) { kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); xen_unregister_watchers(be->vif); - xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); xenvif_free(be->vif); be->vif = NULL; } @@ -435,7 +435,6 @@ static void backend_disconnect(struct ba unsigned int queue_index;
xen_unregister_watchers(vif); - xenbus_rm(XBT_NIL, be->dev->nodename, "hotplug-status"); #ifdef CONFIG_DEBUG_FS xenvif_debugfs_delif(vif); #endif /* CONFIG_DEBUG_FS */