4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Roopa Prabhu roopa@cumulusnetworks.com
[ Upstream commit 5025f7f7d506fba9b39e7fe8ca10f6f34cb9bc2d ]
rtnl_configure_link sets dev->rtnl_link_state to RTNL_LINK_INITIALIZED and unconditionally calls __dev_notify_flags to notify user-space of dev flags.
current call sequence for rtnl_configure_link rtnetlink_newlink rtnl_link_ops->newlink rtnl_configure_link (unconditionally notifies userspace of default and new dev flags)
If a newlink handler wants to call rtnl_configure_link early, we will end up with duplicate notifications to user-space.
This patch fixes rtnl_configure_link to check rtnl_link_state and call __dev_notify_flags with gchanges = 0 if already RTNL_LINK_INITIALIZED.
Later in the series, this patch will help the following sequence where a driver implementing newlink can call rtnl_configure_link to initialize the link early.
makes the following call sequence work: rtnetlink_newlink rtnl_link_ops->newlink (vxlan) -> rtnl_configure_link (initializes link and notifies user-space of default dev flags) rtnl_configure_link (updates dev flags if requested by user ifm and notifies user-space of new dev flags)
Signed-off-by: Roopa Prabhu roopa@cumulusnetworks.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/rtnetlink.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2339,9 +2339,12 @@ int rtnl_configure_link(struct net_devic return err; }
- dev->rtnl_link_state = RTNL_LINK_INITIALIZED; - - __dev_notify_flags(dev, old_flags, ~0U); + if (dev->rtnl_link_state == RTNL_LINK_INITIALIZED) { + __dev_notify_flags(dev, old_flags, 0U); + } else { + dev->rtnl_link_state = RTNL_LINK_INITIALIZED; + __dev_notify_flags(dev, old_flags, ~0U); + } return 0; } EXPORT_SYMBOL(rtnl_configure_link);