On Wed, 19 Feb 2025 09:28:07 +0100 Greg Kroah-Hartman wrote:
6.13-stable review patch. If anyone has any objections, please let me know.
From: Jakub Kicinski kuba@kernel.org
[ Upstream commit 5112457f3d8e41f987908266068af88ef9f3ab78 ]
Some uAPI (netdev netlink) hide net_device's sub-objects while the interface is down to ensure uniform behavior across drivers. To remove the rtnl_lock dependency from those uAPIs we need a way to safely tell if the device is down or up.
Add an indication of whether device is open or closed, protected by netdev->lock. The semantics are the same as IFF_UP, but taking netdev_lock around every write to ->flags would be a lot of code churn.
We don't want to blanket the entire open / close path by netdev_lock, because it will prevent us from applying it to specific structures - core helpers won't be able to take that lock from any function called by the drivers on open/close paths.
So the state of the flag is "pessimistic", as in it may report false negatives, but never false positives.
Reviewed-by: Joe Damato jdamato@fastly.com Reviewed-by: Eric Dumazet edumazet@google.com Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://patch.msgid.link/20250115035319.559603-5-kuba@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Stable-dep-of: 011b03359038 ("Revert "net: skb: introduce and use a single page frag cache"") Signed-off-by: Sasha Levin sashal@kernel.org
please drop