From facd15dfd69122042502d99ab8c9f888b48ee994 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 4 Dec 2023 21:47:07 +0100 Subject: net: core: synchronize link-watch when carrier is queried There are multiple ways to query for the carrier state: through rtnetlink, sysfs, and (possibly) ethtool. Synchronize linkwatch work before these operations so that we don't have a situation where userspace queries the carrier state between the driver's carrier off->on transition and linkwatch running and expects it to work, when really (at least) TX cannot work until linkwatch has run. I previously posted a longer explanation of how this applies to wireless [1] but with this wireless can simply query the state before sending data, to ensure the kernel is ready for it. [1] https://lore.kernel.org/all/346b21d87c69f817ea3c37caceb34f1f56255884.camel@sipsolutions.net/ Signed-off-by: Johannes Berg Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20231204214706.303c62768415.I1caedccae72ee5a45c9085c5eb49c145ce1c0dd5@changeid Signed-off-by: Jakub Kicinski --- include/linux/netdevice.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index cb96aad6a6ee..1b935ee341b4 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4229,6 +4229,15 @@ static inline void netdev_ref_replace(struct net_device *odev, */ void linkwatch_fire_event(struct net_device *dev); +/** + * linkwatch_sync_dev - sync linkwatch for the given device + * @dev: network device to sync linkwatch for + * + * Sync linkwatch for the given device, removing it from the + * pending work list (if queued). + */ +void linkwatch_sync_dev(struct net_device *dev); + /** * netif_carrier_ok - test if carrier present * @dev: network device -- cgit v1.2.3