diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2025-03-24 15:45:32 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-03-25 10:06:49 -0700 |
| commit | 310ae9eb2617c62deedef8f121d7ca1ae774fa76 (patch) | |
| tree | 2257965b50c36fe428e5040ef6f040e675bbda35 | |
| parent | 0a65dcf6249b75c841b4218426b0d246a805c7e0 (diff) | |
net: designate queue -> napi linking as "ops protected"
netdev netlink is the only reader of netdev_{,rx_}queue->napi,
and it already holds netdev->lock. Switch protection of
the writes to netdev->lock to "ops protected".
The expectation will be now that accessing queue->napi
will require netdev->lock for "ops locked" drivers, and
rtnl_lock for all other drivers.
Current "ops locked" drivers don't require any changes.
gve and netdevsim use _locked() helpers right next to
netif_queue_set_napi() so they must be holding the instance
lock. iavf doesn't call it. bnxt is a bit messy but all paths
seem locked.
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250324224537.248800-7-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | include/linux/netdevice.h | 5 | ||||
| -rw-r--r-- | include/net/netdev_lock.h | 8 | ||||
| -rw-r--r-- | include/net/netdev_rx_queue.h | 2 | ||||
| -rw-r--r-- | net/core/dev.c | 3 |
4 files changed, 13 insertions, 5 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 60ef367d8575..fa79145518d1 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -710,7 +710,7 @@ struct netdev_queue { * slow- / control-path part */ /* NAPI instance for the queue - * Readers and writers must hold RTNL + * "ops protected", see comment about net_device::lock */ struct napi_struct *napi; @@ -2526,7 +2526,8 @@ struct net_device { * Double ops protects: * @real_num_rx_queues, @real_num_tx_queues * - * Also protects some fields in struct napi_struct. + * Also protects some fields in: + * struct napi_struct, struct netdev_queue, struct netdev_rx_queue * * Ordering: take after rtnl_lock. */ diff --git a/include/net/netdev_lock.h b/include/net/netdev_lock.h index efd302375ef2..1c0c9a94cc22 100644 --- a/include/net/netdev_lock.h +++ b/include/net/netdev_lock.h @@ -56,6 +56,14 @@ static inline void netdev_ops_assert_locked(const struct net_device *dev) ASSERT_RTNL(); } +static inline void +netdev_ops_assert_locked_or_invisible(const struct net_device *dev) +{ + if (dev->reg_state == NETREG_REGISTERED || + dev->reg_state == NETREG_UNREGISTERING) + netdev_ops_assert_locked(dev); +} + static inline int netdev_lock_cmp_fn(const struct lockdep_map *a, const struct lockdep_map *b) { diff --git a/include/net/netdev_rx_queue.h b/include/net/netdev_rx_queue.h index af40842f229d..b2238b551dce 100644 --- a/include/net/netdev_rx_queue.h +++ b/include/net/netdev_rx_queue.h @@ -24,7 +24,7 @@ struct netdev_rx_queue { struct xsk_buff_pool *pool; #endif /* NAPI instance for the queue - * Readers and writers must hold RTNL + * "ops protected", see comment about net_device::lock */ struct napi_struct *napi; struct pp_memory_provider_params mp_params; diff --git a/net/core/dev.c b/net/core/dev.c index 2d9be3ecd5e6..ab74e1f005d2 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6901,8 +6901,7 @@ void netif_queue_set_napi(struct net_device *dev, unsigned int queue_index, if (WARN_ON_ONCE(napi && !napi->dev)) return; - if (dev->reg_state >= NETREG_REGISTERED) - ASSERT_RTNL(); + netdev_ops_assert_locked_or_invisible(dev); switch (type) { case NETDEV_QUEUE_TYPE_RX: |