@@ -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;
@@ -2522,7 +2522,8 @@ 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.
*/
@@ -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)
{
@@ -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;
@@ -6886,8 +6886,7 @@ 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:
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. Signed-off-by: Jakub Kicinski <kuba@kernel.org> --- include/linux/netdevice.h | 5 +++-- include/net/netdev_lock.h | 8 ++++++++ include/net/netdev_rx_queue.h | 2 +- net/core/dev.c | 3 +-- 4 files changed, 13 insertions(+), 5 deletions(-)