[...]

> diff --git a/drivers/net/ethernet/airoha/airoha_eth.h b/drivers/net/ethernet/airoha/airoha_eth.h
> index 447a5a9552bb..fa9a8edce22f 100644
> --- a/drivers/net/ethernet/airoha/airoha_eth.h
> +++ b/drivers/net/ethernet/airoha/airoha_eth.h
> @@ -572,11 +572,12 @@ struct airoha_qdma {
>  
>  enum airoha_dev_flags {
>  	AIROHA_DEV_F_WAN,
> +	AIROHA_DEV_F_TX_QOS,
>  };
>  
>  struct airoha_gdm_dev {
> +	struct airoha_qdma __rcu *qdma;
>  	struct airoha_gdm_port *port;
> -	struct airoha_qdma *qdma;
>  	struct airoha_eth *eth;
>  
>  	DECLARE_BITMAP(qos_sq_bmap, AIROHA_NUM_QOS_CHANNELS);
> @@ -589,6 +590,11 @@ struct airoha_gdm_dev {
>  	int nbq;
>  
>  	struct airoha_hw_stats stats;
> +
> +	/* Serialize netdev_tx_completed_queue() calls per TX queue during
> +	 * QDMA migration.
> +	 */
> +	spinlock_t txq_lock[AIROHA_NUM_NETDEV_TX_RINGS];
>  };
>  
>  struct airoha_gdm_port {
> @@ -712,6 +718,16 @@ int airoha_get_fe_port(struct airoha_gdm_dev *dev);
>  bool airoha_is_valid_gdm_dev(struct airoha_eth *eth,
>  			     struct airoha_gdm_dev *dev);
>  
> +extern struct mutex flow_offload_mutex;

commenting on sashiko's report:
https://sashiko.dev/#/patchset/20260725-airoha-ethtool-priv_flags-v12-0-5136a30b2157%40kernel.org

- Would it be safer to namespace this mutex here to prevent potential multiple
  definition errors during the build?
  - I guess we can rename the mutex if required in a subsequent patch.

Regards,
Lorenzo

> +
> +static inline struct airoha_qdma *
> +airoha_qdma_deref(struct airoha_gdm_dev *dev)
> +{
> +	return rcu_dereference_protected(dev->qdma,
> +					 lockdep_rtnl_is_held() ||
> +					 lockdep_is_held(&flow_offload_mutex));
> +}
> +
>  void airoha_ppe_set_xmit_frame_size(struct airoha_gdm_dev *dev);
>  void airoha_ppe_set_cpu_port(struct airoha_gdm_dev *dev, u8 ppe_id, u8 fport);
>  bool airoha_ppe_is_enabled(struct airoha_eth *eth, int index);
> diff --git a/drivers/net/ethernet/airoha/airoha_ppe.c b/drivers/net/ethernet/airoha/airoha_ppe.c
> index e4c3644dd6ec..33ddf0d07855 100644
> --- a/drivers/net/ethernet/airoha/airoha_ppe.c
> +++ b/drivers/net/ethernet/airoha/airoha_ppe.c
> @@ -15,7 +15,10 @@
>  #include "airoha_regs.h"
>  #include "airoha_eth.h"
>  
> -static DEFINE_MUTEX(flow_offload_mutex);
> +/* Serialize airoha_gdm_dev flags, QDMA pointer and PPE CPU port
> + * configuration.
> + */
> +DEFINE_MUTEX(flow_offload_mutex);
>  static DEFINE_SPINLOCK(ppe_lock);
>  
>  static const struct rhashtable_params airoha_flow_table_params = {
> @@ -86,8 +89,8 @@ static u32 airoha_ppe_get_timestamp(struct airoha_ppe *ppe)
>  
>  void airoha_ppe_set_cpu_port(struct airoha_gdm_dev *dev, u8 ppe_id, u8 fport)
>  {
> -	struct airoha_qdma *qdma = dev->qdma;
> -	struct airoha_eth *eth = qdma->eth;
> +	struct airoha_qdma *qdma = airoha_qdma_deref(dev);
> +	struct airoha_eth *eth = dev->eth;
>  	u8 qdma_id = qdma - &eth->qdma[0];
>  	u32 fe_cpu_port;
>  
> diff --git a/drivers/net/ethernet/airoha/airoha_regs.h b/drivers/net/ethernet/airoha/airoha_regs.h
> index 6fed63d013b4..442b48c9b991 100644
> --- a/drivers/net/ethernet/airoha/airoha_regs.h
> +++ b/drivers/net/ethernet/airoha/airoha_regs.h
> @@ -375,6 +375,7 @@
>  
>  #define REG_SRC_PORT_FC_MAP6		0x2298
>  #define FC_ID_OF_SRC_PORT_MASK(_n)	GENMASK(4 + ((_n) << 3), ((_n) << 3))
> +#define FC_MAP6_DEF_VALUE		0x1b1a1918
>  
>  #define REG_WAN_MTU0			0x2300
>  #define WAN_MTU1_MASK			GENMASK(29, 16)
> 
> -- 
> 2.55.0
>