[PATCH] ethdev: fix strict aliasing lead to link cannot be up

[Morten Brørup]

> From: fengchengwen [mailto:fengchengwen at huawei.com]
> Sent: Thursday, 11 April 2024 13.58

[...]

> Plus: yes, this patch mixes atomic and non-atomic access, but the main
> reason is that we want to simplify the implementation.

Yes, your design in patch v3 follows the current standard design pattern for atomics in DPDK.
I agree with you on this.

Thank you for describing the alternative, though.

> If we want to separate it clearly,
> maybe we should defined as this:
>     struct rte_eth_link {
>         union {
>             RTE_ATOMIC(uint64_t) atomic64; /**< used for atomic64
> read/write */
>             struct {
>                 uint64_t val64;
>             };
>             struct {
>                 uint32_t link_speed;	    /**< RTE_ETH_SPEED_NUM_ */
>                 uint16_t link_duplex  : 1;  /**<
> RTE_ETH_LINK_[HALF/FULL]_DUPLEX */
>                 uint16_t link_autoneg : 1;  /**<
> RTE_ETH_LINK_[AUTONEG/FIXED] */
>                 uint16_t link_status  : 1;  /**< RTE_ETH_LINK_[DOWN/UP]
> */
>             };
>         };
>     };

PS: More review comments provided in reply to the v3 patch.