Re: [PATCH net-next] eea: Add basic driver framework for Alibaba Elastic Ethernet Adaptor

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

On 10/07/2025 12:28, Xuan Zhuo wrote:
> +/* notify */
> +bool ering_kick(struct ering *ering)
> +{
> +	union {
> +		u64 data;
> +		struct db db;
> +	} val;
> +
> +	val.db.kick_flags = EEA_IDX_PRESENT;
> +	val.db.idx = cpu_to_le16(ering->sq.hw_idx);
> +
> +	writeq(val.data, (void __iomem *)ering->db);
> +
> +	return true;
> +}
> +

[...]

> +static inline bool ering_irq_unactive(struct ering *ering)
> +{
> +	union {
> +		u64 data;
> +		struct db db;
> +	} val;
> +
> +	if (ering->mask == EEA_IRQ_MASK)
> +		return true;
> +
> +	ering->mask = EEA_IRQ_MASK;
> +
> +	val.db.kick_flags = EEA_IRQ_MASK;
> +
> +	writeq(val.data, (void __iomem *)ering->db);
> +
> +	return true;
> +}
> +
> +static inline bool ering_irq_active(struct ering *ering, struct ering *tx_ering)
> +{
> +	union {
> +		u64 data;
> +		struct db db;
> +	} val;
> +
> +	if (ering->mask == EEA_IRQ_UNMASK)
> +		return true;
> +
> +	ering->mask = EEA_IRQ_UNMASK;
> +
> +	val.db.kick_flags = EEA_IRQ_UNMASK;
> +
> +	val.db.tx_cq_head = cpu_to_le16(tx_ering->cq.hw_idx);
> +	val.db.rx_cq_head = cpu_to_le16(ering->cq.hw_idx);
> +
> +	writeq(val.data, (void __iomem *)ering->db);
> +
> +	return true;
> +}

in addition to Andrew's comments, these union { ... } val will have
partial garbage values, which will later be directly sent to FW. I
believe it may cause some troubles and it's better to initialize val
before actually use it.