Re: [PATCH net-next 3/4] s390/diag: add diag26c support

[David Miller <davem@davemloft.net>]

From: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Date: Mon, 19 Jun 2017 13:22:24 +0200

> +#define DIAG26C_GET_MAC	0x0000
> +struct diag26c_mac_req {
> +	u32	resp_buf_len;
> +	u32	resp_version;
> +	u16	op_code;
> +	u16	devno;
> +	u8	res[4];
> +} __packed;

The packed attribute is not necessary here, the structure will be
perfectly packed together because of the types used and the order of
the members.

__packed is to be used only in the last possible resort for
correctness and every effort whatsoever should be used to avoid using
it.

> +
> +struct diag26c_mac_resp {
> +	u32	version;
> +	u8	mac[ETH_ALEN];
> +	u16	res;
> +} __packed __aligned(8);

Using packed with an 8 byte alignment is even more unnecessary.

Again, it is not needed, so please don't use it.

> + */
> +static inline int __diag26c(void *req, void *resp, enum diag26c_sc subcode)

Do not mark functions inline in *.c files, let the compiler decide.