On 2/18/2026 1:38 AM, Gustavo A. R. Silva wrote:
>
>>> @@ -1652,7 +1656,7 @@ struct roam_ctrl_cmd {
>>> union {
>>> u8 bssid[ETH_ALEN]; /* WMI_FORCE_ROAM */
>>> u8 roam_mode; /* WMI_SET_ROAM_MODE */
>>> - struct bss_bias_info bss; /* WMI_SET_HOST_BIAS */
>>> + struct bss_bias_info_hdr bss; /* WMI_SET_HOST_BIAS */
>>> struct low_rssi_scan_params params; /* WMI_SET_LRSSI_SCAN_PARAMS
>>> */
>>> } __packed info;
>>
>> That bss member appears to be completely unused
>> (bssid, roam_mode, and params are used)
>>
>> So IMO the better solution is to remove bss from the union.
>> And I think struct bss_bias and struct bss_bias_info can also be removed.
>
> Even if they're not used, are you sure they aren't there simply
> to define the memory layout of struct roam_ctrl_cmd?
>
> As Kees commented[1], struct roam_ctrl_cmd appears to be a
> hardware interface... See below:
>
> drivers/net/wireless/ath/ath6kl/wmi.c:
> 755 /*
> 756 * Mechanism to modify the roaming behavior in the firmware. The lower
> rssi
> 757 * at which the station has to roam can be passed with
> 758 * WMI_SET_LRSSI_SCAN_PARAMS. Subtract 96 from RSSI to get the signal
> level
> 759 * in dBm.
> 760 */
> 761 int ath6kl_wmi_set_roam_lrssi_cmd(struct wmi *wmi, u8 lrssi)
> 762 {
> 763 struct sk_buff *skb;
> 764 struct roam_ctrl_cmd *cmd;
> 765
> 766 skb = ath6kl_wmi_get_new_buf(sizeof(*cmd));
> 767 if (!skb)
> 768 return -ENOMEM;
> 769
> 770 cmd = (struct roam_ctrl_cmd *) skb->data;
> ...
> }
yes, it defines a hardware interface. But note the 'info' is a union, and each
member of the union is there to support a specific value of roam_ctrl. And
since the WMI_SET_HOST_BIAS roam_ctrl is not used, the only important thing to
consider with your patch is that the location of the roam_ctrl field must not
change, and hence the size of union info must not change.
pahole of the original:
struct roam_ctrl_cmd {
union {
u8 bssid[6]; /* 0 6 */
u8 roam_mode; /* 0 1 */
struct bss_bias_info bss; /* 0 1 */
struct low_rssi_scan_params params; /* 0 8 */
} info; /* 0 8 */
u8 roam_ctrl; /* 8 1 */
/* size: 9, cachelines: 1, members: 2 */
/* last cacheline: 9 bytes */
} __attribute__((__packed__));
pahole with struct bss removed:
struct roam_ctrl_cmd {
union {
u8 bssid[6]; /* 0 6 */
u8 roam_mode; /* 0 1 */
struct low_rssi_scan_params params; /* 0 8 */
} info; /* 0 8 */
u8 roam_ctrl; /* 8 1 */
/* size: 9, cachelines: 1, members: 2 */
/* last cacheline: 9 bytes */
} __attribute__((__packed__));
So the size of the message and the location of roam_ctrl is unchanged.
/jeff
