On Thu, 2019-01-24 at 19:05 +0100, Mathieu Malaterre wrote:
> During refactor in commit 9e478066eae4 ("mac80211: fix MU-MIMO
> follow-MAC mode") a new struct 'action' was declared with packed
> attribute as:
>
> struct {
> struct ieee80211_hdr_3addr hdr;
> u8 category;
> u8 action_code;
> } __packed action;
>
> But since struct 'ieee80211_hdr_3addr' is declared with an aligned
> keyword as:
>
> struct ieee80211_hdr {
> __le16 frame_control;
> __le16 duration_id;
> u8 addr1[ETH_ALEN];
> u8 addr2[ETH_ALEN];
> u8 addr3[ETH_ALEN];
> __le16 seq_ctrl;
> u8 addr4[ETH_ALEN];
> } __packed __aligned(2);
>
> Solve the ambiguity of placing aligned structure in a packed one by
> removing the packed attribute from struct. This seems to be the behavior
> of gcc anyway, since the following is still compiling:
>
> BUILD_BUG_ON(sizeof(action) != IEEE80211_MIN_ACTION_SIZE + 1);
I'm not sure this will work on all platforms, didn't something like
alpha pad out u8's to u32 when not requiring packing?
I guess I'd feel better about using __packed __aligned(2) here as well,
which should solve the warning too?
johannes
