From: Johannes Berg <[email protected]> Fix cfg80211_gen_new_bssid() to not rely on u64 modulo arithmetic, which isn't needed since we really just want to mask there. Also, clean it up to calculate the mask only once and use GENMASK_ULL() instead of open-coding the mask calculation.
Signed-off-by: Johannes Berg <[email protected]> --- include/net/cfg80211.h | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index b61b71f369c7..02a4d5a80521 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -5475,22 +5475,20 @@ cfg80211_inform_bss_frame(struct wiphy *wiphy, * @bssid: transmitter BSSID * @max_bssid: max BSSID indicator, taken from Multiple BSSID element * @mbssid_index: BSSID index, taken from Multiple BSSID index element - * @new_bssid_addr: address of the resulting BSSID + * @new_bssid: address of the resulting BSSID */ static inline void cfg80211_gen_new_bssid(const u8 *bssid, u8 max_bssid, - u8 mbssid_index, u8 *new_bssid_addr) + u8 mbssid_index, u8 *new_bssid) { - u64 bssid_tmp, new_bssid; - u64 lsb_n; + u64 bssid_u64 = ether_addr_to_u64(bssid); + u64 mask = GENMASK_ULL(max_bssid - 1, 0); + u64 new_bssid_u64; - bssid_tmp = ether_addr_to_u64(bssid); + new_bssid_u64 = bssid_u64 & ~mask; - lsb_n = bssid_tmp & ((1 << max_bssid) - 1); - new_bssid = bssid_tmp; - new_bssid &= ~((1 << max_bssid) - 1); - new_bssid |= (lsb_n + mbssid_index) % (1 << max_bssid); + new_bssid_u64 |= ((bssid_u64 & mask) + mbssid_index) & mask; - u64_to_ether_addr(new_bssid, new_bssid_addr); + u64_to_ether_addr(new_bssid_u64, new_bssid); } /** -- 2.17.2
