From: Johannes Berg <johannes.berg@xxxxxxxxx>
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 <johannes.berg@xxxxxxxxx>
---
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..3f7820b2ea4d 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_addr);
+ 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
