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From: Johannes Berg <johannes.berg@intel.com>
Date: Tue, 14 Feb 2023 20:08:15 +0100
Subject: [PATCH] wifi: mac80211: fix off-by-one link setting
References: bsc#1012628
Patch-mainline: 6.2.3
Git-commit: cf08e29db760b144bde51e2444f3430c75763e26

[ Upstream commit cf08e29db760b144bde51e2444f3430c75763e26 ]

The convention for find_first_bit() is 0-based, while ffs()
is 1-based, so this is now off-by-one. I cannot reproduce the
gcc-9 problem, but since the -1 is now removed, I'm hoping it
will still avoid the original issue.

Reported-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Fixes: 1d8d4af43474 ("wifi: mac80211: avoid u32_encode_bits() warning")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 net/mac80211/tx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 118648af..7699fb41 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -4434,7 +4434,7 @@ static void ieee80211_mlo_multicast_tx(struct net_device *dev,
 	u32 ctrl_flags = IEEE80211_TX_CTRL_MCAST_MLO_FIRST_TX;
 
 	if (hweight16(links) == 1) {
-		ctrl_flags |= u32_encode_bits(find_first_bit(&links, 16) - 1,
+		ctrl_flags |= u32_encode_bits(__ffs(links),
 					      IEEE80211_TX_CTRL_MLO_LINK);
 
 		__ieee80211_subif_start_xmit(skb, sdata->dev, 0, ctrl_flags,
-- 
2.35.3