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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Colin Ian King <colin.king@canonical.com>,
        Johannes Berg <johannes.berg@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 27/33] mac80211: fix rate mask reset
Date:   Mon, 29 Mar 2021 09:58:12 +0200
Message-Id: <20210329075606.132283469@linuxfoundation.org>
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From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit 1944015fe9c1d9fa5e9eb7ffbbb5ef8954d6753b ]

Coverity reported the strange "if (~...)" condition that's
always true. It suggested that ! was intended instead of ~,
but upon further analysis I'm convinced that what really was
intended was a comparison to 0xff/0xffff (in HT/VHT cases
respectively), since this indicates that all of the rates
are enabled.

Change the comparison accordingly.

I'm guessing this never really mattered because a reset to
not having a rate mask is basically equivalent to having a
mask that enables all rates.

Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: 2ffbe6d33366 ("mac80211: fix and optimize MCS mask handling")
Fixes: b119ad6e726c ("mac80211: add rate mask logic for vht rates")
Reviewed-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210212112213.36b38078f569.I8546a20c80bc1669058eb453e213630b846e107b@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/mac80211/cfg.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 8360fda24bca..eac20f4ab924 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2448,14 +2448,14 @@ static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
 			continue;
 
 		for (j = 0; j < IEEE80211_HT_MCS_MASK_LEN; j++) {
-			if (~sdata->rc_rateidx_mcs_mask[i][j]) {
+			if (sdata->rc_rateidx_mcs_mask[i][j] != 0xff) {
 				sdata->rc_has_mcs_mask[i] = true;
 				break;
 			}
 		}
 
 		for (j = 0; j < NL80211_VHT_NSS_MAX; j++) {
-			if (~sdata->rc_rateidx_vht_mcs_mask[i][j]) {
+			if (sdata->rc_rateidx_vht_mcs_mask[i][j] != 0xffff) {
 				sdata->rc_has_vht_mcs_mask[i] = true;
 				break;
 			}
-- 
2.30.1