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From:   John Wood <john.wood@gmx.com>
To:     Felix Fietkau <nbd@nbd.name>,
        Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>,
        Ryder Lee <ryder.lee@mediatek.com>
Cc:     John Wood <john.wood@gmx.com>, Kalle Valo <kvalo@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Shayne Chen <shayne.chen@mediatek.com>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] mt76/mt7915: Fix unsigned compared against zero
Date:   Sat, 12 Jun 2021 16:35:05 +0200
Message-Id: <20210612143505.7637-1-john.wood@gmx.com>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

The mt7915_dpd_freq_idx() function can return a negative value but this
value is assigned to an unsigned variable named idx. Then, the code
tests if this variable is less than zero. This can never happen with an
unsigned type.

So, change the idx type to a signed one.

Addresses-Coverity-ID: 1484753 ("Unsigned compared against 0")
Fixes: 495184ac91bb8 ("mt76: mt7915: add support for applying pre-calibrat=
ion data")
Signed-off-by: John Wood <john.wood@gmx.com>
=2D--
 drivers/net/wireless/mediatek/mt76/mt7915/mcu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c b/drivers/net=
/wireless/mediatek/mt76/mt7915/mcu.c
index b3f14ff67c5a..764f25a828fa 100644
=2D-- a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
@@ -3440,8 +3440,9 @@ int mt7915_mcu_apply_tx_dpd(struct mt7915_phy *phy)
 {
 	struct mt7915_dev *dev =3D phy->dev;
 	struct cfg80211_chan_def *chandef =3D &phy->mt76->chandef;
-	u16 total =3D 2, idx, center_freq =3D chandef->center_freq1;
+	u16 total =3D 2, center_freq =3D chandef->center_freq1;
 	u8 *cal =3D dev->cal, *eep =3D dev->mt76.eeprom.data;
+	int idx;

 	if (!(eep[MT_EE_DO_PRE_CAL] & MT_EE_WIFI_CAL_DPD))
 		return 0;
=2D-
2.25.1