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From:   Colin King <colin.king@canonical.com>
To:     Woojung Huh <woojung.huh@microchip.com>,
        UNGLinuxDriver@microchip.com, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, Marek Vasut <marex@denx.de>,
        Tristram Ha <Tristram.Ha@microchip.com>, netdev@vger.kernel.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH][next] net: dsa: ksz: Make reg_mib_cnt a u8 as it never exceeds 255
Date:   Wed, 28 Apr 2021 13:00:10 +0100
Message-Id: <20210428120010.337959-1-colin.king@canonical.com>
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From: Colin Ian King <colin.king@canonical.com>

Currently the for-loop in ksz8_port_init_cnt is causing a static
analysis infinite loop warning with the comparison of
mib->cnt_ptr < dev->reg_mib_cnt. This occurs because mib->cnt_ptr
is a u8 and dev->reg_mib_cnt is an int and the analyzer determines
that mib->cnt_ptr potentially can wrap around to zero if the value
in dev->reg_mib_cnt is > 255. However, this value is never this
large, it is always less than 256 so make reg_mib_cnt a u8.

Addresses-Coverity: ("Infinite loop")
Fixes: e66f840c08a2 ("net: dsa: ksz: Add Microchip KSZ8795 DSA driver")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/dsa/microchip/ksz_common.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index e0bbdca64375..2e6bfd333f50 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -69,7 +69,7 @@ struct ksz_device {
 	int cpu_ports;			/* port bitmap can be cpu port */
 	int phy_port_cnt;
 	int port_cnt;
-	int reg_mib_cnt;
+	u8 reg_mib_cnt;
 	int mib_cnt;
 	const struct mib_names *mib_names;
 	phy_interface_t compat_interface;
-- 
2.30.2