[PATCH][next] net: dsa: ksz: Make reg_mib_cnt a u8 as it never exceeds 255

[PATCH][next] net: dsa: ksz: Make reg_mib_cnt a u8 as it never exceeds 255

[Colin King]

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

Re: [PATCH][next] net: dsa: ksz: Make reg_mib_cnt a u8 as it never exceeds 255

[Florian Fainelli]

On 4/28/2021 5:00 AM, Colin King wrote:
> 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.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH][next] net: dsa: ksz: Make reg_mib_cnt a u8 as it never exceeds 255

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Wed, 28 Apr 2021 13:00:10 +0100 you wrote:
> 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.
> 
> [...]

Here is the summary with links:
  - [next] net: dsa: ksz: Make reg_mib_cnt a u8 as it never exceeds 255
    https://git.kernel.org/netdev/net-next/c/12c2bb96c3f1

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html