Re: [PATCH] mt7601u: fix always true expression
From: Kalle Valo
Date: Sun Apr 11 2021 - 05:30:26 EST
Colin King <colin.king@xxxxxxxxxxxxx> wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> Currently the expression ~nic_conf1 is always true because nic_conf1
> is a u16 and according to 6.5.3.3 of the C standard the ~ operator
> promotes the u16 to an integer before flipping all the bits. Thus
> the top 16 bits of the integer result are all set so the expression
> is always true. If the intention was to flip all the bits of nic_conf1
> then casting the integer result back to a u16 is a suitabel fix.
>
> Interestingly static analyzers seem to thing a bitwise ! should be
> used instead of ~ for this scenario, so I think the original intent
> of the expression may need some extra consideration.
>
> Addresses-Coverity: ("Logical vs. bitwise operator")
> Fixes: c869f77d6abb ("add mt7601u driver")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> Acked-by: Jakub Kicinski <kubakici@xxxxx>
Patch applied to wireless-drivers-next.git, thanks.
87fce88658ba mt7601u: fix always true expression
--
https://patchwork.kernel.org/project/linux-wireless/patch/20210225183241.1002129-1-colin.king@xxxxxxxxxxxxx/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches