netdev - Re: [PATCH net-next] net: mvpp2: Initialize link in mvpp2_isr_handle_{xlg,gmac

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Date:   Thu, 10 Sep 2020 15:28:11 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     natechancellor@...il.com
Cc:     kuba@...nel.org, rmk+kernel@...linux.org.uk, andrew@...n.ch,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        clang-built-linux@...glegroups.com
Subject: Re: [PATCH net-next] net: mvpp2: Initialize link in
 mvpp2_isr_handle_{xlg,gmac_internal}

From: Nathan Chancellor <natechancellor@...il.com>
Date: Thu, 10 Sep 2020 10:48:27 -0700

> Clang warns (trimmed for brevity):
> 
> drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:3073:7: warning:
> variable 'link' is used uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
>                 if (val & MVPP22_XLG_STATUS_LINK_UP)
>                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:3075:31: note:
> uninitialized use occurs here
>                 mvpp2_isr_handle_link(port, link);
>                                             ^~~~
> ...
> drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:3090:8: warning:
> variable 'link' is used uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
>                         if (val & MVPP2_GMAC_STATUS0_LINK_UP)
>                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:3092:32: note:
> uninitialized use occurs here
>                         mvpp2_isr_handle_link(port, link);
>                                                     ^~~~
> 
> Initialize link to false like it was before the refactoring that
> happened around link status so that a valid valid is always passed into
> mvpp2_isr_handle_link.
> 
> Fixes: 36cfd3a6e52b ("net: mvpp2: restructure "link status" interrupt handling")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1151
> Signed-off-by: Nathan Chancellor <natechancellor@...il.com>

This got fixed via another change, a much mode simply one in fact,
changing the existing assignments to be unconditional and of the
form "link = (bits & MASK);"