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

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Date:   Thu, 10 Sep 2020 17:31:42 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     David Miller <davem@...emloft.net>
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}

On Thu, Sep 10, 2020 at 03:28:11PM -0700, David Miller wrote:
> 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);"

Ah great, that is indeed cleaner, thank you for letting me know!

Cheers,
Nathan