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

From: Nathan Chancellor <natechancellor@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: kuba@kernel.org, rmk+kernel@armlinux.org.uk, andrew@lunn.ch,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: Re: [PATCH net-next] net: mvpp2: Initialize link in mvpp2_isr_handle_{xlg,gmac_internal}
Date: Thu, 10 Sep 2020 17:31:42 -0700	[thread overview]
Message-ID: <20200911003142.GA2469103@ubuntu-n2-xlarge-x86> (raw)
In-Reply-To: <20200910.152811.210183159970625640.davem@davemloft.net>

On Thu, Sep 10, 2020 at 03:28:11PM -0700, David Miller wrote:
> From: Nathan Chancellor <natechancellor@gmail.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@gmail.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