netdev - Re: [PATCH] ibmvnic: Fix possibly uninitialized old_num_tx

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Date:   Tue, 2 Mar 2021 12:55:21 -0800
From:   Sukadev Bhattiprolu <sukadev@...ux.ibm.com>
To:     Michal Suchanek <msuchanek@...e.de>
Cc:     netdev@...r.kernel.org, Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Dany Madden <drt@...ux.ibm.com>, Lijun Pan <ljp@...ux.ibm.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ibmvnic: Fix possibly uninitialized old_num_tx_queues
 variable warning.

Michal Suchanek [msuchanek@...e.de] wrote:
> GCC 7.5 reports:
> ../drivers/net/ethernet/ibm/ibmvnic.c: In function 'ibmvnic_reset_init':
> ../drivers/net/ethernet/ibm/ibmvnic.c:5373:51: warning: 'old_num_tx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
> ../drivers/net/ethernet/ibm/ibmvnic.c:5373:6: warning: 'old_num_rx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
> 
> The variable is initialized only if(reset) and used only if(reset &&
> something) so this is a false positive. However, there is no reason to
> not initialize the variables unconditionally avoiding the warning.

Yeah, its a false positive, but initializing doesn't hurt.
> 
> Fixes: 635e442f4a48 ("ibmvnic: merge ibmvnic_reset_init and ibmvnic_init")
> Signed-off-by: Michal Suchanek <msuchanek@...e.de>

Reviewed-by: Sukadev Bhattiprolu <sukadev@...ux.ibm.com>