linux-kernel - Re: [PATCH] qla2xxx: avoid maybe

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Date:	Wed, 16 Mar 2016 14:05:07 +0000
From:	Himanshu Madhani <himanshu.madhani@...gic.com>
To:	Arnd Bergmann <arnd@...db.de>,
	James Bottomley <jejb@...ux.vnet.ibm.com>
CC:	Dept-Eng QLA2xxx Upstream <qla2xxx-upstream@...gic.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	Nicholas Bellinger <nab@...ux-iscsi.org>,
	Quinn Tran <quinn.tran@...gic.com>,
	Alexei Potashnik <alexei@...estorage.com>,
	Bart Van Assche <bart.vanassche@...disk.com>,
	Swapnil Nagle <swapnil.nagle@...estorage.com>,
	linux-scsi <linux-scsi@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] qla2xxx: avoid maybe_uninitialized warning



On 3/16/16, 5:59 AM, "Arnd Bergmann" <arnd@...db.de> wrote:

>On Tuesday 15 March 2016 14:49:14 James Bottomley wrote:
>> On Tue, 2016-03-15 at 22:40 +0100, Arnd Bergmann wrote:
>> > 
>> > This slightly rearranges the code to move the second if() block
>> > into the first one, to avoid the warning while retaining the
>> > behavior of the code.
>> 
>> I thought our usual policy was to ask someone to fix the compiler when
>> it emitted a spurious warning.
>
>No, the rule is that we shouldn't blindly add initializations to
>the variables when the compiler should have figured it out.
>
>In this case, I wouldn't expect the compiler to ever see through
>the unlikely() macro, and I'm not adding a potentially counterproductive
>initialization, so I see no reason not to apply the patch.

I would like to keep unlikely() macro in the code. This patch looks good.

Acked-By: Himanshu Madhani <himanshu.madhani@...gic.com>

>
>Making it easier for the compiler to figure out what is going
>on should also lead to slightly better object code. If you think
>my patch makes it less readable, an alternative would be to remove
>the 'unlikely', which also gets rid of the warning.
>
>	Arnd