Re: [PATCH] powerpc/powernv/sriov: fix unsigned int win compared to less than zero

From: Michael Ellerman <mpe@ellerman.id.au>
To: Andrew Donnellan <ajd@linux.ibm.com>,
	xiakaixu1987@gmail.com, fbarrat@linux.ibm.com,
	benh@kernel.crashing.org, paulus@samba.org
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	Kaixu Xia <kaixuxia@tencent.com>
Subject: Re: [PATCH] powerpc/powernv/sriov: fix unsigned int win compared to less than zero
Date: Tue, 17 Nov 2020 14:07:29 +1100	[thread overview]
Message-ID: <87zh3g3clq.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <40b8ba6f-4916-55c2-a1f0-b7daa3c2e201@linux.ibm.com>

Andrew Donnellan <ajd@linux.ibm.com> writes:

> On 10/11/20 10:19 pm, xiakaixu1987@gmail.com wrote:
>> From: Kaixu Xia <kaixuxia@tencent.com>
>> 
>> Fix coccicheck warning:
>> 
>> ./arch/powerpc/platforms/powernv/pci-sriov.c:443:7-10: WARNING: Unsigned expression compared with zero: win < 0
>> ./arch/powerpc/platforms/powernv/pci-sriov.c:462:7-10: WARNING: Unsigned expression compared with zero: win < 0
>> 
>> Reported-by: Tosk Robot <tencent_os_robot@tencent.com>
>> Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
>
> This seems like the right fix, the value assigned to win can indeed be 
> -1 so it should be signed. Thanks for sending the patch.
>
> Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>

I'll add:

  Fixes: 39efc03e3ee8 ("powerpc/powernv/sriov: Move M64 BAR allocation into a helper")

Which I think is the culprit as it changed:

  if (win >= phb->ioda.m64_bar_idx + 1)

to:

  if (win < 0)

cheers