Re: [PATCH 2/6] fpga: zynqmp: Initialized variables before using it

From: Xu Yilun
Date: Tue Mar 15 2022 - 12:15:58 EST


On Tue, Mar 15, 2022 at 11:48:11AM +0000, Nava kishore Manne wrote:
> Hi Yilun,
>
> Thanks for providing the review comments.
> Please find my response inline.
>
> > -----Original Message-----
> > From: Xu Yilun <yilun.xu@xxxxxxxxx>
> > Sent: Friday, March 11, 2022 7:58 PM
> > To: Nava kishore Manne <navam@xxxxxxxxxx>
> > Cc: mdf@xxxxxxxxxx; hao.wu@xxxxxxxxx; trix@xxxxxxxxxx; Michal Simek
> > <michals@xxxxxxxxxx>; linux-fpga@xxxxxxxxxxxxxxx; linux-
> > kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > Subject: Re: [PATCH 2/6] fpga: zynqmp: Initialized variables before using it
> >
> > On Tue, Mar 08, 2022 at 03:15:15PM +0530, Nava kishore Manne wrote:
> > > This patch initialized variables with the proper value.
> > > Addresses-Coverity: "uninit_use: Using uninitialized value"
> > >
> > > Signed-off-by: Nava kishore Manne <nava.manne@xxxxxxxxxx>
> > > ---
> > > drivers/fpga/zynqmp-fpga.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/fpga/zynqmp-fpga.c b/drivers/fpga/zynqmp-fpga.c
> > > index c60f20949c47..e931d69819a7 100644
> > > --- a/drivers/fpga/zynqmp-fpga.c
> > > +++ b/drivers/fpga/zynqmp-fpga.c
> > > @@ -41,7 +41,7 @@ static int zynqmp_fpga_ops_write(struct
> > fpga_manager *mgr,
> > > const char *buf, size_t size)
> > > {
> > > struct zynqmp_fpga_priv *priv;
> > > - dma_addr_t dma_addr;
> > > + dma_addr_t dma_addr = 0;
> >
> > The first use of this variable is as an output parameter:
> >
> > kbuf = dma_alloc_coherent(priv->dev, size, &dma_addr,
> > GFP_KERNEL);
> >
> > So I don't think it needs to be initialized as 0.
> >
>
> This issue is found by Coverity Scan, Whether this param is input/output this fix will not impact the actual functionality.
> In order to fix the issues reported by the Coverity tool, this fix is needed.

I didn't see issues about this piece of code, so I don't think we need
the fix just to make the tool happy. Maybe the tool could be improved to
help us better.

Thanks,
Yilun

>
> Regards,
> Navakishore.