[PATCH] dma: imx-dma: fix signedness bug

[PATCH] dma: imx-dma: fix signedness bug

[Vasiliy Kulikov]

mxdmac->channel was unsigned, so check (imxdmac->channel < 0) for
failed imx_dma_request_by_prio() made no sence.  Explicitly check
signed values.

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
---
 drivers/dma/imx-dma.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
index 346be62..75d870f 100644
--- a/drivers/dma/imx-dma.c
+++ b/drivers/dma/imx-dma.c
@@ -335,7 +335,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
 
 		imxdmac->imxdma_channel = imx_dma_request_by_prio("dmaengine",
 				DMA_PRIO_MEDIUM);
-		if (imxdmac->channel < 0)
+		if ((int)imxdmac->channel < 0)
 			goto err_init;
 
 		imx_dma_setup_handlers(imxdmac->imxdma_channel,
-- 
1.7.0.4

Re: [PATCH] dma: imx-dma: fix signedness bug

[Sascha Hauer]

On Sun, Oct 17, 2010 at 06:51:50PM +0400, Vasiliy Kulikov wrote:
> mxdmac->channel was unsigned, so check (imxdmac->channel < 0) for
> failed imx_dma_request_by_prio() made no sence.  Explicitly check
> signed values.
> 
> Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>

Acked-by: Sascha Hauer <s.hauer@pengutronix.de>

> ---
>  drivers/dma/imx-dma.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
> index 346be62..75d870f 100644
> --- a/drivers/dma/imx-dma.c
> +++ b/drivers/dma/imx-dma.c
> @@ -335,7 +335,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
>  
>  		imxdmac->imxdma_channel = imx_dma_request_by_prio("dmaengine",
>  				DMA_PRIO_MEDIUM);
> -		if (imxdmac->channel < 0)
> +		if ((int)imxdmac->channel < 0)
>  			goto err_init;
>  
>  		imx_dma_setup_handlers(imxdmac->imxdma_channel,
> -- 
> 1.7.0.4
> 
> 

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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Re: [PATCH] dma: imx-dma: fix signedness bug

[Dan Williams]

On Sun, Oct 17, 2010 at 7:51 AM, Vasiliy Kulikov <segooon@gmail.com> wrote:
> mxdmac->channel was unsigned, so check (imxdmac->channel < 0) for
> failed imx_dma_request_by_prio() made no sence.  Explicitly check
> signed values.
>
> Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
> ---
>  drivers/dma/imx-dma.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
> index 346be62..75d870f 100644
> --- a/drivers/dma/imx-dma.c
> +++ b/drivers/dma/imx-dma.c
> @@ -335,7 +335,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
>
>                imxdmac->imxdma_channel = imx_dma_request_by_prio("dmaengine",
>                                DMA_PRIO_MEDIUM);
> -               if (imxdmac->channel < 0)
> +               if ((int)imxdmac->channel < 0)
>                        goto err_init;

Should this be:

               if ((int)imxdmac->channel < 0) {
                       ret = -ENODEV;
                       goto err_init;
               }

...because I get the following in my compilation tests.
drivers/dma/imx-dma.c: In function 'imxdma_probe':
drivers/dma/imx-dma.c:324: warning: 'ret' may be used uninitialized in
this function

--
Dan
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Re: [PATCH] dma: imx-dma: fix signedness bug

[Sascha Hauer]

On Tue, Oct 19, 2010 at 03:26:05PM -0700, Dan Williams wrote:
> On Sun, Oct 17, 2010 at 7:51 AM, Vasiliy Kulikov <segooon@gmail.com> wrote:
> > mxdmac->channel was unsigned, so check (imxdmac->channel < 0) for
> > failed imx_dma_request_by_prio() made no sence.  Explicitly check
> > signed values.
> >
> > Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
> > ---
> >  drivers/dma/imx-dma.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
> > index 346be62..75d870f 100644
> > --- a/drivers/dma/imx-dma.c
> > +++ b/drivers/dma/imx-dma.c
> > @@ -335,7 +335,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
> >
> >                imxdmac->imxdma_channel = imx_dma_request_by_prio("dmaengine",
> >                                DMA_PRIO_MEDIUM);
> > -               if (imxdmac->channel < 0)
> > +               if ((int)imxdmac->channel < 0)
> >                        goto err_init;
> 
> Should this be:
> 
>                if ((int)imxdmac->channel < 0) {
>                        ret = -ENODEV;
>                        goto err_init;
>                }
> 
> ...because I get the following in my compilation tests.

Yes, ret is clearly used uninitialized. I wonder why my gcc-4.3.2 compiler
does not warn me about this :(

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
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Re: [PATCH] dma: imx-dma: fix signedness bug

[Sascha Hauer]

mxdmac->channel was unsigned, so check (imxdmac->channel < 0) for
failed imx_dma_request_by_prio() made no sence.  Explicitly check
signed values.
Also, fix uninitialzed use of ret.

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---

Here's an updated patch fixing both issues.

 drivers/dma/imx-dma.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
index 346be62..f629e49 100644
--- a/drivers/dma/imx-dma.c
+++ b/drivers/dma/imx-dma.c
@@ -335,8 +335,10 @@ static int __init imxdma_probe(struct platform_device *pdev)
 
 		imxdmac->imxdma_channel = imx_dma_request_by_prio("dmaengine",
 				DMA_PRIO_MEDIUM);
-		if (imxdmac->channel < 0)
+		if ((int)imxdmac->channel < 0) {
+			ret = -ENODEV;
 			goto err_init;
+		}
 
 		imx_dma_setup_handlers(imxdmac->imxdma_channel,
 		       imxdma_irq_handler, imxdma_err_handler, imxdmac);
-- 
1.7.2.3

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |