Re: [PATCH] staging: comedi: fix sparse warning in ni_mio_common.c

Re: [PATCH] staging: comedi: fix sparse warning in ni_mio_common.c

[Ian Abbott]

On 20/06/15 17:47, Geliang Tang wrote:
> This patch fixes the following sparse warning:
>
> drivers/staging/comedi/drivers/ni_mio_common.c:573:26: warning: shift
> too big (4294967295) for type int
>
> Signed-off-by: Geliang Tang <geliangtang@163.com>
> ---
>   drivers/staging/comedi/drivers/ni_mio_common.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
> index 6cc304a..420f752 100644
> --- a/drivers/staging/comedi/drivers/ni_mio_common.c
> +++ b/drivers/staging/comedi/drivers/ni_mio_common.c
> @@ -570,7 +570,7 @@ static inline void ni_set_bitfield(struct comedi_device *dev, int reg,
>   static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel)
>   {
>   	if (channel < 4)
> -		return 1 << channel;
> +		return 1 << (channel & 0x03);
>   	if (channel == 4)
>   		return 0x3;
>   	if (channel == 5)
>

Surely that's a false positive sparse warning?

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti@mev.co.uk> )=-
-=(                          Web: http://www.mev.co.uk/  )=-
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Re: [PATCH] staging: comedi: fix sparse warning in ni_mio_common.c

[Greg KH]

On Sat, Jun 20, 2015 at 04:47:33PM +0000, Geliang Tang wrote:
> This patch fixes the following sparse warning:
> 
> drivers/staging/comedi/drivers/ni_mio_common.c:573:26: warning: shift
> too big (4294967295) for type int
> 
> Signed-off-by: Geliang Tang <geliangtang@163.com>
> ---
>  drivers/staging/comedi/drivers/ni_mio_common.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
> index 6cc304a..420f752 100644
> --- a/drivers/staging/comedi/drivers/ni_mio_common.c
> +++ b/drivers/staging/comedi/drivers/ni_mio_common.c
> @@ -570,7 +570,7 @@ static inline void ni_set_bitfield(struct comedi_device *dev, int reg,
>  static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel)
>  {
>  	if (channel < 4)
> -		return 1 << channel;
> +		return 1 << (channel & 0x03);

Look at the code, this change makes no sense.

Sometimes tools are wrong, use them as a hint, not as something that has
to be silenced.

greg k-h
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[PATCH] staging: comedi: fix sparse warning in ni_mio_common.c

[Geliang Tang]

This patch fixes the following sparse warning:

drivers/staging/comedi/drivers/ni_mio_common.c:573:26: warning: shift
too big (4294967295) for type int

Signed-off-by: Geliang Tang <geliangtang@163.com>
---
 drivers/staging/comedi/drivers/ni_mio_common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
index 6cc304a..420f752 100644
--- a/drivers/staging/comedi/drivers/ni_mio_common.c
+++ b/drivers/staging/comedi/drivers/ni_mio_common.c
@@ -570,7 +570,7 @@ static inline void ni_set_bitfield(struct comedi_device *dev, int reg,
 static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel)
 {
 	if (channel < 4)
-		return 1 << channel;
+		return 1 << (channel & 0x03);
 	if (channel == 4)
 		return 0x3;
 	if (channel == 5)
-- 
1.9.1


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