[Linux-kernel-mentee, PATCH] media: dvb_frontend.h: Fix shifting signed 32-bit value problem

[Linux-kernel-mentee, PATCH] media: dvb_frontend.h: Fix shifting signed 32-bit value problem

[Luke Nowakowski-Krijger]

Fix DVBFE_ALGO_RECOVERY and DVBFE_ALGO_SEARCH_ERROR to use U cast which
fixes undefined behavior error by certain compilers. 

Signed-off-by: Luke Nowakowski-Krijger <lnowakow@eng.ucsd.edu>
---
 include/media/dvb_frontend.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/media/dvb_frontend.h b/include/media/dvb_frontend.h
index f05cd7b94a2c..472fe5871d94 100644
--- a/include/media/dvb_frontend.h
+++ b/include/media/dvb_frontend.h
@@ -144,7 +144,7 @@ enum dvbfe_algo {
 	DVBFE_ALGO_HW			= (1 <<  0),
 	DVBFE_ALGO_SW			= (1 <<  1),
 	DVBFE_ALGO_CUSTOM		= (1 <<  2),
-	DVBFE_ALGO_RECOVERY		= (1 << 31)
+	DVBFE_ALGO_RECOVERY		= (1U << 31)
 };
 
 /**
@@ -175,7 +175,7 @@ enum dvbfe_search {
 	DVBFE_ALGO_SEARCH_FAILED	= (1 <<  2),
 	DVBFE_ALGO_SEARCH_INVALID	= (1 <<  3),
 	DVBFE_ALGO_SEARCH_AGAIN		= (1 <<  4),
-	DVBFE_ALGO_SEARCH_ERROR		= (1 << 31),
+	DVBFE_ALGO_SEARCH_ERROR		= (1U << 31),
 };
 
 /**
-- 
2.20.1

Re: [Linux-kernel-mentee, PATCH] media: dvb_frontend.h: Fix shifting signed 32-bit value problem

[Fabio Estevam]

Hi Luke,

On Thu, Jul 4, 2019 at 3:22 PM Luke Nowakowski-Krijger
<lnowakow@eng.ucsd.edu> wrote:
>
> Fix DVBFE_ALGO_RECOVERY and DVBFE_ALGO_SEARCH_ERROR to use U cast which
> fixes undefined behavior error by certain compilers.
>
> Signed-off-by: Luke Nowakowski-Krijger <lnowakow@eng.ucsd.edu>
> ---
>  include/media/dvb_frontend.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/media/dvb_frontend.h b/include/media/dvb_frontend.h
> index f05cd7b94a2c..472fe5871d94 100644
> --- a/include/media/dvb_frontend.h
> +++ b/include/media/dvb_frontend.h
> @@ -144,7 +144,7 @@ enum dvbfe_algo {
>         DVBFE_ALGO_HW                   = (1 <<  0),
>         DVBFE_ALGO_SW                   = (1 <<  1),
>         DVBFE_ALGO_CUSTOM               = (1 <<  2),
> -       DVBFE_ALGO_RECOVERY             = (1 << 31)
> +       DVBFE_ALGO_RECOVERY             = (1U << 31)

You could switch all these definitions to use the BIT() macro instead.

Re: [Linux-kernel-mentees] [Linux-kernel-mentee, PATCH] media: dvb_frontend.h: Fix shifting signed 32-bit value problem

[Greg KH]

On Thu, Jul 04, 2019 at 10:04:22AM -0700, Luke Nowakowski-Krijger wrote:
> Fix DVBFE_ALGO_RECOVERY and DVBFE_ALGO_SEARCH_ERROR to use U cast which
> fixes undefined behavior error by certain compilers. 
> 
> Signed-off-by: Luke Nowakowski-Krijger <lnowakow@eng.ucsd.edu>
> ---
>  include/media/dvb_frontend.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/media/dvb_frontend.h b/include/media/dvb_frontend.h
> index f05cd7b94a2c..472fe5871d94 100644
> --- a/include/media/dvb_frontend.h
> +++ b/include/media/dvb_frontend.h
> @@ -144,7 +144,7 @@ enum dvbfe_algo {
>  	DVBFE_ALGO_HW			= (1 <<  0),
>  	DVBFE_ALGO_SW			= (1 <<  1),
>  	DVBFE_ALGO_CUSTOM		= (1 <<  2),
> -	DVBFE_ALGO_RECOVERY		= (1 << 31)
> +	DVBFE_ALGO_RECOVERY		= (1U << 31)

BIT() is better for stuff like this.

thanks,

greg k-h