2021-07-30 13:25:14

by Fabio Aiuto

Subject: [PATCH] staging: rtl8723bs: remove unused BIT macros definitions

BIT(x) macro used all over the driver is defined in
include/vsdo/bit.h as

- #define BIT(nr) (UL(1) << (nr))

which is safer than the local BIT macros declared.
Local macros shift a signed integer which brings
unespected results. For example:

(unsigned long)(1 << 31) => 0xffffffff80000000

shift.c:

int main() {
printf("%lx\n", (unsigned long)(1 << 31));
printf("%lx\n", (unsigned long)(1U << 31));
return 0;
}
---

$ ./shift
ffffffff80000000
80000000
---

So just remove redundant, less safe macro declarations.

Suggested-by: David Sterba <[email protected]>
Signed-off-by: Fabio Aiuto <[email protected]>
---
drivers/staging/rtl8723bs/include/osdep_service.h | 4 ----
drivers/staging/rtl8723bs/include/wifi.h | 8 --------
2 files changed, 12 deletions(-)

diff --git a/drivers/staging/rtl8723bs/include/osdep_service.h b/drivers/staging/rtl8723bs/include/osdep_service.h
index b49838c7e457..bde415db4114 100644
--- a/drivers/staging/rtl8723bs/include/osdep_service.h
+++ b/drivers/staging/rtl8723bs/include/osdep_service.h
@@ -14,10 +14,6 @@

#include <osdep_service_linux.h>

-#ifndef BIT
- #define BIT(x) (1 << (x))
-#endif
-
#define BIT0 0x00000001
#define BIT1 0x00000002
#define BIT2 0x00000004
diff --git a/drivers/staging/rtl8723bs/include/wifi.h b/drivers/staging/rtl8723bs/include/wifi.h
index 0bd7b662b972..f03e26818d45 100644
--- a/drivers/staging/rtl8723bs/include/wifi.h
+++ b/drivers/staging/rtl8723bs/include/wifi.h
@@ -7,14 +7,6 @@
#ifndef _WIFI_H_
#define _WIFI_H_

-
-#ifdef BIT
-/* error "BIT define occurred earlier elsewhere!\n" */
-#undef BIT
-#endif
-#define BIT(x) (1 << (x))
-
-
#define WLAN_ETHHDR_LEN 14
#define WLAN_ETHADDR_LEN 6
#define WLAN_IEEE_OUI_LEN 3
--
2.20.1

2021-07-30 13:34:40

by Greg Kroah-Hartman

Subject: Re: [PATCH] staging: rtl8723bs: remove unused BIT macros definitions

On Fri, Jul 30, 2021 at 03:21:03PM +0200, Fabio Aiuto wrote:
> BIT(x) macro used all over the driver is defined in
> include/vsdo/bit.h as
>
> - #define BIT(nr) (UL(1) << (nr))
>
> which is safer than the local BIT macros declared.
> Local macros shift a signed integer which brings
> unespected results. For example:
>
> (unsigned long)(1 << 31) => 0xffffffff80000000
>
> shift.c:
>
> int main() {
> printf("%lx\n", (unsigned long)(1 << 31));
> printf("%lx\n", (unsigned long)(1U << 31));
> return 0;
> }
> ---
>
> $ ./shift
> ffffffff80000000
> 80000000
> ---

Don't put "---" in a changelog text, otherwise the signed-off-by will be
cut off. Can you resend it with that changed to something else like
"---------------" or anything else?

thanks,

greg k-h

2021-07-30 13:36:50

by Fabio Aiuto

Subject: Re: [PATCH] staging: rtl8723bs: remove unused BIT macros definitions

Hello Greg,

On Fri, Jul 30, 2021 at 03:32:36PM +0200, Greg KH wrote:
> On Fri, Jul 30, 2021 at 03:21:03PM +0200, Fabio Aiuto wrote:
> > BIT(x) macro used all over the driver is defined in
> > include/vsdo/bit.h as
> >
> > - #define BIT(nr) (UL(1) << (nr))
> >
> > which is safer than the local BIT macros declared.
> > Local macros shift a signed integer which brings
> > unespected results. For example:
> >
> > (unsigned long)(1 << 31) => 0xffffffff80000000
> >
> > shift.c:
> >
> > int main() {
> > printf("%lx\n", (unsigned long)(1 << 31));
> > printf("%lx\n", (unsigned long)(1U << 31));
> > return 0;
> > }
> > ---
> >
> > $ ./shift
> > ffffffff80000000
> > 80000000
> > ---
>
> Don't put "---" in a changelog text, otherwise the signed-off-by will be
> cut off. Can you resend it with that changed to something else like
> "---------------" or anything else?
>
> thanks,
>
> greg k-h

sure I'm about to send a v2,

thank you,

fabio