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From: Fabio Aiuto <fabioaiuto83@gmail.com>
To: gregkh@linuxfoundation.org
Cc: hdegoede@redhat.com, Larry.Finger@lwfinger.net,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
	David Sterba <dsterba@suse.cz>
Subject: [PATCH] staging: rtl8723bs: remove unused BIT macros definitions
Date: Fri, 30 Jul 2021 15:21:03 +0200	[thread overview]
Message-ID: <20210730132103.4996-1-fabioaiuto83@gmail.com> (raw)

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 <dsterba@suse.cz>
Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
---
 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


             reply	other threads:[~2021-07-30 13:21 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 13:21 Fabio Aiuto [this message]
2021-07-30 13:32 ` Greg KH
2021-07-30 13:35   ` Fabio Aiuto
  -- strict thread matches above, loose matches on Subject: below --
2021-07-30 13:19 Fabio Aiuto
2021-07-30 13:23 ` Fabio Aiuto

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