Feb 20 2015

Staging: rtl8723au: Use put_unaligned_le16 

Author: Vaishali Thakkar <vthakkar1994@gmail.com>

Using byte ordering functions and then memcpy() is risky and
prone to hide errors which are hard to track down. So, this
patch introduces the use of function put_unaligned_le16 which
makes the code clear. Here, use of variable tim_bitmap_le
and variable itself is removed. Also, to be compatible with the
changes header file is added too.

Coccinelle is used to do this change and semantic patch used for
this is as follows:

@a@
typedef __le16;
__le16 e16;
identifier tmp;
expression ptr;
expression y,e;
type T;
@@

- tmp = cpu_to_le16(y);

<+... when != tmp
(
- memcpy(ptr, (T)&tmp, \(2\|sizeof(__le16)\|sizeof(e16)\));
+ put_unaligned_le16(y,ptr);
|
- memcpy(ptr, (T)&tmp, ...);
+ put_unaligned_le16(y,ptr);
)
...+>
? tmp = e

@@ type T; identifier a.tmp; @@

- T tmp;
...when != tmp

Signed-off-by: Vaishali Thakkar 
Reviewed-by: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman 

---
 drivers/staging/rtl8723au/core/rtw_ap.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
 
diff --git a/drivers/staging/rtl8723au/core/rtw_ap.c b/drivers/staging/rtl8723au/core/rtw_ap.c
index c6327c0..7fa4352 100644
--- a/drivers/staging/rtl8723au/core/rtw_ap.c
+++ b/drivers/staging/rtl8723au/core/rtw_ap.c
@@ -20,6 +20,7 @@
 #include <wifi.h>
 #include <rtl8723a_cmd.h>
 #include <rtl8723a_hal.h>
+#include <asm/unaligned.h>
 
 extern unsigned char WMM_OUI23A[];
 extern unsigned char WPS_OUI23A[];
@@ -72,11 +73,8 @@ static void update_BCNTIM(struct rtw_adapter *padapter)
 	struct wlan_bssid_ex *pnetwork_mlmeext = &pmlmeinfo->network;
 	unsigned char *pie = pnetwork_mlmeext->IEs;
 	u8 *p, *dst_ie, *premainder_ie = NULL, *pbackup_remainder_ie = NULL;
-	__le16 tim_bitmap_le;
 	uint offset, tmp_len, tim_ielen, tim_ie_offset, remainder_ielen;
 
-	tim_bitmap_le = cpu_to_le16(pstapriv->tim_bitmap);
-
 	p = rtw_get_ie23a(pie, WLAN_EID_TIM, &tim_ielen,
 			  pnetwork_mlmeext->IELength);
 	if (p != NULL && tim_ielen > 0) {
@@ -143,9 +141,9 @@ static void update_BCNTIM(struct rtw_adapter *padapter)
 		*dst_ie++ = 0;
 
 	if (tim_ielen == 4) {
-		*dst_ie++ = *(u8 *)&tim_bitmap_le;
+		*dst_ie++ = pstapriv->tim_bitmap & 0xff;
 	} else if (tim_ielen == 5) {
-		memcpy(dst_ie, &tim_bitmap_le, 2);
+		put_unaligned_le16(pstapriv->tim_bitmap, dst_ie);
 		dst_ie += 2;
 	}

qlambert