carl9170: fix memory leak issue in async cmd macro wrappers

This patch continues where the previous commit:
	"carl9170: fix async command buffer leak"
left off.

Similar to carl9170_reboot/carl9170_powersave, the
carl9170_async_regwrite* macros would leak the
temporary command buffer, if __carl9170_exec_cmd
fails to upload the command to the device.
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/carl9170/cmd.h

@@ -116,8 +116,9 @@ __regwrite_out :							\
 } while (0);
 
 
-#define carl9170_async_get_buf()					\
+#define carl9170_async_regwrite_get_buf()				\
 do {									\
+	__nreg = 0;							\
 	__cmd = carl9170_cmd_buf(__carl, CARL9170_CMD_WREG_ASYNC,	\
 				 CARL9170_MAX_CMD_PAYLOAD_LEN);		\
 	if (__cmd == NULL) {						\
@@ -128,38 +129,42 @@ do {									\
 
 #define carl9170_async_regwrite_begin(carl)				\
 do {									\
-	int __nreg = 0, __err = 0;					\
 	struct ar9170 *__carl = carl;					\
 	struct carl9170_cmd *__cmd;					\
-	carl9170_async_get_buf();					\
+	unsigned int __nreg;						\
+	int  __err = 0;							\
+	carl9170_async_regwrite_get_buf();				\
 
-#define carl9170_async_regwrite(r, v) do {				\
-	__cmd->wreg.regs[__nreg].addr = cpu_to_le32(r);			\
-	__cmd->wreg.regs[__nreg].val = cpu_to_le32(v);			\
-	__nreg++;							\
-	if ((__nreg >= PAYLOAD_MAX/2)) {				\
-		if (IS_ACCEPTING_CMD(__carl)) {				\
+#define carl9170_async_regwrite_flush()					\
+do {									\
+	if (__cmd == NULL || __nreg == 0)				\
+		break;							\
+									\
+	if (IS_ACCEPTING_CMD(__carl) && __nreg) {			\
 		__cmd->hdr.len = 8 * __nreg;				\
-			__err = __carl9170_exec_cmd(__carl, __cmd, true);\
+		__err = __carl9170_exec_cmd(__carl, __cmd, true);	\
 		__cmd = NULL;						\
-			carl9170_async_get_buf();			\
-		} else {						\
-			goto __async_regwrite_out;			\
+		break;							\
 	}								\
-		__nreg = 0;						\
-		if (__err)						\
 	goto __async_regwrite_out;					\
-	}								\
 } while (0)
 
-#define carl9170_async_regwrite_finish()				\
+#define carl9170_async_regwrite(r, v) do {				\
+	if (__cmd == NULL)						\
+		carl9170_async_regwrite_get_buf();			\
+	__cmd->wreg.regs[__nreg].addr = cpu_to_le32(r);			\
+	__cmd->wreg.regs[__nreg].val = cpu_to_le32(v);			\
+	__nreg++;							\
+	if ((__nreg >= PAYLOAD_MAX / 2))				\
+		carl9170_async_regwrite_flush();			\
+} while (0)
+
+#define carl9170_async_regwrite_finish() do {				\
 __async_regwrite_out :							\
-	if (__err == 0 && __nreg) {					\
-		__cmd->hdr.len = 8 * __nreg;				\
-		if (IS_ACCEPTING_CMD(__carl))				\
-			__err = __carl9170_exec_cmd(__carl, __cmd, true);\
-		__nreg = 0;						\
-	}
+	if (__cmd != NULL && __err == 0)				\
+		carl9170_async_regwrite_flush();			\
+	kfree(__cmd);							\
+} while (0)								\
 
 #define carl9170_async_regwrite_result()				\
 	__err;								\