[PATCH] net: usb: hso: use swap macro in hso_kick_transmit

[PATCH] net: usb: hso: use swap macro in hso_kick_transmit

[Gustavo A. R. Silva]

Make use of the swap macro and remove unnecessary variable *temp*.
This makes the code easier to read and maintain. Also, slightly
refactor some code due to the removal of *temp*.

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/net/usb/hso.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index de305ea..78d128e 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1732,7 +1732,6 @@ static int hso_serial_ioctl(struct tty_struct *tty,
 /* starts a transmit */
 static void hso_kick_transmit(struct hso_serial *serial)
 {
-	u8 *temp;
 	unsigned long flags;
 	int res;
 
@@ -1748,14 +1747,11 @@ static void hso_kick_transmit(struct hso_serial *serial)
 		goto out;
 
 	/* Switch pointers around to avoid memcpy */
-	temp = serial->tx_buffer;
-	serial->tx_buffer = serial->tx_data;
-	serial->tx_data = temp;
+	swap(serial->tx_buffer, serial->tx_data);
 	serial->tx_data_count = serial->tx_buffer_count;
 	serial->tx_buffer_count = 0;
 
-	/* If temp is set, it means we switched buffers */
-	if (temp && serial->write_data) {
+	if (serial->write_data) {
 		res = serial->write_data(serial);
 		if (res >= 0)
 			serial->tx_urb_used = 1;
-- 
2.7.4

Re: [PATCH] net: usb: hso: use swap macro in hso_kick_transmit

[David Miller]

From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Mon, 9 Jul 2018 10:40:48 -0500

> @@ -1748,14 +1747,11 @@ static void hso_kick_transmit(struct hso_serial *serial)
>  		goto out;
>  
>  	/* Switch pointers around to avoid memcpy */
> -	temp = serial->tx_buffer;
> -	serial->tx_buffer = serial->tx_data;
> -	serial->tx_data = temp;
> +	swap(serial->tx_buffer, serial->tx_data);
>  	serial->tx_data_count = serial->tx_buffer_count;
>  	serial->tx_buffer_count = 0;
>  
> -	/* If temp is set, it means we switched buffers */
> -	if (temp && serial->write_data) {
> +	if (serial->write_data) {

I think temp can be NULL here, you have to retain this check.

Re: [PATCH] net: usb: hso: use swap macro in hso_kick_transmit

[Gustavo A. R. Silva]

Hi David,

On 07/12/2018 12:58 AM, David Miller wrote:
> From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
> Date: Mon, 9 Jul 2018 10:40:48 -0500
> 
>> @@ -1748,14 +1747,11 @@ static void hso_kick_transmit(struct hso_serial *serial)
>>  		goto out;
>>  
>>  	/* Switch pointers around to avoid memcpy */
>> -	temp = serial->tx_buffer;
>> -	serial->tx_buffer = serial->tx_data;
>> -	serial->tx_data = temp;
>> +	swap(serial->tx_buffer, serial->tx_data);
>>  	serial->tx_data_count = serial->tx_buffer_count;
>>  	serial->tx_buffer_count = 0;
>>  
>> -	/* If temp is set, it means we switched buffers */
>> -	if (temp && serial->write_data) {
>> +	if (serial->write_data) {
> 
> I think temp can be NULL here, you have to retain this check.
> 

I see. Well, in that case I will check serial->tx_data instead.

Thanks for the feedback.
--
Gustavo