[PATCH] {tty: serial, nand: onenand}: remove variable 'ufstat' set but not used

[PATCH] {tty: serial, nand: onenand}: remove variable 'ufstat' set but not used

[Chen Wandun]

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/tty/serial/samsung_tty.c: In function s3c24xx_serial_rx_chars_dma:
drivers/tty/serial/samsung_tty.c:549:24: warning: variable ufstat set but not used [-Wunused-but-set-variable]

Signed-off-by: Chen Wandun <chenwandun@huawei.com>
---
 drivers/tty/serial/samsung_tty.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 83fd516..ab3c7d1 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -546,7 +546,7 @@ static void s3c24xx_serial_rx_drain_fifo(struct s3c24xx_uart_port *ourport);
 
 static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
 {
-	unsigned int utrstat, ufstat, received;
+	unsigned int utrstat, received;
 	struct s3c24xx_uart_port *ourport = dev_id;
 	struct uart_port *port = &ourport->port;
 	struct s3c24xx_uart_dma *dma = ourport->dma;
@@ -556,7 +556,7 @@ static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
 	struct dma_tx_state state;
 
 	utrstat = rd_regl(port, S3C2410_UTRSTAT);
-	ufstat = rd_regl(port, S3C2410_UFSTAT);
+	rd_regl(port, S3C2410_UFSTAT);
 
 	spin_lock_irqsave(&port->lock, flags);
 
-- 
2.7.4

Re: [PATCH] {tty: serial, nand: onenand}: remove variable 'ufstat' set but not used

[Greg KH]

On Fri, Nov 22, 2019 at 07:12:39PM +0800, Chen Wandun wrote:
> Fixes gcc '-Wunused-but-set-variable' warning:
> 
> drivers/tty/serial/samsung_tty.c: In function s3c24xx_serial_rx_chars_dma:
> drivers/tty/serial/samsung_tty.c:549:24: warning: variable ufstat set but not used [-Wunused-but-set-variable]
> 
> Signed-off-by: Chen Wandun <chenwandun@huawei.com>

Your subject line is really odd, can you please fix that up and resend?

thanks,

greg k-h

Re: [PATCH] {tty: serial, nand: onenand}: remove variable 'ufstat' set but not used

[Chen Wandun]

On 2019/11/22 19:14, Greg KH wrote:
> On Fri, Nov 22, 2019 at 07:12:39PM +0800, Chen Wandun wrote:
>> Fixes gcc '-Wunused-but-set-variable' warning:
>>
>> drivers/tty/serial/samsung_tty.c: In function s3c24xx_serial_rx_chars_dma:
>> drivers/tty/serial/samsung_tty.c:549:24: warning: variable ufstat set but not used [-Wunused-but-set-variable]
>>
>> Signed-off-by: Chen Wandun <chenwandun@huawei.com>
> 
> Your subject line is really odd, can you please fix that up and resend?
I check the git log of drivers/tty/serial/samsung_tty.c,
it seem like the subject line should be:
{tty: serial, nand: onenand}: samsung: remove variable 'ufstat' set but not used

Is that OK?

Thanks
Chen Wandun
> 
> thanks,
> 
> greg k-h
> 
> .
> 

Re: [PATCH] {tty: serial, nand: onenand}: remove variable 'ufstat' set but not used

[Greg KH]

On Fri, Nov 22, 2019 at 07:33:47PM +0800, Chen Wandun wrote:
> 
> 
> On 2019/11/22 19:14, Greg KH wrote:
> > On Fri, Nov 22, 2019 at 07:12:39PM +0800, Chen Wandun wrote:
> > > Fixes gcc '-Wunused-but-set-variable' warning:
> > > 
> > > drivers/tty/serial/samsung_tty.c: In function s3c24xx_serial_rx_chars_dma:
> > > drivers/tty/serial/samsung_tty.c:549:24: warning: variable ufstat set but not used [-Wunused-but-set-variable]
> > > 
> > > Signed-off-by: Chen Wandun <chenwandun@huawei.com>
> > 
> > Your subject line is really odd, can you please fix that up and resend?
> I check the git log of drivers/tty/serial/samsung_tty.c,
> it seem like the subject line should be:
> {tty: serial, nand: onenand}: samsung: remove variable 'ufstat' set but not used
> 
> Is that OK?

No.  What does this patch have to do with nand?

That was from a previous patch that modified two drivers at once.  You
are not touching the nand driver.

thanks,

greg k-h

[PATCH v2] tty: serial: samsung: remove variable 'ufstat' set but not used

[Chen Wandun]

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/tty/serial/samsung_tty.c: In function s3c24xx_serial_rx_chars_dma:
drivers/tty/serial/samsung_tty.c:549:24: warning: variable ufstat set but not used [-Wunused-but-set-variable]

Signed-off-by: Chen Wandun <chenwandun@huawei.com>
---
 drivers/tty/serial/samsung_tty.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 83fd516..ab3c7d1 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -546,7 +546,7 @@ static void s3c24xx_serial_rx_drain_fifo(struct s3c24xx_uart_port *ourport);
 
 static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
 {
-	unsigned int utrstat, ufstat, received;
+	unsigned int utrstat, received;
 	struct s3c24xx_uart_port *ourport = dev_id;
 	struct uart_port *port = &ourport->port;
 	struct s3c24xx_uart_dma *dma = ourport->dma;
@@ -556,7 +556,7 @@ static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
 	struct dma_tx_state state;
 
 	utrstat = rd_regl(port, S3C2410_UTRSTAT);
-	ufstat = rd_regl(port, S3C2410_UFSTAT);
+	rd_regl(port, S3C2410_UFSTAT);
 
 	spin_lock_irqsave(&port->lock, flags);
 
-- 
2.7.4

Re: [PATCH v2] tty: serial: samsung: remove variable 'ufstat' set but not used

[Jiri Slaby]

On 22. 11. 19, 13:04, Chen Wandun wrote:
> Fixes gcc '-Wunused-but-set-variable' warning:
> 
> drivers/tty/serial/samsung_tty.c: In function s3c24xx_serial_rx_chars_dma:
> drivers/tty/serial/samsung_tty.c:549:24: warning: variable ufstat set but not used [-Wunused-but-set-variable]
> 
> Signed-off-by: Chen Wandun <chenwandun@huawei.com>
> ---
>  drivers/tty/serial/samsung_tty.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> index 83fd516..ab3c7d1 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -546,7 +546,7 @@ static void s3c24xx_serial_rx_drain_fifo(struct s3c24xx_uart_port *ourport);
>  
>  static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
>  {
> -	unsigned int utrstat, ufstat, received;
> +	unsigned int utrstat, received;
>  	struct s3c24xx_uart_port *ourport = dev_id;
>  	struct uart_port *port = &ourport->port;
>  	struct s3c24xx_uart_dma *dma = ourport->dma;
> @@ -556,7 +556,7 @@ static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
>  	struct dma_tx_state state;
>  
>  	utrstat = rd_regl(port, S3C2410_UTRSTAT);
> -	ufstat = rd_regl(port, S3C2410_UFSTAT);
> +	rd_regl(port, S3C2410_UFSTAT);

The question (CCed some samsung people) is whether we have to spend the
cycles reading the register at all? Does it have side-effects?

thanks,
-- 
js
suse labs

Re: [PATCH v2] tty: serial: samsung: remove variable 'ufstat' set but not used

[Marek Szyprowski]

Hi Jiri,

On 22.11.2019 13:08, Jiri Slaby wrote:
> On 22. 11. 19, 13:04, Chen Wandun wrote:
>> Fixes gcc '-Wunused-but-set-variable' warning:
>>
>> drivers/tty/serial/samsung_tty.c: In function s3c24xx_serial_rx_chars_dma:
>> drivers/tty/serial/samsung_tty.c:549:24: warning: variable ufstat set but not used [-Wunused-but-set-variable]
>>
>> Signed-off-by: Chen Wandun <chenwandun@huawei.com>
>> ---
>>   drivers/tty/serial/samsung_tty.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
>> index 83fd516..ab3c7d1 100644
>> --- a/drivers/tty/serial/samsung_tty.c
>> +++ b/drivers/tty/serial/samsung_tty.c
>> @@ -546,7 +546,7 @@ static void s3c24xx_serial_rx_drain_fifo(struct s3c24xx_uart_port *ourport);
>>   
>>   static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
>>   {
>> -	unsigned int utrstat, ufstat, received;
>> +	unsigned int utrstat, received;
>>   	struct s3c24xx_uart_port *ourport = dev_id;
>>   	struct uart_port *port = &ourport->port;
>>   	struct s3c24xx_uart_dma *dma = ourport->dma;
>> @@ -556,7 +556,7 @@ static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
>>   	struct dma_tx_state state;
>>   
>>   	utrstat = rd_regl(port, S3C2410_UTRSTAT);
>> -	ufstat = rd_regl(port, S3C2410_UFSTAT);
>> +	rd_regl(port, S3C2410_UFSTAT);
> The question (CCed some samsung people) is whether we have to spend the
> cycles reading the register at all? Does it have side-effects?

Reading this register doesn't have any side effects, so it is safe to 
remove rd_regl(port, S3C2410_UFSTAT) at all in this function. Tested on 
Exynos5422-based OdroidXU3 board.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland