[PATCH V2] staging: gpib: Change return type and error code of fluke_get_dma_residue

[PATCH V2] staging: gpib: Change return type and error code of fluke_get_dma_residue

[Everest K.C.]

fluke_get_dma_residue() returns unsigned int with -1 as error code.
This error cannot be caught.
Fix this by changing the return type of the function to int and 
returning the error code, that was captured. Also, change the data 
type of variable residue to int in the function fluke_dma_read().

Fixes: 55936779f496 ("staging: gpib: Add Fluke cda based cards GPIB driver")
Signed-off-by: Everest K.C. <everestkc@everestkc.com.np>
---
V1 -> V2: - Fixed the caller
	  - Updated the changelog

 drivers/staging/gpib/eastwood/fluke_gpib.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/gpib/eastwood/fluke_gpib.c b/drivers/staging/gpib/eastwood/fluke_gpib.c
index f9f149db222d..378687eb619f 100644
--- a/drivers/staging/gpib/eastwood/fluke_gpib.c
+++ b/drivers/staging/gpib/eastwood/fluke_gpib.c
@@ -536,7 +536,7 @@ static int fluke_accel_write(gpib_board_t *board, uint8_t *buffer, size_t length
 	return 0;
 }
 
-static unsigned int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t cookie)
+static int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t cookie)
 {
 	struct dma_tx_state state;
 	int result;
@@ -544,7 +544,7 @@ static unsigned int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t co
 	result = dmaengine_pause(chan);
 	if (result < 0) {
 		pr_err("fluke_gpib: dma pause failed?\n");
-		return -1;
+		return result;
 	}
 	dmaengine_tx_status(chan, cookie, &state);
 	// hardware doesn't support resume, so dont call this
@@ -559,7 +559,7 @@ static int fluke_dma_read(gpib_board_t *board, uint8_t *buffer,
 	struct nec7210_priv *nec_priv = &e_priv->nec7210_priv;
 	int retval = 0;
 	unsigned long flags;
-	unsigned int residue;
+	int residue;
 	dma_addr_t bus_address;
 	struct dma_async_tx_descriptor *tx_desc;
 	dma_cookie_t dma_cookie;
-- 
2.43.0

Re: [PATCH V2] staging: gpib: Change return type and error code of fluke_get_dma_residue

[Shuah Khan]

On 10/17/24 03:25, Everest K.C. wrote:
> fluke_get_dma_residue() returns unsigned int with -1 as error code.
> This error cannot be caught.
> Fix this by changing the return type of the function to int and
> returning the error code, that was captured. Also, change the data
> type of variable residue to int in the function fluke_dma_read().> 
> Fixes: 55936779f496 ("staging: gpib: Add Fluke cda based cards GPIB driver")
> Signed-off-by: Everest K.C. <everestkc@everestkc.com.np>
> ---
> V1 -> V2: - Fixed the caller
> 	  - Updated the changelog
> 
>   drivers/staging/gpib/eastwood/fluke_gpib.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/gpib/eastwood/fluke_gpib.c b/drivers/staging/gpib/eastwood/fluke_gpib.c
> index f9f149db222d..378687eb619f 100644
> --- a/drivers/staging/gpib/eastwood/fluke_gpib.c
> +++ b/drivers/staging/gpib/eastwood/fluke_gpib.c
> @@ -536,7 +536,7 @@ static int fluke_accel_write(gpib_board_t *board, uint8_t *buffer, size_t length
>   	return 0;
>   }
>   
> -static unsigned int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t cookie)
> +static int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t cookie)
>   {
>   	struct dma_tx_state state;
>   	int result;
> @@ -544,7 +544,7 @@ static unsigned int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t co
>   	result = dmaengine_pause(chan);

As a side note, out of 21  dmaengine_pause() callers, just 3 check
the return value, spanning spi, stanging, tty, sound: core and soc

This exact same problem is in staging/gpib/fmh_gpib/fmh_gpib.c
unsigned int fmh_gpib_get_dma_residue() returns -1

>   	if (result < 0) {
>   		pr_err("fluke_gpib: dma pause failed?\n");

This could be a dev_err using dma_chan_dev

> -		return -1;
> +		return result;
>   	}
>   	dmaengine_tx_status(chan, cookie, &state);
>   	// hardware doesn't support resume, so dont call this
> @@ -559,7 +559,7 @@ static int fluke_dma_read(gpib_board_t *board, uint8_t *buffer,
>   	struct nec7210_priv *nec_priv = &e_priv->nec7210_priv;
>   	int retval = 0;
>   	unsigned long flags;
> -	unsigned int residue;
> +	int residue;
>   	dma_addr_t bus_address;
>   	struct dma_async_tx_descriptor *tx_desc;
>   	dma_cookie_t dma_cookie;

Looks good to me.

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah

Re: [PATCH V2] staging: gpib: Change return type and error code of fluke_get_dma_residue

[Dan Carpenter]

On Thu, Oct 17, 2024 at 03:25:10AM -0600, Everest K.C. wrote:
> fluke_get_dma_residue() returns unsigned int with -1 as error code.
> This error cannot be caught.
> Fix this by changing the return type of the function to int and 
> returning the error code, that was captured. Also, change the data 
> type of variable residue to int in the function fluke_dma_read().
> 
> Fixes: 55936779f496 ("staging: gpib: Add Fluke cda based cards GPIB driver")
> Signed-off-by: Everest K.C. <everestkc@everestkc.com.np>
> ---
> V1 -> V2: - Fixed the caller
> 	  - Updated the changelog
> 

Thanks!

Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>

regards,
dan carpenter