[PATCH] staging: gpib: Change return type of fluke_get_dma_residue

[PATCH] staging: gpib: Change return type of fluke_get_dma_residue

[Kees Bakker]

The function fluke_get_dma_residue returns an error as a negative value.
So the return type must not be unsigned.

This was detected by Coverity, CID 1600782

Signed-off-by: Kees Bakker <kees@ijzerbout.nl>
---
 v1 -> v2: change type of `residue` var; add note about Coverity CID in commit message

 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..3843e986f104 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;
@@ -549,7 +549,7 @@ static unsigned int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t co
 	dmaengine_tx_status(chan, cookie, &state);
 	// hardware doesn't support resume, so dont call this
 	// method unless the dma transfer is done.
-	return state.residue;
+	return (int)state.residue;
 }
 
 static int fluke_dma_read(gpib_board_t *board, uint8_t *buffer,
@@ -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;
-- 
2.47.0

Re: [PATCH] staging: gpib: Change return type of fluke_get_dma_residue

[Greg KH]

On Tue, Oct 15, 2024 at 10:33:30PM +0200, Kees Bakker wrote:
> The function fluke_get_dma_residue returns an error as a negative value.
> So the return type must not be unsigned.
> 
> This was detected by Coverity, CID 1600782
> 
> Signed-off-by: Kees Bakker <kees@ijzerbout.nl>
> ---
>  v1 -> v2: change type of `residue` var; add note about Coverity CID in commit message

There is no "v2" in the subject line :(

Please fix and send a v3.

thanks,

greg k-h

[PATCH] staging: gpib: Change return type of fluke_get_dma_residue

[Kees Bakker]

The function fluke_get_dma_residue returns an error as a negative value.
So the return type must not be unsigned.

Signed-off-by: Kees Bakker <kees@ijzerbout.nl>
---
 drivers/staging/gpib/eastwood/fluke_gpib.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/gpib/eastwood/fluke_gpib.c b/drivers/staging/gpib/eastwood/fluke_gpib.c
index f9f149db222d..77bbe2b587b1 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;
@@ -549,7 +549,7 @@ static unsigned int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t co
 	dmaengine_tx_status(chan, cookie, &state);
 	// hardware doesn't support resume, so dont call this
 	// method unless the dma transfer is done.
-	return state.residue;
+	return (int)state.residue;
 }
 
 static int fluke_dma_read(gpib_board_t *board, uint8_t *buffer,
-- 
2.47.0

Re: [PATCH] staging: gpib: Change return type of fluke_get_dma_residue

[Greg KH]

On Tue, Oct 15, 2024 at 10:33:30PM +0200, Kees Bakker wrote:
> The function fluke_get_dma_residue returns an error as a negative value.
> So the return type must not be unsigned.
> 
> Signed-off-by: Kees Bakker <kees@ijzerbout.nl>
> ---
>  drivers/staging/gpib/eastwood/fluke_gpib.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/gpib/eastwood/fluke_gpib.c b/drivers/staging/gpib/eastwood/fluke_gpib.c
> index f9f149db222d..77bbe2b587b1 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;
> @@ -549,7 +549,7 @@ static unsigned int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t co
>  	dmaengine_tx_status(chan, cookie, &state);
>  	// hardware doesn't support resume, so dont call this
>  	// method unless the dma transfer is done.
> -	return state.residue;
> +	return (int)state.residue;

Then why isn't residue an int?  Shouldn't that be also changed?

thanks,

greg k-h

Re: [PATCH] staging: gpib: Change return type of fluke_get_dma_residue

[Kees Bakker]

Op 19-10-2024 om 09:59 schreef Greg KH:
> On Tue, Oct 15, 2024 at 10:33:30PM +0200, Kees Bakker wrote:
>> The function fluke_get_dma_residue returns an error as a negative value.
>> So the return type must not be unsigned.
>>
>> Signed-off-by: Kees Bakker <kees@ijzerbout.nl>
>> ---
>>   drivers/staging/gpib/eastwood/fluke_gpib.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/staging/gpib/eastwood/fluke_gpib.c b/drivers/staging/gpib/eastwood/fluke_gpib.c
>> index f9f149db222d..77bbe2b587b1 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;
>> @@ -549,7 +549,7 @@ static unsigned int fluke_get_dma_residue(struct dma_chan *chan, dma_cookie_t co
>>   	dmaengine_tx_status(chan, cookie, &state);
>>   	// hardware doesn't support resume, so dont call this
>>   	// method unless the dma transfer is done.
>> -	return state.residue;
>> +	return (int)state.residue;
> Then why isn't residue an int?  Shouldn't that be also changed?
Good catch. I need to resend a patch.

>
> thanks,
>
> greg k-h