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@xxxxxxxxxxxx>
> ---
> v1 -> v2: change type of `residue` var; add note about Coverity CID in commit message
> v2 -> v3: add version in the subject (sorry Greg)
>
> 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;
Shouldn't you be checking the result of dmaengine_tx_status instead?
residue is a u32 and is NOT an error here so I think the unsigned value
here is correct as that's not going to give you what you expect it to
give you.
thanks,
greg k-h
