Op 07-11-2024 om 09:25 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.
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.
I'm not the author, so I leave that up to David.
However, in the mean time you have already signed off on a similar
change in commit 14bcf831f0d [1], so my patch won't apply anymore.
Note that there is a function fmh_gpib_get_dma_residue which is
identical to fluke_get_dma_residue.
That one was changed in the same way, commit 039beaa5ace1 [2]
[1]
https://lore.kernel.org/r/20241017092511.17621-1-everestkc@xxxxxxxxxxxxxxxx
[2]
https://lore.kernel.org/r/20241017220740.30370-1-everestkc@xxxxxxxxxxxxxxxx
thanks,
greg k-h
