Hi Matti,
It might be better but I am not pretty sure whether have to have both
gains and times, so I modified 'ret' in places where issues might arise,
rather than adding a restriction in iio_gts_sanity_check().
In the corner case, there is a restriction that both num_hwgain and
num_itime cannot be 0 simultaneously in the iio_gts_sanity_check().
However, in the gain_to_scaletables() , if num_itime is 1 and num_hwgain
is 0, the 'gain_bytes' becomes 0 and 'all_gains' is not null after the
'for' loop, which causes the subsequent 'while' or 'for' to become
ineffective, leading to an undefined 'ret' being returned in the 'free_out'.
Yours,
-- Zicheng
On 2024/10/31 15:13, Matti Vaittinen wrote:
Hi Zicheng,
Thanks for the patch.
On 31/10/2024 03:45, Zicheng Qu wrote:
Initialize the variable ret at the time of declaration to prevent it
from
being returned without a defined value. Fixes smatch warning:
drivers/iio/industrialio-gts-helper.c:256 gain_to_scaletables() error:
uninitialized symbol 'ret'.
Cc: stable@xxxxxxxxxxxxxxx # v6.6+
Fixes: 38416c28e168 ("iio: light: Add gain-time-scale helpers")
Signed-off-by: Zicheng Qu <quzicheng@xxxxxxxxxx>
---
drivers/iio/industrialio-gts-helper.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iio/industrialio-gts-helper.c
b/drivers/iio/industrialio-gts-helper.c
index 59d7615c0f56..c5dc5b51693d 100644
--- a/drivers/iio/industrialio-gts-helper.c
+++ b/drivers/iio/industrialio-gts-helper.c
@@ -167,7 +167,7 @@ static int iio_gts_gain_cmp(const void *a, const
void *b)
static int gain_to_scaletables(struct iio_gts *gts, int **gains,
int **scales)
{
- int ret, i, j, new_idx, time_idx;
+ int i, j, new_idx, time_idx, ret = 0;
int *all_gains;
size_t gain_bytes;
So, if I read it right, this handles a (corner) case where there is no
times given. I am not sure how well such use has been considered
because the point of GTS is helping out with cases where the gain and
integration time both impact to scale.
How do you see the benefits of the gts if there is no such shared
impact to scale? Sure the gts could still provide the 'standard table
format' to present the gains (or times), and conversions from the
register values to gains (or times), and perhaps the available scale
table(s) - but I suppose it also brings a lot of unused code and some
initialization overhead. (I have a vague feeling this was discussed
with Jonathan during the reviews).
Reason I am asking these questions is that I wonder if the usage
should be limited to cases where we have both gains and times? We
could check this in the iio_gts_sanity_check(). (And, I am actually a
bit surprized this check was not implemented).
Well, initialization fixes a potential bug here and does not really
cost much - so big thanks to you :)
Reviewed-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
Yours,
-- Matti Vaittinen
