Re: [PATCH] dmaengine: ioatdma: use !kstrtoint(), not sscanf()!=-1

[Dave Jiang]

On 5/26/26 11:06 AM, Alexander A. Klimov wrote:
> 
> 
> On 5/26/26 16:49, Dave Jiang wrote:
>>
>>
>> On 5/25/26 11:13 PM, Alexander A. Klimov wrote:
>>> Depending on the user input, sscanf() may return 0 for 0 success.
>>> But intr_coalesce_store() wants sscanf() to parse one number,
>>> so expect 1 from sscanf(), not any int except -1.
>>>
>>> While on it, fix typo in %du by using just %d,
>>> as this interface expects %d or %d\n.
>>> Latter made scripts/checkpatch.pl complain,
>>> so use kstrtoint() instead of sscanf().
>>>
>>> Fixes: 268e2519f5b7 ("dmaengine: ioatdma: Add intr_coalesce sysfs entry")
>>> Signed-off-by: Alexander A. Klimov <grandmaster@xxxxxxxxxxxx>
>>> ---
>>>   drivers/dma/ioat/sysfs.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/dma/ioat/sysfs.c b/drivers/dma/ioat/sysfs.c
>>> index e796ddb5383f..f59df569956a 100644
>>> --- a/drivers/dma/ioat/sysfs.c
>>> +++ b/drivers/dma/ioat/sysfs.c
>>> @@ -144,7 +144,7 @@ size_t count)
>>>       int intr_coalesce = 0;
>>>       struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
>>>   -    if (sscanf(page, "%du", &intr_coalesce) != -1) {
>>> +    if (!kstrtoint(page, 10, &intr_coalesce)) {
>>
>> looks good. We can probably use kstrtouint() since we are expecting a positive number always.
> 
> This would break `return -EINVAL;` below

Shouldn't we just drop the < 0 compare since it's no longer needed?

> 
>>
>> DJ
>>
>>>           if ((intr_coalesce < 0) ||
>>>               (intr_coalesce > IOAT_INTRDELAY_MASK))
>>>               return -EINVAL;
>>
>