Re: [PATCH] ath5k: fix WARNING opportunity for swap.

From: Mahmoud Matook
Date: Sat Aug 12 2023 - 00:57:23 EST


On 08. 08. 23, 21:42, Mahmoud Matook wrote:
>> On 08/08, Jiri Slaby wrote:
>>
>>>> On 07. 08. 23, 22:10, Mahmoud Maatuq wrote:
>>>> coccinielle reported the following:
>>>> ./drivers/net/wireless/ath/ath5k/phy.c:1573:25-26: WARNING opportunity for swap()
>>>>
>>>>
>>> OK, once again:
>>> https://lore.kernel.org/all/0c3acbd4-6ab2-5cc5-6293-54e30093cce2@xxxxxxxxxx/
>>
>>
>> I had a look at the commit history, to see why the original developer
>> didn't use sort() function, and name the array variable sort but found
>> nothing.
>> I have some doubts that he might did that intentionally, so not to call
>> sort() function for such small array

> It happens once in 10 s and in a work. No worries about that.

if it's the case so make sense to use sort().
but should I send the modifications on the same thread?
as the subject needs to be changed.
ex: repalce double loop with sort function
replace bubble sort with heap sort.

>> and avoid the cost of context switching.

> What context switching?

I used the wrong expression, I meant function call overhead
e.g store/load registers.

>>>> diff --git a/drivers/net/wireless/ath/ath5k/phy.c b/drivers/net/wireless/ath/ath5k/phy.c
>>>> index 5797ef9c73d7..f87eb684f223 100644
>>>> --- a/drivers/net/wireless/ath/ath5k/phy.c
>>>> +++ b/drivers/net/wireless/ath/ath5k/phy.c
>>>> @@ -1562,16 +1562,13 @@ static s16
>>>> ath5k_hw_get_median_noise_floor(struct ath5k_hw *ah)
>>>> {
>>>> s16 sort[ATH5K_NF_CAL_HIST_MAX];
>>>> - s16 tmp;
>>>> int i, j;
>>>> memcpy(sort, ah->ah_nfcal_hist.nfval, sizeof(sort));
>>>> for (i = 0; i < ATH5K_NF_CAL_HIST_MAX - 1; i++) {
>>>> for (j = 1; j < ATH5K_NF_CAL_HIST_MAX - i; j++) {
>>>> if (sort[j] > sort[j - 1]) {
>>>> - tmp = sort[j];
>>>> - sort[j] = sort[j - 1];
>>>> - sort[j - 1] = tmp;
>>>> + swap(sort[j], sort[j - 1]);
>>>> }
>>>> }
>>>> }
>>>
>>> --
>>> js
>>> suse labs
>
> --
> js
> suse labs