2021-12-27 19:18:11

by Nathan Chancellor

Subject: [PATCH] iwlwifi: mvm: Use div_s64 instead of do_div in iwl_mvm_ftm_rtt_smoothing()

When building ARCH=arm allmodconfig:

drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c: In function ‘iwl_mvm_ftm_rtt_smoothing’:
./include/asm-generic/div64.h:222:35: error: comparison of distinct pointer types lacks a cast [-Werror]
222 | (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
| ^~
drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c:1070:9: note: in expansion of macro ‘do_div’
1070 | do_div(rtt_avg, 100);
| ^~~~~~

do_div() has to be used with an unsigned 64-bit integer dividend but
rtt_avg is a signed 64-bit integer.

div_s64() expects a signed 64-bit integer dividend and signed 32-bit
divisor, which fits this scenario, so use that function here to fix the
warning.

Fixes: 8b0f92549f2c ("iwlwifi: mvm: fix 32-bit build in FTM")
Signed-off-by: Nathan Chancellor <[email protected]>
---
drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c b/drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c
index 9449d1af3c11..628aee634b2a 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c
@@ -1066,8 +1066,7 @@ static void iwl_mvm_ftm_rtt_smoothing(struct iwl_mvm *mvm,
overshoot = IWL_MVM_FTM_INITIATOR_SMOOTH_OVERSHOOT;
alpha = IWL_MVM_FTM_INITIATOR_SMOOTH_ALPHA;

- rtt_avg = alpha * rtt + (100 - alpha) * resp->rtt_avg;
- do_div(rtt_avg, 100);
+ rtt_avg = div_s64(alpha * rtt + (100 - alpha) * resp->rtt_avg, 100);

IWL_DEBUG_INFO(mvm,
"%pM: prev rtt_avg=%lld, new rtt_avg=%lld, rtt=%lld\n",

base-commit: bcbddc4f9d020a4a0b881cc065729c3aaeb28098
--
2.34.1

2022-01-10 00:33:35

by Jakub Kicinski

Subject: Re: [PATCH] iwlwifi: mvm: Use div_s64 instead of do_div in iwl_mvm_ftm_rtt_smoothing()

> When building ARCH=arm allmodconfig:
>
> drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c: In function ‘iwl_mvm_ftm_rtt_smoothing’:
> ./include/asm-generic/div64.h:222:35: error: comparison of distinct pointer types lacks a cast [-Werror]
> 222 | (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
> | ^~
> drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c:1070:9: note: in expansion of macro ‘do_div’
> 1070 | do_div(rtt_avg, 100);
> | ^~~~~~

Let me take this one directly to net-next, hope that's okay.

Thanks!

2022-01-10 08:08:18

by Kalle Valo

Subject: Re: [PATCH] iwlwifi: mvm: Use div_s64 instead of do_div in iwl_mvm_ftm_rtt_smoothing()

Jakub Kicinski <[email protected]> writes:

>> When building ARCH=arm allmodconfig:
>>
>> drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c: In function
>> ‘iwl_mvm_ftm_rtt_smoothing’:
>> ./include/asm-generic/div64.h:222:35: error: comparison of distinct
>> pointer types lacks a cast [-Werror]
>> 222 | (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
>> | ^~
>> drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c:1070:9: note:
>> in expansion of macro ‘do_div’
>> 1070 | do_div(rtt_avg, 100);
>> | ^~~~~~
>
> Let me take this one directly to net-next, hope that's okay.

Thanks, please do, I was offline for a longer period and just came back.

--
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