iwlwifi: mvm: Use div_s64 instead of do_div in iwl_mvm_ftm_rtt_smoothing()

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

Posted by Nathan Chancellor 4 years, 6 months ago

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 <nathan@kernel.org>
---
 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

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

Posted by Jakub Kicinski 4 years, 5 months ago

> 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!

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

Posted by Kalle Valo 4 years, 5 months ago

Jakub Kicinski <kuba@kernel.org> 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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