On Tue, 2019-02-19 at 11:05 -0800, Nick Desaulniers wrote:

On Tue, Feb 19, 2019 at 10:21 AM Nathan Chancellor
[off-list ref] wrote:

quoted

Clang warns:

drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c:465:2:
warning:
comparison of distinct pointer types ('typeof ((rtt_avg)) *' (aka
'long
long *') and 'uint64_t *' (aka 'unsigned long long *'))
[-Wcompare-distinct-pointer-types]
        do_div(rtt_avg, 6666);
        ^~~~~~~~~~~~~~~~~~~~~
include/asm-generic/div64.h:222:28: note: expanded from macro
'do_div'
        (void)(((typeof((n)) *)0) == ((uint64_t *)0));  \
               ~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~
1 warning generated.

do_div expects an unsigned dividend. Use div64_s64, which expects a
signed dividend.

Eh, IIRC, signed vs unsigned division has implications for rounding
towards zero or not, but I doubt that the round trip time average
(RTT
avg) should ever be negative.  General rule of thumb for C is to keep
arithmetic signed (even when working with non zero values), so rather
than make the literal (6666) a unsigned long, I agree with your
change
to keep the division signed as well.  Thanks for the fix.
Reviewed-by: Nick Desaulniers <redacted>

Thanks for the patch and for the review.  I've applied this to our
internal tree and it will be sent upstreaming following our normal
upstreaming process.

--
Cheers,
Luca.