Le 21/01/2022 à 14:34, David Laight a écrit :
From: Jiapeng Chong
Sent: 21 January 2022 11:50
Subject: [PATCH] staging: pi433: using div64_u64() instead of do_div()
Clean the following coccicheck warning:
./drivers/staging/pi433/rf69.c:286:1-7: WARNING: do_div() does a
64-by-32 division, please consider using div64_u64 instead.
That is one of patchcheck's worse warnings.
You need to check the domain of the divisor, not its type.
do_div() exists to avoid expensive 64bit divides when the
divisor is small.
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
Moreover, the patch is broken by itself.
See [1] were it was already reported that do_div() and div64_u64() don't
have the same calling convention.
Looks that div64_u64() and div64_ul() works the same way.
CJ
[1]:
https://lore.kernel.org/linux-kernel/20211117112559.jix3hmx7uwqmuryg@xxxxxxxxxxxxxx/
