On Wed, Feb 09, 2022 at 08:15:13PM +0100, Christophe JAILLET wrote: > 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 > > > > - > > 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. We could mark those as __must_check functions. regards, dan carpenter
