Messages in this thread | | | Date | Mon, 6 Dec 2021 10:24:07 +0800 | Subject | Re: [kbuild-all] Re: lib/atomic64.c:82:5: warning: no previous prototype for 'generic_atomic64_and_return' | From | Rong Chen <> |
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On 11/26/21 19:47, Mark Rutland wrote: > On Fri, Nov 12, 2021 at 07:08:19AM +0800, kernel test robot wrote: >> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >> head: debe436e77c72fcee804fb867f275e6d31aa999c >> commit: 1bdadf46eff6804ace5fa46b6856da4799f12b5c locking/atomic: atomic64: support ARCH_ATOMIC >> date: 6 months ago >> config: arc-randconfig-r032-20211109 (attached as .config) >> compiler: arc-elf-gcc (GCC) 11.2.0 >> reproduce (this is a W=1 build): >> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross >> chmod +x ~/bin/make.cross >> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bdadf46eff6804ace5fa46b6856da4799f12b5c >> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >> git fetch --no-tags linus master >> git checkout 1bdadf46eff6804ace5fa46b6856da4799f12b5c >> # save the attached .config to linux build tree >> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=arc >> >> If you fix the issue, kindly add following tag as appropriate >> Reported-by: kernel test robot <lkp@intel.com> >> >> All warnings (new ones prefixed by >>): >>>> lib/atomic64.c:82:5: warning: no previous prototype for 'generic_atomic64_and_return' [-Wmissing-prototypes] >>>> lib/atomic64.c:82:5: warning: no previous prototype for 'generic_atomic64_or_return' [-Wmissing-prototypes] >>>> lib/atomic64.c:82:5: warning: no previous prototype for 'generic_atomic64_xor_return' [-Wmissing-prototypes] > Ah, there are not meant to be return forms of the and/or/xor operations, so > we're pointlessly building code that cannot be used (but this is not otherwise > harmful). > > That said, I think this is nothing to do with commit: > > 1bdadf46eff6804a ("locking/atomic: atomic64: support ARCH_ATOMIC") > > ... and is in fact a latent issue introduced by commit: > > 28aa2bda2211f432 ("locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}()") > > ... where we accidentally left the: > > ATOMIC64_OP_RETURN(op, c_op) > > ... line for the and/or/xor atomics, even though that wasn't necessary. > > This is trivial to avoid, so I'll send a patch shortly. > > Thanks, > Mark.
Hi Mark,
Thanks for the fix, the bot can't always find the first introduced commit with the bisection method.
Best Regards, Rong Chen
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