On Tue, Sep 25, 2018 at 1:24 PM Nick Desaulniers <[email protected]> wrote: > > On Tue, Sep 25, 2018 at 12:45 PM Nathan Chancellor > <[email protected]> wrote: > > > > Clang warns that if the default case is taken, ret will be > > uninitialized. > > > > ./arch/arm64/include/asm/percpu.h:196:2: warning: variable 'ret' is used > > uninitialized whenever switch default is taken > > [-Wsometimes-uninitialized] > > default: > > ^~~~~~~ > > ./arch/arm64/include/asm/percpu.h:200:9: note: uninitialized use occurs > > here > > return ret; > > ^~~ > > ./arch/arm64/include/asm/percpu.h:157:19: note: initialize the variable > > 'ret' to silence this warning > > unsigned long ret, loop; > > ^ > > = 0 > > > > This warning appears several times while building the erofs filesystem. > > While it's not strictly wrong, the BUILD_BUG will prevent this from > > becoming a true problem. Initialize ret to 0 in the default case right > > before the BUILD_BUG to silence all of these warnings. > > Clang does semantic analysis BEFORE inlining/optimizations, so I can't
s/I/it/ > determine that default is never reachable. Nathan, thanks for this > patch. > Reviewed-by: Nick Desaulniers <[email protected]> > > > > > Reported-by: Prasad Sodagudi <[email protected]> > > Signed-off-by: Nathan Chancellor <[email protected]> > > --- > > arch/arm64/include/asm/percpu.h | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/arch/arm64/include/asm/percpu.h > > b/arch/arm64/include/asm/percpu.h > > index 9234013e759e..21a81b59a0cc 100644 > > --- a/arch/arm64/include/asm/percpu.h > > +++ b/arch/arm64/include/asm/percpu.h > > @@ -96,6 +96,7 @@ static inline unsigned long __percpu_##op(void *ptr, > > \ > > : [val] "Ir" (val)); \ > > break; \ > > default: \ > > + ret = 0; \ > > BUILD_BUG(); \ > > } \ > > \ > > @@ -125,6 +126,7 @@ static inline unsigned long __percpu_read(void *ptr, > > int size) > > ret = READ_ONCE(*(u64 *)ptr); > > break; > > default: > > + ret = 0; > > BUILD_BUG(); > > } > > > > @@ -194,6 +196,7 @@ static inline unsigned long __percpu_xchg(void *ptr, > > unsigned long val, > > : [val] "r" (val)); > > break; > > default: > > + ret = 0; > > BUILD_BUG(); > > } > > > > -- > > 2.19.0 > > > > > -- > Thanks, > ~Nick Desaulniers -- Thanks, ~Nick Desaulniers
