Commit 92972124 authored Sep 25, 2018 by Nathan Chancellor Committed by Greg Kroah-Hartman Nov 27, 2018

arm64: percpu: Initialize ret in the default case



[ Upstream commit b5bb425871186303e6936fa2581521bdd1964a58 ]

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.

Reported-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 09fbe8ad

arch/arm64/include/asm/percpu.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -84,6 +84,7 @@ static inline unsigned long __percpu_##op(void *ptr, \
		: [val] "Ir" (val)); \
		break; \
		default: \
		ret = 0; \
		BUILD_BUG(); \
		} \
		\
		@@ -113,6 +114,7 @@ static inline unsigned long __percpu_read(void *ptr, int size)
		ret = ACCESS_ONCE((u64 )ptr);
		break;
		default:
		ret = 0;
		BUILD_BUG();
		}

		@@ -182,6 +184,7 @@ static inline unsigned long __percpu_xchg(void *ptr, unsigned long val,
		: [val] "r" (val));
		break;
		default:
		ret = 0;
		BUILD_BUG();
		}