From: Nathan Chancellor <natechancellor@gmail.com> commit 380324734956c64cd060e1db4304f3117ac15809 upstream. Clang warns: In file included from ../arch/s390/purgatory/purgatory.c:10: In file included from ../include/linux/kexec.h:18: In file included from ../include/linux/crash_core.h:6: In file included from ../include/linux/elfcore.h:5: In file included from ../include/linux/user.h:1: In file included from ../arch/s390/include/asm/user.h:11: ../arch/s390/include/asm/page.h:45:6: warning: converting the result of '<<' to a boolean always evaluates to false [-Wtautological-constant-compare] if (PAGE_DEFAULT_KEY) ^ ../arch/s390/include/asm/page.h:23:44: note: expanded from macro 'PAGE_DEFAULT_KEY' #define PAGE_DEFAULT_KEY (PAGE_DEFAULT_ACC << 4) ^ 1 warning generated. Explicitly compare this against zero to silence the warning as it is intended to be used in a boolean context. Fixes: de3fa841e429 ("s390/mm: fix compile for PAGE_DEFAULT_KEY != 0") Link: https://github.com/ClangBuiltLinux/linux/issues/860 Link: https://lkml.kernel.org/r/20200214064207.10381-1-natechancellor@gmail.com Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- arch/s390/include/asm/page.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h index ac3c86b..349b1c1 100644 --- a/arch/s390/include/asm/page.h +++ b/arch/s390/include/asm/page.h @@ -42,7 +42,7 @@ static inline void storage_key_init_range(unsigned long start, unsigned long end) { - if (PAGE_DEFAULT_KEY) + if (PAGE_DEFAULT_KEY != 0) __storage_key_init_range(start, end); } -- 1.8.3