s390/mm: Explicitly compare PAGE_DEFAULT_KEY against zero in storage_key_init_range
authorNathan Chancellor <natechancellor@gmail.com>
Fri, 14 Feb 2020 06:42:07 +0000 (23:42 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 28 Feb 2020 14:42:57 +0000 (15:42 +0100)
commit4ff38ff9c21fe52266fe01b8f2bdc4f846fd68c0
treee95f012a1a04e1f413b2d5b92bd93e1d24017092
parent1d982f7f03d28dfdd6f9562d13c94ccbbb3b9e11
s390/mm: Explicitly compare PAGE_DEFAULT_KEY against zero in storage_key_init_range

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>
arch/s390/include/asm/page.h