ACPI: fix false-positive -Wuninitialized warning
authorArnd Bergmann <arnd@arndb.de>
Fri, 12 Jul 2019 09:01:21 +0000 (11:01 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 6 Aug 2019 17:06:50 +0000 (19:06 +0200)
commitc0cca0e97ce47e62dbfea72bce1cba71aa19e010
treec780029dfb657fe63a01d714bcdaab98c386cba0
parent80f58147da0f40bc427dcd96c6bcf07786c41c11
ACPI: fix false-positive -Wuninitialized warning

[ Upstream commit dfd6f9ad36368b8dbd5f5a2b2f0a4705ae69a323 ]

clang gets confused by an uninitialized variable in what looks
to it like a never executed code path:

arch/x86/kernel/acpi/boot.c:618:13: error: variable 'polarity' is uninitialized when used here [-Werror,-Wuninitialized]
        polarity = polarity ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
                   ^~~~~~~~
arch/x86/kernel/acpi/boot.c:606:32: note: initialize the variable 'polarity' to silence this warning
        int rc, irq, trigger, polarity;
                                      ^
                                       = 0
arch/x86/kernel/acpi/boot.c:617:12: error: variable 'trigger' is uninitialized when used here [-Werror,-Wuninitialized]
        trigger = trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE;
                  ^~~~~~~
arch/x86/kernel/acpi/boot.c:606:22: note: initialize the variable 'trigger' to silence this warning
        int rc, irq, trigger, polarity;
                            ^
                             = 0

This is unfortunately a design decision in clang and won't be fixed.

Changing the acpi_get_override_irq() macro to an inline function
reliably avoids the issue.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
include/linux/acpi.h