On Sun, 24 Aug 2025, kernel test robot wrote:
All warnings (new ones prefixed by >>):
In file included from sound/soc/codecs/mt6660.c:15:
sound/soc/codecs/mt6660.h:28:1: warning: alignment 1 of 'struct mt6660_chip' is less than 8 [-Wpacked-not-aligned]
28 | }; | ^
sound/soc/codecs/mt6660.h:25:22: warning: 'io_lock' offset 49 in 'struct mt6660_chip' isn't aligned to 8 [-Wpacked-not-aligned]
25 | struct mutex io_lock; | ^~~~~~~
Misalignment warnings like this one won't work if you just pick an alignment arbitrarily i.e. to suit whatever bitfield you happen to need.
Instead, I think I would naturally align the actual locks, that is, arch_spinlock_t and arch_rwlock_t in include/linux/spinlock_types*.h.