On Fri, Oct 12, 2018 at 04:56:55PM -0700, Andrew Morton wrote: > There are several reasons for using raw_*, so an explanatory comment at > each site is called for. > > However it would be smarter to stop "using raw_* for several reasons". > Instead, create a differently named variant for each such reason. ie, do > > /* > * Nice comment goes here. It explains all the possible reasons why -rt > * might use a raw_spin_lock when a spin_lock could otherwise be used. > */ > #define raw_spin_lock_for_rt raw_spinlock > > Then use raw_spin_lock_for_rt() at all such sites. The whole raw_spinlock_t is for RT, no other reason. It is the one true spinlock. >From this, it naturally follows that: - nesting order: raw_spinlock_t < spinlock_t < mutex_t - raw_spinlock_t sections must be bounded The patch under discussion is the result of the nesting order rule; and is allowed to violate the second rule, by virtue of it being debug code. There are no other reasons; and I'm somewhat confused by what you propose.
