On Tue, May 09, 2023 at 09:30:39PM +0200, Peter Zijlstra wrote: > On Tue, May 09, 2023 at 12:56:27PM -0400, Kent Overstreet wrote: > > From: Kent Overstreet <kent.overstreet@xxxxxxxxx> > > > > This patch adds lock_class_is_held(), which can be used to assert that a > > particular type of lock is not held. > > How is lock_is_held_type() not sufficient? Which is what's used to > implement lockdep_assert_held*(). I should've looked at that before - it returns a tristate, so it's closer than I thought, but this is used in contexts where we don't have a lock or lockdep_map to pass and need to pass the lock_class_key instead. e.g, when initializing a btree_trans, or waiting on btree node IO, we need to assert that no btree node locks are held. Looking at the code, __lock_is_held() -> match_held_lock() has to care about a bunch of stuff related to subclasses that doesn't seem relevant to lock_class_is_held() - lock_class_is_held() is practically no code in comparison, so I'm inclined to think they should just be separate. But I'm not the lockdep expert :) Thoughts?
