Messages in this thread | | | Date | Tue, 9 May 2023 16:11:19 -0400 | From | Kent Overstreet <> | Subject | Re: [PATCH 02/32] locking/lockdep: lock_class_is_held() |
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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@gmail.com> > > > > 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?
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