On Tue, May 09, 2023 at 09:31:47PM +0200, Peter Zijlstra wrote: > On Tue, May 09, 2023 at 12:56:28PM -0400, Kent Overstreet wrote: > > This adds a method to tell lockdep not to check lock ordering within a > > lock class - but to still check lock ordering w.r.t. other lock types. > > > > This is for bcachefs, where for btree node locks we have our own > > deadlock avoidance strategy w.r.t. other btree node locks (cycle > > detection), but we still want lockdep to check lock ordering w.r.t. > > other lock types. > > > > ISTR you had a much nicer version of this where you gave a custom order > function -- what happend to that? Actually, I spoke too soon; this patch and the other series with the comparison function solve different problems. For bcachefs btree node locks, we don't have a defined lock ordering at all - we do full runtime cycle detection, so we don't want lockdep checking for self deadlock because we're handling that but we _do_ want lockdep checking lock ordering of btree node locks w.r.t. other locks in the system.
