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    SubjectRe: [PATCH 03/32] locking/lockdep: lockdep_set_no_check_recursion()
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    On 5/9/23 16:35, Kent Overstreet wrote:
    > On Tue, May 09, 2023 at 04:27:46PM -0400, Waiman Long wrote:
    >> On 5/9/23 16:18, Kent Overstreet wrote:
    >>> 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.
    >> Maybe you can use lock_set_novalidate_class() instead.
    > No, we want that to go away, this is the replacement.

    OK, you can mention that in the commit log then.

    Cheers,
    Longman

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