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    SubjectRe: [GIT PULL] f2fs for 5.18
    On Tue, Mar 22, 2022 at 10:37 AM Waiman Long <longman@redhat.com> wrote:
    >
    > AFAICS, the read-unfair rwsem code is created to resolve a potential
    > lock starvation problem that they found on linux-5.10.y stable tree. I
    > believe I have fixed that in the v5.11 kernel, see commit 2f06f702925
    > ("locking/rwsem: Prevent potential lock starvation").

    Ahh.

    Adding Tim Murray to the cc, since he was the source of that odd
    reader-unfair thing.

    I really *really* dislike people thinking they can do locking
    primitives, because history has taught us that they are wrong.

    Even when people get the semantics and memory ordering right (which is
    not always the case, but at least the f2fs code uses real lock
    primitives - just oddly - and should thus be ok), it invariably tends
    to be a sign of something else being very wrong.

    And I can easily believe that in this case it's due to a rmsem issue
    that was already fixed long long ago as per Waiman.

    Can people please test with the actual modern rwsem code and with the
    odd reader-unfair locks disabled?

    Linus

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