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    SubjectRe: [PATCH 2/2] xen: make xen_qlock_wait() nestable
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    On Mon, 2018-10-01 at 09:16 +0200, Juergen Gross wrote:
    > - /* If irq pending already clear it and return. */
    > + /* Guard against reentry. */
    > + local_irq_save(flags);
    > +
    > + /* If irq pending already clear it. */
    > if (xen_test_irq_pending(irq)) {
    > xen_clear_irq_pending(irq);
    > - return;
    > + } else if (READ_ONCE(*byte) == val) {
    > + /* Block until irq becomes pending (or a spurious wakeup) */
    > + xen_poll_irq(irq);
    > }


    Does this still allow other IRQs to wake it from xen_poll_irq()?

    In the case where process-context code is spinning for a lock without
    disabling interrupts, we *should* allow interrupts to occur still...
    does this?
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