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    SubjectRe: [RFC][PATCH] irq: remove IRQF_DISABLED
    On Mon, 02 Mar 2009 13:21:17 +0100 Peter Zijlstra <peterz@infradead.org> wrote:

    >
    > People are playing odd games with IRQF_DISABLED, remove it.
    >
    > Its not reliable, since shared interrupt lines could disable it for you,
    > and its possible and allowed for archs to disable IRQs to limit IRQ nesting.
    >
    > Therefore, simply mandate that _ALL_ IRQ handlers are run with IRQs disabled.
    >
    > [ This _should_ not break anything, since we've mandated that IRQ handlers
    > _must_ be able to deal with this for a _long_ time ]
    >
    > IRQ handlers should be fast, no if buts and any other exceptions. We also have
    > plenty instrumentation to find any offending IRQ latency sources.

    Changelog is a bit cruddy. What are these "odd games" and why are they
    so serious as to warrant a fairly drastic-looking patch?

    Where are these odd games being played, and what are the implications
    to those codesites of having their ball taken away? etc.


    wrt the patch itself - it would make life easier if we were to leave
    the IRQF_DISABLED definition in place for a while. I'm counting 47 new
    additions of references to IRQF_DISABLED in linux-next/-mm. It would
    grease the wheels a bit were these things (and out-of-tree drivers) to
    not instabreak. One could add a nice runtime warning at request_irq()
    time, leave that in place until everything is fixed up.



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