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    SubjectRe: 2.6.19-rc6: known regressions (v4)


    On Wed, 22 Nov 2006, Pavel Emelianov wrote:
    >
    > This works for me, but is this normal that desc's fields are
    > modified non-atomically in note_interrupt()?

    This is all inside the normal interrupt handling logic, so it should be
    exactly as safe as any interrupt is: we don't allow the _same_ interrupt
    to be entered recursively at the same time.

    So yes, the counts etc are done non-atomically, but the code around it all
    guarantees that only one concurrent invocation happens per irq descriptor,
    so it's all ok.

    (The one exception to that may be the "desc->status" modification in case
    the irq is determined to have screamed, since "status" can be modified by
    a recursive interrupt coming in, but (a) that's a "this irq is dead"
    schenario _anyway_ and (b) if we ever care, we should lock it _there_, not
    somewhere else).

    Linus
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