Arnd, Rob, Linus, Many thanks for your constructive feedback so far ! Is there anything in general about this set that would prevent it from being mainlined? Perhaps I am trying to do too much at once, dropping a patchset that is too complex to be properly reviewed? I've been thinking about reworking the host to its simplest, yet feature- complete form. Just serialize all card accesses with a single lock. Then the kernel thread, kqueue, kcache, kref etc would all disappear. The price we pay is a reduction in performance/parallelism. We could then increase parallelism at a later stage. Would that be of any help? Comments on v3 will go into v4 shortly. (Rob, I'm not sure how to address your feedback, other than to s/host/slot/g ?) Yours, Sven