Getting at parameters on kernel.inline probes?

[Alan D. Brunelle]

I'm looking into a quick blktrace -> SystemTAP set of functions, and ran 
into a problem right at the start:

// static inline void blk_add_trace_rq(struct request_queue *q,
//                                     struct request *rq,
//                                     u32 what)
probe kernel.inline("blk_add_trace_rq") {
        print($q)
        print($rq)
        print($what)
}

% stap -vg stap_bt.stp
Pass 1: parsed user script and 46 library script(s) in 
90usr/10sys/96real ms.
semantic error: unresolved target-symbol expression: identifier '$q' at 
stap_bt.stp:5:15
semantic error: unresolved target-symbol expression: identifier '$rq' at 
stap_bt.stp:6:15
semantic error: unresolved target-symbol expression: identifier '$what' 
at stap_bt.stp:7:15
semantic error: unresolved target-symbol expression: identifier '$rq' at 
stap_bt.stp:6:15
semantic error: unresolved target-symbol expression: identifier '$what' 
at stap_bt.stp:7:15
semantic error: unresolved target-symbol expression: identifier '$q' at 
stap_bt.stp:5:15
semantic error: unresolved target-symbol expression: identifier '$rq' at 
stap_bt.stp:6:15
semantic error: unresolved target-symbol expression: identifier '$what' 
at stap_bt.stp:7:15
semantic error: unresolved target-symbol expression: identifier '$rq' at 
stap_bt.stp:6:15
semantic error: unresolved target-symbol expression: identifier '$what' 
at stap_bt.stp:7:15
Pass 2: analyzed script: 2 probe(s), 1 function(s), 0 global(s) in 
100usr/20sys/128real ms.
Pass 2: analysis failed.  Try again with more '-v' (verbose) options.

Is there some magic needed, or is it not possible (in all cases) to get 
at parameters to in-lined functions?

Thanks,
Alan