In message <200409301409.25904.jhb_at_FreeBSD.org>, John Baldwin writes: >On Thursday 30 September 2004 03:06 am, Poul-Henning Kamp wrote: >> I had this one out on arch_at_ previously. I'm very interested in informed >> feedback on how we deal with locking for service api's like this. > >I would suggest that the caller should ask for a unit before it needs a lock >and if it finds that it doesn't need the unit after all it can give it back >in the error handling. That is, this is similar to malloc'ing a structure up >front, then grabbing locks and making changes, then after releasing the lock >free'ing the structure if it turned out we didn't need it. Right. My personal guess is that driver->attach() and driver->probe() will never get out from Giant (I can't seriously see the benefits as being bigger than the effort) and therefore I think the problem of locking API's like this can be wholesale ignored for a very long time. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk_at_FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.Received on Thu Sep 30 2004 - 16:58:05 UTC
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