On Tuesday 16 May 2006 12:25, Johannes Stezenbach wrote: > On Tue, May 16, 2006, Andrew de Quincey wrote: > > On Sunday 14 May 2006 11:38, Johannes Stezenbach wrote: > > > On Sat, May 13, 2006, Oliver Endriss wrote: > > > > Is chaining used anywhere else than in the lnbp21 driver? > > > > > > > > I introduced it because I thought that it would be a good idea to > > > > limit the number of private pointers in struct dvb_frontend. ;-) > > > > > > > > Obviously it makes life harder, not easier. So just remove chaining > > > > from lnbp21.[ch], and rename misc_priv to something like sec_priv... > > > > > > > > Imho it's not worth the trouble. ;-) > > > > > > IMHO this "chaining" of the release function is a bad > > > concept. The card driver does the attach, so it should also > > > do the release. > > > > > > Consider: > > > foo = foo_attach(); > > > bar = bar_attach(foo); > > > ... > > > bar->release(); > > > // do we leak foo now is it magically cleaned up? > > > > > > Please keep it simple and stupid, the four drivers which > > > use lnbp21 can also keep a lnbp21 pointer around and > > > release it explicitly. > > > > Hmm, well we could make a rule that you never chain the release() > > function, even though you are allowed to do so for the other function > > pointers... would this be ok? Then we would always have a pointer to each > > used module, and hence using symbol_put_addr() would be fine. > > IMHO it is the card driver which creates an instance of the > demod/pll/lnbp etc. driver, so it *owns* the reference. The > chaining of the fe->ops function pointers is an implementation > detail, it could e.g. also be implemented by keeping one > fe->ops per driver and have dvb_frontend call them in order. > > So there is a conceptual difference between chaining fe->ops > and passing ownership to some other module. > > IOW, chaining ->release() is not the problem, but having > ->release() decrement the refcount of some other module is. Hmm, sorry, not sure what you mean here - where is one module decrementing the refcount of another module? Ah, do you mean the symbol_put in the current dvb_attach() ? _______________________________________________ linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
