On Tue, 2005-01-25 at 07:08 +0100, Heiko Carstens wrote: > > Originally this generic device was part of your adapter structure. Now > > you're trying to separate it and causing these problems. What it's > > Could you please elaborate where this patch does cause a problem?
You're look to be breaking the simplicity rules. Object lifetimes are very tricky things to manage, so what I want you to explain is why you have to make this more difficult buy making the object separately managed instead of treating it as a sub object of the adapter which shares the adapter's lifetime rules. What's the justification for this? > > apparently telling us is that you have some problem with the object > > lifetime rules in your code. > > Why should this generic_services device have different lifetime rules > > from the object in which it used to reside? > > It doesn't. And this was not supposed to fix anything. It's just that > Andreas liked the code better with allocating the generic_services > struct device seperately. Please note that the lifetime of the adapter > device this struct device was embedded into is always longer than the > lifetime of the generic_services device. > Therefore I can't see why you complain about this piece of code. generic devices are supposed to represent existing kernel objects, which is why they're usually embedded in existing structures. It seems to be unique within the kernel to allocate a generic device without an enveloping structure (like a scsi_device, mca_device, pci_device etc), so I was wondering why you need to do it this way? Simplicity says that you want to manage the lifetimes of as few objects as you can get away with (SCSI tries to put all lifetime rules in either the mid-layer or the transport classes so the driver code doesn't usually have to worry about them). The reason being that lifetime rules are very easy to get wrong and have fairly nasty consequences if you do get them wrong (pointers into free'd memory etc.). James > Since I didn't get an answer to this: > http://marc.theaimsgroup.com/?l=linux-scsi&m=110551973013105&w=2 > my assumption was that it's that obvious to everyone else that I'm > wrong that it isn't even worth writing an answer. > Now I follow Greg's rules and still get complaints... > > Thanks, > Heiko > > - > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
