I wrote: > If you only count pending transactions, you know when to deregister the > device from the idr. But you don't know when it's OK to free the > device's memory. > > If you cont only references to the memory, you know when it is OK to > free it but you don't know when to deregister from the idr. PS: However, if you never copy the idr's reference, then you don't need that other ref-counter. To avoid such copies, every site which looks up the device in the idr would have to perform all its accesses to the device while inside an sg_index_lock protected section. Then only the transactions have copies of the pointer to the device representation in memory. This of course means that the transaction counter is equal to the reference counter (plus the one reference of the idr which you don't need to count because you remove that reference when there is also no transaction anymore). -- Stefan Richter -=====-==--= ---= -==== http://arcgraph.de/sr/ -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
