A few hours ago I wrote: > copyin() is called by the system call code and returns > efault after validating the address, before actually > touching it.
This is the traditional way of doing things but is clearly expensive as validating a user address takes forever and a bit. Do we blindly use whatever address is passed in and then add checking to the page fault code to figure out if we should just return efault? This would be a blatant example of optimizing the common case at small cost for the error case which most people probably don't care about. -michael
