Hi, Greg, On Fri, Oct 01, 2004 at 01:14:56PM -0700, Greg KH wrote: > On Fri, Oct 01, 2004 at 03:50:56PM -0400, lml@xxxxxxxxxxxxxxxx wrote: > > Hi, > > > > I am not sure how the reference counter can protect the data by just > > checking the number of usage. For example, one thread gets the object > > and increases the counter, while another can get the same object at > > the same time. If there is no locking, how can the reference counter > > solve the race contention. > > > > Or may be I missed some important part. > > You did. Your reference count needs to be an atomic value. Just use a > struct kref, it handles all of the logic for you. Yes, I know the reference counter is usually atomic_t, but two threads can "get" the object and this "get" only increases the atomic value. After that, they canread/write the object at the same time, right? It sounds like only the reference counter is atomic, while the content of the object is not protected. Please correct me if I am wrong. I am still using 2.4 kernel so there is no struct kref, but the principle, which I am not clear, should be the same. Thanks, LML > > greg k-h -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
