On Wed, 2015-06-24 at 19:44 +0530, ratheesh kannoth wrote: > On Wed, Jun 24, 2015 at 6:16 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: > > You misunderstood the comment. > > > > Comment only stated that sock_hold() must be used in contexts where > > caller owns a reference (and will eventually release it later with > > sock_put(). > > > > There is nothing about having a lock here. > > Thanks. I think, i did not put the question right. > > I understood the comment perfectly. Suppose i need to use the > sock_hold in some callbacks ( say netdev_notifier chain callback) > function. How can i gurantee race won't happen at the point where i > call sock_hold(). > If i put the question in another way - say kernel is doing a > sock_put() on a socket, and at the same time the netdev_callback > function( that i implemented ) is called on another core ( in smp > machine ). and the callback is holding (sock_hold()) on the same > sock. You can not possibly use sock_hold() from the callback, unless you already took a reference on the socket _before_ callback was called, to make sure socket would not disappear. Its hard to understand what you try to do here. If you worry because socket would disappear when "kernel is doing a sock_put()", then it means you did not take the needed extra reference to make sure callback would access a valid socket. -- To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.linux-learn.org/faqs
