On Tue, Oct 30, 2012 at 10:26:46AM -0400, Chas Williams (CONTRACTOR) wrote: > In message > <[email protected]>,Krzysztof Mazur > writes: > > as i recall from way back, this shouldnt be necessary. closing a vcc > for an attached protocol isnt supposed to require addtional locking > or synchronization.
Such locking is already used by vcc_sendmsg() and I think we should do here exacly what vcc_sendmsg() does. > > vcc_release() locks the socket and vcc_destroy_socket() calls the device's > vcc close routine and pushes a NULL skb to the attached protocol. > this NULL push is supposed to let the attached protocol that no more > sends and recvs can be handled. > > that said, the order for the device vcc close and push does seem > reversed. since i imagine there could be a pending pppoatm_send() > during this interval. the push of the NULL skb is allowed to wait for > the subprotocol to finish its cleanup/shutdown. Yes, this problem can be probably fixed by reversing close and push and adding some synchronization to pppoatm_unassign_vcc(), but I think we need that locking anyway, for instance for synchronization for checking and incrementing sk->sk_wmem_alloc, between pppoatm_send() and vcc_sendmsg(). Thanks. Krzysiek -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
