On (07/20/17 12:28), H??kon Bugge wrote: > cp->cp_send_gen is treated as a normal variable, although it may be > used by different threads.
I'm confused by that assertion. If you look at the comments right above the change in your patch, there is a note that acquire_in_xmit/release_in_xmit are the synchronization/serialization points. Can you please clarify? > --- a/net/rds/send.c > +++ b/net/rds/send.c > @@ -170,8 +170,8 @@ int rds_send_xmit(struct rds_conn_path *cp) > * The acquire_in_xmit() check above ensures that only one > * caller can increment c_send_gen at any time. > */ > - cp->cp_send_gen++; > - send_gen = cp->cp_send_gen; > + send_gen = READ_ONCE(cp->cp_send_gen) + 1; > + WRITE_ONCE(cp->cp_send_gen, send_gen); > --Sowmini
