On Sat, 12 Nov 2005, Paul E. McKenney wrote:
> > > > > The above can simply be "n->next = *nl;". The reason is that this change
> > > > > of state is not visible to RCU readers until after the following statement,
> > > > > and it therefore need not be an RCU-reader-safe assignment. You only need
> > > > > to use rcu_assign_pointer() when the results of the assignment are
> > > > > immediately visible to RCU readers.
> > > >
> > > > Correct, the rcu call isn't really needed. It doesn't hurt perceptibly,
> > > > though, and part of the RCU documentation states:
> > > >
> > > > * ... More importantly, this
> > > > * call documents which pointers will be dereferenced by RCU read-side
> > > > * code.
> > > >
> > > > For that reason, I felt it was worth putting it in.
> > >
> > > But the following statement does a much better job of documenting the
> > > pointer that is to be RCU-dereferenced. Duplicate documentation can
> > > be just as confusing as no documentation.
> >
> > It's not really duplicate documentation since _both_ pointers are to be
> > RCU-dereferenced. But maybe you mean that only the second pointer can be
> > RCU-dereferenced at the time the write occurs? I don't think that's what
> > the documentation comment intended.
>
> I am the guy who wrote that documentation ocmment. ;-)
In that case I bow to your advice. :-)
Alan Stern
-
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/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
