Re: [PATCH tip/core/rcu 04/14] rcu: Add a gcc-style structureinitializer for RCU pointers

From: Paul E. McKenney
Date: Fri Jun 15 2012 - 18:50:04 EST


On Fri, Jun 15, 2012 at 02:50:21PM -0700, Josh Triplett wrote:
> On Fri, Jun 15, 2012 at 01:48:13PM -0700, Josh Triplett wrote:
> > On Fri, Jun 15, 2012 at 01:13:05PM -0700, Paul E. McKenney wrote:
> > > From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
> > >
> > > RCU_INIT_POINTER() returns a value that is never used, and which should
> > > be abolished due to terminal ugliness:
> > >
> > > q = RCU_INIT_POINTER(global_p, p);
> > >
> > > However, there are two uses that cannot be handled by a do-while
> > > formulation because they do gcc-style initialization:
> > >
> > > RCU_INIT_POINTER(.real_cred, &init_cred),
> > > RCU_INIT_POINTER(.cred, &init_cred),
> > >
> > > This usage is clever, but not necessarily the nicest approach. This
> > > commit therefore creates an INIT_RCU_POINTER() macro that is specifically
> > > designed for gcc-style initialization.
> >
> > The concept seems fine, but the names seem entirely non-obvious.
> > RCU_INIT_POINTER versus INIT_RCU_POINTER?
>
> Suggestion: RCU_POINTER_INITIALIZER, following the example of many other
> *_INITIALIZER macros elsewhere in the kernel.

Sold!

Thanx, Paul

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