lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20140619210733.GQ4904@linux.vnet.ibm.com>
Date:	Thu, 19 Jun 2014 14:07:33 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	Lai Jiangshan <laijs@...fujitsu.com>, cl@...ux-foundation.org,
	kmo@...erainc.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/6] percpu-refcount: implement percpu_ref_reinit() and
 percpu_ref_is_zero()

On Thu, Jun 19, 2014 at 03:06:00PM -0400, Tejun Heo wrote:
> Hello,
> 
> On Thu, Jun 19, 2014 at 10:05:49AM -0700, Paul E. McKenney wrote:
> > If you mean what I think you mean by load_acquire_depends(), it is spelled
> > "rcu_dereference()" or, in this case, where you are never removing anything
> > that has been added, "rcu_dereference_raw()".  Because you are never
> > removing anything, you don't need rcu_read_lock() or rcu_read_unlock(),
> > thus you don't want lockdep yelling at you about not having RCU read-side
> > critical sections, thus rcu_dereference_raw().
> 
> Yeah, along that line but it's kinda weird to use rcu_dereference()
> when RCU isn't involved.  It'd be clearer to have something like
> load_acquire_depends() and then define RCU deref in terms of it.
> 
> This is purely notational and clarifiying in the documentation is
> probably enough.

OK.  If there end up being too many non-RCU uses of rcu_dereference_raw(),
then it might make sense to create a new primitive.  But it is not like
we have any shortage of them just now.  ;-)

							Thanx, Paul

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ