linux-kernel - Re: [PATCH] Move kfree_call_rcu() to slab

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: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20180102202454.GQ7829@linux.vnet.ibm.com>
Date:   Tue, 2 Jan 2018 12:24:54 -0800
From:   "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:     Rao Shoaib <rao.shoaib@...cle.com>
Cc:     Matthew Wilcox <willy@...radead.org>, linux-kernel@...r.kernel.org,
        brouer@...hat.com, linux-mm@...ck.org
Subject: Re: [PATCH] Move kfree_call_rcu() to slab_common.c

On Thu, Dec 21, 2017 at 07:17:35PM -0800, Rao Shoaib wrote:
> 
> 
> On 12/21/2017 05:39 PM, Paul E. McKenney wrote:
> >>I left it out on purpose because the call in tiny is a little different
> >>
> >>rcutiny.h:
> >>
> >>static inline void kfree_call_rcu(struct rcu_head *head,
> >>                   void (*func)(struct rcu_head *rcu))
> >>{
> >>     call_rcu(head, func);
> >>}
> >>
> >>tree.c:
> >>
> >>void kfree_call_rcu(struct rcu_head *head,
> >>             void (*func)(struct rcu_head *rcu))
> >>{
> >>     __call_rcu(head, func, rcu_state_p, -1, 1);
> >>}
> >>EXPORT_SYMBOL_GPL(kfree_call_rcu);
> >>
> >>If we want the code to be exactly same I can create a lazy version
> >>for tiny as well. However,  I don not know where to move
> >>kfree_call_rcu() from it's current home in rcutiny.h though. Any
> >>thoughts ?
> >I might be missing something subtle here, but in case I am not, my
> >suggestion is to simply rename rcutiny.h's kfree_call_rcu() and otherwise
> >leave it as is.  If you want to update the type of the second argument,
> >which got missed back in the day, there is always this:
> >
> >static inline void call_rcu_lazy(struct rcu_head *head, rcu_callback_t func)
> >{
> >	call_rcu(head, func);
> >}
> >
> >The reason that Tiny RCU doesn't handle laziness specially is because
> >Tree RCU's handling of laziness is a big no-op on the single CPU systems
> >on which Tiny RCU runs.  So Tiny RCU need do nothing special to support
> >laziness.
> >
> >							Thanx, Paul
> >
> Hi Paul,
> 
> I can not just change the name as __kfree_call_rcu macro calls
> kfree_call_rcu(). I have made tiny version of kfree_call_rcu() call
> rcu_call_lazy() which calls call_rcu(). As far as the type is
> concerned, my bad, I cut and posted from an older release. Latest
> code is already using the typedef.

Hello, Rao,

Perhaps it would be best if you simply reposted the latest patch.  ;-)

							Thanx, Paul