linux-kernel - Re: [PATCH 8/8] fs/aio: Use rcu_work instead of explicit rcu and work item

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: <20180321175356.GD2149215@devbig577.frc2.facebook.com>
Date:   Wed, 21 Mar 2018 10:53:56 -0700
From:   Tejun Heo <tj@...nel.org>
To:     Oleg Nesterov <oleg@...hat.com>
Cc:     torvalds@...ux-foundation.org, jannh@...gle.com,
        paulmck@...ux.vnet.ibm.com, bcrl@...ck.org,
        viro@...iv.linux.org.uk, kent.overstreet@...il.com,
        security@...nel.org, linux-kernel@...r.kernel.org,
        kernel-team@...com
Subject: Re: [PATCH 8/8] fs/aio: Use rcu_work instead of explicit rcu and
 work item

Hello,

On Wed, Mar 21, 2018 at 06:17:43PM +0100, Oleg Nesterov wrote:
> Mostly I am asking because I do not really understand
> "[PATCH 6/8] RCU, workqueue: Implement rcu_work".
> 
> I mean, the code looks simple and correct but why does it play with
> WORK_STRUCT_PENDING_BIT? IOW, I do not see a "good" use-case when 2 or more
> queue_rcu_work()'s can use the same rwork and hit work_pending() == T. And
> what the caller should do if queue_rcu_work() returns false?

It's just following standard workqueue conventions.  We can try to
make it more specialized but then flush_rcu_work()'s behavior would
have to different too and it gets confusing quickly.  Unless there are
overriding reasons to deviate, I'd like to keep it consistent.

Thanks.

-- 
tejun