From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Elena Reshetova
<elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-audit-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
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peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org,
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hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org,
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arnd-r2nGTMty4D4@public.gmane.org,
luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
Hans Liljestrand
<ishkamiel-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
David Windsor <dwindsor-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH 12/19] kernel: convert css_set.refcount from atomic_t to refcount_t
Date: Mon, 6 Mar 2017 14:54:39 -0500 [thread overview]
Message-ID: <20170306195439.GD19696@htj.duckdns.org> (raw)
In-Reply-To: <1487585948-6401-13-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Hello,
On Mon, Feb 20, 2017 at 12:19:01PM +0200, Elena Reshetova wrote:
> @@ -134,10 +135,13 @@ static inline void put_css_set(struct css_set *cset)
> * can see it. Similar to atomic_dec_and_lock(), but for an
> * rwlock
> */
> - if (atomic_add_unless(&cset->refcount, -1, 1))
> + spin_lock_irqsave(&css_set_lock, flags);
> + if (refcount_read(&cset->refcount) != 1) {
> + WARN_ON(refcount_dec_and_test(&cset->refcount));
> + spin_unlock_irqrestore(&css_set_lock, flags);
> return;
> + }
This isn't an equivalent conversion and should have been mentioned in
the patch description. Hmm... and I'm not sure this is a good idea.
Can't we add the matching operation on refcount_t rather than adding
extra locking like this?
Thanks.
--
tejun
next prev parent reply other threads:[~2017-03-06 19:54 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-20 10:18 [PATCH 00/19] Kernel subsystem refcounter conversions Elena Reshetova
2017-02-20 10:18 ` [PATCH 01/19] kernel: convert sighand_struct.count from atomic_t to refcount_t Elena Reshetova
[not found] ` <1487585948-6401-2-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-02-20 12:30 ` kbuild test robot
2017-02-20 12:42 ` kbuild test robot
2017-02-20 10:18 ` [PATCH 02/19] kernel: convert signal_struct.sigcnt " Elena Reshetova
2017-02-20 10:18 ` [PATCH 03/19] kernel: convert user_struct.__count " Elena Reshetova
2017-02-20 10:18 ` [PATCH 04/19] kernel: convert task_struct.usage " Elena Reshetova
2017-02-20 10:18 ` [PATCH 06/19] kernel: convert perf_event_context.refcount " Elena Reshetova
[not found] ` <1487585948-6401-7-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-02-20 10:28 ` Peter Zijlstra
[not found] ` <20170220102825.GL6500-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2017-02-20 12:14 ` Reshetova, Elena
2017-02-20 10:18 ` [PATCH 07/19] kernel: convert ring_buffer.refcount " Elena Reshetova
2017-02-20 10:18 ` [PATCH 08/19] kernel: convert ring_buffer.aux_refcount " Elena Reshetova
2017-02-20 10:18 ` [PATCH 09/19] kernel: convert uprobe.ref " Elena Reshetova
2017-02-20 10:18 ` [PATCH 10/19] kernel: convert nsproxy.count " Elena Reshetova
2017-02-20 10:19 ` [PATCH 11/19] kernel: convert cgroup_namespace.count " Elena Reshetova
2017-03-06 19:55 ` Tejun Heo
2017-02-20 10:19 ` [PATCH 12/19] kernel: convert css_set.refcount " Elena Reshetova
[not found] ` <1487585948-6401-13-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-03-06 19:54 ` Tejun Heo [this message]
2017-03-07 19:12 ` Reshetova, Elena
2017-03-07 19:21 ` Tejun Heo
2017-02-20 10:19 ` [PATCH 13/19] kernel: convert group_info.usage " Elena Reshetova
[not found] ` <1487585948-6401-1-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-02-20 10:18 ` [PATCH 05/19] kernel: convert task_struct.stack_refcount " Elena Reshetova
2017-02-20 10:19 ` [PATCH 14/19] kernel: convert cred.usage " Elena Reshetova
2017-02-20 10:19 ` [PATCH 15/19] kernel: convert audit_tree.count " Elena Reshetova
[not found] ` <1487585948-6401-16-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-02-20 22:07 ` Paul Moore
[not found] ` <CAHC9VhQW7xFHBLNQOQRKMftStu_aHjbUmp96VJrcfWzxuzE_kw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-02-21 7:15 ` Reshetova, Elena
2017-02-28 22:11 ` Paul Moore
2017-03-01 0:16 ` Kees Cook
2017-03-01 19:35 ` Paul Moore
2017-03-01 23:04 ` Kees Cook
[not found] ` <CAHC9VhQBB9srK85meAi41pxD0Vse3NiX1-zmKGXcoYh0vB_=9A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-04-11 19:01 ` Paul Moore
2017-04-18 6:33 ` Reshetova, Elena
2017-02-20 10:19 ` [PATCH 16/19] kernel: convert audit_watch.count " Elena Reshetova
2017-02-20 10:19 ` [PATCH 17/19] kernel: convert numa_group.refcount " Elena Reshetova
2017-02-20 10:19 ` [PATCH 18/19] kernel: convert futex_pi_state.refcount " Elena Reshetova
2017-02-20 10:19 ` [PATCH 19/19] kernel: convert kcov.refcount " Elena Reshetova
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