Date: Tue, 11 Aug 2015 17:25:24 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Nitin Gupta <ngupta@vflare.org>, linux-kernel@vger.kernel.org,
        paulmck@linux.vnet.ibm.com, peterz@infradead.org
Subject: Re: [PATCH] zram: fix possible race when checking idle_strm
Message-ID: <20150811082524.GA562@swordfish>
References: <1438934609-16924-1-git-send-email-iamjoonsoo.kim@lge.com>
 <20150807091457.GL1891@swordfish>
 <20150807095816.GP1891@swordfish>
 <20150810003229.GA26074@js1304-P5Q-DELUXE>
 <20150810232633.GA7197@bgram>
 <20150811082527.GA351@js1304-P5Q-DELUXE>
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On (08/11/15 17:25), Joonsoo Kim wrote:
[..]
> > "SLEEP AND WAKE-UP FUNCTIONS
> > ---------------------------
> > 
> > Sleeping and waking on an event flagged in global data ...
> > ...
> > ...
> > ...
> > 
> > A general memory barrier is interpolated automatically by set_current_state()
> > after it has altered the task state:"
> > 
> > So I think your T1-7 assumption is not true.
> > 
> > As well, there are many examples under drivers/ to use the global data
> > as event flag without locking or atomic.
> > 
> 
> Okay. Now, I'm convinced that race is not possible. I will drop this
> patch.

yep, Minchan found it first. thanks guys.

	-ss
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