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From: Jeff Moyer <jmoyer@redhat.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Benjamin LaHaise <bcrl@kvack.org>, linux-aio@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/3] aio: make aio_ring->dead boolean
References: <20150618175209.GA10060@redhat.com>
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X-PCLoadLetter: What the f**k does that mean?
Date: Thu, 18 Jun 2015 14:02:47 -0400
In-Reply-To: <20150618175209.GA10060@redhat.com> (Oleg Nesterov's message of
	"Thu, 18 Jun 2015 19:52:09 +0200")
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Oleg Nesterov <oleg@redhat.com> writes:

> "atomic_t dead" makes no sense. atomic_read() is the plain LOAD,
> it doesn't have some "additional" synchronization with xchg().
>
> And now that kill_ioctx() sets "dead" under mm->ioctx_lock we do
> not even need xchg().
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>

> @@ -765,7 +765,7 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
>  err_cleanup:
>  	aio_nr_sub(ctx->max_reqs);
>  err_ctx:
> -	atomic_set(&ctx->dead, 1);
> +	ctx->dead = true; /* unneeded */

I was hoping you'd remove this line entirely.

-Jeff