From mboxrd@z Thu Jan  1 00:00:00 1970
From: Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH 1/4] signalfd: add ability to return siginfo in a raw
	format
Date: Tue, 25 Dec 2012 16:27:16 +0100
Message-ID: <20121225152716.GA3198@redhat.com>
References: <1356336807-5517-1-git-send-email-avagin@openvz.org> <1356336807-5517-2-git-send-email-avagin@openvz.org> <20121224165306.GA9553@redhat.com> <CANaxB-x=fQROdwD1OyU8=Ai9tXWm9QTSsGgfKvPbjn57ER6aZg@mail.gmail.com> <20121225143043.GA1813@redhat.com>
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Cc: linux-kernel@vger.kernel.org, criu@openvz.org,
	linux-fsdevel@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	David Howells <dhowells@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	Pavel Emelyanov <xemul@parallels.com>,
	Cyrill Gorcunov <gorcunov@openvz.org>
To: Andrey Wagin <avagin@gmail.com>
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On 12/25, Oleg Nesterov wrote:
>
> And if we add another format we should think
> twice.

And btw this applies to the whole series.

I guess that probably you actually need DUMP, not DEQUEUE. but the
latter is not trivial. However, perhaps we can do this assuming that
all other threads are sleeping and nobody can do dequeue_signal().
Say, we can play with ppos/llseek. If *ppos is not zero,
signalfd_dequeue() could dump the nth entry from list or return 0.

Oleg.