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Date: Wed, 27 Feb 2013 19:38:50 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Andrey Vagin <avagin@openvz.org>
Cc: linux-kernel@vger.kernel.org, criu@openvz.org, linux-api@vger.kernel.org,
        Roland McGrath <roland@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
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        "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>,
        Pavel Emelyanov <xemul@parallels.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Pedro Alves <palves@redhat.com>
Subject: Re: [PATCH 1/2] ptrace: add ability to retrieve signals without
	removing from a queue (v3)
Message-ID: <20130227183850.GA6042@redhat.com>
References: <1361975829-1738-1-git-send-email-avagin@openvz.org>
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On 02/27, Andrey Vagin wrote:
>
> +struct ptrace_peeksiginfo_args {
> +	__u64 off;	/* from which siginfo to start */

Cough... You are optimist. You want to handle the case when the
tracee has 1 << 33 or more pending sigqueues. OK good luck ;)

Looks correct, just one nit.

> +	for (i = 0; i < arg.nr; i++) {
> ...
> +		data += sizeof(siginfo_t);
> +
> +		if (signal_pending(current)) {
> +			i++; /* accounting the current siginfo */
> +			break;
> +		}

Imho, this is confusing. Just do

	for (i = 0; i < arg.nr; ) {
		...

		data += sizeof(siginfo_t);
		i++;

		if (signal_pending(current))
			break;

Oleg.