From patchwork Wed Mar 18 15:03:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 11445489 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0108590 for ; Wed, 18 Mar 2020 15:03:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D3D5D20757 for ; Wed, 18 Mar 2020 15:03:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dbrHblWu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727122AbgCRPD6 (ORCPT ); Wed, 18 Mar 2020 11:03:58 -0400 Received: from us-smtp-delivery-74.mimecast.com ([216.205.24.74]:59475 "EHLO us-smtp-delivery-74.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727126AbgCRPD6 (ORCPT ); Wed, 18 Mar 2020 11:03:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584543837; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=e/8oKaNwBTjhOkAOmc6Y3YdVNmuI5yN2hQOJFhQz4lM=; b=dbrHblWuA5j9HNlrRQv8yRwYzIgQWVu8ziYI4oKiGxKd3vIkKKt3bmRzfMIhrsXU781QP7 eh82eMuZc3uop+OGNGYG16A3oCenOoDbFbgEBnyHbjqDxkUo/WENkRcjbQvxubzObmyOoi LD43iEyOvwh3evnAYoCnKD4jGh9Yvvk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-11-FfNo_gf4O0Wxy5Ttl7H2sQ-1; Wed, 18 Mar 2020 11:03:55 -0400 X-MC-Unique: FfNo_gf4O0Wxy5Ttl7H2sQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9A0DEA1366; Wed, 18 Mar 2020 15:03:53 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-113-126.rdu2.redhat.com [10.10.113.126]) by smtp.corp.redhat.com (Postfix) with ESMTP id EF0415C241; Wed, 18 Mar 2020 15:03:50 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 04/17] pipe: Add O_NOTIFICATION_PIPE [ver #5] From: David Howells To: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk Cc: dhowells@redhat.com, casey@schaufler-ca.com, sds@tycho.nsa.gov, nicolas.dichtel@6wind.com, raven@themaw.net, christian@brauner.io, andres@anarazel.de, jlayton@redhat.com, dray@redhat.com, kzak@redhat.com, keyrings@vger.kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 18 Mar 2020 15:03:50 +0000 Message-ID: <158454383029.2863966.1921520389317717899.stgit@warthog.procyon.org.uk> In-Reply-To: <158454378820.2863966.10496767254293183123.stgit@warthog.procyon.org.uk> References: <158454378820.2863966.10496767254293183123.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.21 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: keyrings-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org Add an O_NOTIFICATION_PIPE flag that can be passed to pipe2() to indicate that the pipe being created is going to be used for notifications. This suppresses the use of splice(), vmsplice(), tee() and sendfile() on the pipe as calling iov_iter_revert() on a pipe when a kernel notification message has been inserted into the middle of a multi-buffer splice will be messy. The flag is given the same value as O_EXCL as it seems unlikely that this flag will ever be applicable to pipes and I don't want to use up another O_* bit unnecessarily. An alternative could be to add a pipe3() system call. Signed-off-by: David Howells --- include/uapi/linux/watch_queue.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/uapi/linux/watch_queue.h b/include/uapi/linux/watch_queue.h index 5f3d21e8a34b..9df72227f515 100644 --- a/include/uapi/linux/watch_queue.h +++ b/include/uapi/linux/watch_queue.h @@ -3,6 +3,9 @@ #define _UAPI_LINUX_WATCH_QUEUE_H #include +#include + +#define O_NOTIFICATION_PIPE O_EXCL /* Parameter to pipe2() selecting notification pipe */ enum watch_notification_type { WATCH_TYPE_META = 0, /* Special record */