From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-683775-1522996025-2-900827524405579839 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='de', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-api-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1522996025; b=bftWb/oBAPYoinbgJPNmDtJ1Q6tq+IjDw01efXE4jztmRBli6C 3MATyg1YgXPZahZtOMQGCGSjgHKiI5MreLl9Y8SAvGougiOGG19zx3Xb6ZbDyTiX uuqF1emP/QeAAE2OiN6byCWyu8qS/hJU0JWgTUqTMq8p2HQ8vJPssUMlaIRVb6n2 64EtXKBdB9AQVeNINGQOHr1OxTK72OkzfNmEYXfXRcMtyaVkZCwKiXqpa0I755JA Q9gpCzNrwvYk+AtyHYzTPb6UFGuT91Aw7Ly+/5yG3BDLXGSwAeu1x/vZNBRmi83a kdkf3F5UW6esKbbmfV8lHm5sCRy7DDuwBoHA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=fm2; t=1522996025; bh=uX9ZKAE7//QKX5y9S1TSwLLXZPObPV vke1NXBte3bH8=; b=G/oR7IdNgKf8t9S6Z7HkpRvQO+PgPtqeoPlBrxmw4huyks axvyjoRQ/aO96g5oE8E81a6xXUFIYZKE85OYJWgfk8Nf0unX8OmbL0C4WkuWdnnR XbczhFYwm+b3exgmVBDBk1yU+BAtrCMGQh4z6exf0coN/NngLrV66V5r+gmGAIxZ DJ7lyvPX+E8CMjQyXtoyJiVemf2g2F+Nf+ETRBSdIP0MCyunjiqNxZ/a+PFOpNcQ fP4TkgdlrSzkLxANanXJ7QWASWsgoA1jwxgTcyiTqINcgA0Ru9fe5YwWQpCjCRnf RAC61gAVU75dt6dqNunCA4VRaI5qE/ZljHGcGVLg== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=lst.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lst.de header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=lst.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lst.de header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfH8CRgDf0AihY/jD/1ClEFBn/Wv+VtLoAKaK73lNEKsMNXmowKABne2Ql9AVPlMmF0hFH9Aj8hX5Mzkaes/AGzm0aXpEcuQJv3QXSBeVstiBV95l/C25 JX+HoPkwMJ0siAlGpem7zpiaFxvTMDc8rXDRAJyRXNQD1HX4WBYUr55D93B6bQa3rVrGXtZGOQsqMbXrO3e/hkJOnXuGkK1XTUYTCOxHRny1/AByvHNY7M26 X-CM-Analysis: v=2.3 cv=E8HjW5Vl c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=kj9zAlcOel0A:10 a=Kd1tUaAdevIA:10 a=VwQbUJbxAAAA:8 a=mtmhXxi6JtwZn0RyJdYA:9 a=CjuIK1q_8ugA:10 a=x8gzFH9gYPwA:10 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752045AbeDFG1D (ORCPT ); Fri, 6 Apr 2018 02:27:03 -0400 Received: from verein.lst.de ([213.95.11.211]:53602 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752014AbeDFG1C (ORCPT ); Fri, 6 Apr 2018 02:27:02 -0400 Date: Fri, 6 Apr 2018 08:27:00 +0200 From: Christoph Hellwig To: Al Viro Cc: Christoph Hellwig , Avi Kivity , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: io_pgetevents & aio fsync V2 Message-ID: <20180406062700.GA20714@lst.de> References: <20180328072639.16885-1-hch@lst.de> <20180406031630.GU30522@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180406031630.GU30522@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Fri, Apr 06, 2018 at 04:16:30AM +0100, Al Viro wrote: > BTW, this is only tangentially related, but... does *anything* call > io_submit() for huge amounts of iocb? Check in do_io_submit() is > insane - "no more than MAX_LONG total of _pointers_". Compat variant > goes for "no more than a page worth of pointers" and there's > a hard limit in ioctx_alloc() - we can't ever get more than > 8M slots in ring buffer... Logical upper bound for io_submit is nr_events passed to io_setup(), which is bound by aio_max_nr. Except that we never actually check against nr_events (or max_reqs as it is known in kernel) in io_submit. Sigh..