From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CC1CC43463 for ; Sun, 20 Sep 2020 15:15:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E1C12073A for ; Sun, 20 Sep 2020 15:15:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="BEHRWzks" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726315AbgITPPX (ORCPT ); Sun, 20 Sep 2020 11:15:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726267AbgITPPX (ORCPT ); Sun, 20 Sep 2020 11:15:23 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BFF7C061755; Sun, 20 Sep 2020 08:15:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Ucf7HoNcpbOE1Nwd0GkK0r+4jGnJB6Awau+HMvD5QTQ=; b=BEHRWzksrTjJ0cz6kn/YL4kbO9 O0S1oDQ5afrWGBLkgZVov0K5DX5P8n3kQPInesZq8Opmeexe0KTNU5zkAjvbPAa7Vu+AwqUEF9kkV s09ZOl4m8v1spojFIQBVRxpVintgH+lHEWDdjnkhUWSJDFXQaimPUKpk6c+gLvdLoxlpoR55UirIR C7FOSIh6C1I8oA+JRJOY1riBqiSdxp8JHhQOJrK3Az+Zf34gwu76Cu4rYBA3pcShPktuZzK8Fl9p+ KTdDanCXPZQo05/zui4ihlNXLDU70euY+ORH9c4QQIqcTHg/9okYwp8yGFJLLvFCR++YjtJR+fDE0 5GxFYx2A==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kK13W-00060V-36; Sun, 20 Sep 2020 15:15:10 +0000 Date: Sun, 20 Sep 2020 16:15:10 +0100 From: Matthew Wilcox To: Christoph Hellwig Cc: Alexander Viro , Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , linux-arm-kernel@lists.infradead.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-ID: <20200920151510.GS32101@casper.infradead.org> References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918124533.3487701-2-hch@lst.de> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Fri, Sep 18, 2020 at 02:45:25PM +0200, Christoph Hellwig wrote: > Add a flag to force processing a syscall as a compat syscall. This is > required so that in_compat_syscall() works for I/O submitted by io_uring > helper threads on behalf of compat syscalls. Al doesn't like this much, but my suggestion is to introduce two new opcodes -- IORING_OP_READV32 and IORING_OP_WRITEV32. The compat code can translate IORING_OP_READV to IORING_OP_READV32 and then the core code can know what that user pointer is pointing to.