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=-3.8 required=3.0 tests=BAYES_00, 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 98A7DC4363D for ; Wed, 23 Sep 2020 15:03:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 26D4A21D7D for ; Wed, 23 Sep 2020 15:03:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 26D4A21D7D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4C5F18E0006; Wed, 23 Sep 2020 11:03:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 44EC78E0001; Wed, 23 Sep 2020 11:03:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 33FE88E0006; Wed, 23 Sep 2020 11:03:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0113.hostedemail.com [216.40.44.113]) by kanga.kvack.org (Postfix) with ESMTP id 1E4BE8E0001 for ; Wed, 23 Sep 2020 11:03:41 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 6A8081346D8 for ; Wed, 23 Sep 2020 15:03:40 +0000 (UTC) X-FDA: 77294645400.09.mine86_5c0055f27157 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin09.hostedemail.com (Postfix) with ESMTP id 38AEA18695051; Wed, 23 Sep 2020 14:59:14 +0000 (UTC) X-HE-Tag: mine86_5c0055f27157 X-Filterd-Recvd-Size: 3261 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [195.92.253.2]) by imf04.hostedemail.com (Postfix) with ESMTP; Wed, 23 Sep 2020 14:59:13 +0000 (UTC) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kL6EX-004bOc-Io; Wed, 23 Sep 2020 14:59:01 +0000 Date: Wed, 23 Sep 2020 15:59:01 +0100 From: Al Viro To: Christoph Hellwig Cc: Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , David Laight , linux-arm-kernel@lists.infradead.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 5/9] fs: remove various compat readv/writev helpers Message-ID: <20200923145901.GN3421308@ZenIV.linux.org.uk> References: <20200923060547.16903-1-hch@lst.de> <20200923060547.16903-6-hch@lst.de> <20200923142549.GK3421308@ZenIV.linux.org.uk> <20200923143251.GA14062@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200923143251.GA14062@lst.de> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Sep 23, 2020 at 04:32:51PM +0200, Christoph Hellwig wrote: > On Wed, Sep 23, 2020 at 03:25:49PM +0100, Al Viro wrote: > > On Wed, Sep 23, 2020 at 08:05:43AM +0200, Christoph Hellwig wrote: > > > COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd, > > > - const struct compat_iovec __user *,vec, > > > + const struct iovec __user *, vec, > > > > Um... Will it even compile? > > > > > #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64 > > > COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd, > > > - const struct compat_iovec __user *,vec, > > > + const struct iovec __user *, vec, > > > > Ditto. Look into include/linux/compat.h and you'll see > > > > asmlinkage long compat_sys_preadv64(unsigned long fd, > > const struct compat_iovec __user *vec, > > unsigned long vlen, loff_t pos); > > > > How does that manage to avoid the compiler screaming bloody > > murder? > > That's a very good question. But it does not just compile but actually > works. Probably because all the syscall wrappers mean that we don't > actually generate the normal names. I just tried this: > > --- a/include/linux/syscalls.h > +++ b/include/linux/syscalls.h > @@ -468,7 +468,7 @@ asmlinkage long sys_lseek(unsigned int fd, off_t offset, > asmlinkage long sys_read(unsigned int fd, char __user *buf, size_t count); > asmlinkage long sys_write(unsigned int fd, const char __user *buf, > size_t count); > -asmlinkage long sys_readv(unsigned long fd, > +asmlinkage long sys_readv(void *fd, > > for fun, and the compiler doesn't care either.. Try to build it for sparc or ppc...