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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 432ECC3A5A7 for ; Tue, 3 Sep 2019 14:46:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BD2620882 for ; Tue, 3 Sep 2019 14:46:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="OjWQuRT4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729306AbfICOq2 (ORCPT ); Tue, 3 Sep 2019 10:46:28 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:51668 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725782AbfICOq1 (ORCPT ); Tue, 3 Sep 2019 10:46:27 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x83EiP6p126612; Tue, 3 Sep 2019 14:46:21 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2019-08-05; bh=21BM/9yHmlJT8xTxjIp4TcPp8l3pTDXDNo0NbefEYw4=; b=OjWQuRT4yJAZafQR3w2lROdHEOuL66K13PkbJrfGwvgnyv667/qBIuXKBOtRSntLbpWG KrZu95g+NeWCY0macYDIJDTKu12/vzuO4uha/EhFyRpTXwcFdPweiMFa83Oy7074GMIS bMjX9aomlT1foPp0w4eYcYtT366MdmswWAFXpLDEILKvuU/P3TIrvOfJ1rYFyMExq03R FQinb5WjnOPEEkOSIUrXQVRGhqHjexRhoUIof82Y9kSupayFI3ReHBI6GA3bE8Se69y9 QzlTAnR9+zwNWMbQ9Wr0yZa2Vwtma7z6XUBA61THOS++f778A3MuyBsiSEO2vBVtWVCF Lg== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by aserp2120.oracle.com with ESMTP id 2ussx904yb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 03 Sep 2019 14:46:21 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x83EhNVf144250; Tue, 3 Sep 2019 14:46:21 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 2usk7dwk22-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 03 Sep 2019 14:46:21 +0000 Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x83EkJd7016572; Tue, 3 Sep 2019 14:46:20 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 03 Sep 2019 07:46:19 -0700 Date: Tue, 3 Sep 2019 07:46:22 -0700 From: "Darrick J. Wong" To: Christoph Hellwig Cc: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, Goldwyn Rodrigues , Matthew Bobrowski Subject: Re: [PATCH 2/2] iomap: move the iomap_dio_rw ->end_io callback into a structure Message-ID: <20190903144622.GY5354@magnolia> References: <20190903130327.6023-1-hch@lst.de> <20190903130327.6023-3-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190903130327.6023-3-hch@lst.de> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9368 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909030155 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9368 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909030155 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Sep 03, 2019 at 03:03:27PM +0200, Christoph Hellwig wrote: > Add a new iomap_dio_ops structure that for now just contains the end_io > handler. This avoid storing the function pointer in a mutable structure, > which is a possible exploit vector for kernel code execution, and prepares > for adding a submit_io handler that btrfs needs. > > Signed-off-by: Christoph Hellwig Looks ok, Reviewed-by: Darrick J. Wong --D > --- > fs/iomap/direct-io.c | 21 ++++++++++----------- > fs/xfs/xfs_file.c | 6 +++++- > include/linux/iomap.h | 10 +++++++--- > 3 files changed, 22 insertions(+), 15 deletions(-) > > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > index 2ccf1c6460d4..1fc28c2da279 100644 > --- a/fs/iomap/direct-io.c > +++ b/fs/iomap/direct-io.c > @@ -24,7 +24,7 @@ > > struct iomap_dio { > struct kiocb *iocb; > - iomap_dio_end_io_t *end_io; > + const struct iomap_dio_ops *dops; > loff_t i_size; > loff_t size; > atomic_t ref; > @@ -72,15 +72,14 @@ static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap, > > static ssize_t iomap_dio_complete(struct iomap_dio *dio) > { > + const struct iomap_dio_ops *dops = dio->dops; > struct kiocb *iocb = dio->iocb; > struct inode *inode = file_inode(iocb->ki_filp); > loff_t offset = iocb->ki_pos; > - ssize_t ret; > + ssize_t ret = dio->error; > > - if (dio->end_io) > - ret = dio->end_io(iocb, dio->size, dio->error, dio->flags); > - else > - ret = dio->error; > + if (dops && dops->end_io) > + ret = dops->end_io(iocb, dio->size, ret, dio->flags); > > if (likely(!ret)) { > ret = dio->size; > @@ -98,9 +97,9 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) > * one is a pretty crazy thing to do, so we don't support it 100%. If > * this invalidation fails, tough, the write still worked... > * > - * And this page cache invalidation has to be after dio->end_io(), as > - * some filesystems convert unwritten extents to real allocations in > - * end_io() when necessary, otherwise a racing buffer read would cache > + * And this page cache invalidation has to be after ->end_io(), as some > + * filesystems convert unwritten extents to real allocations in > + * ->end_io() when necessary, otherwise a racing buffer read would cache > * zeros from unwritten extents. > */ > if (!dio->error && > @@ -393,7 +392,7 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, > */ > ssize_t > iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > - const struct iomap_ops *ops, iomap_dio_end_io_t end_io) > + const struct iomap_ops *ops, const struct iomap_dio_ops *dops) > { > struct address_space *mapping = iocb->ki_filp->f_mapping; > struct inode *inode = file_inode(iocb->ki_filp); > @@ -418,7 +417,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > atomic_set(&dio->ref, 1); > dio->size = 0; > dio->i_size = i_size_read(inode); > - dio->end_io = end_io; > + dio->dops = dops; > dio->error = 0; > dio->flags = 0; > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 3d8e6db9ef77..1ffb179f35d2 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -443,6 +443,10 @@ xfs_dio_write_end_io( > return error; > } > > +static const struct iomap_dio_ops xfs_dio_write_ops = { > + .end_io = xfs_dio_write_end_io, > +}; > + > /* > * xfs_file_dio_aio_write - handle direct IO writes > * > @@ -543,7 +547,7 @@ xfs_file_dio_aio_write( > } > > trace_xfs_file_direct_write(ip, count, iocb->ki_pos); > - ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, xfs_dio_write_end_io); > + ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, &xfs_dio_write_ops); > > /* > * If unaligned, this is the only IO in-flight. If it has not yet > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 50bb746d2216..7aa5d6117936 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -188,10 +188,14 @@ sector_t iomap_bmap(struct address_space *mapping, sector_t bno, > */ > #define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */ > #define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */ > -typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t size, int error, > - unsigned int flags); > + > +struct iomap_dio_ops { > + int (*end_io)(struct kiocb *iocb, ssize_t size, int error, > + unsigned flags); > +}; > + > ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > - const struct iomap_ops *ops, iomap_dio_end_io_t end_io); > + const struct iomap_ops *ops, const struct iomap_dio_ops *dops); > int iomap_dio_iopoll(struct kiocb *kiocb, bool spin); > > #ifdef CONFIG_SWAP > -- > 2.20.1 >