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[156.151.31.86]) by mx.google.com with ESMTPS id bg2si16115035plb.117.2019.05.02.00.16.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 May 2019 00:16:15 -0700 (PDT) Received-SPF: pass (google.com: domain of william.kucharski@oracle.com designates 156.151.31.86 as permitted sender) client-ip=156.151.31.86; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=nR8WtxOm; spf=pass (google.com: domain of william.kucharski@oracle.com designates 156.151.31.86 as permitted sender) smtp.mailfrom=william.kucharski@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4264cwP036575; Thu, 2 May 2019 06:08:32 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=content-type : mime-version : subject : from : in-reply-to : date : cc : content-transfer-encoding : message-id : references : to; s=corp-2018-07-02; bh=8E/Xlfqhfo0vf1+GOu+GJdon4fjnIK8RWeWcR7c5CxQ=; b=nR8WtxOm+plPvZHMSK561p3KEYr+W5P6dt5wv8Wdyq6G6c4sXKsJ27dNGyglUgYLlvQw TiwiQ/8ArXmSJ9Q7w4ZZqnOHmUKWrMN27w4kkS53VuPtYwVISOfzQg8cxC83uMEFA0AY ptwm+dRcbI2QNQ2sKnrVBJjEfy5X3NGrEgla0ZjGVVtT7DkKeko/waa8V/JrixHuQk56 atmQcJgoSXiGDQebmXLhT1JEYypI7ONEyIAva38jMv4vOxLlwbvrWeL2xYOzmBI9We+P Y5PyHQUo4Q4VPRHo3QiEAr7J7oq9mMKN/9QfJgBAmoTHtmy586V2N2g2r6kmRLxrYyyd Xg== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2130.oracle.com with ESMTP id 2s6xhyecfj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 02 May 2019 06:08:32 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4266meq072708; Thu, 2 May 2019 06:08:32 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3020.oracle.com with ESMTP id 2s6xhgmfew-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 02 May 2019 06:08:31 +0000 Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x4268UcT005438; Thu, 2 May 2019 06:08:30 GMT Received: from [192.168.0.100] (/73.243.10.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 01 May 2019 23:08:30 -0700 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Subject: Re: [PATCH 5/4] 9p: pass the correct prototype to read_cache_page From: William Kucharski In-Reply-To: <20190501173443.GA19969@lst.de> Date: Thu, 2 May 2019 00:08:29 -0600 Cc: Andrew Morton , Sami Tolvanen , Kees Cook , Nick Desaulniers , linux-mtd@lists.infradead.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20190501160636.30841-1-hch@lst.de> <20190501173443.GA19969@lst.de> To: Christoph Hellwig X-Mailer: Apple Mail (2.3445.104.11) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9244 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=8.0.1-1810050000 definitions=main-1905020048 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9244 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=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905020048 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: 1) You need to pass "filp" rather than "filp->private_data" to = read_cache_pages() in v9fs_fid_readpage(). The patched code passes "filp->private_data" as the "data" parameter to read_cache_pages(), which would generate a call to: filler(data, page) which would become a call to: static int v9fs_vfs_readpage(struct file *filp, struct page *page) {=09 return v9fs_fid_readpage(filp->private_data, page); } which would then effectively become: v9fs_fid_readpage(filp->private_data->private_data, page) Which isn't correct; because data is a void *, no error is thrown when v9fs_vfs_readpages treats filp->private_data as if it is filp. 2) I'd also like to see an explicit comment in do_read_cache_page() = along the lines of: /* * If a custom page filler was passed in use it, otherwise use the * standard readpage() routine defined for the address_space. * */ 3) Patch 5/4? Otherwise it looks good. Reviewed-by: William Kucharski > On May 1, 2019, at 11:34 AM, Christoph Hellwig wrote: >=20 > Fix the callback 9p passes to read_cache_page to actually have the > proper type expected. Casting around function pointers can easily > hide typing bugs, and defeats control flow protection. >=20 > Signed-off-by: Christoph Hellwig > --- > fs/9p/vfs_addr.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) >=20 > diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c > index 0bcbcc20f769..02e0fc51401e 100644 > --- a/fs/9p/vfs_addr.c > +++ b/fs/9p/vfs_addr.c > @@ -50,8 +50,9 @@ > * @page: structure to page > * > */ > -static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page) > +static int v9fs_fid_readpage(void *data, struct page *page) > { > + struct p9_fid *fid =3D data; > struct inode *inode =3D page->mapping->host; > struct bio_vec bvec =3D {.bv_page =3D page, .bv_len =3D = PAGE_SIZE}; > struct iov_iter to; > @@ -122,7 +123,8 @@ static int v9fs_vfs_readpages(struct file *filp, = struct address_space *mapping, > if (ret =3D=3D 0) > return ret; >=20 > - ret =3D read_cache_pages(mapping, pages, (void = *)v9fs_vfs_readpage, filp); > + ret =3D read_cache_pages(mapping, pages, v9fs_fid_readpage, > + filp->private_data); > p9_debug(P9_DEBUG_VFS, " =3D %d\n", ret); > return ret; > }