From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752089AbeBWAY7 (ORCPT ); Thu, 22 Feb 2018 19:24:59 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:41586 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751723AbeBWAY6 (ORCPT ); Thu, 22 Feb 2018 19:24:58 -0500 Subject: Re: [PATCH 5/9] drm/xen-front: Implement handling of shared display buffers To: Oleksandr Andrushchenko , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, airlied@linux.ie, daniel.vetter@intel.com, seanpaul@chromium.org, gustavo@padovan.org, jgross@suse.com, konrad.wilk@oracle.com Cc: Oleksandr Andrushchenko References: <1519200222-20623-1-git-send-email-andr2000@gmail.com> <1519200222-20623-6-git-send-email-andr2000@gmail.com> From: Boris Ostrovsky Message-ID: <11ce6c96-1739-435c-4b6f-c9f5d02a2905@oracle.com> Date: Thu, 22 Feb 2018 19:25:18 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1519200222-20623-6-git-send-email-andr2000@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8812 signatures=668677 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=588 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1802230002 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/21/2018 03:03 AM, Oleksandr Andrushchenko wrote: > > static int __init xen_drv_init(void) > { > + /* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */ > + BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); Why BUILD_BUG_ON? This should simply not load if page sizes are different. > + ret = gnttab_map_refs(map_ops, NULL, buf->pages, buf->num_pages); > + BUG_ON(ret); We should try not to BUG*(). There are a few in this patch (and possibly others) that I think can be avoided. > + > +static int alloc_storage(struct xen_drm_front_shbuf *buf) > +{ > + if (buf->sgt) { > + buf->pages = kvmalloc_array(buf->num_pages, > + sizeof(struct page *), GFP_KERNEL); > + if (!buf->pages) > + return -ENOMEM; > + > + if (drm_prime_sg_to_page_addr_arrays(buf->sgt, buf->pages, > + NULL, buf->num_pages) < 0) > + return -EINVAL; > + } > + > + buf->grefs = kcalloc(buf->num_grefs, sizeof(*buf->grefs), GFP_KERNEL); > + if (!buf->grefs) > + return -ENOMEM; > + > + buf->directory = kcalloc(get_num_pages_dir(buf), PAGE_SIZE, GFP_KERNEL); > + if (!buf->directory) > + return -ENOMEM; You need to clean up on errors. -boris > + > + return 0; > +}