From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755041AbeDWLCx (ORCPT ); Mon, 23 Apr 2018 07:02:53 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:46266 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754784AbeDWLBc (ORCPT ); Mon, 23 Apr 2018 07:01:32 -0400 From: Dong Jia Shi To: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org Cc: cohuck@redhat.com, borntraeger@de.ibm.com, bjsdjshi@linux.ibm.com, pasic@linux.ibm.com, pmorel@linux.ibm.com, Dong Jia Shi Subject: [PATCH v2 3/5] vfio: ccw: refactor and improve pfn_array_alloc_pin() Date: Mon, 23 Apr 2018 13:01:11 +0200 X-Mailer: git-send-email 2.13.5 In-Reply-To: <20180423110113.59385-1-bjsdjshi@linux.vnet.ibm.com> References: <20180423110113.59385-1-bjsdjshi@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18042311-0016-0000-0000-00000894DCF3 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008905; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000257; SDB=6.01022058; UDB=6.00521638; IPR=6.00801293; MB=3.00020722; MTD=3.00000008; XFM=3.00000015; UTC=2018-04-23 11:01:30 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18042311-0017-0000-0000-00003E600A12 Message-Id: <20180423110113.59385-4-bjsdjshi@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-23_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804230116 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This refactors pfn_array_alloc_pin() and also improves it by adding defensive code in error handling so that calling pfn_array_unpin_free() after error return won't lead to problem. This mainly does: 1. Merge pfn_array_pin() into pfn_array_alloc_pin(), since there is no other user of pfn_array_pin(). As a result, also remove kernel-doc for pfn_array_pin() and add/update kernel-doc for pfn_array_alloc_pin() and struct pfn_array. 2. For a vfio_pin_pages() failure, set pa->pa_nr to zero to indicate zero pages were pinned. 3. Set pa->pa_iova_pfn to NULL right after it was freed. Suggested-by: Pierre Morel , Signed-off-by: Dong Jia Shi --- drivers/s390/cio/vfio_ccw_cp.c | 82 +++++++++++++++++++----------------------- 1 file changed, 36 insertions(+), 46 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index e8fe7450702e..340804b45f6a 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -29,7 +29,7 @@ struct pfn_array { unsigned long *pa_iova_pfn; /* Array that receives PFNs of the pages pinned. */ unsigned long *pa_pfn; - /* Number of pages to pin/pinned from @pa_iova. */ + /* Number of pages pinned from @pa_iova. */ int pa_nr; }; @@ -50,64 +50,33 @@ struct ccwchain { }; /* - * pfn_array_pin() - pin user pages in memory + * pfn_array_alloc_pin() - alloc memory for PFNs, then pin user pages in memory * @pa: pfn_array on which to perform the operation * @mdev: the mediated device to perform pin/unpin operations + * @iova: target guest physical address + * @len: number of bytes that should be pinned from @iova * - * Attempt to pin user pages in memory. + * Attempt to allocate memory for PFNs, and pin user pages in memory. * * Usage of pfn_array: - * Any field in this structure should be initialized by caller. - * We expect @pa->pa_nr > 0, and its value will be assigned by callee. + * We expect (pa_nr == 0) and (pa_iova_pfn == NULL), any field in + * this structure will be filled in by this function. * * Returns: * Number of pages pinned on success. - * If @pa->pa_nr is 0 or negative, returns 0. + * If @pa->pa_nr is not 0, or @pa->pa_iova_pfn is not NULL initially, + * returns -EINVAL. * If no pages were pinned, returns -errno. */ -static int pfn_array_pin(struct pfn_array *pa, struct device *mdev) -{ - int i, ret; - - if (pa->pa_nr <= 0) { - pa->pa_nr = 0; - return 0; - } - - pa->pa_iova_pfn[0] = pa->pa_iova >> PAGE_SHIFT; - for (i = 1; i < pa->pa_nr; i++) - pa->pa_iova_pfn[i] = pa->pa_iova_pfn[i - 1] + 1; - - ret = vfio_pin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr, - IOMMU_READ | IOMMU_WRITE, pa->pa_pfn); - - if (ret > 0 && ret != pa->pa_nr) { - vfio_unpin_pages(mdev, pa->pa_iova_pfn, ret); - pa->pa_nr = 0; - return 0; - } - - return ret; -} - -/* Unpin the pages before releasing the memory. */ -static void pfn_array_unpin_free(struct pfn_array *pa, struct device *mdev) -{ - vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr); - pa->pa_nr = 0; - kfree(pa->pa_iova_pfn); -} - -/* Alloc memory for PFNs, then pin pages with them. */ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, u64 iova, unsigned int len) { - int ret = 0; + int i, ret = 0; if (!len) return 0; - if (pa->pa_nr) + if (pa->pa_nr || pa->pa_iova_pfn) return -EINVAL; pa->pa_iova = iova; @@ -124,18 +93,39 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, return -ENOMEM; pa->pa_pfn = pa->pa_iova_pfn + pa->pa_nr; - ret = pfn_array_pin(pa, mdev); + pa->pa_iova_pfn[0] = pa->pa_iova >> PAGE_SHIFT; + for (i = 1; i < pa->pa_nr; i++) + pa->pa_iova_pfn[i] = pa->pa_iova_pfn[i - 1] + 1; + + ret = vfio_pin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr, + IOMMU_READ | IOMMU_WRITE, pa->pa_pfn); - if (ret > 0) - return ret; - else if (!ret) + if (ret < 0) { + goto err_out; + } else if (ret > 0 && ret != pa->pa_nr) { + vfio_unpin_pages(mdev, pa->pa_iova_pfn, ret); ret = -EINVAL; + goto err_out; + } + + return ret; +err_out: + pa->pa_nr = 0; kfree(pa->pa_iova_pfn); + pa->pa_iova_pfn = NULL; return ret; } +/* Unpin the pages before releasing the memory. */ +static void pfn_array_unpin_free(struct pfn_array *pa, struct device *mdev) +{ + vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr); + pa->pa_nr = 0; + kfree(pa->pa_iova_pfn); +} + static int pfn_array_table_init(struct pfn_array_table *pat, int nr) { pat->pat_pa = kcalloc(nr, sizeof(*pat->pat_pa), GFP_KERNEL); -- 2.13.5