From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757322AbdDQWiL (ORCPT ); Mon, 17 Apr 2017 18:38:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46002 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755404AbdDQWiG (ORCPT ); Mon, 17 Apr 2017 18:38:06 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com B563231F3E5 Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=alex.williamson@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com B563231F3E5 Subject: [PATCH v5 2/3] vfio/type1: Prune vfio_pin_page_external() From: Alex Williamson To: alex.williamson@redhat.com, kvm@vger.kernel.org Cc: eric.auger@redhat.com, kwankhede@nvidia.com, peterx@redhat.com, linux-kernel@vger.kernel.org, slp@redhat.com Date: Mon, 17 Apr 2017 16:38:05 -0600 Message-ID: <20170417223804.25720.4068.stgit@gimli.home> In-Reply-To: <20170417223158.25720.59453.stgit@gimli.home> References: <20170417223158.25720.59453.stgit@gimli.home> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Mon, 17 Apr 2017 22:38:05 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With vfio_lock_acct() testing the locked memory limit under mmap_sem, it's redundant to do it here for a single page. We can also reorder our tests such that we can avoid testing for reserved pages if we're not doing accounting and let vfio_lock_acct() test the process CAP_IPC_LOCK. Finally, this function oddly returns 1 on success. Update to return zero on success, -errno on error. Since the function only pins a single page, there's no need to return the number of pages pinned. N.B. vfio_pin_pages_remote() can pin a large contiguous range of pages before calling vfio_lock_acct(). If we were to similarly remove the extra test there, a user could temporarily pin far more pages than they're allowed. Suggested-by: Kirti Wankhede Suggested-by: Eric Auger Reviewed-by: Kirti Wankhede Signed-off-by: Alex Williamson --- drivers/vfio/vfio_iommu_type1.c | 35 ++++++++--------------------------- 1 file changed, 8 insertions(+), 27 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index a8a079ba9477..372e4f626138 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -482,43 +482,26 @@ static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova, static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr, unsigned long *pfn_base, bool do_accounting) { - unsigned long limit; - bool lock_cap = has_capability(dma->task, CAP_IPC_LOCK); struct mm_struct *mm; int ret; - bool rsvd; mm = get_task_mm(dma->task); if (!mm) return -ENODEV; ret = vaddr_get_pfn(mm, vaddr, dma->prot, pfn_base); - if (ret) - goto pin_page_exit; - - rsvd = is_invalid_reserved_pfn(*pfn_base); - limit = task_rlimit(dma->task, RLIMIT_MEMLOCK) >> PAGE_SHIFT; - - if (!rsvd && !lock_cap && mm->locked_vm + 1 > limit) { - put_pfn(*pfn_base, dma->prot); - pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK (%ld) exceeded\n", - __func__, dma->task->comm, task_pid_nr(dma->task), - limit << PAGE_SHIFT); - ret = -ENOMEM; - goto pin_page_exit; - } - - if (!rsvd && do_accounting) { - ret = vfio_lock_acct(dma->task, 1, &lock_cap); + if (!ret && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) { + ret = vfio_lock_acct(dma->task, 1, NULL); if (ret) { put_pfn(*pfn_base, dma->prot); - goto pin_page_exit; + if (ret == -ENOMEM) + pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK " + "(%ld) exceeded\n", __func__, + dma->task->comm, task_pid_nr(dma->task), + task_rlimit(dma->task, RLIMIT_MEMLOCK)); } } - ret = 1; - -pin_page_exit: mmput(mm); return ret; } @@ -598,10 +581,8 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, remote_vaddr = dma->vaddr + iova - dma->iova; ret = vfio_pin_page_external(dma, remote_vaddr, &phys_pfn[i], do_accounting); - if (ret <= 0) { - WARN_ON(!ret); + if (ret) goto pin_unwind; - } ret = vfio_add_to_pfn_list(dma, iova, phys_pfn[i]); if (ret) {