From patchwork Tue Nov 12 00:06:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Hubbard X-Patchwork-Id: 11238177 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 81C561864 for ; Tue, 12 Nov 2019 00:08:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EAE82184C for ; Tue, 12 Nov 2019 00:08:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="OOy4osFx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727790AbfKLAIh (ORCPT ); Mon, 11 Nov 2019 19:08:37 -0500 Received: from hqemgate15.nvidia.com ([216.228.121.64]:16770 "EHLO hqemgate15.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727539AbfKLAH1 (ORCPT ); Mon, 11 Nov 2019 19:07:27 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Mon, 11 Nov 2019 16:06:23 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Mon, 11 Nov 2019 16:07:25 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Mon, 11 Nov 2019 16:07:25 -0800 Received: from HQMAIL111.nvidia.com (172.20.187.18) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 12 Nov 2019 00:07:24 +0000 Received: from rnnvemgw01.nvidia.com (10.128.109.123) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Tue, 12 Nov 2019 00:07:23 +0000 Received: from blueforge.nvidia.com (Not Verified[10.110.48.28]) by rnnvemgw01.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Mon, 11 Nov 2019 16:07:23 -0800 From: John Hubbard To: Andrew Morton CC: Al Viro , Alex Williamson , Benjamin Herrenschmidt , =?utf-8?b?QmrDtnJuIFQ=?= =?utf-8?b?w7ZwZWw=?= , Christoph Hellwig , Dan Williams , Daniel Vetter , Dave Chinner , David Airlie , "David S . Miller" , Ira Weiny , Jan Kara , Jason Gunthorpe , Jens Axboe , Jonathan Corbet , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Magnus Karlsson , Mauro Carvalho Chehab , Michael Ellerman , Michal Hocko , Mike Kravetz , Paul Mackerras , Shuah Khan , Vlastimil Babka , , , , , , , , , , , , , LKML , John Hubbard Subject: [PATCH v3 18/23] vfio, mm: pin_longterm_pages (FOLL_PIN) and put_user_page() conversion Date: Mon, 11 Nov 2019 16:06:55 -0800 Message-ID: <20191112000700.3455038-19-jhubbard@nvidia.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191112000700.3455038-1-jhubbard@nvidia.com> References: <20191112000700.3455038-1-jhubbard@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1573517183; bh=sSwCrqRKuW3/2RqWIzTidmab8smfkfN0es5ZTEERORQ=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Transfer-Encoding:Content-Type; b=OOy4osFxRkHKhA4WgKXA5YhAniGLgnKkjxLIGE/ThvfX2DPQ68rl1TsLA9SZKnLVn dYYRm0QhBsaxq6ZHWmxSUwrNxOdd5Uyvb9KY+cvPN+kIh4WUWvxM/2f8kdLFhfLOzd sWevWhJFRkTu6vo+N0WxrYIOePZqIWcSyYJLSG9lwE5m0RgdK+/gdZXtsKPQQYnMWf xuhkwC8xNeb8u+BqAdzbH6Ylg8hYBWh5afDxUQfn7DyEWsylkTKvwQHs+WSfP4IPH1 58EeEb3okxK1KQAuYGIG7WJdZ33PHrGTE5RJvv/ycocsc+rQoqaJsyFcHJdnqX/pZX cyNKl7RGcRWQg== Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 1. Change vfio from get_user_pages(FOLL_LONGTERM), to pin_longterm_pages(), which sets both FOLL_LONGTERM and FOLL_PIN. 2. Because all FOLL_PIN-acquired pages must be released via put_user_page(), also convert the put_page() call over to put_user_pages(). Note that this effectively changes the code's behavior in vfio_iommu_type1.c: put_pfn(): it now ultimately calls set_page_dirty_lock(), instead of set_page_dirty(). This is probably more accurate. As Christoph Hellwig put it, "set_page_dirty() is only safe if we are dealing with a file backed page where we have reference on the inode it hangs off." [1] [1] https://lore.kernel.org/r/20190723153640.GB720@lst.de Cc: Alex Williamson Signed-off-by: John Hubbard --- drivers/vfio/vfio_iommu_type1.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 017689b7c32b..07bec0bdd316 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -327,9 +327,8 @@ static int put_pfn(unsigned long pfn, int prot) { if (!is_invalid_reserved_pfn(pfn)) { struct page *page = pfn_to_page(pfn); - if (prot & IOMMU_WRITE) - SetPageDirty(page); - put_page(page); + + put_user_pages_dirty_lock(&page, 1, prot & IOMMU_WRITE); return 1; } return 0; @@ -348,8 +347,8 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, flags |= FOLL_WRITE; down_read(&mm->mmap_sem); - ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags | FOLL_LONGTERM, - page, vmas, NULL); + ret = pin_longterm_pages_remote(NULL, mm, vaddr, 1, flags, page, vmas, + NULL); /* * The lifetime of a vaddr_get_pfn() page pin is * userspace-controlled. In the fs-dax case this could @@ -359,7 +358,7 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, */ if (ret > 0 && vma_is_fsdax(vmas[0])) { ret = -EOPNOTSUPP; - put_page(page[0]); + put_user_page(page[0]); } up_read(&mm->mmap_sem);