From patchwork Wed Nov 13 04:27:05 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Hubbard X-Patchwork-Id: 11240809 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 8301C1390 for ; Wed, 13 Nov 2019 04:27:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 63F1622466 for ; Wed, 13 Nov 2019 04:27:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="qjhMc7Df" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727938AbfKME14 (ORCPT ); Tue, 12 Nov 2019 23:27:56 -0500 Received: from hqemgate16.nvidia.com ([216.228.121.65]:4078 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727793AbfKME1Z (ORCPT ); Tue, 12 Nov 2019 23:27:25 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate16.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 12 Nov 2019 20:26:18 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Tue, 12 Nov 2019 20:27:14 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Tue, 12 Nov 2019 20:27:14 -0800 Received: from HQMAIL109.nvidia.com (172.20.187.15) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 13 Nov 2019 04:27:14 +0000 Received: from HQMAIL107.nvidia.com (172.20.187.13) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 13 Nov 2019 04:27:13 +0000 Received: from hqnvemgw03.nvidia.com (10.124.88.68) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Wed, 13 Nov 2019 04:27:13 +0000 Received: from blueforge.nvidia.com (Not Verified[10.110.48.28]) by hqnvemgw03.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Tue, 12 Nov 2019 20:27:13 -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 v4 18/23] vfio, mm: pin_longterm_pages (FOLL_PIN) and put_user_page() conversion Date: Tue, 12 Nov 2019 20:27:05 -0800 Message-ID: <20191113042710.3997854-19-jhubbard@nvidia.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191113042710.3997854-1-jhubbard@nvidia.com> References: <20191113042710.3997854-1-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=1573619178; bh=RnRJrtQN+5UdnoCHLTDDIM4Uj622/kU3w0i+XdRmMBA=; 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=qjhMc7DfDfE2CnJipE9Xpl78yOetq8IYJMcdij2E87o2gYbsY3HvkrNGoCBE1zhjB iEXY0QBl3z0SU6UNwKxhykkW/44Bl/Q8vMQSXrYw74NoxNaevVAm1iweV5QjbRkgep JOjsCcQaxpo5Rt6AJEY78o2ZvoCRHib9Z/KCUYQ0Ra4LJKR1P24Fbb7G36ATvoGY/Y X+gfAvG2oB+COHXkO2SpSW8oWfxTDU8v5JiW7EZg9xPqChqszkip4WXUSWTAF4gN+f qLyabne88cZ0zx9eQXpcq6StPfiaEhYdSIr91A5rCi5IG4s6TubWJlmTOposhtAaZl uT3Mrf/92U1Qg== Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@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 | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 7301b710c9a4..1603459805f1 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; @@ -347,8 +346,8 @@ 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, NULL, NULL); + ret = pin_longterm_pages_remote(NULL, mm, vaddr, 1, flags, page, NULL, + NULL); if (ret == 1) { *pfn = page_to_pfn(page[0]); return 0;