From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDA83C433DF for ; Thu, 25 Jun 2020 02:54:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A843C20789 for ; Thu, 25 Jun 2020 02:54:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="tGJIN5xG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389617AbgFYCyx (ORCPT ); Wed, 24 Jun 2020 22:54:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52952 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389357AbgFYCyw (ORCPT ); Wed, 24 Jun 2020 22:54:52 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 540D6C061573 for ; Wed, 24 Jun 2020 19:54:51 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id l63so2583666pge.12 for ; Wed, 24 Jun 2020 19:54:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=fAhw99hSHSp4oWrS0namYNm6Go3NsuSaLTMdS2js2yg=; b=tGJIN5xGsgN1is4VPvkWyDq1pQcJK/f4mEt+aWjJHg7bZ3RJcDogKlmQ0OSbuVj4dk m8f1/44VpRJ3kiSvogq4WXlZ3AY6U2bU3iwIhwsi9/432OcHSqoK785PT1o24waKPk3y JkpBWrh9BmojPyt6eC9QUQqiXQK5t8N4VSGy8DmuPGEt9bR/ONK3zzbAggeOqH7PR7UW TlCDWeZoRDnx4wuJN4Y2p4v0QoXAKAgzmw1+ZZV1tyk93pdcs1CcjpKikxhpATOSO5Lc RsNnXAUUon3g9H+ZafgA/DX3BsvOxBOIRnnzmEgwjDKYQudXSSRn33PYSWi6eyNCcZWx whGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=fAhw99hSHSp4oWrS0namYNm6Go3NsuSaLTMdS2js2yg=; b=tImNQCHoSM+o05vGvFn1d36AP1eFAnIKe9wxDEP52yWMtzmYC3UfXptfkRDCJ79YVF BPFx//nUKPXjqX00541T8l6ec7ptQTfqiug1smRWAXYvFXGgv6dBodQgLNnKZmEZwE32 bIes8gT0lOftiTtpSzTS0c0L6pLcpea2AD8Nc42J9k3M8RffZ0aPF1QUd1FOKporW7eD C59Ym+BoyGv8FZsQtEHRlEcWPHCAhzcOHC23aZvpZ5tRoMi3pLpfrO/xVrZ9vWNncHL1 QIAMH4lejHevAqEkzObB41lxig55FePFGe1gnPx8Mk66AIoOH22t1UjjPcbZvEe7ucU1 AFuQ== X-Gm-Message-State: AOAM533e0elF7r7heEuHJuRPjWdRKHpLGJT76WxbmnrN2PrrTunLwkHC mLE9NQnZEGKWP3Jk1/DLz9WOyovp17w= X-Google-Smtp-Source: ABdhPJypIwr6XPQgemt6CJF4aVOuSE9P8rFDuFGhKBDr+zcFrzEKlnZEEU3wYydNz5mYaZJaYnAkvg== X-Received: by 2002:a63:de18:: with SMTP id f24mr23694179pgg.415.1593053690835; Wed, 24 Jun 2020 19:54:50 -0700 (PDT) Received: from jordon-HP-15-Notebook-PC.domain.name ([122.182.254.114]) by smtp.gmail.com with ESMTPSA id y10sm18593000pgi.54.2020.06.24.19.54.47 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Jun 2020 19:54:50 -0700 (PDT) From: Souptick Joarder To: boris.ostrovsky@oracle.com, jgross@suse.com, sstabellini@kernel.org Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, Souptick Joarder , John Hubbard , Paul Durrant Subject: [PATCH 1/2] xen/privcmd: Corrected error handling path and mark pages dirty Date: Thu, 25 Jun 2020 08:32:39 +0530 Message-Id: <1593054160-12628-1-git-send-email-jrdr.linux@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Previously, if lock_pages() end up partially mapping pages, it used to return -ERRNO due to which unlock_pages() have to go through each pages[i] till *nr_pages* to validate them. This can be avoided by passing correct number of partially mapped pages & -ERRNO separately, while returning from lock_pages() due to error. With this fix unlock_pages() doesn't need to validate pages[i] till *nr_pages* for error scenario and few condition checks can be ignored. As discussed, pages need to be marked as dirty before unpinned it in unlock_pages() which was oversight. Signed-off-by: Souptick Joarder Cc: John Hubbard Cc: Boris Ostrovsky Cc: Paul Durrant --- Hi, I'm compile tested this, but unable to run-time test, so any testing help is much appriciated. drivers/xen/privcmd.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index a250d11..0da417c 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -580,43 +580,44 @@ static long privcmd_ioctl_mmap_batch( static int lock_pages( struct privcmd_dm_op_buf kbufs[], unsigned int num, - struct page *pages[], unsigned int nr_pages) + struct page *pages[], unsigned int nr_pages, int *pinned) { unsigned int i; + int errno = 0, page_count = 0; for (i = 0; i < num; i++) { unsigned int requested; - int pinned; + *pinned += page_count; requested = DIV_ROUND_UP( offset_in_page(kbufs[i].uptr) + kbufs[i].size, PAGE_SIZE); if (requested > nr_pages) return -ENOSPC; - pinned = get_user_pages_fast( + page_count = get_user_pages_fast( (unsigned long) kbufs[i].uptr, requested, FOLL_WRITE, pages); - if (pinned < 0) - return pinned; + if (page_count < 0) { + errno = page_count; + return errno; + } - nr_pages -= pinned; - pages += pinned; + nr_pages -= page_count; + pages += page_count; } - return 0; + return errno; } static void unlock_pages(struct page *pages[], unsigned int nr_pages) { unsigned int i; - if (!pages) - return; - for (i = 0; i < nr_pages; i++) { - if (pages[i]) - put_page(pages[i]); + if (!PageDirty(page)) + set_page_dirty_lock(page); + put_page(pages[i]); } } @@ -630,6 +631,7 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata) struct xen_dm_op_buf *xbufs = NULL; unsigned int i; long rc; + int pinned = 0; if (copy_from_user(&kdata, udata, sizeof(kdata))) return -EFAULT; @@ -683,9 +685,11 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata) goto out; } - rc = lock_pages(kbufs, kdata.num, pages, nr_pages); - if (rc) + rc = lock_pages(kbufs, kdata.num, pages, nr_pages, &pinned); + if (rc < 0) { + nr_pages = pinned; goto out; + } for (i = 0; i < kdata.num; i++) { set_xen_guest_handle(xbufs[i].h, kbufs[i].uptr); -- 1.9.1