From patchwork Fri Oct 2 21:02:30 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ross Zwisler X-Patchwork-Id: 7318941 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 7FDD4BEEA4 for ; Fri, 2 Oct 2015 21:03:02 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B9EE120871 for ; Fri, 2 Oct 2015 21:03:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C0C812086F for ; Fri, 2 Oct 2015 21:03:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751751AbbJBVCq (ORCPT ); Fri, 2 Oct 2015 17:02:46 -0400 Received: from mga14.intel.com ([192.55.52.115]:36142 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751299AbbJBVCo (ORCPT ); Fri, 2 Oct 2015 17:02:44 -0400 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga103.fm.intel.com with ESMTP; 02 Oct 2015 14:02:44 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,624,1437462000"; d="scan'208";a="818198819" Received: from theros.lm.intel.com ([10.232.112.146]) by fmsmga002.fm.intel.com with ESMTP; 02 Oct 2015 14:02:43 -0700 From: Ross Zwisler To: linux-kernel@vger.kernel.org Cc: Ross Zwisler , Alexander Viro , Matthew Wilcox , linux-fsdevel@vger.kernel.org, Andrew Morton , Dan Williams , Dave Chinner , Jan Kara , "Kirill A. Shutemov" , linux-nvdimm@lists.01.org Subject: [PATCH 1/3] Revert "dax: fix NULL pointer in __dax_pmd_fault()" Date: Fri, 2 Oct 2015 15:02:30 -0600 Message-Id: <1443819752-17091-2-git-send-email-ross.zwisler@linux.intel.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1443819752-17091-1-git-send-email-ross.zwisler@linux.intel.com> References: <1443819752-17091-1-git-send-email-ross.zwisler@linux.intel.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This reverts commit 8346c416d17bf5b4ea1508662959bb62e73fd6a5. This commit did fix the issue it intended to fix, but it turns out that the locking changes introduced by these two commits: commit 843172978bb9 ("dax: fix race between simultaneous faults") commit 46c043ede471 ("mm: take i_mmap_lock in unmap_mapping_range() for DAX") had other issues as well, so they need to just be reverted. The list of issues in DAX after these commits (some newly introduced by the commits, some preexisting) can be found here: https://lkml.org/lkml/2015/9/25/602 Signed-off-by: Ross Zwisler --- fs/dax.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index bcfb14b..7ae6df7 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -569,20 +569,8 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE) goto fallback; - sector = bh.b_blocknr << (blkbits - 9); - if (buffer_unwritten(&bh) || buffer_new(&bh)) { int i; - - length = bdev_direct_access(bh.b_bdev, sector, &kaddr, &pfn, - bh.b_size); - if (length < 0) { - result = VM_FAULT_SIGBUS; - goto out; - } - if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR)) - goto fallback; - for (i = 0; i < PTRS_PER_PMD; i++) clear_pmem(kaddr + i * PAGE_SIZE, PAGE_SIZE); wmb_pmem(); @@ -635,6 +623,7 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, result = VM_FAULT_NOPAGE; spin_unlock(ptl); } else { + sector = bh.b_blocknr << (blkbits - 9); length = bdev_direct_access(bh.b_bdev, sector, &kaddr, &pfn, bh.b_size); if (length < 0) {