From patchwork Mon Apr 18 21:35:29 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 611905 X-Patchwork-Delegate: tytso@mit.edu Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3qphKw0Bg7z9sXR for ; Tue, 19 Apr 2016 07:36:36 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752242AbcDRVf4 (ORCPT ); Mon, 18 Apr 2016 17:35:56 -0400 Received: from mx2.suse.de ([195.135.220.15]:33766 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751984AbcDRVfy (ORCPT ); Mon, 18 Apr 2016 17:35:54 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E8ABEAD8A; Mon, 18 Apr 2016 21:35:49 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 6160D1E0953; Mon, 18 Apr 2016 23:35:46 +0200 (CEST) From: Jan Kara To: linux-fsdevel@vger.kernel.org Cc: linux-ext4@vger.kernel.org, linux-mm@kvack.org, Ross Zwisler , Dan Williams , linux-nvdimm@lists.01.org, Matthew Wilcox , Jan Kara Subject: [PATCH 06/18] dax: Remove dead zeroing code from fault handlers Date: Mon, 18 Apr 2016 23:35:29 +0200 Message-Id: <1461015341-20153-7-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.6.6 In-Reply-To: <1461015341-20153-1-git-send-email-jack@suse.cz> References: <1461015341-20153-1-git-send-email-jack@suse.cz> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Now that all filesystems zero out blocks allocated for a fault handler, we can just remove the zeroing from the handler itself. Also add checks that no filesystem returns to us unwritten or new buffer. Signed-off-by: Jan Kara Reviewed-by: Ross Zwisler --- fs/dax.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index c5ccf745d279..ccb8bc399d78 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -587,11 +587,6 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh, error = PTR_ERR(dax.addr); goto out; } - - if (buffer_unwritten(bh) || buffer_new(bh)) { - clear_pmem(dax.addr, PAGE_SIZE); - wmb_pmem(); - } dax_unmap_atomic(bdev, &dax); error = dax_radix_entry(mapping, vmf->pgoff, dax.sector, false, @@ -670,7 +665,7 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, if (error) goto unlock_page; - if (!buffer_mapped(&bh) && !buffer_unwritten(&bh) && !vmf->cow_page) { + if (!buffer_mapped(&bh) && !vmf->cow_page) { if (vmf->flags & FAULT_FLAG_WRITE) { error = get_block(inode, block, &bh, 1); count_vm_event(PGMAJFAULT); @@ -722,7 +717,7 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } /* Filesystem should not return unwritten buffers to us! */ - WARN_ON_ONCE(buffer_unwritten(&bh)); + WARN_ON_ONCE(buffer_unwritten(&bh) || buffer_new(&bh)); error = dax_insert_mapping(inode, &bh, vma, vmf); out: @@ -854,7 +849,7 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, if (get_block(inode, block, &bh, 1) != 0) return VM_FAULT_SIGBUS; alloc = true; - WARN_ON_ONCE(buffer_unwritten(&bh)); + WARN_ON_ONCE(buffer_unwritten(&bh) || buffer_new(&bh)); } bdev = bh.b_bdev; @@ -953,14 +948,6 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, dax_pmd_dbg(&bh, address, "pfn not in memmap"); goto fallback; } - - if (buffer_unwritten(&bh) || buffer_new(&bh)) { - clear_pmem(dax.addr, PMD_SIZE); - wmb_pmem(); - count_vm_event(PGMAJFAULT); - mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); - result |= VM_FAULT_MAJOR; - } dax_unmap_atomic(bdev, &dax); /*