From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:55100) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hE8df-0000Hg-TJ for qemu-devel@nongnu.org; Wed, 10 Apr 2019 04:31:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hE8de-00031v-RG for qemu-devel@nongnu.org; Wed, 10 Apr 2019 04:31:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53872) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hE8dd-00030h-Pj for qemu-devel@nongnu.org; Wed, 10 Apr 2019 04:31:22 -0400 Date: Wed, 10 Apr 2019 04:31:19 -0400 (EDT) From: Pankaj Gupta Message-ID: <299038321.20701113.1554885079188.JavaMail.zimbra@redhat.com> In-Reply-To: <20190410082504.GF1426@quack2.suse.cz> References: <20190410040826.24371-1-pagupta@redhat.com> <20190410040826.24371-5-pagupta@redhat.com> <20190410082504.GF1426@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v5 4/6] dax: check synchronous mapping is supported List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kara Cc: linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-acpi@vger.kernel.org, qemu-devel@nongnu.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, dan j williams , zwisler@kernel.org, vishal l verma , dave jiang , mst@redhat.com, jasowang@redhat.com, willy@infradead.org, rjw@rjwysocki.net, hch@infradead.org, lenb@kernel.org, tytso@mit.edu, adilger kernel , darrick wong , lcapitulino@redhat.com, kwolf@redhat.com, imammedo@redhat.com, jmoyer@redhat.com, nilal@redhat.com, riel@surriel.com, stefanha@redhat.com, aarcange@redhat.com, david@redhat.com, david@fromorbit.com, cohuck@redhat.com, xiaoguangrong eric , pbonzini@redhat.com, kilobyte@angband.pl, yuval shaia > > This patch introduces 'daxdev_mapping_supported' helper > > which checks if 'MAP_SYNC' is supported with filesystem > > mapping. It also checks if corresponding dax_device is > > synchronous. Virtio pmem device is asynchronous and > > does not not support VM_SYNC. > > > > Suggested-by: Jan Kara > > Signed-off-by: Pankaj Gupta > > --- > > include/linux/dax.h | 23 +++++++++++++++++++++++ > > 1 file changed, 23 insertions(+) > > > > diff --git a/include/linux/dax.h b/include/linux/dax.h > > index b896706a5ee9..4a2a60ffec86 100644 > > --- a/include/linux/dax.h > > +++ b/include/linux/dax.h > > @@ -38,6 +38,24 @@ void kill_dax(struct dax_device *dax_dev); > > void dax_write_cache(struct dax_device *dax_dev, bool wc); > > bool dax_write_cache_enabled(struct dax_device *dax_dev); > > bool dax_synchronous(struct dax_device *dax_dev); > > + > > +/* > > + * Callers check if synchronous mapping is enabled for DAX file > > + * and attached dax device is also synchronous. > > + * > > + * dax_synchronous function verifies if dax device is synchronous. > > + * Currently, only virtio pmem device supports asynchronous device > > + * flush. > > + */ > > Thanks for the patch! I'd restructure this comment like: > > /* > * Check if given mapping is supported by the file / underlying device. > */ Sure. > > +static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, > > + struct dax_device *dax_dev) > > +{ > > /* Everyone supports non-sync mappings */ > > + if (!(vma->vm_flags & VM_SYNC)) > > + return true; > /* Sync mappings are supported only for files using DAX */ > > + if (!IS_DAX(file_inode(vma->vm_file))) > > + return false; > /* Underlying device must support persisting through CPU instructions */ > > + return dax_synchronous(dax_dev); > > +} > > #else > > static inline struct dax_device *dax_get_by_host(const char *host) > > { > > @@ -69,6 +87,11 @@ static inline bool dax_synchronous(struct dax_device > > *dax_dev) > > { > > return true; > > } > > +static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, > > + struct dax_device *dax_dev) > > +{ > > + return true; > > This looks wrong. Shouldn't it rather be: > > return !(vma->flags & VM_SYNC); > > ? Right. I will correct this. Thanks, Pankaj > > Honza > -- > Jan Kara > SUSE Labs, CR > 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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=unavailable 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 C45ABC10F11 for ; Wed, 10 Apr 2019 08:32:31 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 91A902075B for ; Wed, 10 Apr 2019 08:32:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91A902075B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:55730 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hE8ek-0000jh-Rm for qemu-devel@archiver.kernel.org; Wed, 10 Apr 2019 04:32:30 -0400 Received: from eggs.gnu.org ([209.51.188.92]:55100) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hE8df-0000Hg-TJ for qemu-devel@nongnu.org; Wed, 10 Apr 2019 04:31:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hE8de-00031v-RG for qemu-devel@nongnu.org; Wed, 10 Apr 2019 04:31:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53872) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hE8dd-00030h-Pj for qemu-devel@nongnu.org; Wed, 10 Apr 2019 04:31:22 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 424F27F6B0; Wed, 10 Apr 2019 08:31:20 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 09AAF108BEF7; Wed, 10 Apr 2019 08:31:20 +0000 (UTC) Received: from zmail21.collab.prod.int.phx2.redhat.com (zmail21.collab.prod.int.phx2.redhat.com [10.5.83.24]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 9C8ED1803385; Wed, 10 Apr 2019 08:31:19 +0000 (UTC) Date: Wed, 10 Apr 2019 04:31:19 -0400 (EDT) From: Pankaj Gupta To: Jan Kara Message-ID: <299038321.20701113.1554885079188.JavaMail.zimbra@redhat.com> In-Reply-To: <20190410082504.GF1426@quack2.suse.cz> References: <20190410040826.24371-1-pagupta@redhat.com> <20190410040826.24371-5-pagupta@redhat.com> <20190410082504.GF1426@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.65.16.19, 10.4.195.8] Thread-Topic: check synchronous mapping is supported Thread-Index: 3OuZRphtFQExf6N3zq0ZSCMeImf/pQ== X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Wed, 10 Apr 2019 08:31:20 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v5 4/6] dax: check synchronous mapping is supported X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: cohuck@redhat.com, kvm@vger.kernel.org, mst@redhat.com, jasowang@redhat.com, david@fromorbit.com, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, adilger kernel , zwisler@kernel.org, aarcange@redhat.com, dave jiang , linux-nvdimm@lists.01.org, vishal l verma , david@redhat.com, willy@infradead.org, hch@infradead.org, linux-acpi@vger.kernel.org, jmoyer@redhat.com, linux-ext4@vger.kernel.org, lenb@kernel.org, kilobyte@angband.pl, riel@surriel.com, yuval shaia , stefanha@redhat.com, pbonzini@redhat.com, dan j williams , lcapitulino@redhat.com, kwolf@redhat.com, nilal@redhat.com, tytso@mit.edu, xiaoguangrong eric , darrick wong , rjw@rjwysocki.net, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, imammedo@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190410083119.P-0FY-r8LTAliWHf_3qubYduEiuEXP_9kXddoAjWGcU@z> > > This patch introduces 'daxdev_mapping_supported' helper > > which checks if 'MAP_SYNC' is supported with filesystem > > mapping. It also checks if corresponding dax_device is > > synchronous. Virtio pmem device is asynchronous and > > does not not support VM_SYNC. > > > > Suggested-by: Jan Kara > > Signed-off-by: Pankaj Gupta > > --- > > include/linux/dax.h | 23 +++++++++++++++++++++++ > > 1 file changed, 23 insertions(+) > > > > diff --git a/include/linux/dax.h b/include/linux/dax.h > > index b896706a5ee9..4a2a60ffec86 100644 > > --- a/include/linux/dax.h > > +++ b/include/linux/dax.h > > @@ -38,6 +38,24 @@ void kill_dax(struct dax_device *dax_dev); > > void dax_write_cache(struct dax_device *dax_dev, bool wc); > > bool dax_write_cache_enabled(struct dax_device *dax_dev); > > bool dax_synchronous(struct dax_device *dax_dev); > > + > > +/* > > + * Callers check if synchronous mapping is enabled for DAX file > > + * and attached dax device is also synchronous. > > + * > > + * dax_synchronous function verifies if dax device is synchronous. > > + * Currently, only virtio pmem device supports asynchronous device > > + * flush. > > + */ > > Thanks for the patch! I'd restructure this comment like: > > /* > * Check if given mapping is supported by the file / underlying device. > */ Sure. > > +static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, > > + struct dax_device *dax_dev) > > +{ > > /* Everyone supports non-sync mappings */ > > + if (!(vma->vm_flags & VM_SYNC)) > > + return true; > /* Sync mappings are supported only for files using DAX */ > > + if (!IS_DAX(file_inode(vma->vm_file))) > > + return false; > /* Underlying device must support persisting through CPU instructions */ > > + return dax_synchronous(dax_dev); > > +} > > #else > > static inline struct dax_device *dax_get_by_host(const char *host) > > { > > @@ -69,6 +87,11 @@ static inline bool dax_synchronous(struct dax_device > > *dax_dev) > > { > > return true; > > } > > +static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, > > + struct dax_device *dax_dev) > > +{ > > + return true; > > This looks wrong. Shouldn't it rather be: > > return !(vma->flags & VM_SYNC); > > ? Right. I will correct this. Thanks, Pankaj > > Honza > -- > Jan Kara > SUSE Labs, CR >