From patchwork Fri Oct 9 19:50:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ira Weiny X-Patchwork-Id: 11828045 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 A8C6614D5 for ; Fri, 9 Oct 2020 19:54:08 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8DA1222B3A for ; Fri, 9 Oct 2020 19:54:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8DA1222B3A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4832D6EE09; Fri, 9 Oct 2020 19:54:07 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id 661DB6EE09; Fri, 9 Oct 2020 19:54:05 +0000 (UTC) IronPort-SDR: PkWvWoxQBgO9ntYoFAms7digAeA8uEKbHL7qvNABkp73FR39j+QVmzeq8ClNoHi3tb62g3ukgK dqASgQWYr/bQ== X-IronPort-AV: E=McAfee;i="6000,8403,9769"; a="164744166" X-IronPort-AV: E=Sophos;i="5.77,355,1596524400"; d="scan'208";a="164744166" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Oct 2020 12:54:04 -0700 IronPort-SDR: NEiErKYZfPZGqrWyxIZ0z43ef9+IKjrcXd9NJIRckxXQwdDEMd5poh/dknsqhifod6Ym/UoaZd Mu4h9c7DJvbA== X-IronPort-AV: E=Sophos;i="5.77,355,1596524400"; d="scan'208";a="462301216" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Oct 2020 12:54:03 -0700 From: ira.weiny@intel.com To: Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra Subject: [PATCH RFC PKS/PMEM 56/58] dax: Stray access protection for dax_direct_access() Date: Fri, 9 Oct 2020 12:50:31 -0700 Message-Id: <20201009195033.3208459-57-ira.weiny@intel.com> X-Mailer: git-send-email 2.28.0.rc0.12.gb6a658bd00c9 In-Reply-To: <20201009195033.3208459-1-ira.weiny@intel.com> References: <20201009195033.3208459-1-ira.weiny@intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-aio@kvack.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-mmc@vger.kernel.org, Dave Hansen , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, target-devel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-kselftest@vger.kernel.org, samba-technical@lists.samba.org, Ira Weiny , ceph-devel@vger.kernel.org, drbd-dev@lists.linbit.com, devel@driverdev.osuosl.org, linux-cifs@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-scsi@vger.kernel.org, linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, x86@kernel.org, amd-gfx@lists.freedesktop.org, linux-afs@lists.infradead.org, cluster-devel@redhat.com, linux-cachefs@redhat.com, intel-wired-lan@lists.osuosl.org, xen-devel@lists.xenproject.org, linux-ext4@vger.kernel.org, Fenghua Yu , linux-um@lists.infradead.org, intel-gfx@lists.freedesktop.org, ecryptfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, reiserfs-devel@vger.kernel.org, linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, Dan Williams , io-uring@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net, netdev@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-btrfs@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Ira Weiny dax_direct_access() is a special case of accessing pmem via a page offset and without a struct page. Because the dax driver is well aware of the special protections it has mapped memory with, call dev_access_[en|dis]able() directly instead of the unnecessary overhead of trying to get a page to kmap. Similar to kmap, we leverage existing functions, dax_read_[un]lock(), because they are already required to surround the use of the memory returned from dax_direct_access(). Signed-off-by: Ira Weiny --- drivers/dax/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index e84070b55463..0ddb3ee73e36 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -30,6 +30,7 @@ static DEFINE_SPINLOCK(dax_host_lock); int dax_read_lock(void) { + dev_access_enable(false); return srcu_read_lock(&dax_srcu); } EXPORT_SYMBOL_GPL(dax_read_lock); @@ -37,6 +38,7 @@ EXPORT_SYMBOL_GPL(dax_read_lock); void dax_read_unlock(int id) { srcu_read_unlock(&dax_srcu, id); + dev_access_disable(false); } EXPORT_SYMBOL_GPL(dax_read_unlock);