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: 11828121 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 1A57C14D5 for ; Fri, 9 Oct 2020 19:54:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0BBB822CAD for ; Fri, 9 Oct 2020 19:54:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391279AbgJITyL (ORCPT ); Fri, 9 Oct 2020 15:54:11 -0400 Received: from mga14.intel.com ([192.55.52.115]:15724 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391245AbgJITyG (ORCPT ); Fri, 9 Oct 2020 15:54:06 -0400 IronPort-SDR: 7qaDjl2/ZxevUxp9SIgeuOAu8od3VQFfONS9RP6IrIk3xZmTXRvkzFi7/Qwdz+i1yGXcanWplh jXuBSYf4vxRQ== X-IronPort-AV: E=McAfee;i="6000,8403,9769"; a="164744163" X-IronPort-AV: E=Sophos;i="5.77,355,1596524400"; d="scan'208";a="164744163" 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 Cc: Ira Weiny , x86@kernel.org, Dave Hansen , Dan Williams , Fenghua Yu , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, kexec@lists.infradead.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, devel@driverdev.osuosl.org, linux-efi@vger.kernel.org, linux-mmc@vger.kernel.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-um@lists.infradead.org, linux-ntfs-dev@lists.sourceforge.net, reiserfs-devel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-nilfs@vger.kernel.org, cluster-devel@redhat.com, ecryptfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-afs@lists.infradead.org, linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, drbd-dev@lists.linbit.com, linux-block@vger.kernel.org, xen-devel@lists.xenproject.org, linux-cachefs@redhat.com, samba-technical@lists.samba.org, intel-wired-lan@lists.osuosl.org 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 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org 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);