Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751856AbdFIUbM (ORCPT ); Fri, 9 Jun 2017 16:31:12 -0400 Received: from mga01.intel.com ([192.55.52.88]:39125 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751594AbdFIUbI (ORCPT ); Fri, 9 Jun 2017 16:31:08 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,319,1493708400"; d="scan'208";a="112557309" Subject: [PATCH v3 04/14] dax, pmem: introduce an optional 'flush' dax_operation From: Dan Williams To: linux-nvdimm@lists.01.org Cc: Matthew Wilcox , x86@kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, Ross Zwisler , hch@lst.de Date: Fri, 09 Jun 2017 13:24:07 -0700 Message-ID: <149703984722.20620.1577767383686219477.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <149703982465.20620.14881139332926778446.stgit@dwillia2-desk3.amr.corp.intel.com> References: <149703982465.20620.14881139332926778446.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2094 Lines: 54 Filesystem-DAX flushes caches whenever it writes to the address returned through dax_direct_access() and when writing back dirty radix entries. That flushing is only required in the pmem case, so add a dax operation to allow pmem to take this extra action, but skip it for other dax capable devices that do not provide a flush routine. An example for this differentiation might be a volatile ram disk where there is no expectation of persistence. In fact the pmem driver itself might front such an address range specified by the NFIT. So, this "no flush" property might be something passed down by the bus / libnvdimm. Cc: Christoph Hellwig Cc: Matthew Wilcox Cc: Ross Zwisler Signed-off-by: Dan Williams --- drivers/nvdimm/pmem.c | 7 +++++++ include/linux/dax.h | 2 ++ 2 files changed, 9 insertions(+) diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 2f3aefe565c6..823b07774244 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -242,9 +242,16 @@ static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, return copy_from_iter_flushcache(addr, bytes, i); } +static void pmem_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, + void *addr, size_t size) +{ + wb_cache_pmem(addr, size); +} + static const struct dax_operations pmem_dax_ops = { .direct_access = pmem_dax_direct_access, .copy_from_iter = pmem_copy_from_iter, + .flush = pmem_dax_flush, }; static void pmem_release_queue(void *q) diff --git a/include/linux/dax.h b/include/linux/dax.h index 28e398f8c59e..407dd3ff6e54 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -19,6 +19,8 @@ struct dax_operations { /* copy_from_iter: dax-driver override for default copy_from_iter */ size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t, struct iov_iter *); + /* flush: optional driver-specific cache management after writes */ + void (*flush)(struct dax_device *, pgoff_t, void *, size_t); }; #if IS_ENABLED(CONFIG_DAX)