From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 369A0386C0A; Thu, 23 Apr 2026 17:02:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776963744; cv=none; b=rX8aRA4DY0Yw/kf4rajuxQkGYa9YFy1FW1XR1f/mqjT8A5LnkeCTFJbQZQkSosiFe+jAJHFy6jlRQS78AsCw7Z6aG0yQUlBZVF4+1RJnyAn7Mo2NylU5XP1KlXZcgqqvWHKrr8U5ujwQ5UGrUsHqED6T/JL3Lqgm+LdqdhVC8vI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776963744; c=relaxed/simple; bh=3HHkPQzEYy3AVQxaCt9xTKxJeWlgn9OWlO/P7JsaLGc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gNBy8Jhc8lks2Ct9/i+GxefWiFecZ65CUvPZyuBWpbkQf3JP6HaNOBgC87uWhqzpp3zlIYj8XWVLZAvSrXVyqes1zr/43A9XHYQitQRjviE1uH5UZk+cjceqZD0Hy6uDK6attStgnsX8ez4nupHF7aqiQtF3p37JnaQ2LRTGkAA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8AC5C2BCAF; Thu, 23 Apr 2026 17:02:23 +0000 (UTC) From: Dave Jiang To: linux-cxl@vger.kernel.org, nvdimm@lists.linux.dev Cc: djbw@kernel.org, iweiny@kernel.org, pasha.tatashin@soleen.com, mclapinski@google.com, rppt@kernel.org, joao.m.martins@oracle.com, jic23@kernel.org, gourry@gourry.net, john@groves.net, rick.p.edgecombe@intel.com Subject: [RFC PATCH 02/12] dax: Save the kva from memremap Date: Thu, 23 Apr 2026 10:02:09 -0700 Message-ID: <20260423170219.281618-3-dave.jiang@intel.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260423170219.281618-1-dave.jiang@intel.com> References: <20260423170219.281618-1-dave.jiang@intel.com> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This patch is partially taken from John Grove's famfs dax series. Save the kva for memremap because we need direct_access() support. Signed-off-by: Dave Jiang --- drivers/dax/dax-private.h | 4 ++++ drivers/dax/device.c | 19 +++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h index c6ae27c982f4..425a515905e5 100644 --- a/drivers/dax/dax-private.h +++ b/drivers/dax/dax-private.h @@ -69,6 +69,8 @@ struct dev_dax_range { * data while the device is activated in the driver. * @region: parent region * @dax_dev: core dax functionality + * @virt_addr: kva from memremap; used by fsdev_dax + * @cached_size: cached size of the memory range for quick access; used by fsdev_dax * @align: alignment of this instance * @target_node: effective numa node if dev_dax memory range is onlined * @dyn_id: is this a dynamic or statically created instance @@ -83,6 +85,8 @@ struct dev_dax_range { struct dev_dax { struct dax_region *region; struct dax_device *dax_dev; + void *virt_addr; + u64 cached_size; unsigned int align; int target_node; bool dyn_id; diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 62206bcb63a6..4ffa3ef60a57 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -370,6 +370,7 @@ static int dax_open(struct inode *inode, struct file *filp) filp->f_sb_err = file_sample_sb_err(filp); filp->private_data = dev_dax; inode->i_flags = S_DAX; + inode->i_size = dev_dax->cached_size; return 0; } @@ -408,7 +409,9 @@ static int dev_dax_probe(struct dev_dax *dev_dax) struct device *dev = &dev_dax->dev; struct dev_pagemap *pgmap; struct inode *inode; + u64 data_offset = 0; struct cdev *cdev; + u64 len = 0; void *addr; int rc, i; @@ -451,6 +454,7 @@ static int dev_dax_probe(struct dev_dax *dev_dax) i, range->start, range->end); return -EBUSY; } + len += range_len(range); } pgmap->type = MEMORY_DEVICE_GENERIC; @@ -461,6 +465,21 @@ static int dev_dax_probe(struct dev_dax *dev_dax) if (IS_ERR(addr)) return PTR_ERR(addr); + /* Detect whether the data is at a non-zero offset into the memory */ + if (pgmap->range.start != dev_dax->ranges[0].range.start) { + u64 phys = dev_dax->ranges[0].range.start; + u64 pgmap_phys = dev_dax->pgmap[0].range.start; + + if (!WARN_ON(pgmap_phys > phys)) + data_offset = phys - pgmap_phys; + + pr_debug("%s: offset detected phys=%llx pgmap_phys=%llx offset=%llx\n", + __func__, phys, pgmap_phys, data_offset); + } + + dev_dax->virt_addr = addr + data_offset; + dev_dax->cached_size = len; + inode = dax_inode(dax_dev); cdev = inode->i_cdev; cdev_init(cdev, &dax_fops); -- 2.53.0