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From: John Groves <John@Groves.net>
To: John Groves <jgroves@micron.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Dan Williams <dan.j.williams@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
	Matthew Wilcox <willy@infradead.org>,
	linux-cxl@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	nvdimm@lists.linux.dev
Cc: John@Groves.net, john@jagalactic.com,
	Dave Chinner <david@fromorbit.com>,
	Christoph Hellwig <hch@infradead.org>,
	dave.hansen@linux.intel.com, gregory.price@memverge.com,
	John Groves <john@groves.net>
Subject: [RFC PATCH 04/20] dev_dax_iomap: Save the kva from memremap
Date: Fri, 23 Feb 2024 11:41:48 -0600	[thread overview]
Message-ID: <66620f69fa3f3664d955649eba7da63fdf8d65ad.1708709155.git.john@groves.net> (raw)
In-Reply-To: <cover.1708709155.git.john@groves.net>

Save the kva from memremap because we need it for iomap rw support

Prior to famfs, there were no iomap users of /dev/dax - so the virtual
address from memremap was not needed.

Also: in some cases dev_dax_probe() is called with the first
dev_dax->range offset past pgmap[0].range. In those cases we need to
add the difference to virt_addr in order to have the physaddr's in
dev_dax->ranges match dev_dax->virt_addr.

Dragons...

Signed-off-by: John Groves <john@groves.net>
---
 drivers/dax/dax-private.h |  1 +
 drivers/dax/device.c      | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
index 446617b73aea..894eb1c66b4a 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -63,6 +63,7 @@ struct dax_mapping {
 struct dev_dax {
 	struct dax_region *region;
 	struct dax_device *dax_dev;
+	u64 virt_addr;
 	unsigned int align;
 	int target_node;
 	bool dyn_id;
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 40ba660013cf..6cd79d00fe1b 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -372,6 +372,7 @@ static int dev_dax_probe(struct dev_dax *dev_dax)
 	struct dax_device *dax_dev = dev_dax->dax_dev;
 	struct device *dev = &dev_dax->dev;
 	struct dev_pagemap *pgmap;
+	u64 data_offset = 0;
 	struct inode *inode;
 	struct cdev *cdev;
 	void *addr;
@@ -426,6 +427,20 @@ 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 = (u64)dev_dax->ranges[0].range.start;
+		u64 pgmap_phys = (u64)dev_dax->pgmap[0].range.start;
+		u64 vmemmap_shift = (u64)dev_dax->pgmap[0].vmemmap_shift;
+
+		if (!WARN_ON(pgmap_phys > phys))
+			data_offset = phys - pgmap_phys;
+
+		pr_notice("%s: offset detected phys=%llx pgmap_phys=%llx offset=%llx shift=%llx\n",
+		       __func__, phys, pgmap_phys, data_offset, vmemmap_shift);
+	}
+	dev_dax->virt_addr = (u64)addr + data_offset;
+
 	inode = dax_inode(dax_dev);
 	cdev = inode->i_cdev;
 	cdev_init(cdev, &dax_fops);
-- 
2.43.0


  parent reply	other threads:[~2024-02-23 17:42 UTC|newest]

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-23 17:41 [RFC PATCH 00/20] Introduce the famfs shared-memory file system John Groves
2024-02-23 17:41 ` [RFC PATCH 01/20] famfs: Documentation John Groves
2024-02-23 17:41 ` [RFC PATCH 02/20] dev_dax_iomap: Add fs_dax_get() func to prepare dax for fs-dax usage John Groves
2024-02-26 12:05   ` Jonathan Cameron
2024-02-26 15:00     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 03/20] dev_dax_iomap: Move dax_pgoff_to_phys from device.c to bus.c since both need it now John Groves
2024-02-26 12:10   ` Jonathan Cameron
2024-02-26 15:13     ` John Groves
2024-02-23 17:41 ` John Groves [this message]
2024-02-26 12:21   ` [RFC PATCH 04/20] dev_dax_iomap: Save the kva from memremap Jonathan Cameron
2024-02-26 15:48     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 05/20] dev_dax_iomap: Add dax_operations for use by fs-dax on devdax John Groves
2024-02-26 12:32   ` Jonathan Cameron
2024-02-26 16:09     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 06/20] dev_dax_iomap: Add CONFIG_DEV_DAX_IOMAP kernel build parameter John Groves
2024-02-26 12:34   ` Jonathan Cameron
2024-02-26 16:12     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 07/20] famfs: Add include/linux/famfs_ioctl.h John Groves
2024-02-24  1:39   ` Randy Dunlap
2024-02-24  2:23     ` John Groves
2024-02-24  3:27       ` Randy Dunlap
2024-02-24 23:32         ` John Groves
2024-02-24 23:40           ` Randy Dunlap
2024-02-26 12:39   ` Jonathan Cameron
2024-02-26 16:44     ` John Groves
2024-02-26 16:56       ` Jonathan Cameron
2024-02-26 18:04         ` John Groves
2024-02-23 17:41 ` [RFC PATCH 08/20] famfs: Add famfs_internal.h John Groves
2024-02-26 12:48   ` Jonathan Cameron
2024-02-26 17:35     ` John Groves
2024-02-27 10:28       ` Jonathan Cameron
2024-02-28  1:06         ` John Groves
2024-02-27 13:38   ` Christian Brauner
2024-02-27 14:12     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 09/20] famfs: Add super_operations John Groves
2024-02-26 12:51   ` Jonathan Cameron
2024-02-26 21:47     ` John Groves
2024-02-27 10:34       ` Jonathan Cameron
2024-02-27 17:48     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 10/20] famfs: famfs_open_device() & dax_holder_operations John Groves
2024-02-26 12:56   ` Jonathan Cameron
2024-02-26 22:22     ` John Groves
2024-02-27 13:39   ` Christian Brauner
2024-02-27 18:38     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 11/20] famfs: Add fs_context_operations John Groves
2024-02-26 13:20   ` Jonathan Cameron
2024-02-26 22:43     ` John Groves
2024-02-27 13:41   ` Christian Brauner
2024-02-28  0:59     ` John Groves
2024-02-28  1:49       ` Randy Dunlap
2024-02-28  8:17         ` Christian Brauner
2024-02-28 10:07       ` Christian Brauner
2024-02-28 12:01         ` Christian Brauner
2024-02-23 17:41 ` [RFC PATCH 12/20] famfs: Add inode_operations and file_system_type John Groves
2024-02-26 13:25   ` Jonathan Cameron
2024-02-26 22:53     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 13/20] famfs: Add iomap_ops John Groves
2024-02-26 13:30   ` Jonathan Cameron
2024-02-26 23:00     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 14/20] famfs: Add struct file_operations John Groves
2024-02-26 13:32   ` Jonathan Cameron
2024-02-26 23:09     ` John Groves
2024-02-23 17:41 ` [RFC PATCH 15/20] famfs: Add ioctl to file_operations John Groves
2024-02-26 13:44   ` Jonathan Cameron
2024-02-23 17:42 ` [RFC PATCH 16/20] famfs: Add fault counters John Groves
2024-02-23 18:23   ` Dave Hansen
2024-02-23 19:56     ` John Groves
2024-02-23 20:04       ` Dan Williams
2024-02-23 20:39         ` John Groves
2024-02-23 21:19           ` Dave Hansen
2024-02-23 23:50             ` Dan Williams
2024-02-24  3:59               ` Matthew Wilcox
2024-02-24  4:30                 ` Dan Williams
2024-02-23 17:42 ` [RFC PATCH 17/20] famfs: Add module stuff John Groves
2024-02-26 13:47   ` Jonathan Cameron
2024-02-27 22:15     ` John Groves
2024-02-23 17:42 ` [RFC PATCH 18/20] famfs: Support character dax via the dev_dax_iomap patch John Groves
2024-02-26 13:52   ` Jonathan Cameron
2024-02-27 22:27     ` John Groves
2024-02-23 17:42 ` [RFC PATCH 19/20] famfs: Update MAINTAINERS file John Groves
2024-02-23 17:42 ` [RFC PATCH 20/20] famfs: Add Kconfig and Makefile plumbing John Groves
2024-02-24  1:50   ` Randy Dunlap
2024-02-24  2:24     ` John Groves
2024-02-24  0:07 ` [RFC PATCH 00/20] Introduce the famfs shared-memory file system Luis Chamberlain
2024-02-26 13:27   ` John Groves
2024-02-26 15:53     ` Luis Chamberlain
2024-02-26 21:16       ` John Groves
2024-02-27  0:58         ` Luis Chamberlain
2024-02-27  2:05           ` John Groves
2024-02-29  2:15             ` Dave Chinner
2024-02-29 14:52               ` John Groves
2024-03-11  1:29                 ` Dave Chinner
2024-02-29  6:52 ` Amir Goldstein
2024-02-29 22:16   ` John Groves
2024-05-17  9:55   ` Miklos Szeredi

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