From: John Groves <John@Groves.net>
To: John Groves <John@Groves.net>, Jonathan Corbet <corbet@lwn.net>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
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,
nvdimm@lists.linux.dev
Cc: John Groves <jgroves@micron.com>,
john@jagalactic.com, Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@infradead.org>,
dave.hansen@linux.intel.com, gregory.price@memverge.com,
Randy Dunlap <rdunlap@infradead.org>,
Jerome Glisse <jglisse@google.com>,
Aravind Ramesh <arramesh@micron.com>,
Ajay Joshi <ajayjoshi@micron.com>,
Eishan Mirakhur <emirakhur@micron.com>,
Ravi Shankar <venkataravis@micron.com>,
Srinivasulu Thanneeru <sthanneeru@micron.com>,
Luis Chamberlain <mcgrof@kernel.org>,
Amir Goldstein <amir73il@gmail.com>,
Chandan Babu R <chandanbabu@kernel.org>,
Bagas Sanjaya <bagasdotme@gmail.com>,
"Darrick J . Wong" <djwong@kernel.org>,
Kent Overstreet <kent.overstreet@linux.dev>,
Steve French <stfrench@microsoft.com>,
Nathan Lynch <nathanl@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Thomas Zimmermann <tzimmermann@suse.de>,
Julien Panis <jpanis@baylibre.com>,
Stanislav Fomichev <sdf@google.com>,
Dongsheng Yang <dongsheng.yang@easystack.cn>,
John Groves <john@groves.net>
Subject: [RFC PATCH v2 04/12] dev_dax_iomap: Save the kva from memremap
Date: Mon, 29 Apr 2024 12:04:20 -0500 [thread overview]
Message-ID: <c46bfb93584b726bae920ce25972470015256d25.1714409084.git.john@groves.net> (raw)
In-Reply-To: <cover.1714409084.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 the start of 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.
This happens with devdax devices that started as pmem and got converted
to devdax. I'm not sure whether the offset is due to label storage, or
page tables, but this works in all known cases.
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..df5b3d975df4 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;
+ void *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..17323b5f6f57 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 = dev_dax->ranges[0].range.start;
+ u64 pgmap_phys = dev_dax->pgmap[0].range.start;
+ u64 vmemmap_shift = dev_dax->pgmap[0].vmemmap_shift;
+
+ if (!WARN_ON(pgmap_phys > phys))
+ data_offset = phys - pgmap_phys;
+
+ pr_debug("%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 = addr + data_offset;
+
inode = dax_inode(dax_dev);
cdev = inode->i_cdev;
cdev_init(cdev, &dax_fops);
--
2.43.0
next prev parent reply other threads:[~2024-04-29 17:05 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-29 17:04 [RFC PATCH v2 00/12] Introduce the famfs shared-memory file system John Groves
2024-04-29 17:04 ` [RFC PATCH v2 01/12] famfs: Introduce famfs documentation John Groves
2024-04-30 6:46 ` Bagas Sanjaya
2024-04-29 17:04 ` [RFC PATCH v2 02/12] dev_dax_iomap: Move dax_pgoff_to_phys() from device.c to bus.c John Groves
2024-04-29 17:04 ` [RFC PATCH v2 03/12] dev_dax_iomap: Add fs_dax_get() func to prepare dax for fs-dax usage John Groves
2024-04-29 17:04 ` John Groves [this message]
2024-04-29 17:04 ` [RFC PATCH v2 05/12] dev_dax_iomap: Add dax_operations for use by fs-dax on devdax John Groves
2024-04-29 17:04 ` [RFC PATCH v2 06/12] dev_dax_iomap: export dax_dev_get() John Groves
2024-04-29 17:04 ` [RFC PATCH v2 07/12] famfs prep: Add fs/super.c:kill_char_super() John Groves
2024-05-02 18:17 ` Al Viro
2024-05-02 22:25 ` John Groves
2024-05-03 9:04 ` Christian Brauner
2024-05-03 15:38 ` John Groves
2024-04-29 17:04 ` [RFC PATCH v2 08/12] famfs: module operations & fs_context John Groves
2024-04-30 11:01 ` Christian Brauner
2024-05-02 15:51 ` John Groves
2024-05-03 14:15 ` John Groves
2024-05-02 18:23 ` Al Viro
2024-05-02 21:50 ` John Groves
2024-04-29 17:04 ` [RFC PATCH v2 09/12] famfs: Introduce inode_operations and super_operations John Groves
2024-04-29 17:04 ` [RFC PATCH v2 10/12] famfs: Introduce file_operations read/write John Groves
2024-05-02 18:29 ` Al Viro
2024-05-02 21:51 ` John Groves
2024-04-29 17:04 ` [RFC PATCH v2 11/12] famfs: Introduce mmap and VM fault handling John Groves
2024-04-29 17:04 ` [RFC PATCH v2 12/12] famfs: famfs_ioctl and core file-to-memory mapping logic & iomap_ops John Groves
2024-04-29 18:32 ` [RFC PATCH v2 00/12] Introduce the famfs shared-memory file system Matthew Wilcox
2024-04-29 23:08 ` Kent Overstreet
2024-04-30 2:24 ` John Groves
2024-04-30 3:11 ` Kent Overstreet
2024-05-01 2:09 ` John Groves
2024-04-30 2:11 ` John Groves
2024-04-30 21:01 ` Matthew Wilcox
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