From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: John Groves <John@Groves.net>
Cc: 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>,
<john@jagalactic.com>, Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@infradead.org>,
<dave.hansen@linux.intel.com>, <gregory.price@memverge.com>
Subject: Re: [RFC PATCH 04/20] dev_dax_iomap: Save the kva from memremap
Date: Mon, 26 Feb 2024 12:21:39 +0000 [thread overview]
Message-ID: <20240226122139.0000135b@Huawei.com> (raw)
In-Reply-To: <66620f69fa3f3664d955649eba7da63fdf8d65ad.1708709155.git.john@groves.net>
On Fri, 23 Feb 2024 11:41:48 -0600
John Groves <John@Groves.net> wrote:
> 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.
Probably good to have info on when this happens and preferably why
this dragon is there.
>
> 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;
Why as a u64? If it's a virt address why not just void *?
> 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;
Why the cast? Ranges use u64s internally.
> + 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);
pr_debug() + dynamic debug will then deal with __func__ for you.
> + }
> + dev_dax->virt_addr = (u64)addr + data_offset;
> +
> inode = dax_inode(dax_dev);
> cdev = inode->i_cdev;
> cdev_init(cdev, &dax_fops);
next prev parent reply other threads:[~2024-02-26 12:21 UTC|newest]
Thread overview: 105+ 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 ` [RFC PATCH 04/20] dev_dax_iomap: Save the kva from memremap John Groves
2024-02-26 12:21 ` Jonathan Cameron [this message]
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
2024-05-19 5:59 ` Amir Goldstein
2024-05-22 2:05 ` John Groves
2024-05-22 8:58 ` Miklos Szeredi
2024-05-22 10:16 ` Amir Goldstein
2024-05-22 11:28 ` Miklos Szeredi
2024-05-22 13:41 ` Amir Goldstein
2024-05-23 2:49 ` John Groves
2024-05-23 13:57 ` Miklos Szeredi
2024-05-24 0:47 ` John Groves
2024-05-24 7:55 ` Miklos Szeredi
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