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 05/20] dev_dax_iomap: Add dax_operations for use by fs-dax on devdax
Date: Mon, 26 Feb 2024 12:32:45 +0000 [thread overview]
Message-ID: <20240226123245.00000c01@Huawei.com> (raw)
In-Reply-To: <5727b1be956278e3a6c4cf7b728ee4f8f037ae51.1708709155.git.john@groves.net>
On Fri, 23 Feb 2024 11:41:49 -0600
John Groves <John@Groves.net> wrote:
> Notes about this commit:
>
> * These methods are based somewhat loosely on pmem_dax_ops from
> drivers/nvdimm/pmem.c
>
> * dev_dax_direct_access() is returns the hpa, pfn and kva. The kva was
> newly stored as dev_dax->virt_addr by dev_dax_probe().
>
> * The hpa/pfn are used for mmap (dax_iomap_fault()), and the kva is used
> for read/write (dax_iomap_rw())
>
> * dev_dax_recovery_write() and dev_dax_zero_page_range() have not been
> tested yet. I'm looking for suggestions as to how to test those.
>
> Signed-off-by: John Groves <john@groves.net>
> ---
> drivers/dax/bus.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 107 insertions(+)
>
> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
> index 664e8c1b9930..06fcda810674 100644
> --- a/drivers/dax/bus.c
> +++ b/drivers/dax/bus.c
> @@ -10,6 +10,12 @@
> #include "dax-private.h"
> #include "bus.h"
>
> +#if IS_ENABLED(CONFIG_DEV_DAX_IOMAP)
> +#include <linux/backing-dev.h>
> +#include <linux/pfn_t.h>
> +#include <linux/range.h>
> +#endif
> +
Is it worth avoiding includes based on config? Probably not.
> static DEFINE_MUTEX(dax_bus_lock);
>
> #define DAX_NAME_LEN 30
> @@ -1349,6 +1355,101 @@ __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
> }
> EXPORT_SYMBOL_GPL(dax_pgoff_to_phys);
>
> +#if IS_ENABLED(CONFIG_DEV_DAX_IOMAP)
> +
> +
> +static long __dev_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
> + long nr_pages, enum dax_access_mode mode, void **kaddr,
> + pfn_t *pfn)
> +{
> + struct dev_dax *dev_dax = dax_get_private(dax_dev);
> + size_t dax_size = dev_dax_size(dev_dax);
> + size_t size = nr_pages << PAGE_SHIFT;
> + size_t offset = pgoff << PAGE_SHIFT;
> + phys_addr_t phys;
> + u64 virt_addr = dev_dax->virt_addr + offset;
> + pfn_t local_pfn;
> + u64 flags = PFN_DEV|PFN_MAP;
> +
> + WARN_ON(!dev_dax->virt_addr); /* virt_addr must be saved for direct_access */
Fair enough, but from local code point of view, does it make sense to check this
if !kaddr as we won't use this.
> +
> + phys = dax_pgoff_to_phys(dev_dax, pgoff, nr_pages << PAGE_SHIFT);
> +
> + if (kaddr)
> + *kaddr = (void *)virt_addr;
Back to earlier comment on virt_addr as a void *. Definitely looking like
that would be more accurate and simpler! Also not much point in computing
virt_addr unless kaddr is good.
> +
> + local_pfn = phys_to_pfn_t(phys, flags); /* are flags correct? */
If you aren't going to do anything with it for !pfn, move it under the if (pfn).
> + if (pfn)
> + *pfn = local_pfn;
> +
> + /* This the valid size at the specified address */
> + return PHYS_PFN(min_t(size_t, size, dax_size - offset));
> +}
> +
> +
> +static const struct dax_operations dev_dax_ops = {
> + .direct_access = dev_dax_direct_access,
> + .zero_page_range = dev_dax_zero_page_range,
> + .recovery_write = dev_dax_recovery_write,
> +};
> +
> +#endif /* IS_ENABLED(CONFIG_DEV_DAX_IOMAP) */
> +
> struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
> {
> struct dax_region *dax_region = data->dax_region;
> @@ -1404,11 +1505,17 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
> }
> }
>
If we were to make this
if (IS_ENABLED(CONFIG_DEV_DAX_IOMAP))
etc can we avoid the ifdef stuff above and let dead code removal deal with it?
Might need a few stubs - I haven't tried.
> +#if IS_ENABLED(CONFIG_DEV_DAX_IOMAP)
> + /* holder_ops currently populated separately in a slightly hacky way */
> + dax_dev = alloc_dax(dev_dax, &dev_dax_ops);
> +#else
> /*
> * No dax_operations since there is no access to this device outside of
> * mmap of the resulting character device.
> */
> dax_dev = alloc_dax(dev_dax, NULL);
> +#endif
> +
> if (IS_ERR(dax_dev)) {
> rc = PTR_ERR(dax_dev);
> goto err_alloc_dax;
next prev parent reply other threads:[~2024-02-26 12:32 UTC|newest]
Thread overview: 106+ 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
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 [this message]
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
2024-05-25 22:54 ` Dave Chinner
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