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 05/20] dev_dax_iomap: Add dax_operations for use by fs-dax on devdax
Date: Fri, 23 Feb 2024 11:41:49 -0600 [thread overview]
Message-ID: <5727b1be956278e3a6c4cf7b728ee4f8f037ae51.1708709155.git.john@groves.net> (raw)
In-Reply-To: <cover.1708709155.git.john@groves.net>
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
+
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 void write_dax(void *pmem_addr, struct page *page,
+ unsigned int off, unsigned int len)
+{
+ unsigned int chunk;
+ void *mem;
+
+ while (len) {
+ mem = kmap_local_page(page);
+ chunk = min_t(unsigned int, len, PAGE_SIZE - off);
+ memcpy_flushcache(pmem_addr, mem + off, chunk);
+ kunmap_local(mem);
+ len -= chunk;
+ off = 0;
+ page++;
+ pmem_addr += chunk;
+ }
+}
+
+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 */
+
+ phys = dax_pgoff_to_phys(dev_dax, pgoff, nr_pages << PAGE_SHIFT);
+
+ if (kaddr)
+ *kaddr = (void *)virt_addr;
+
+ local_pfn = phys_to_pfn_t(phys, flags); /* are flags correct? */
+ 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 int dev_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
+ size_t nr_pages)
+{
+ long resid = nr_pages << PAGE_SHIFT;
+ long offset = pgoff << PAGE_SHIFT;
+
+ /* Break into one write per dax region */
+ while (resid > 0) {
+ void *kaddr;
+ pgoff_t poff = offset >> PAGE_SHIFT;
+ long len = __dev_dax_direct_access(dax_dev, poff,
+ nr_pages, DAX_ACCESS, &kaddr, NULL);
+ len = min_t(long, len, PAGE_SIZE);
+ write_dax(kaddr, ZERO_PAGE(0), offset, len);
+
+ offset += len;
+ resid -= len;
+ }
+ return 0;
+}
+
+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)
+{
+ return __dev_dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn);
+}
+
+static size_t dev_dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
+ void *addr, size_t bytes, struct iov_iter *i)
+{
+ size_t len, off;
+
+ off = offset_in_page(addr);
+ len = PFN_PHYS(PFN_UP(off + bytes));
+
+ return _copy_from_iter_flushcache(addr, bytes, i);
+}
+
+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 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;
--
2.43.0
next prev parent reply other threads:[~2024-02-23 17:42 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 ` John Groves [this message]
2024-02-26 12:32 ` [RFC PATCH 05/20] dev_dax_iomap: Add dax_operations for use by fs-dax on devdax 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
2024-05-25 22:54 ` Dave Chinner
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