[ndctl PATCH v3 00/10] daxctl: add a new reconfigure-device command

[ndctl PATCH v3 00/10] daxctl: add a new reconfigure-device command

[Vishal Verma]

Changes in v3:
 - In daxctl_dev_get_mode(), remove the subsystem warning, detect dax-class
   and simply make it return devdax

Changes in v2:
 - Add examples to the documentation page (Dave Hansen)
 - Clarify documentation regarding the conversion from system-ram to devdax
 - Remove any references to a persistent config from the documentation -
   those can be added when the feature is added.
 - device.c: validate option compatibility
 - daxctl-list: display numa_node for device listings
 - daxctl-list: display mode for device listings
 - make the options more consistent by adding a '-O' short option
   for --attempt-offline

Add a new daxctl-reconfigure-device command that lets us reconfigure DAX
devices back and forth between 'system-ram' and 'device-dax' modes. It
also includes facilities to online any newly hot-plugged memory
(default), and attempt to offline memory before converting away from the
system-ram mode (not default, requires a --attempt-offline option).

Currently missing from this series is a way to persistently store which
devices have been 'marked' for use as system-ram. This depends on a
config system overhaul in ndctl, and patches for those will follow
separately and are independent of this work.

Example invocations:

1. Reconfigure dax0.0 to system-ram mode, don’t online the memory
    # daxctl reconfigure-device --mode=system-ram --no-online dax0.0
    [
      {
        "chardev":"dax0.0",
        "size":16777216000,
        "numa_node":2,
        "mode":"system-ram"
      }
    ]

2. Reconfigure dax0.0 to devdax mode, attempt to offline the memory
    # daxctl reconfigure-device --human --mode=devdax --attempt-offline dax0.0
    {
      "chardev":"dax0.0",
      "size":"15.63 GiB (16.78 GB)",
      "numa_node":2,
      "mode":"devdax"
    }

3. Reconfigure all dax devices on region0 to system-ram mode
    # daxctl reconfigure-device --mode=system-ram --region=0 all
    [
      {
        "chardev":"dax0.0",
        "size":16777216000,
        "numa_node":2,
        "mode":"system-ram"
      },
      {
        "chardev":"dax0.1",
        "size":16777216000,
        "numa_node":3,
        "mode":"system-ram"
      }
    ]

These patches can also be found in the 'kmem-pending' branch on github:
https://github.com/pmem/ndctl/tree/kmem-pending

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>


Vishal Verma (10):
  libdaxctl: add interfaces in support of device modes
  libdaxctl: cache 'subsystem' in daxctl_ctx
  libdaxctl: add interfaces to enable/disable devices
  libdaxctl: add interfaces to get/set the online state for a node
  daxctl/list: add numa_node for device listings
  libdaxctl: add an interface to get the mode for a dax device
  daxctl: add a new reconfigure-device command
  Documentation/daxctl: add a man page for daxctl-reconfigure-device
  contrib/ndctl: fix region-id completions for daxctl
  contrib/ndctl: add bash-completion for daxctl-reconfigure-device

 Documentation/daxctl/Makefile.am              |   3 +-
 .../daxctl/daxctl-reconfigure-device.txt      | 118 ++++
 contrib/ndctl                                 |  34 +-
 daxctl/Makefile.am                            |   2 +
 daxctl/builtin.h                              |   1 +
 daxctl/daxctl.c                               |   1 +
 daxctl/device.c                               | 237 ++++++++
 daxctl/lib/Makefile.am                        |   3 +-
 daxctl/lib/libdaxctl-private.h                |  21 +
 daxctl/lib/libdaxctl.c                        | 552 +++++++++++++++++-
 daxctl/lib/libdaxctl.sym                      |  14 +
 daxctl/libdaxctl.h                            |  16 +
 util/json.c                                   |  22 +
 13 files changed, 1013 insertions(+), 11 deletions(-)
 create mode 100644 Documentation/daxctl/daxctl-reconfigure-device.txt
 create mode 100644 daxctl/device.c

-- 
2.20.1

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[ndctl PATCH v3 01/10] libdaxctl: add interfaces in support of device modes

[Vishal Verma]

In preparation for libdaxctl and daxctl to grow operational modes for
DAX devices, add the following supporting APIs:

  daxctl_dev_get_ctx
  daxctl_dev_is_enabled

Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 daxctl/lib/libdaxctl.c   | 30 ++++++++++++++++++++++++++++++
 daxctl/lib/libdaxctl.sym |  6 ++++++
 daxctl/libdaxctl.h       |  2 ++
 3 files changed, 38 insertions(+)

diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
index c2e3a52..70f896b 100644
--- a/daxctl/lib/libdaxctl.c
+++ b/daxctl/lib/libdaxctl.c
@@ -559,6 +559,36 @@ static void dax_regions_init(struct daxctl_ctx *ctx)
 	}
 }
 
+static int is_enabled(const char *drvpath)
+{
+	struct stat st;
+
+	if (lstat(drvpath, &st) < 0 || !S_ISLNK(st.st_mode))
+		return 0;
+	else
+		return 1;
+}
+
+DAXCTL_EXPORT int daxctl_dev_is_enabled(struct daxctl_dev *dev)
+{
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	char *path = dev->dev_buf;
+	int len = dev->buf_len;
+
+	if (snprintf(path, len, "%s/driver", dev->dev_path) >= len) {
+		err(ctx, "%s: buffer too small!\n",
+				daxctl_dev_get_devname(dev));
+		return 0;
+	}
+
+	return is_enabled(path);
+}
+
+DAXCTL_EXPORT struct daxctl_ctx *daxctl_dev_get_ctx(struct daxctl_dev *dev)
+{
+	return dev->region->ctx;
+}
+
 DAXCTL_EXPORT struct daxctl_dev *daxctl_dev_get_first(struct daxctl_region *region)
 {
 	dax_devices_init(region);
diff --git a/daxctl/lib/libdaxctl.sym b/daxctl/lib/libdaxctl.sym
index 84d3a69..c4af9a7 100644
--- a/daxctl/lib/libdaxctl.sym
+++ b/daxctl/lib/libdaxctl.sym
@@ -50,3 +50,9 @@ LIBDAXCTL_5 {
 global:
 	daxctl_region_get_path;
 } LIBDAXCTL_4;
+
+LIBDAXCTL_6 {
+global:
+	daxctl_dev_get_ctx;
+	daxctl_dev_is_enabled;
+} LIBDAXCTL_5;
diff --git a/daxctl/libdaxctl.h b/daxctl/libdaxctl.h
index 1d13ea2..e20ccb4 100644
--- a/daxctl/libdaxctl.h
+++ b/daxctl/libdaxctl.h
@@ -67,6 +67,8 @@ const char *daxctl_dev_get_devname(struct daxctl_dev *dev);
 int daxctl_dev_get_major(struct daxctl_dev *dev);
 int daxctl_dev_get_minor(struct daxctl_dev *dev);
 unsigned long long daxctl_dev_get_size(struct daxctl_dev *dev);
+struct daxctl_ctx *daxctl_dev_get_ctx(struct daxctl_dev *dev);
+int daxctl_dev_is_enabled(struct daxctl_dev *dev);
 
 #define daxctl_dev_foreach(region, dev) \
         for (dev = daxctl_dev_get_first(region); \
-- 
2.20.1

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[ndctl PATCH v3 02/10] libdaxctl: cache 'subsystem' in daxctl_ctx

[Vishal Verma]

The 'DAX subsystem' in effect is determined at region or device init
time, and dictates the sysfs base paths for all device/region
operations. In preparation for adding bind/unbind functionality, cache
the subsystem as determined at init time in the library context.

Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 daxctl/lib/libdaxctl.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
index 70f896b..f8f5b8c 100644
--- a/daxctl/lib/libdaxctl.c
+++ b/daxctl/lib/libdaxctl.c
@@ -46,6 +46,7 @@ struct daxctl_ctx {
 	void *userdata;
 	int regions_init;
 	struct list_head regions;
+	enum dax_subsystem subsys;
 };
 
 /**
@@ -96,6 +97,7 @@ DAXCTL_EXPORT int daxctl_new(struct daxctl_ctx **ctx)
 	dbg(c, "log_priority=%d\n", c->ctx.log_priority);
 	*ctx = c;
 	list_head_init(&c->regions);
+	c->subsys = DAX_UNKNOWN;
 
 	return 0;
 }
@@ -454,14 +456,18 @@ static void dax_devices_init(struct daxctl_region *region)
 	for (i = 0; i < ARRAY_SIZE(dax_subsystems); i++) {
 		char *region_path;
 
-		if (i == DAX_BUS)
+		if (i == DAX_BUS) {
 			region_path = region->region_path;
-		else if (i == DAX_CLASS) {
+			if (ctx->subsys == DAX_UNKNOWN)
+				ctx->subsys = DAX_BUS;
+		} else if (i == DAX_CLASS) {
 			if (asprintf(&region_path, "%s/dax",
 						region->region_path) < 0) {
 				dbg(ctx, "region path alloc fail\n");
 				continue;
 			}
+			if (ctx->subsys == DAX_UNKNOWN)
+				ctx->subsys = DAX_CLASS;
 		} else
 			continue;
 		sysfs_device_parse(ctx, region_path, daxdev_fmt, region,
@@ -539,6 +545,8 @@ static void __dax_regions_init(struct daxctl_ctx *ctx, enum dax_subsystem subsys
 		free(dev_path);
 		if (!region)
 			err(ctx, "add_dax_region() for %s failed\n", de->d_name);
+		if (ctx->subsys == DAX_UNKNOWN)
+			ctx->subsys = subsys;
 	}
 	closedir(dir);
 }
-- 
2.20.1

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[ndctl PATCH v3 03/10] libdaxctl: add interfaces to enable/disable devices

[Vishal Verma]

Add new libdaxctl interfaces to disable a device_dax based devices, and
to enable it into a given mode. The modes available are 'device_dax',
and 'system-ram', where device_dax is the normal device DAX mode used
via a character device, and 'system-ram' uses the kernel's 'kmem'
facility to hotplug the device into the system's memory space, and can
be used as normal system memory.

This adds the following new interfaces:

  daxctl_dev_disable;
  daxctl_dev_enable_devdax;
  daxctl_dev_enable_ram;

Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 daxctl/lib/Makefile.am         |   3 +-
 daxctl/lib/libdaxctl-private.h |  15 ++
 daxctl/lib/libdaxctl.c         | 241 +++++++++++++++++++++++++++++++++
 daxctl/lib/libdaxctl.sym       |   3 +
 daxctl/libdaxctl.h             |   9 ++
 5 files changed, 270 insertions(+), 1 deletion(-)

diff --git a/daxctl/lib/Makefile.am b/daxctl/lib/Makefile.am
index d3d4852..9f0e444 100644
--- a/daxctl/lib/Makefile.am
+++ b/daxctl/lib/Makefile.am
@@ -16,7 +16,8 @@ libdaxctl_la_SOURCES =\
 	libdaxctl.c
 
 libdaxctl_la_LIBADD =\
-	$(UUID_LIBS)
+	$(UUID_LIBS) \
+	$(KMOD_LIBS)
 
 daxctl_modprobe_data_DATA = daxctl.conf
 
diff --git a/daxctl/lib/libdaxctl-private.h b/daxctl/lib/libdaxctl-private.h
index 4a462e7..e64d0a7 100644
--- a/daxctl/lib/libdaxctl-private.h
+++ b/daxctl/lib/libdaxctl-private.h
@@ -13,6 +13,8 @@
 #ifndef _LIBDAXCTL_PRIVATE_H_
 #define _LIBDAXCTL_PRIVATE_H_
 
+#include <libkmod.h>
+
 #define DAXCTL_EXPORT __attribute__ ((visibility("default")))
 
 enum dax_subsystem {
@@ -26,6 +28,11 @@ static const char *dax_subsystems[] = {
 	[DAX_BUS] = "/sys/bus/dax/devices",
 };
 
+static const char *dax_modules[] = {
+	[DAXCTL_DEV_MODE_DEVDAX] = "device_dax",
+	[DAXCTL_DEV_MODE_RAM] = "kmem",
+};
+
 /**
  * struct daxctl_region - container for dax_devices
  */
@@ -53,6 +60,14 @@ struct daxctl_dev {
 	char *dev_path;
 	struct list_node list;
 	unsigned long long size;
+	struct kmod_module *module;
+	struct kmod_list *kmod_list;
 	struct daxctl_region *region;
 };
+
+static inline int check_kmod(struct kmod_ctx *kmod_ctx)
+{
+	return kmod_ctx ? 0 : -ENXIO;
+}
+
 #endif /* _LIBDAXCTL_PRIVATE_H_ */
diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
index f8f5b8c..d50b321 100644
--- a/daxctl/lib/libdaxctl.c
+++ b/daxctl/lib/libdaxctl.c
@@ -47,6 +47,7 @@ struct daxctl_ctx {
 	int regions_init;
 	struct list_head regions;
 	enum dax_subsystem subsys;
+	struct kmod_ctx *kmod_ctx;
 };
 
 /**
@@ -85,12 +86,20 @@ DAXCTL_EXPORT void daxctl_set_userdata(struct daxctl_ctx *ctx, void *userdata)
  */
 DAXCTL_EXPORT int daxctl_new(struct daxctl_ctx **ctx)
 {
+	struct kmod_ctx *kmod_ctx;
 	struct daxctl_ctx *c;
+	int rc = 0;
 
 	c = calloc(1, sizeof(struct daxctl_ctx));
 	if (!c)
 		return -ENOMEM;
 
+	kmod_ctx = kmod_new(NULL, NULL);
+	if (check_kmod(kmod_ctx) != 0) {
+		rc = -ENXIO;
+		goto out;
+	}
+
 	c->refcount = 1;
 	log_init(&c->ctx, "libdaxctl", "DAXCTL_LOG");
 	info(c, "ctx %p created\n", c);
@@ -98,8 +107,12 @@ DAXCTL_EXPORT int daxctl_new(struct daxctl_ctx **ctx)
 	*ctx = c;
 	list_head_init(&c->regions);
 	c->subsys = DAX_UNKNOWN;
+	c->kmod_ctx = kmod_ctx;
 
 	return 0;
+out:
+	free(c);
+	return rc;
 }
 
 /**
@@ -134,6 +147,7 @@ DAXCTL_EXPORT void daxctl_unref(struct daxctl_ctx *ctx)
 	list_for_each_safe(&ctx->regions, region, _r, list)
 		free_region(region, &ctx->regions);
 
+	kmod_unref(ctx->kmod_ctx);
 	info(ctx, "context %p released\n", ctx);
 	free(ctx);
 }
@@ -191,6 +205,7 @@ static void free_dev(struct daxctl_dev *dev, struct list_head *head)
 {
 	if (head)
 		list_del_from(head, &dev->list);
+	kmod_module_unref_list(dev->kmod_list);
 	free(dev->dev_buf);
 	free(dev->dev_path);
 	free(dev);
@@ -308,6 +323,27 @@ DAXCTL_EXPORT struct daxctl_region *daxctl_new_region(struct daxctl_ctx *ctx,
 	return region;
 }
 
+static struct kmod_list *to_module_list(struct daxctl_ctx *ctx,
+		const char *alias)
+{
+	struct kmod_list *list = NULL;
+	int rc;
+
+	if (!ctx->kmod_ctx || !alias)
+		return NULL;
+	if (alias[0] == 0)
+		return NULL;
+
+	rc = kmod_module_new_from_lookup(ctx->kmod_ctx, alias, &list);
+	if (rc < 0 || !list) {
+		dbg(ctx, "failed to find modules for alias: %s %d list: %s\n",
+				alias, rc, list ? "populated" : "empty");
+		return NULL;
+	}
+
+	return list;
+}
+
 static void *add_dax_dev(void *parent, int id, const char *daxdev_base)
 {
 	const char *devname = devpath_to_devname(daxdev_base);
@@ -317,6 +353,7 @@ static void *add_dax_dev(void *parent, int id, const char *daxdev_base)
 	struct daxctl_dev *dev, *dev_dup;
 	char buf[SYSFS_ATTR_SIZE];
 	struct stat st;
+	int rc;
 
 	if (!path)
 		return NULL;
@@ -348,6 +385,18 @@ static void *add_dax_dev(void *parent, int id, const char *daxdev_base)
 		goto err_read;
 	dev->buf_len = strlen(daxdev_base) + 50;
 
+	sprintf(path, "%s/modalias", daxdev_base);
+	rc = sysfs_read_attr(ctx, path, buf);
+	/* older kernels may be lack the modalias attribute */
+	if (rc < 0 && rc != -ENOENT)
+		goto err_read;
+	if (rc == 0) {
+		dev->kmod_list = to_module_list(ctx, buf);
+		if (dev->kmod_list == NULL)
+			goto err_read;
+	} else
+		dbg(ctx, "%s: modalias attribute missing\n", devname);
+
 	daxctl_dev_foreach(region, dev_dup)
 		if (dev_dup->id == dev->id) {
 			free_dev(dev, NULL);
@@ -577,6 +626,83 @@ static int is_enabled(const char *drvpath)
 		return 1;
 }
 
+static int daxctl_bind(struct daxctl_ctx *ctx, const char *devname,
+		const char *mod_name)
+{
+	DIR *dir;
+	int rc = 0;
+	char path[200];
+	struct dirent *de;
+	const int len = sizeof(path);
+
+	if (!devname) {
+		err(ctx, "missing devname\n");
+		return -EINVAL;
+	}
+
+	/* this is only called by daxctl_dev_enable which gates on dax-bus */
+	if (snprintf(path, len, "/sys/bus/dax/drivers") >= len) {
+		err(ctx, "%s: buffer too small!\n", devname);
+		return -ENXIO;
+	}
+
+	dir = opendir(path);
+	if (!dir) {
+		err(ctx, "%s: opendir(\"%s\") failed\n", devname, path);
+		return -ENXIO;
+	}
+
+	while ((de = readdir(dir)) != NULL) {
+		char *drv_path;
+
+		if (de->d_ino == 0)
+			continue;
+		if (de->d_name[0] == '.')
+			continue;
+		if (strcmp(de->d_name, mod_name) != 0)
+			continue;
+
+		if (asprintf(&drv_path, "%s/%s/new_id", path, de->d_name) < 0) {
+			err(ctx, "%s: path allocation failure\n", devname);
+			rc = -ENOMEM;
+			break;
+		}
+		rc = sysfs_write_attr_quiet(ctx, drv_path, devname);
+		free(drv_path);
+
+		if (asprintf(&drv_path, "%s/%s/bind", path, de->d_name) < 0) {
+			err(ctx, "%s: path allocation failure\n", devname);
+			rc = -ENOMEM;
+			break;
+		}
+		rc = sysfs_write_attr_quiet(ctx, drv_path, devname);
+		free(drv_path);
+		break;
+	}
+	closedir(dir);
+
+	if (rc) {
+		dbg(ctx, "%s: bind failed\n", devname);
+		return rc;
+	}
+	return 0;
+}
+
+static int daxctl_unbind(struct daxctl_ctx *ctx, const char *devpath)
+{
+	const char *devname = devpath_to_devname(devpath);
+	char path[200];
+	const int len = sizeof(path);
+
+	/* this is only called by daxctl_dev_disable which gates on dax-bus */
+	if (snprintf(path, len, "%s/driver/unbind", devpath) >= len) {
+		err(ctx, "%s: buffer too small!\n", devname);
+		return -ENXIO;
+	}
+
+	return sysfs_write_attr(ctx, path, devname);
+}
+
 DAXCTL_EXPORT int daxctl_dev_is_enabled(struct daxctl_dev *dev)
 {
 	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
@@ -592,6 +718,121 @@ DAXCTL_EXPORT int daxctl_dev_is_enabled(struct daxctl_dev *dev)
 	return is_enabled(path);
 }
 
+static int daxctl_insert_kmod_for_mode(struct daxctl_dev *dev,
+		const char *mod_name)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	struct kmod_list *iter;
+	int rc = -ENXIO;
+
+	if (dev->kmod_list == NULL) {
+		err(ctx, "%s: a modalias lookup list was not created\n",
+				devname);
+		return rc;
+	}
+
+	kmod_list_foreach(iter, dev->kmod_list) {
+		struct kmod_module *mod = kmod_module_get_module(iter);
+		const char *name = kmod_module_get_name(mod);
+
+		if (strcmp(name, mod_name) != 0) {
+			kmod_module_unref(mod);
+			continue;
+		}
+		dbg(ctx, "%s inserting module: %s\n", devname, name);
+		rc = kmod_module_probe_insert_module(mod,
+				KMOD_PROBE_APPLY_BLACKLIST, NULL, NULL, NULL,
+				NULL);
+		if (rc < 0) {
+			err(ctx, "%s: insert failure: %d\n", devname, rc);
+			return rc;
+		}
+		dev->module = mod;
+	}
+
+	if (rc == -ENXIO)
+		err(ctx, "%s: Unable to find module: %s in alias list\n",
+				devname, mod_name);
+	return rc;
+}
+
+static int daxctl_dev_enable(struct daxctl_dev *dev, enum daxctl_dev_mode mode)
+{
+	struct daxctl_region *region = daxctl_dev_get_region(dev);
+	const char *devname = daxctl_dev_get_devname(dev);
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	const char *mod_name = dax_modules[mode];
+	int rc;
+
+	if (daxctl_dev_is_enabled(dev))
+		return 0;
+
+	if (ctx->subsys != DAX_BUS) {
+		err(ctx, "%s: invalid operation for dax subsystem\n", devname);
+		err(ctx, "%s:  see daxctl-migrate-device-model(1)\n", devname);
+		return -ENXIO;
+	}
+
+	if (mode == DAXCTL_DEV_MODE_UNKNOWN || mod_name == NULL) {
+		err(ctx, "%s: Invalid mode: %d\n", devname, mode);
+		return -EINVAL;
+	}
+
+	rc = daxctl_insert_kmod_for_mode(dev, mod_name);
+	if (rc)
+		return rc;
+
+	rc = daxctl_bind(ctx, devname, mod_name);
+	if (!daxctl_dev_is_enabled(dev)) {
+		err(ctx, "%s: failed to enable\n", devname);
+		return rc ? rc : -ENXIO;
+	}
+
+	region->devices_init = 0;
+	dax_devices_init(region);
+	rc = 0;
+	dbg(ctx, "%s: enabled\n", devname);
+	return rc;
+}
+
+DAXCTL_EXPORT int daxctl_dev_enable_devdax(struct daxctl_dev *dev)
+{
+	return daxctl_dev_enable(dev, DAXCTL_DEV_MODE_DEVDAX);
+}
+
+DAXCTL_EXPORT int daxctl_dev_enable_ram(struct daxctl_dev *dev)
+{
+	return daxctl_dev_enable(dev, DAXCTL_DEV_MODE_RAM);
+}
+
+DAXCTL_EXPORT int daxctl_dev_disable(struct daxctl_dev *dev)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+
+	if (!daxctl_dev_is_enabled(dev))
+		return 0;
+
+	if (ctx->subsys != DAX_BUS) {
+		err(ctx, "%s: invalid operation for dax subsystem\n", devname);
+		err(ctx, "%s:  see daxctl-migrate-device-model(1)\n", devname);
+		return -ENXIO;
+	}
+
+	daxctl_unbind(ctx, dev->dev_path);
+
+	if (daxctl_dev_is_enabled(dev)) {
+		err(ctx, "%s: failed to disable\n", devname);
+		return -EBUSY;
+	}
+
+	kmod_module_unref(dev->module);
+	dbg(ctx, "%s: disabled\n", devname);
+
+	return 0;
+}
+
 DAXCTL_EXPORT struct daxctl_ctx *daxctl_dev_get_ctx(struct daxctl_dev *dev)
 {
 	return dev->region->ctx;
diff --git a/daxctl/lib/libdaxctl.sym b/daxctl/lib/libdaxctl.sym
index c4af9a7..19904a2 100644
--- a/daxctl/lib/libdaxctl.sym
+++ b/daxctl/lib/libdaxctl.sym
@@ -55,4 +55,7 @@ LIBDAXCTL_6 {
 global:
 	daxctl_dev_get_ctx;
 	daxctl_dev_is_enabled;
+	daxctl_dev_disable;
+	daxctl_dev_enable_devdax;
+	daxctl_dev_enable_ram;
 } LIBDAXCTL_5;
diff --git a/daxctl/libdaxctl.h b/daxctl/libdaxctl.h
index e20ccb4..b80488e 100644
--- a/daxctl/libdaxctl.h
+++ b/daxctl/libdaxctl.h
@@ -69,6 +69,9 @@ int daxctl_dev_get_minor(struct daxctl_dev *dev);
 unsigned long long daxctl_dev_get_size(struct daxctl_dev *dev);
 struct daxctl_ctx *daxctl_dev_get_ctx(struct daxctl_dev *dev);
 int daxctl_dev_is_enabled(struct daxctl_dev *dev);
+int daxctl_dev_disable(struct daxctl_dev *dev);
+int daxctl_dev_enable_devdax(struct daxctl_dev *dev);
+int daxctl_dev_enable_ram(struct daxctl_dev *dev);
 
 #define daxctl_dev_foreach(region, dev) \
         for (dev = daxctl_dev_get_first(region); \
@@ -81,6 +84,12 @@ int daxctl_dev_is_enabled(struct daxctl_dev *dev);
              region != NULL; \
              region = daxctl_region_get_next(region))
 
+enum daxctl_dev_mode {
+	DAXCTL_DEV_MODE_UNKNOWN,
+	DAXCTL_DEV_MODE_RAM,
+	DAXCTL_DEV_MODE_DEVDAX,
+};
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
-- 
2.20.1

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[ndctl PATCH v3 04/10] libdaxctl: add interfaces to get/set the online state for a node

[Vishal Verma]

In preparation for converting DAX devices for use as system-ram via the
kernel's 'kmem' facility, add libndctl helpers to manipulate the sysfs
interfaces to get the target_node of a DAX device, and to online,
offline, and query the state of hotplugged memory sections associated
with a given node.

This adds the following new interfaces:

  daxctl_dev_get_target_node
  daxctl_dev_online_node
  daxctl_dev_offline_node
  daxctl_dev_node_is_online

Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 daxctl/lib/libdaxctl-private.h |   6 +
 daxctl/lib/libdaxctl.c         | 228 +++++++++++++++++++++++++++++++++
 daxctl/lib/libdaxctl.sym       |   4 +
 daxctl/libdaxctl.h             |   4 +
 4 files changed, 242 insertions(+)

diff --git a/daxctl/lib/libdaxctl-private.h b/daxctl/lib/libdaxctl-private.h
index e64d0a7..ef443aa 100644
--- a/daxctl/lib/libdaxctl-private.h
+++ b/daxctl/lib/libdaxctl-private.h
@@ -33,6 +33,11 @@ static const char *dax_modules[] = {
 	[DAXCTL_DEV_MODE_RAM] = "kmem",
 };
 
+enum node_state {
+	NODE_OFFLINE,
+	NODE_ONLINE,
+};
+
 /**
  * struct daxctl_region - container for dax_devices
  */
@@ -63,6 +68,7 @@ struct daxctl_dev {
 	struct kmod_module *module;
 	struct kmod_list *kmod_list;
 	struct daxctl_region *region;
+	int target_node;
 };
 
 static inline int check_kmod(struct kmod_ctx *kmod_ctx)
diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
index d50b321..aab2364 100644
--- a/daxctl/lib/libdaxctl.c
+++ b/daxctl/lib/libdaxctl.c
@@ -28,6 +28,7 @@
 #include "libdaxctl-private.h"
 
 static const char *attrs = "dax_region";
+static const char *node_base = "/sys/devices/system/node";
 
 static void free_region(struct daxctl_region *region, struct list_head *head);
 
@@ -397,6 +398,12 @@ static void *add_dax_dev(void *parent, int id, const char *daxdev_base)
 	} else
 		dbg(ctx, "%s: modalias attribute missing\n", devname);
 
+	sprintf(path, "%s/target_node", daxdev_base);
+	if (sysfs_read_attr(ctx, path, buf) == 0)
+		dev->target_node = strtol(buf, NULL, 0);
+	else
+		dev->target_node = -1;
+
 	daxctl_dev_foreach(region, dev_dup)
 		if (dev_dup->id == dev->id) {
 			free_dev(dev, NULL);
@@ -897,3 +904,224 @@ DAXCTL_EXPORT unsigned long long daxctl_dev_get_size(struct daxctl_dev *dev)
 {
 	return dev->size;
 }
+
+DAXCTL_EXPORT int daxctl_dev_get_target_node(struct daxctl_dev *dev)
+{
+	return dev->target_node;
+}
+
+static int online_one_memblock(struct daxctl_dev *dev, char *path)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	const char *mode = "online_movable";
+	char buf[SYSFS_ATTR_SIZE];
+	int rc;
+
+	rc = sysfs_read_attr(ctx, path, buf);
+	if (rc) {
+		err(ctx, "%s: Failed to read %s: %s\n",
+			devname, path, strerror(-rc));
+		return rc;
+	}
+
+	/*
+	 * if already online, possibly due to kernel config or a udev rule,
+	 * there is nothing to do and we can skip over the memblock
+	 */
+	if (strncmp(buf, "online", 6) == 0)
+		return 0;
+
+	rc = sysfs_write_attr_quiet(ctx, path, mode);
+	if (rc)
+		err(ctx, "%s: Failed to online %s: %s\n",
+			devname, path, strerror(-rc));
+	return rc;
+}
+
+static int offline_one_memblock(struct daxctl_dev *dev, char *path)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	const char *mode = "offline";
+	char buf[SYSFS_ATTR_SIZE];
+	int rc;
+
+	rc = sysfs_read_attr(ctx, path, buf);
+	if (rc) {
+		err(ctx, "%s: Failed to read %s: %s\n",
+			devname, path, strerror(-rc));
+		return rc;
+	}
+
+	/* if already offline, there is nothing to do */
+	if (strncmp(buf, "offline", 6) == 0)
+		return 0;
+
+	rc = sysfs_write_attr_quiet(ctx, path, mode);
+	if (rc)
+		err(ctx, "%s: Failed to offline %s: %s\n",
+			devname, path, strerror(-rc));
+	return rc;
+}
+
+static int daxctl_dev_node_set_state(struct daxctl_dev *dev,
+		enum node_state state)
+{
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	int target_node, rc, changed = 0;
+	struct dirent *de;
+	char *node_path;
+	DIR *node_dir;
+
+	target_node = daxctl_dev_get_target_node(dev);
+	if (target_node < 0) {
+		err(ctx, "%s: Unable to get target node\n",
+			daxctl_dev_get_devname(dev));
+		return -ENXIO;
+	}
+
+	rc = asprintf(&node_path, "%s/node%d", node_base, target_node);
+	if (rc < 0)
+		return -ENOMEM;
+
+	node_dir = opendir(node_path);
+	if (!node_dir) {
+		rc = -errno;
+		goto out_path;
+	}
+
+	errno = 0;
+	while ((de = readdir(node_dir)) != NULL) {
+		char *mem_path;
+
+		if (strcmp(de->d_name, ".") == 0 ||
+				strcmp(de->d_name, "..") == 0)
+			continue;
+		if (strncmp(de->d_name, "memory", 6) == 0) {
+			rc = asprintf(&mem_path, "%s/%s/state",
+				node_path, de->d_name);
+			if (rc < 0) {
+				rc = -ENOMEM;
+				goto out_dir;
+			}
+			if (state == NODE_ONLINE)
+				rc = online_one_memblock(dev, mem_path);
+			else if (state == NODE_OFFLINE)
+				rc = offline_one_memblock(dev, mem_path);
+			else
+				rc = -EINVAL;
+			free(mem_path);
+			if (rc)
+				goto out_dir;
+			changed++;
+		}
+		errno = 0;
+	}
+	if (errno) {
+		rc = -errno;
+		goto out_dir;
+	}
+	rc = changed;
+
+out_dir:
+	closedir(node_dir);
+out_path:
+	free(node_path);
+	return rc;
+}
+
+DAXCTL_EXPORT int daxctl_dev_online_node(struct daxctl_dev *dev)
+{
+	return daxctl_dev_node_set_state(dev, NODE_ONLINE);
+}
+
+DAXCTL_EXPORT int daxctl_dev_offline_node(struct daxctl_dev *dev)
+{
+	return daxctl_dev_node_set_state(dev, NODE_OFFLINE);
+}
+
+static int memblock_is_online(struct daxctl_dev *dev, char *path)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	char buf[SYSFS_ATTR_SIZE];
+	int rc;
+
+	rc = sysfs_read_attr(ctx, path, buf);
+	if (rc) {
+		err(ctx, "%s: Failed to read %s: %s\n",
+			devname, path, strerror(-rc));
+		return rc;
+	}
+
+	if (strncmp(buf, "online", 6) == 0)
+		return 1;
+
+	return 0;
+}
+
+DAXCTL_EXPORT int daxctl_dev_node_is_online(struct daxctl_dev *dev)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	int target_node, rc, num_online = 0;
+	struct dirent *de;
+	char *node_path;
+	DIR *node_dir;
+
+	target_node = daxctl_dev_get_target_node(dev);
+	if (target_node < 0) {
+		err(ctx, "%s: Unable to get target node\n", devname);
+		return -ENXIO;
+	}
+
+	rc = asprintf(&node_path, "%s/node%d", node_base, target_node);
+	if (rc < 0)
+		return -ENOMEM;
+
+	node_dir = opendir(node_path);
+	if (!node_dir) {
+		rc = -errno;
+		goto out_path;
+	}
+
+	errno = 0;
+	while ((de = readdir(node_dir)) != NULL) {
+		char *mem_path;
+
+		if (strcmp(de->d_name, ".") == 0 ||
+				strcmp(de->d_name, "..") == 0)
+			continue;
+		if (strncmp(de->d_name, "memory", 6) == 0) {
+			rc = asprintf(&mem_path, "%s/%s/state",
+				node_path, de->d_name);
+			if (rc < 0) {
+				rc = -ENOMEM;
+				goto out_dir;
+			}
+			rc = memblock_is_online(dev, mem_path);
+			if (rc < 0) {
+				err(ctx, "%s: Unable to determine state: %s\n",
+					devname, mem_path);
+				goto out_dir;
+			}
+			if (rc > 0)
+				num_online++;
+			free(mem_path);
+		}
+		errno = 0;
+	}
+	if (errno) {
+		rc = -errno;
+		goto out_dir;
+	}
+	rc = num_online;
+
+out_dir:
+	closedir(node_dir);
+out_path:
+	free(node_path);
+	return rc;
+
+}
diff --git a/daxctl/lib/libdaxctl.sym b/daxctl/lib/libdaxctl.sym
index 19904a2..cc47ed6 100644
--- a/daxctl/lib/libdaxctl.sym
+++ b/daxctl/lib/libdaxctl.sym
@@ -54,8 +54,12 @@ global:
 LIBDAXCTL_6 {
 global:
 	daxctl_dev_get_ctx;
+	daxctl_dev_get_target_node;
 	daxctl_dev_is_enabled;
 	daxctl_dev_disable;
 	daxctl_dev_enable_devdax;
 	daxctl_dev_enable_ram;
+	daxctl_dev_online_node;
+	daxctl_dev_offline_node;
+	daxctl_dev_node_is_online;
 } LIBDAXCTL_5;
diff --git a/daxctl/libdaxctl.h b/daxctl/libdaxctl.h
index b80488e..db0d4ea 100644
--- a/daxctl/libdaxctl.h
+++ b/daxctl/libdaxctl.h
@@ -68,10 +68,14 @@ int daxctl_dev_get_major(struct daxctl_dev *dev);
 int daxctl_dev_get_minor(struct daxctl_dev *dev);
 unsigned long long daxctl_dev_get_size(struct daxctl_dev *dev);
 struct daxctl_ctx *daxctl_dev_get_ctx(struct daxctl_dev *dev);
+int daxctl_dev_get_target_node(struct daxctl_dev *dev);
 int daxctl_dev_is_enabled(struct daxctl_dev *dev);
 int daxctl_dev_disable(struct daxctl_dev *dev);
 int daxctl_dev_enable_devdax(struct daxctl_dev *dev);
 int daxctl_dev_enable_ram(struct daxctl_dev *dev);
+int daxctl_dev_online_node(struct daxctl_dev *dev);
+int daxctl_dev_offline_node(struct daxctl_dev *dev);
+int daxctl_dev_node_is_online(struct daxctl_dev *dev);
 
 #define daxctl_dev_foreach(region, dev) \
         for (dev = daxctl_dev_get_first(region); \
-- 
2.20.1

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[ndctl PATCH v3 05/10] daxctl/list: add numa_node for device listings

[Vishal Verma]

The kernel provides a 'target_node' attribute for dax devices. When
converting a dax device to the system-ram mode, the memory is hotplugged
into this numa node. It would be helpful to print this in device
listings so that it is easy for applications to detect the numa node to
which the new memory belongs.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 util/json.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/util/json.c b/util/json.c
index babdc8c..b7ce719 100644
--- a/util/json.c
+++ b/util/json.c
@@ -271,6 +271,7 @@ struct json_object *util_daxctl_dev_to_json(struct daxctl_dev *dev,
 {
 	const char *devname = daxctl_dev_get_devname(dev);
 	struct json_object *jdev, *jobj;
+	int node;
 
 	jdev = json_object_new_object();
 	if (!devname || !jdev)
@@ -284,6 +285,13 @@ struct json_object *util_daxctl_dev_to_json(struct daxctl_dev *dev,
 	if (jobj)
 		json_object_object_add(jdev, "size", jobj);
 
+	node = daxctl_dev_get_target_node(dev);
+	if (node >= 0) {
+		jobj = json_object_new_int(node);
+		if (jobj)
+			json_object_object_add(jdev, "numa_node", jobj);
+	}
+
 	return jdev;
 }
 
-- 
2.20.1

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[ndctl PATCH v3 06/10] libdaxctl: add an interface to get the mode for a dax device

[Vishal Verma]

In preparation for a reconfigure-device command, add an interface to
retrieve the 'mode' of a dax device. This will allow the
reconfigure-device command (and via daxctl_dev_to_json()), also
daxctl-list) to print the mode on device listings via a list command or
immediately after a mode change.

Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 daxctl/lib/libdaxctl.c   | 41 ++++++++++++++++++++++++++++++++++++++++
 daxctl/lib/libdaxctl.sym |  1 +
 daxctl/libdaxctl.h       |  1 +
 util/json.c              | 14 ++++++++++++++
 4 files changed, 57 insertions(+)

diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
index aab2364..5c85328 100644
--- a/daxctl/lib/libdaxctl.c
+++ b/daxctl/lib/libdaxctl.c
@@ -12,6 +12,8 @@
  */
 #include <stdio.h>
 #include <errno.h>
+#include <limits.h>
+#include <libgen.h>
 #include <stdlib.h>
 #include <dirent.h>
 #include <unistd.h>
@@ -840,6 +842,45 @@ DAXCTL_EXPORT int daxctl_dev_disable(struct daxctl_dev *dev)
 	return 0;
 }
 
+DAXCTL_EXPORT enum daxctl_dev_mode daxctl_dev_get_mode(struct daxctl_dev *dev)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	int rc = DAXCTL_DEV_MODE_UNKNOWN;
+	char path[200];
+	const int len = sizeof(path);
+	char *mod_path, *mod_base;
+
+	if (!daxctl_dev_is_enabled(dev))
+		return rc;
+
+	/* dax-class model only has conventional devdax devices */
+	if (ctx->subsys != DAX_BUS)
+		return DAXCTL_DEV_MODE_DEVDAX;
+
+	if (snprintf(path, len, "%s/driver/module", dev->dev_path) >= len) {
+		err(ctx, "%s: buffer too small!\n", devname);
+		return -ENXIO;
+	}
+
+	mod_path = realpath(path, NULL);
+	if (!mod_path) {
+		rc = -errno;
+		err(ctx, "%s:  unable to determine module: %s\n", devname,
+			strerror(errno));
+		return rc;
+	}
+
+	mod_base = basename(mod_path);
+	if (strcmp(mod_base, dax_modules[DAXCTL_DEV_MODE_RAM]) == 0)
+		rc = DAXCTL_DEV_MODE_RAM;
+	else if (strcmp(mod_base, dax_modules[DAXCTL_DEV_MODE_DEVDAX]) == 0)
+		rc = DAXCTL_DEV_MODE_DEVDAX;
+
+	free(mod_path);
+	return rc;
+}
+
 DAXCTL_EXPORT struct daxctl_ctx *daxctl_dev_get_ctx(struct daxctl_dev *dev)
 {
 	return dev->region->ctx;
diff --git a/daxctl/lib/libdaxctl.sym b/daxctl/lib/libdaxctl.sym
index cc47ed6..d53976d 100644
--- a/daxctl/lib/libdaxctl.sym
+++ b/daxctl/lib/libdaxctl.sym
@@ -62,4 +62,5 @@ global:
 	daxctl_dev_online_node;
 	daxctl_dev_offline_node;
 	daxctl_dev_node_is_online;
+	daxctl_dev_get_mode;
 } LIBDAXCTL_5;
diff --git a/daxctl/libdaxctl.h b/daxctl/libdaxctl.h
index db0d4ea..4f9088f 100644
--- a/daxctl/libdaxctl.h
+++ b/daxctl/libdaxctl.h
@@ -76,6 +76,7 @@ int daxctl_dev_enable_ram(struct daxctl_dev *dev);
 int daxctl_dev_online_node(struct daxctl_dev *dev);
 int daxctl_dev_offline_node(struct daxctl_dev *dev);
 int daxctl_dev_node_is_online(struct daxctl_dev *dev);
+enum daxctl_dev_mode daxctl_dev_get_mode(struct daxctl_dev *dev);
 
 #define daxctl_dev_foreach(region, dev) \
         for (dev = daxctl_dev_get_first(region); \
diff --git a/util/json.c b/util/json.c
index b7ce719..4f13222 100644
--- a/util/json.c
+++ b/util/json.c
@@ -271,6 +271,7 @@ struct json_object *util_daxctl_dev_to_json(struct daxctl_dev *dev,
 {
 	const char *devname = daxctl_dev_get_devname(dev);
 	struct json_object *jdev, *jobj;
+	enum daxctl_dev_mode mode;
 	int node;
 
 	jdev = json_object_new_object();
@@ -292,6 +293,19 @@ struct json_object *util_daxctl_dev_to_json(struct daxctl_dev *dev,
 			json_object_object_add(jdev, "numa_node", jobj);
 	}
 
+	mode = daxctl_dev_get_mode(dev);
+	if (mode > 0) {
+		jobj = NULL;
+		if (mode == DAXCTL_DEV_MODE_RAM)
+			jobj = json_object_new_string("system-ram");
+		else if (mode == DAXCTL_DEV_MODE_DEVDAX)
+			jobj = json_object_new_string("devdax");
+		else
+			jobj = json_object_new_string("unknown");
+		if (jobj)
+			json_object_object_add(jdev, "mode", jobj);
+	}
+
 	return jdev;
 }
 
-- 
2.20.1

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[ndctl PATCH v3 07/10] daxctl: add a new reconfigure-device command

[Vishal Verma]

Add a new command 'daxctl-reconfigure-device'. This is used to switch
the mode of a dax device between regular 'device_dax' and
'system-memory'. The command also uses the memory hotplug sysfs
interfaces to online the newly available memory when converting to
'system-ram', and to attempt to offline the memory when converting back
to a DAX device.

Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 daxctl/Makefile.am |   2 +
 daxctl/builtin.h   |   1 +
 daxctl/daxctl.c    |   1 +
 daxctl/device.c    | 237 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 241 insertions(+)
 create mode 100644 daxctl/device.c

diff --git a/daxctl/Makefile.am b/daxctl/Makefile.am
index 94f73f9..66dcc7f 100644
--- a/daxctl/Makefile.am
+++ b/daxctl/Makefile.am
@@ -15,10 +15,12 @@ daxctl_SOURCES =\
 		daxctl.c \
 		list.c \
 		migrate.c \
+		device.c \
 		../util/json.c
 
 daxctl_LDADD =\
 	lib/libdaxctl.la \
 	../libutil.a \
 	$(UUID_LIBS) \
+	$(KMOD_LIBS) \
 	$(JSON_LIBS)
diff --git a/daxctl/builtin.h b/daxctl/builtin.h
index 00ef5e9..756ba2a 100644
--- a/daxctl/builtin.h
+++ b/daxctl/builtin.h
@@ -6,4 +6,5 @@
 struct daxctl_ctx;
 int cmd_list(int argc, const char **argv, struct daxctl_ctx *ctx);
 int cmd_migrate(int argc, const char **argv, struct daxctl_ctx *ctx);
+int cmd_reconfig_device(int argc, const char **argv, struct daxctl_ctx *ctx);
 #endif /* _DAXCTL_BUILTIN_H_ */
diff --git a/daxctl/daxctl.c b/daxctl/daxctl.c
index 2e41747..e1ba7b8 100644
--- a/daxctl/daxctl.c
+++ b/daxctl/daxctl.c
@@ -71,6 +71,7 @@ static struct cmd_struct commands[] = {
 	{ "list", .d_fn = cmd_list },
 	{ "help", .d_fn = cmd_help },
 	{ "migrate-device-model", .d_fn = cmd_migrate },
+	{ "reconfigure-device", .d_fn = cmd_reconfig_device },
 };
 
 int main(int argc, const char **argv)
diff --git a/daxctl/device.c b/daxctl/device.c
new file mode 100644
index 0000000..12644c5
--- /dev/null
+++ b/daxctl/device.c
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2019 Intel Corporation. All rights reserved. */
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <limits.h>
+#include <util/json.h>
+#include <util/filter.h>
+#include <json-c/json.h>
+#include <daxctl/libdaxctl.h>
+#include <util/parse-options.h>
+#include <ccan/array_size/array_size.h>
+
+static struct {
+	const char *dev;
+	const char *mode;
+	int region_id;
+	bool no_online;
+	bool do_offline;
+	bool human;
+	bool verbose;
+} param = {
+	.region_id = -1,
+};
+
+static int dev_disable(struct daxctl_dev *dev)
+{
+	int rc;
+
+	if (!daxctl_dev_is_enabled(dev))
+		return 0;
+
+	rc = daxctl_dev_disable(dev);
+	if (rc)
+		fprintf(stderr, "%s: disable failed: %s\n",
+			daxctl_dev_get_devname(dev), strerror(-rc));
+
+	return rc;
+}
+
+static int reconfig_mode_ram(struct daxctl_dev *dev)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	int rc;
+
+	rc = dev_disable(dev);
+	if (rc)
+		return rc;
+	rc = daxctl_dev_enable_ram(dev);
+	if (rc)
+		return rc;
+
+	if (param.no_online)
+		return 0;
+
+	rc = daxctl_dev_online_node(dev);
+	if (rc < 0) {
+		fprintf(stderr, "%s: unable to online memory: %s\n",
+			devname, strerror(-rc));
+		return rc;
+	}
+	if (param.verbose)
+		fprintf(stderr, "%s: onlined %d memory sections\n",
+			devname, rc);
+
+	return 0;
+}
+
+static int reconfig_mode_devdax(struct daxctl_dev *dev)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	int rc;
+
+	if (param.do_offline) {
+		rc = daxctl_dev_offline_node(dev);
+		if (rc < 0) {
+			fprintf(stderr, "%s: unable to offline memory: %s\n",
+				devname, strerror(-rc));
+			return rc;
+		}
+		if (param.verbose)
+			fprintf(stderr, "%s: offlined %d memory sections\n",
+				devname, rc);
+	}
+
+	rc = daxctl_dev_node_is_online(dev);
+	if (rc < 0) {
+		fprintf(stderr, "%s: unable to determine node state: %s\n",
+			devname, strerror(-rc));
+		return rc;
+	}
+	if (rc > 0) {
+		if (param.verbose) {
+			fprintf(stderr, "%s: found %d memory sections online\n",
+				devname, rc);
+			fprintf(stderr, "%s: refusing to change modes\n",
+				devname);
+		}
+		return -EBUSY;
+	}
+
+	rc = dev_disable(dev);
+	if (rc)
+		return rc;
+
+	rc = daxctl_dev_enable_devdax(dev);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+static int do_reconfig(struct daxctl_dev *dev, enum daxctl_dev_mode mode)
+{
+	int rc = 0;
+
+	switch (mode) {
+	case DAXCTL_DEV_MODE_RAM:
+		rc = reconfig_mode_ram(dev);
+		break;
+	case DAXCTL_DEV_MODE_DEVDAX:
+		rc = reconfig_mode_devdax(dev);
+		break;
+	default:
+		fprintf(stderr, "%s: unknown mode: %d\n",
+			daxctl_dev_get_devname(dev), mode);
+		rc = -EINVAL;
+	}
+
+	return rc;
+}
+
+int cmd_reconfig_device(int argc, const char **argv, struct daxctl_ctx *ctx)
+{
+	const struct option options[] = {
+		OPT_INTEGER('r', "region", &param.region_id,
+				"restrict to the given region"),
+		OPT_STRING('m', "mode", &param.mode, "mode",
+				"mode to switch the device to"),
+		OPT_BOOLEAN('N', "no-online", &param.no_online,
+				"don't auto-online memory sections"),
+		OPT_BOOLEAN('O', "attempt-offline", &param.do_offline,
+				"attempt to offline memory sections"),
+		OPT_BOOLEAN('u', "human", &param.human,
+				"use human friendly number formats"),
+		OPT_BOOLEAN('v', "verbose", &param.verbose,
+				"emit more debug messages"),
+		OPT_END(),
+	};
+	const char * const u[] = {
+		"daxctl reconfigure-device [<options>] <device> ...",
+		NULL
+	};
+	enum daxctl_dev_mode mode = DAXCTL_DEV_MODE_UNKNOWN;
+	struct json_object *jdevs = json_object_new_array();
+	struct daxctl_region *region;
+	struct json_object *jdev;
+	int i, rc = 0, done = 0;
+	unsigned long flags = 0;
+	struct daxctl_dev *dev;
+
+        argc = parse_options(argc, argv, options, u, 0);
+	if (argc == 0)
+		usage_with_options(u, options);
+	for (i = 0; i < argc; i++) {
+		if (strcmp(argv[i], "all") == 0) {
+			argv[0] = "all";
+			argc = 1;
+			break;
+		}
+	}
+
+	if (param.human)
+		flags |= UTIL_JSON_HUMAN;
+
+	if (!param.mode) {
+		fprintf(stderr, "error: a 'mode' option is required\n");
+		usage_with_options(u, options);
+	}
+	if (strcmp(param.mode, "system-ram") == 0) {
+		mode = DAXCTL_DEV_MODE_RAM;
+		if (param.do_offline) {
+			fprintf(stderr,
+				"can't --attempt-offline for system-ram mode\n");
+			return -EINVAL;
+		}
+	} else if (strcmp(param.mode, "devdax") == 0) {
+		mode = DAXCTL_DEV_MODE_DEVDAX;
+		if (param.no_online) {
+			fprintf(stderr,
+				"can't --no-online for devdax mode\n");
+			return -EINVAL;
+		}
+	}
+
+	daxctl_region_foreach(ctx, region) {
+		if (param.region_id >= 0 && param.region_id
+				!= daxctl_region_get_id(region))
+			continue;
+
+		daxctl_dev_foreach(region, dev) {
+			bool dev_requested = false;
+
+			for (i = 0; i < argc; i++) {
+				if ((strcmp(daxctl_dev_get_devname(dev),
+						argv[i]) == 0) ||
+						(strcmp(argv[i], "all") == 0)) {
+					dev_requested = true;
+					break;
+				}
+			}
+			if (dev_requested) {
+				rc = do_reconfig(dev, mode);
+				if (rc < 0)
+					goto out_err;
+				done++;
+				if (!jdevs)
+					continue;
+				jdev = util_daxctl_dev_to_json(dev, flags);
+				if (jdev)
+					json_object_array_add(jdevs, jdev);
+			}
+		}
+	}
+	if (jdevs)
+		util_display_json_array(stdout, jdevs, flags);
+
+	fprintf(stderr, "reconfigured %d device%s\n", done,
+		done == 1 ? "" : "s");
+	return 0;
+
+out_err:
+	fprintf(stderr, "error reconfiguring %s: %s\n",
+		daxctl_dev_get_devname(dev), strerror(-rc));
+	return rc;
+}
-- 
2.20.1

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[ndctl PATCH v3 08/10] Documentation/daxctl: add a man page for daxctl-reconfigure-device

[Vishal Verma]

Add a man page describing the new daxctl-reconfigure-device command.

Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 Documentation/daxctl/Makefile.am              |   3 +-
 .../daxctl/daxctl-reconfigure-device.txt      | 118 ++++++++++++++++++
 2 files changed, 120 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/daxctl/daxctl-reconfigure-device.txt

diff --git a/Documentation/daxctl/Makefile.am b/Documentation/daxctl/Makefile.am
index 6aba035..715fbad 100644
--- a/Documentation/daxctl/Makefile.am
+++ b/Documentation/daxctl/Makefile.am
@@ -28,7 +28,8 @@ endif
 man1_MANS = \
 	daxctl.1 \
 	daxctl-list.1 \
-	daxctl-migrate-device-model.1
+	daxctl-migrate-device-model.1 \
+	daxctl-reconfigure-device.1
 
 CLEANFILES = $(man1_MANS)
 
diff --git a/Documentation/daxctl/daxctl-reconfigure-device.txt b/Documentation/daxctl/daxctl-reconfigure-device.txt
new file mode 100644
index 0000000..b575091
--- /dev/null
+++ b/Documentation/daxctl/daxctl-reconfigure-device.txt
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0
+
+daxctl-reconfigure-device(1)
+============================
+
+NAME
+----
+daxctl-reconfigure-device - Reconfigure a dax device into a different mode
+
+SYNOPSIS
+--------
+[verse]
+'daxctl reconfigure-device' <dax0.0> [<dax1.0>...<daxY.Z>] [<options>]
+
+EXAMPLES
+--------
+
+* Reconfigure dax0.0 to system-ram mode, don't online the memory
+----
+# daxctl reconfigure-device --mode=system-ram --no-online dax0.0
+[
+  {
+    "chardev":"dax0.0",
+    "size":16777216000,
+    "numa_node":2,
+    "mode":"system-ram"
+  }
+]
+----
+
+* Reconfigure dax0.0 to devdax mode, attempt to offline the memory
+----
+# daxctl reconfigure-device --human --mode=devdax --attempt-offline dax0.0
+{
+  "chardev":"dax0.0",
+  "size":"15.63 GiB (16.78 GB)",
+  "numa_node":2,
+  "mode":"devdax"
+}
+----
+
+* Reconfigure all dax devices on region0 to system-ram mode
+----
+# daxctl reconfigure-device --mode=system-ram --region=0 all
+[
+  {
+    "chardev":"dax0.0",
+    "size":16777216000,
+    "numa_node":2,
+    "mode":"system-ram"
+  },
+  {
+    "chardev":"dax0.1",
+    "size":16777216000,
+    "numa_node":3,
+    "mode":"system-ram"
+  }
+]
+----
+
+DESCRIPTION
+-----------
+
+Reconfigure the operational mode of a dax device. This can be used to convert
+a regular 'devdax' mode device to the 'system-ram' mode which allows for the dax
+range to be hot-plugged into the system as regular memory.
+
+NOTE: This is a destructive operation. Any data on the dax device *will* be
+lost.
+
+OPTIONS
+-------
+-r::
+--region=::
+	Restrict the reconfigure operation to devices belonging to the
+	specified region(s). A device-dax region is a contiguous range of
+	memory that hosts one or more /dev/daxX.Y devices, where X is the
+	region id and Y is the device instance id.
+
+-m::
+--mode=::
+	Specify the mode to which the dax device(s) should be reconfigured.
+	- "system-ram": hotplug the device into system memory.
+
+	- "devdax": switch to the normal "device dax" mode. This may not work
+	  on kernels prior to v5.2. In such a case, a reboot is the only way to
+	  switch back to 'devdax' mode.
+
+-N::
+--no-online::
+	By default, memory sections provided by system-ram devices will be
+	brought online automatically and immediately. Use this option to
+	disable the automatic onlining behavior.
+
+-O::
+--attempt-offline::
+	When converting from "system-ram" mode to "devdax", it is expected
+	that all the memory sections are first made offline. By default,
+	daxctl won't touch online memory. However with this option, attempt
+	to offline the memory on the NUMA node associated with the dax device
+	before converting it back to "devdax" mode.
+
+-u::
+--human::
+	By default the command will output machine-friendly raw-integer
+	data. Instead, with this flag, numbers representing storage size
+	will be formatted as human readable strings with units, other
+	fields are converted to hexadecimal strings.
+
+-v::
+--verbose::
+	Emit more debug messages for the reconfiguration process
+
+include::../copyright.txt[]
+
+SEE ALSO
+--------
+linkdaxctl:daxctl-list[1]
-- 
2.20.1

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[ndctl PATCH v3 09/10] contrib/ndctl: fix region-id completions for daxctl

[Vishal Verma]

The completion helpers for daxctl assumed the region arguments for
specifying daxctl regions were the same as ndctl regions, i.e.
"regionX". This is not true - daxctl region arguments are a simple
numeric 'id'.

Add a new helper __daxctl_get_regions() to complete daxctl region IDs
properly.

While at it, fix a useless use of 'echo' in __daxctl_get_devs() and
quoting in __daxctl_comp_options()

Fixes: d6790a32f32c ("daxctl: Add bash-completion")
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 contrib/ndctl | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/contrib/ndctl b/contrib/ndctl
index 396a344..cacee2d 100755
--- a/contrib/ndctl
+++ b/contrib/ndctl
@@ -531,8 +531,14 @@ _ndctl()
 
 __daxctl_get_devs()
 {
-	local opts="--devices $*"
-	echo "$(daxctl list $opts | grep -E "^\s*\"chardev\":" | cut -d\" -f4)"
+	local opts=("--devices" "$*")
+	daxctl list "${opts[@]}" | grep -E "^\s*\"chardev\":" | cut -d'"' -f4
+}
+
+__daxctl_get_regions()
+{
+	local opts=("--regions" "$*")
+	daxctl list "${opts[@]}" | grep -E "^\s*\"id\":" | grep -Eo "[0-9]+"
 }
 
 __daxctlcomp()
@@ -561,10 +567,10 @@ __daxctl_comp_options()
 		local cur_arg=${cur##*=}
 		case $cur_subopt in
 		--region)
-			opts=$(__ndctl_get_regions -i)
+			opts="$(__daxctl_get_regions -i)"
 			;;
 		--dev)
-			opts=$(__daxctl_get_devs -i)
+			opts="$(__daxctl_get_devs -i)"
 			;;
 		*)
 			return
-- 
2.20.1

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[ndctl PATCH v3 10/10] contrib/ndctl: add bash-completion for daxctl-reconfigure-device

[Vishal Verma]

Add bash completion helpers for the new daxctl-reconfigure-device
command.

Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 contrib/ndctl | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/contrib/ndctl b/contrib/ndctl
index cacee2d..1850343 100755
--- a/contrib/ndctl
+++ b/contrib/ndctl
@@ -547,7 +547,7 @@ __daxctlcomp()
 
 	COMPREPLY=( $( compgen -W "$1" -- "$2" ) )
 	for cword in "${COMPREPLY[@]}"; do
-		if [[ "$cword" == @(--region|--dev) ]]; then
+		if [[ "$cword" == @(--region|--dev|--mode) ]]; then
 			COMPREPLY[$i]="${cword}="
 		else
 			COMPREPLY[$i]="${cword} "
@@ -572,6 +572,9 @@ __daxctl_comp_options()
 		--dev)
 			opts="$(__daxctl_get_devs -i)"
 			;;
+		--mode)
+			opts="system-ram devdax"
+			;;
 		*)
 			return
 			;;
@@ -582,8 +585,19 @@ __daxctl_comp_options()
 
 __daxctl_comp_non_option_args()
 {
-	# there aren't any commands that accept non option arguments yet
-	return
+	local subcmd=$1
+	local cur=$2
+	local opts
+
+	case $subcmd in
+	reconfigure-device)
+		opts="$(__daxctl_get_devs -i) all"
+		;;
+	*)
+		return
+		;;
+	esac
+	__daxctlcomp "$opts" "$cur"
 }
 
 __daxctl_main()
-- 
2.20.1

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Re: [ndctl PATCH v3 00/10] daxctl: add a new reconfigure-device command

[Pavel Tatashin]

On Thu, May 16, 2019 at 6:40 PM Vishal Verma <vishal.l.verma@intel.com> wrote:
>
> Changes in v3:
>  - In daxctl_dev_get_mode(), remove the subsystem warning, detect dax-class
>    and simply make it return devdax

Hi Vishal,

I am still getting the same error as before:

# ndctl create-namespace --mode devdax --map mem -e namespace0.0 -f
[  141.525873] dax0.0 initialised, 524288 pages in 7ms
libdaxctl: __sysfs_device_parse: dax0.0: add_dev() failed
...

I am building it via buildroot, and can share the initramfs file or
anything that can help you with fixing this issue.

Thank you,
Pavel
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Re: [ndctl PATCH v3 00/10] daxctl: add a new reconfigure-device command

[Verma, Vishal L]

On Fri, 2019-05-17 at 11:30 -0400, Pavel Tatashin wrote:
> On Thu, May 16, 2019 at 6:40 PM Vishal Verma <vishal.l.verma@intel.com
> > wrote:
> > Changes in v3:
> >  - In daxctl_dev_get_mode(), remove the subsystem warning, detect
> > dax-class
> >    and simply make it return devdax
> 
> Hi Vishal,
> 
> I am still getting the same error as before:
> 
> # ndctl create-namespace --mode devdax --map mem -e namespace0.0 -f
> [  141.525873] dax0.0 initialised, 524288 pages in 7ms
> libdaxctl: __sysfs_device_parse: dax0.0: add_dev() failed
> ...
> 
> I am building it via buildroot, and can share the initramfs file or
> anything that can help you with fixing this issue.

Hi Pavel,

I've still not been able to hit this in my testing, is it something you
hit only after applying these patches? i.e. does plain v65 work?
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Re: [ndctl PATCH v3 00/10] daxctl: add a new reconfigure-device command

[Pavel Tatashin]

> Hi Pavel,
>
> I've still not been able to hit this in my testing, is it something you
> hit only after applying these patches? i.e. does plain v65 work?

Yes, plain v65 works, but with these patches I see this error.

I use buildroot to build initramfs with ndctl. Here is how ndctl.mk looks like:

NDCTL_VERSION = ed17fd1
NDCTL_SITE = $(call github,pmem,ndctl,$(NDCTL_VERSION))
NDCTL_LICENSE = GNU Lesser General Public License v2.1
NDCTL_LICENSE_FILES = COPYING

#NDCTL_AUTORECv65ONF = YES
define NDCTL_RUN_AUTOGEN
        cd $(@D) && PATH=$(BR_PATH) ./autogen.sh
endef
NDCTL_PRE_CONFIGURE_HOOKS += NDCTL_RUN_AUTOGEN
NDCTL_LDFLAGS = $(TARGET_LDFLAGS)
NDCTL_CONF_OPTS = \
        --without-bash \
        --without-keyutils \
        --without-systemd

$(eval $(autotools-package))

This version works,  but when I change:
NDCTL_VERSION = 9ee82c8

I get add_dev error.

Pasha
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Re: [ndctl PATCH v3 00/10] daxctl: add a new reconfigure-device command

[Verma, Vishal L]

On Fri, 2019-05-17 at 13:41 -0400, Pavel Tatashin wrote:
> > Hi Pavel,
> > 
> > I've still not been able to hit this in my testing, is it something
> > you
> > hit only after applying these patches? i.e. does plain v65 work?
> 
> Yes, plain v65 works, but with these patches I see this error.
> 
Hm, So there are only two patches that touch the add_dax_dev function:

  2bf9a8e libdaxctl: add interfaces to enable/disable devices
  25be8f4 libdaxctl: add interfaces to get/set the online state for a node

And of these, the second one to get the target node doesn't return an
error in any case.

The first one can fail, so it must be that condition you're hitting, but
I'm not sure in what way it is failing.

The exact check is:

	sprintf(path, "%s/modalias", daxdev_base);
	rc = sysfs_read_attr(ctx, path, buf);
	/* older kernels may be lack the modalias attribute */
	if (rc < 0 && rc != -ENOENT)
		goto err_read;
	if (rc == 0) {
		dev->kmod_list = to_module_list(ctx, buf);
		if (dev->kmod_list == NULL)
			goto err_read;
	} else
		dbg(ctx, "%s: modalias attribute missing\n", devname);

Do you have the file:

  /sys/bus/dax/devices/dax0.0/modalias

And what does it contain? On my system:

  $ cat /sys/bus/dax/devices/dax0.0/modalias 
  dax:t0

If this is missing, it would seem you're not correctly in 'dax-bus'
mode, but that is kind of required for the kmem functionality anyway, so
I'm not sure where we might be tripping.
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Re: [ndctl PATCH v3 00/10] daxctl: add a new reconfigure-device command

[Verma, Vishal L]

On Mon, 2019-05-20 at 23:34 +0000, Verma, Vishal L wrote:
> On Fri, 2019-05-17 at 13:41 -0400, Pavel Tatashin wrote:
> > > Hi Pavel,
> > > 
> > > I've still not been able to hit this in my testing, is it
something
> > > you
> > > hit only after applying these patches? i.e. does plain v65 work?
> > 
> > Yes, plain v65 works, but with these patches I see this error.
> > 
> Hm, So there are only two patches that touch the add_dax_dev function:
> 
>   2bf9a8e libdaxctl: add interfaces to enable/disable devices
>   25be8f4 libdaxctl: add interfaces to get/set the online state for a
node
> 
> And of these, the second one to get the target node doesn't return an
> error in any case.
> 
> The first one can fail, so it must be that condition you're hitting,
but
> I'm not sure in what way it is failing.
> 
> The exact check is:
> 
> 	sprintf(path, "%s/modalias", daxdev_base);
> 	rc = sysfs_read_attr(ctx, path, buf);
> 	/* older kernels may be lack the modalias attribute */
> 	if (rc < 0 && rc != -ENOENT)
> 		goto err_read;
> 	if (rc == 0) {
> 		dev->kmod_list = to_module_list(ctx, buf);
> 		if (dev->kmod_list == NULL)
> 			goto err_read;

Dan points out that it might actually be the kmod portion that might be
failing. Is libkmod present in the buildroot setup, and has a depmod run
completed successfully before this point?

In any case, this incremental patch should /at least/ delay the error
until you actually try to enable a kmem device. I'll fold this into the
next version of the series.

8<----


>From 2df9b6401a69833fa709ab1ad83ac27b545aeb9e Mon Sep 17 00:00:00 2001
From: Vishal Verma <vishal.l.verma@intel.com>
Date: Wed, 22 May 2019 12:01:28 -0600
Subject: [ndctl PATCH] fixup! libdaxctl: add interfaces to
enable/disable
 devices

---
 daxctl/lib/libdaxctl.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
index 5c85328..9d23d12 100644
--- a/daxctl/lib/libdaxctl.c
+++ b/daxctl/lib/libdaxctl.c
@@ -393,12 +393,8 @@ static void *add_dax_dev(void *parent, int id,
const char *daxdev_base)
 	/* older kernels may be lack the modalias attribute */
 	if (rc < 0 && rc != -ENOENT)
 		goto err_read;
-	if (rc == 0) {
+	if (rc == 0)
 		dev->kmod_list = to_module_list(ctx, buf);
-		if (dev->kmod_list == NULL)
-			goto err_read;
-	} else
-		dbg(ctx, "%s: modalias attribute missing\n", devname);
 
 	sprintf(path, "%s/target_node", daxdev_base);
 	if (sysfs_read_attr(ctx, path, buf) == 0)
-- 
2.20.1


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