[ndctl PATCH v8 07/13] daxctl: add a new reconfigure-device command

[Vishal Verma <vishal.l.verma@intel.com>]

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    | 503 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 507 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..2629804
--- /dev/null
+++ b/daxctl/device.c
@@ -0,0 +1,503 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2019 Intel Corporation. All rights reserved. */
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <unistd.h>
+#include <limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/sysmacros.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 force;
+	bool human;
+	bool verbose;
+} param = {
+	.region_id = -1,
+};
+
+enum dev_mode {
+	DAXCTL_DEV_MODE_UNKNOWN,
+	DAXCTL_DEV_MODE_DEVDAX,
+	DAXCTL_DEV_MODE_RAM,
+};
+
+static enum dev_mode reconfig_mode = DAXCTL_DEV_MODE_UNKNOWN;
+static unsigned long flags;
+
+enum device_action {
+	ACTION_RECONFIG,
+};
+
+#define BASE_OPTIONS() \
+OPT_INTEGER('r', "region", &param.region_id, "restrict to the given region"), \
+OPT_BOOLEAN('u', "human", &param.human, "use human friendly number formats"), \
+OPT_BOOLEAN('v', "verbose", &param.verbose, "emit more debug messages")
+
+#define RECONFIG_OPTIONS() \
+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('f', "force", &param.force, \
+		"attempt to offline memory sections before reconfiguration")
+
+static const struct option reconfig_options[] = {
+	BASE_OPTIONS(),
+	RECONFIG_OPTIONS(),
+	OPT_END(),
+};
+
+static const char *parse_device_options(int argc, const char **argv,
+		enum device_action action, const struct option *options,
+		const char *usage, struct daxctl_ctx *ctx)
+{
+	const char * const u[] = {
+		usage,
+		NULL
+	};
+	int i, rc = 0;
+
+	argc = parse_options(argc, argv, options, u, 0);
+
+	/* Handle action-agnostic non-option arguments */
+	if (argc == 0) {
+		char *action_string;
+
+		switch (action) {
+		case ACTION_RECONFIG:
+			action_string = "reconfigure";
+			break;
+		default:
+			action_string = "<>";
+			break;
+		}
+		fprintf(stderr, "specify a device to %s, or \"all\"\n",
+			action_string);
+		rc = -EINVAL;
+	}
+	for (i = 1; i < argc; i++) {
+		fprintf(stderr, "unknown extra parameter \"%s\"\n", argv[i]);
+		rc = -EINVAL;
+	}
+
+	if (rc) {
+		usage_with_options(u, options);
+		return NULL;
+	}
+
+	/* Handle action-agnostic options */
+	if (param.verbose)
+		daxctl_set_log_priority(ctx, LOG_DEBUG);
+	if (param.human)
+		flags |= UTIL_JSON_HUMAN;
+
+	/* Handle action-specific options */
+	switch (action) {
+	case ACTION_RECONFIG:
+		if (!param.mode) {
+			fprintf(stderr, "error: a 'mode' option is required\n");
+			usage_with_options(u, reconfig_options);
+			rc = -EINVAL;
+		}
+		if (strcmp(param.mode, "system-ram") == 0) {
+			reconfig_mode = DAXCTL_DEV_MODE_RAM;
+		} else if (strcmp(param.mode, "devdax") == 0) {
+			reconfig_mode = DAXCTL_DEV_MODE_DEVDAX;
+			if (param.no_online) {
+				fprintf(stderr,
+					"--no-online is incompatible with --mode=devdax\n");
+				rc =  -EINVAL;
+			}
+		}
+		break;
+	}
+	if (rc) {
+		usage_with_options(u, options);
+		return NULL;
+	}
+
+	return argv[0];
+}
+
+static int dev_online_memory(struct daxctl_dev *dev)
+{
+	struct daxctl_memory *mem = daxctl_dev_get_memory(dev);
+	const char *devname = daxctl_dev_get_devname(dev);
+	int num_sections, num_on, rc;
+
+	if (!mem) {
+		fprintf(stderr, "%s: failed to get the memory object\n",
+			devname);
+		return -ENXIO;
+	}
+
+	/* get total number of sections and sections already online */
+	num_sections = daxctl_memory_num_sections(mem);
+	if (num_sections < 0) {
+		fprintf(stderr, "%s: failed to get number of memory sections\n",
+			devname);
+		return num_sections;
+	}
+
+	num_on = daxctl_memory_is_online(mem);
+	if (num_on < 0) {
+		fprintf(stderr, "%s: failed to determine online state: %s\n",
+			devname, strerror(-num_on));
+		return num_on;
+	}
+	if (num_on == num_sections) {
+		fprintf(stderr, "%s: all memory sections (%d) already online\n",
+			devname, num_on);
+		return 1;
+	}
+	if (num_on > 0)
+		fprintf(stderr, "%s: %d memory section%s already online\n",
+			devname, num_on,
+			num_on == 1 ? "" : "s");
+
+	/* online the remaining sections */
+	rc = daxctl_memory_online(mem);
+	if (rc < 0) {
+		fprintf(stderr, "%s: failed to online memory: %s\n",
+			devname, strerror(-rc));
+		return rc;
+	}
+	if (param.verbose)
+		fprintf(stderr, "%s: %d memory section%s onlined\n", devname, rc,
+			rc == 1 ? "" : "s");
+
+	/* all sections should now be online */
+	num_on = daxctl_memory_is_online(mem);
+	if (num_on < 0) {
+		fprintf(stderr, "%s: failed to determine online state: %s\n",
+			devname, strerror(-num_on));
+		return num_on;
+	}
+	if (num_on < num_sections) {
+		fprintf(stderr, "%s: failed to online %d memory sections\n",
+			devname, num_sections - num_on);
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static int dev_offline_memory(struct daxctl_dev *dev)
+{
+	struct daxctl_memory *mem = daxctl_dev_get_memory(dev);
+	const char *devname = daxctl_dev_get_devname(dev);
+	int num_sections, num_on, num_off, rc;
+
+	if (!mem) {
+		fprintf(stderr, "%s: failed to get the memory object\n",
+			devname);
+		return -ENXIO;
+	}
+
+	/* get total number of sections and sections already offline */
+	num_sections = daxctl_memory_num_sections(mem);
+	if (num_sections < 0) {
+		fprintf(stderr, "%s: failed to get number of memory sections\n",
+			devname);
+		return num_sections;
+	}
+
+	num_on = daxctl_memory_is_online(mem);
+	if (num_on < 0) {
+		fprintf(stderr, "%s: failed to determine online state: %s\n",
+			devname, strerror(-num_on));
+		return num_on;
+	}
+
+	num_off = num_sections - num_on;
+	if (num_off == num_sections) {
+		fprintf(stderr, "%s: all memory sections (%d) already offline\n",
+			devname, num_off);
+		return 1;
+	}
+	if (num_off)
+		fprintf(stderr, "%s: %d memory section%s already offline\n",
+			devname, num_off,
+			num_off == 1 ? "" : "s");
+
+	/* offline the remaining sections */
+	rc = daxctl_memory_offline(mem);
+	if (rc < 0) {
+		fprintf(stderr, "%s: failed to offline memory: %s\n",
+			devname, strerror(-rc));
+		return rc;
+	}
+	if (param.verbose)
+		fprintf(stderr, "%s: %d memory section%s offlined\n", devname, rc,
+			rc == 1 ? "" : "s");
+
+	/* all sections should now be ofline */
+	num_on = daxctl_memory_is_online(mem);
+	if (num_on < 0) {
+		fprintf(stderr, "%s: failed to determine online state: %s\n",
+			devname, strerror(-num_on));
+		return num_on;
+	}
+	if (num_on) {
+		fprintf(stderr, "%s: failed to offline %d memory sections\n",
+			devname, num_on);
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static int disable_devdax_device(struct daxctl_dev *dev)
+{
+	struct daxctl_memory *mem = daxctl_dev_get_memory(dev);
+	const char *devname = daxctl_dev_get_devname(dev);
+	int rc;
+
+	if (mem) {
+		fprintf(stderr, "%s was already in system-ram mode\n",
+			devname);
+		return 1;
+	}
+	rc = daxctl_dev_disable(dev);
+	if (rc) {
+		fprintf(stderr, "%s: disable failed: %s\n",
+			daxctl_dev_get_devname(dev), strerror(-rc));
+		return rc;
+	}
+	return 0;
+}
+
+static int reconfig_mode_system_ram(struct daxctl_dev *dev)
+{
+	int rc, skip_enable = 0;
+
+	if (daxctl_dev_is_enabled(dev)) {
+		rc = disable_devdax_device(dev);
+		if (rc < 0)
+			return rc;
+		if (rc > 0)
+			skip_enable = 1;
+	}
+
+	if (!skip_enable) {
+		rc = daxctl_dev_enable_ram(dev);
+		if (rc)
+			return rc;
+	}
+
+	if (param.no_online)
+		return 0;
+
+	return dev_online_memory(dev);
+}
+
+static int disable_system_ram_device(struct daxctl_dev *dev)
+{
+	struct daxctl_memory *mem = daxctl_dev_get_memory(dev);
+	const char *devname = daxctl_dev_get_devname(dev);
+	int rc;
+
+	if (!mem) {
+		fprintf(stderr, "%s was already in devdax mode\n", devname);
+		return 1;
+	}
+
+	if (param.force) {
+		rc = dev_offline_memory(dev);
+		if (rc < 0)
+			return rc;
+	}
+
+	rc = daxctl_memory_is_online(mem);
+	if (rc < 0) {
+		fprintf(stderr, "%s: failed to determine online 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 = daxctl_dev_disable(dev);
+	if (rc) {
+		fprintf(stderr, "%s: disable failed: %s\n",
+			daxctl_dev_get_devname(dev), strerror(-rc));
+		return rc;
+	}
+	return 0;
+}
+
+static int reconfig_mode_devdax(struct daxctl_dev *dev)
+{
+	int rc;
+
+	if (daxctl_dev_is_enabled(dev)) {
+		rc = disable_system_ram_device(dev);
+		if (rc)
+			return rc;
+	}
+
+	rc = daxctl_dev_enable_devdax(dev);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+static int verify_dax_bus_model(struct daxctl_dev *dev)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	char *dev_path, *subsys_path, *resolved;
+	struct stat sb;
+	int rc;
+
+	if (asprintf(&dev_path, "/dev/%s", devname) < 0)
+		return -ENOMEM;
+
+	rc = lstat(dev_path, &sb);
+	if (rc < 0) {
+		rc = -errno;
+		fprintf(stderr, "%s: stat for %s failed: %s\n",
+			devname, dev_path, strerror(-rc));
+		goto out_dev;;
+	}
+
+	if (asprintf(&subsys_path, "/sys/dev/char/%d:%d/subsystem",
+			major(sb.st_rdev), minor(sb.st_rdev)) < 0) {
+		rc = -ENOMEM;
+		goto out_dev;
+	}
+
+	resolved = realpath(subsys_path, NULL);
+	if (!resolved) {
+		rc = -errno;
+		fprintf(stderr, "%s:  unable to determine subsys: %s\n",
+			devname, strerror(errno));
+		goto out_subsys;
+	}
+
+	if (strcmp(resolved, "/sys/bus/dax") == 0)
+		rc = 0;
+	else
+		rc = -ENXIO;
+
+	free(resolved);
+out_subsys:
+	free(subsys_path);
+out_dev:
+	free(dev_path);
+	return rc;
+}
+
+static int do_reconfig(struct daxctl_dev *dev, enum dev_mode mode,
+		struct json_object **jdevs)
+{
+	const char *devname = daxctl_dev_get_devname(dev);
+	struct json_object *jdev;
+	int rc = 0;
+
+	if (verify_dax_bus_model(dev) != 0) {
+		fprintf(stderr, "%s: dax-class device model unsupported\n",
+			devname);
+		return -ENXIO;
+	}
+
+	switch (mode) {
+	case DAXCTL_DEV_MODE_RAM:
+		rc = reconfig_mode_system_ram(dev);
+		break;
+	case DAXCTL_DEV_MODE_DEVDAX:
+		rc = reconfig_mode_devdax(dev);
+		break;
+	default:
+		fprintf(stderr, "%s: unknown mode requested: %d\n",
+			devname, mode);
+		rc = -EINVAL;
+	}
+
+	*jdevs = json_object_new_array();
+	if (*jdevs) {
+		jdev = util_daxctl_dev_to_json(dev, flags);
+		if (jdev)
+			json_object_array_add(*jdevs, jdev);
+	}
+
+	return rc;
+}
+
+static int do_xaction_device(const char *device, enum device_action action,
+		struct daxctl_ctx *ctx, int *processed)
+{
+	struct json_object *jdevs = NULL;
+	struct daxctl_region *region;
+	struct daxctl_dev *dev;
+	int rc = -ENXIO;
+
+	*processed = 0;
+
+	daxctl_region_foreach(ctx, region) {
+		if (param.region_id >= 0 && param.region_id
+				!= daxctl_region_get_id(region))
+			continue;
+
+		daxctl_dev_foreach(region, dev) {
+			if (!util_daxctl_dev_filter(dev, device))
+				continue;
+
+			switch (action) {
+			case ACTION_RECONFIG:
+				rc = do_reconfig(dev, reconfig_mode, &jdevs);
+				if (rc == 0)
+					(*processed)++;
+				break;
+			default:
+				rc = -EINVAL;
+				break;
+			}
+		}
+	}
+
+	/*
+	 * jdevs is the containing json array for all devices we are reporting
+	 * on. It therefore needs to be outside the region/device iterators,
+	 * and passed in to the do_<action> functions to add their objects to
+	 */
+	if (jdevs)
+		util_display_json_array(stdout, jdevs, flags);
+
+	return rc;
+}
+
+int cmd_reconfig_device(int argc, const char **argv, struct daxctl_ctx *ctx)
+{
+	char *usage = "daxctl reconfigure-device <device> [<options>]";
+	const char *device = parse_device_options(argc, argv, ACTION_RECONFIG,
+			reconfig_options, usage, ctx);
+	int processed, rc;
+
+	rc = do_xaction_device(device, ACTION_RECONFIG, ctx, &processed);
+	if (rc < 0)
+		fprintf(stderr, "error reconfiguring devices: %s\n",
+				strerror(-rc));
+
+	fprintf(stderr, "reconfigured %d device%s\n", processed,
+			processed == 1 ? "" : "s");
+	return rc;
+}
-- 
2.20.1

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