[PATCH 13/21] nd: add interleave-set state-tracking infrastructure

From: Dan Williams
Date: Fri Apr 17 2015 - 21:39:22 EST

On platforms that have firmware support for reading/writing per-dimm
label space, a portion of the dimm may be accessible via an interleave
set PMEM mapping in addition to the dimm's BLK (block-data-window
aperture(s)) interface. A label, stored in a "configuration data
region" on the dimm, disambiguates which dimm addresses are accessed
through which exclusive interface.

Add infrastructure that allows the kernel to block modifications to a
label in the set while any member dimm is active. Note that this is
meant only for enforcing "no modifications of active labels" via the
coarse ioctl command. Adding/deleting namespaces from an active
interleave set will only be possible via sysfs.

Another aspect of tracking interleave sets is tracking their integrity
when DIMMs in a set are physically re-ordered. For this purpose we
generate an "interleave-set cookie" that can be recorded in a label and
validated against the current configuration.

Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/block/nd/bus.c | 41 +++++++++
drivers/block/nd/core.c | 51 ++++++++++++
drivers/block/nd/dimm_devs.c | 18 ++++
drivers/block/nd/nd-private.h | 17 ++++
drivers/block/nd/nd.h | 4 +
drivers/block/nd/region_devs.c | 176 ++++++++++++++++++++++++++++++++++++++++
6 files changed, 305 insertions(+), 2 deletions(-)

diff --git a/drivers/block/nd/bus.c b/drivers/block/nd/bus.c
index c98fe05a4c9b..944d7d7845fe 100644
--- a/drivers/block/nd/bus.c
+++ b/drivers/block/nd/bus.c
@@ -79,7 +79,10 @@ static int nd_bus_probe(struct device *dev)
if (!try_module_get(provider))
return -ENXIO;

+ nd_region_probe_start(nd_bus, dev);
rc = nd_drv->probe(dev);
+ nd_region_probe_end(nd_bus, dev, rc);
+
dev_dbg(&nd_bus->dev, "%s.probe(%s) = %d\n", dev->driver->name,
dev_name(dev), rc);
if (rc != 0)
@@ -95,6 +98,8 @@ static int nd_bus_remove(struct device *dev)
int rc;

rc = nd_drv->remove(dev);
+ nd_region_notify_remove(nd_bus, dev, rc);
+
dev_dbg(&nd_bus->dev, "%s.remove(%s) = %d\n", dev->driver->name,
dev_name(dev), rc);
module_put(provider);
@@ -269,6 +274,33 @@ void nd_bus_destroy_ndctl(struct nd_bus *nd_bus)
device_destroy(nd_class, MKDEV(nd_bus_major, nd_bus->id));
}

+static void wait_nd_bus_probe_idle(struct nd_bus *nd_bus)
+{
+ do {
+ if (nd_bus->probe_active == 0)
+ break;
+ nd_bus_unlock(&nd_bus->dev);
+ wait_event(nd_bus->probe_wait, nd_bus->probe_active == 0);
+ nd_bus_lock(&nd_bus->dev);
+ } while (true);
+}
+
+/* set_config requires an idle interleave set */
+static int nd_cmd_clear_to_send(struct nd_dimm *nd_dimm, unsigned int cmd)
+{
+ struct nd_bus *nd_bus;
+
+ if (!nd_dimm || cmd != NFIT_CMD_SET_CONFIG_DATA)
+ return 0;
+
+ nd_bus = walk_to_nd_bus(&nd_dimm->dev);
+ wait_nd_bus_probe_idle(nd_bus);
+
+ if (atomic_read(&nd_dimm->busy))
+ return -EBUSY;
+ return 0;
+}
+
static int __nd_ioctl(struct nd_bus *nd_bus, struct nd_dimm *nd_dimm,
int read_only, unsigned int cmd, unsigned long arg)
{
@@ -399,11 +431,18 @@ static int __nd_ioctl(struct nd_bus *nd_bus, struct nd_dimm *nd_dimm,
goto out;
}

+ nd_bus_lock(&nd_bus->dev);
+ rc = nd_cmd_clear_to_send(nd_dimm, _IOC_NR(cmd));
+ if (rc)
+ goto out_unlock;
+
rc = nfit_desc->nfit_ctl(nfit_desc, nd_dimm, _IOC_NR(cmd), buf, buf_len);
if (rc < 0)
- goto out;
+ goto out_unlock;
if (copy_to_user(p, buf, buf_len))
rc = -EFAULT;
+ out_unlock:
+ nd_bus_unlock(&nd_bus->dev);
out:
if (is_vmalloc_addr(buf))
vfree(buf);
diff --git a/drivers/block/nd/core.c b/drivers/block/nd/core.c
index c795e8057061..976cd5e3ebaf 100644
--- a/drivers/block/nd/core.c
+++ b/drivers/block/nd/core.c
@@ -31,6 +31,36 @@ static bool warn_checksum;
module_param(warn_checksum, bool, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(warn_checksum, "Turn checksum errors into warnings");

+void nd_bus_lock(struct device *dev)
+{
+ struct nd_bus *nd_bus = walk_to_nd_bus(dev);
+
+ if (!nd_bus)
+ return;
+ mutex_lock(&nd_bus->reconfig_mutex);
+}
+EXPORT_SYMBOL(nd_bus_lock);
+
+void nd_bus_unlock(struct device *dev)
+{
+ struct nd_bus *nd_bus = walk_to_nd_bus(dev);
+
+ if (!nd_bus)
+ return;
+ mutex_unlock(&nd_bus->reconfig_mutex);
+}
+EXPORT_SYMBOL(nd_bus_unlock);
+
+bool is_nd_bus_locked(struct device *dev)
+{
+ struct nd_bus *nd_bus = walk_to_nd_bus(dev);
+
+ if (!nd_bus)
+ return false;
+ return mutex_is_locked(&nd_bus->reconfig_mutex);
+}
+EXPORT_SYMBOL(is_nd_bus_locked);
+
/**
* nd_dimm_by_handle - lookup an nd_dimm by its corresponding nfit_handle
* @nd_bus: parent bus of the dimm
@@ -49,6 +79,20 @@ struct nd_dimm *nd_dimm_by_handle(struct nd_bus *nd_bus, u32 nfit_handle)
return nd_dimm;
}

+u64 nd_fletcher64(void __iomem *addr, size_t len)
+{
+ u32 lo32 = 0;
+ u64 hi32 = 0;
+ int i;
+
+ for (i = 0; i < len; i += 4) {
+ lo32 = readl(addr + i);
+ hi32 += lo32;
+ }
+
+ return hi32 << 32 | lo32;
+}
+
static void nd_bus_release(struct device *dev)
{
struct nd_bus *nd_bus = container_of(dev, struct nd_bus, dev);
@@ -60,6 +104,7 @@ static void nd_bus_release(struct device *dev)

list_for_each_entry_safe(nd_spa, _spa, &nd_bus->spas, list) {
list_del_init(&nd_spa->list);
+ kfree(nd_spa->nd_set);
kfree(nd_spa);
}
list_for_each_entry_safe(nd_dcr, _dcr, &nd_bus->dcrs, list) {
@@ -205,8 +250,10 @@ static void *nd_bus_new(struct device *parent,
INIT_LIST_HEAD(&nd_bus->memdevs);
INIT_LIST_HEAD(&nd_bus->dimms);
INIT_LIST_HEAD(&nd_bus->list);
+ init_waitqueue_head(&nd_bus->probe_wait);
INIT_RADIX_TREE(&nd_bus->dimm_radix, GFP_KERNEL);
nd_bus->id = ida_simple_get(&nd_ida, 0, 0, GFP_KERNEL);
+ mutex_init(&nd_bus->reconfig_mutex);
if (nd_bus->id < 0) {
kfree(nd_bus);
return NULL;
@@ -570,6 +617,10 @@ static struct nd_bus *nd_bus_probe(struct nd_bus *nd_bus)
if (rc)
goto err;

+ rc = nd_bus_init_interleave_sets(nd_bus);
+ if (rc)
+ goto err;
+
rc = nd_bus_create_ndctl(nd_bus);
if (rc)
goto err;
diff --git a/drivers/block/nd/dimm_devs.c b/drivers/block/nd/dimm_devs.c
index d15ca75804ac..6192d9c82b9b 100644
--- a/drivers/block/nd/dimm_devs.c
+++ b/drivers/block/nd/dimm_devs.c
@@ -287,6 +287,22 @@ static ssize_t commands_show(struct device *dev,
}
static DEVICE_ATTR_RO(commands);

+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct nd_dimm *nd_dimm = to_nd_dimm(dev);
+
+ /*
+ * The state may be in the process of changing, userspace should
+ * quiesce probing if it wants a static answer
+ */
+ nd_bus_lock(dev);
+ nd_bus_unlock(dev);
+ return sprintf(buf, "%s\n", atomic_read(&nd_dimm->busy)
+ ? "active" : "idle");
+}
+static DEVICE_ATTR_RO(state);
+
static struct attribute *nd_dimm_attributes[] = {
&dev_attr_handle.attr,
&dev_attr_phys_id.attr,
@@ -294,6 +310,7 @@ static struct attribute *nd_dimm_attributes[] = {
&dev_attr_device.attr,
&dev_attr_format.attr,
&dev_attr_serial.attr,
+ &dev_attr_state.attr,
&dev_attr_revision.attr,
&dev_attr_commands.attr,
NULL,
@@ -364,6 +381,7 @@ static struct nd_dimm *nd_dimm_create(struct nd_bus *nd_bus,
if (nd_dimm->id < 0)
goto err_ida;

+ atomic_set(&nd_dimm->busy, 0);
nd_dimm->nd_mem = nd_mem;
dev = &nd_dimm->dev;
dev_set_name(dev, "nmem%d", nd_dimm->id);
diff --git a/drivers/block/nd/nd-private.h b/drivers/block/nd/nd-private.h
index db68e013b9d0..15ca7be507ce 100644
--- a/drivers/block/nd/nd-private.h
+++ b/drivers/block/nd/nd-private.h
@@ -15,6 +15,9 @@
#include <linux/radix-tree.h>
#include <linux/device.h>
#include <linux/sizes.h>
+#include <linux/mutex.h>
+#include <linux/io.h>
+#include "nfit.h"

extern struct list_head nd_bus_list;
extern struct mutex nd_bus_list_mutex;
@@ -33,6 +36,7 @@ enum {
struct nd_bus {
struct nfit_bus_descriptor *nfit_desc;
struct radix_tree_root dimm_radix;
+ wait_queue_head_t probe_wait;
struct module *module;
struct list_head memdevs;
struct list_head dimms;
@@ -41,7 +45,8 @@ struct nd_bus {
struct list_head bdws;
struct list_head list;
struct device dev;
- int id;
+ int id, probe_active;
+ struct mutex reconfig_mutex;
};

struct nd_dimm {
@@ -50,14 +55,20 @@ struct nd_dimm {
struct device dev;
void *provider_data;
int id, nfit_status;
+ atomic_t busy;
struct nd_dimm_delete {
struct nd_bus *nd_bus;
struct nd_mem *nd_mem;
} *del_info;
};

+struct nd_interleave_set {
+ u64 cookie;
+};
+
struct nd_spa {
struct nfit_spa __iomem *nfit_spa;
+ struct nd_interleave_set *nd_set;
struct list_head list;
};

@@ -103,9 +114,13 @@ int __init nd_dimm_init(void);
int __init nd_region_init(void);
void nd_dimm_exit(void);
int nd_region_exit(void);
+void nd_region_probe_start(struct nd_bus *nd_bus, struct device *dev);
+void nd_region_probe_end(struct nd_bus *nd_bus, struct device *dev, int rc);
+void nd_region_notify_remove(struct nd_bus *nd_bus, struct device *dev, int rc);
int nd_bus_create_ndctl(struct nd_bus *nd_bus);
void nd_bus_destroy_ndctl(struct nd_bus *nd_bus);
int nd_bus_register_dimms(struct nd_bus *nd_bus);
int nd_bus_register_regions(struct nd_bus *nd_bus);
+int nd_bus_init_interleave_sets(struct nd_bus *nd_bus);
int nd_match_dimm(struct device *dev, void *data);
#endif /* __ND_PRIVATE_H__ */
diff --git a/drivers/block/nd/nd.h b/drivers/block/nd/nd.h
index 4ac7ff2af4c8..4deed46884c1 100644
--- a/drivers/block/nd/nd.h
+++ b/drivers/block/nd/nd.h
@@ -50,6 +50,7 @@ enum nd_async_mode {

void nd_device_register(struct device *dev);
void nd_device_unregister(struct device *dev, enum nd_async_mode mode);
+u64 nd_fletcher64(void __iomem *addr, size_t len);
extern struct attribute_group nd_device_attribute_group;
struct nd_dimm;
u32 to_nfit_handle(struct nd_dimm *nd_dimm);
@@ -63,4 +64,7 @@ int nd_dimm_firmware_status(struct device *dev);
struct nd_region *to_nd_region(struct device *dev);
int nd_region_to_namespace_type(struct nd_region *nd_region);
int nd_region_register_namespaces(struct nd_region *nd_region, int *err);
+void nd_bus_lock(struct device *dev);
+void nd_bus_unlock(struct device *dev);
+bool is_nd_bus_locked(struct device *dev);
#endif /* __ND_H__ */
diff --git a/drivers/block/nd/region_devs.c b/drivers/block/nd/region_devs.c
index 03b192368e1a..13f45be755a5 100644
--- a/drivers/block/nd/region_devs.c
+++ b/drivers/block/nd/region_devs.c
@@ -10,7 +10,10 @@
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/sort.h>
#include <linux/io.h>
#include "nd-private.h"
#include "nfit.h"
@@ -137,6 +140,21 @@ static ssize_t nstype_show(struct device *dev,
}
static DEVICE_ATTR_RO(nstype);

+static ssize_t set_cookie_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct nd_region *nd_region = to_nd_region(dev);
+ struct nd_spa *nd_spa = nd_region->nd_spa;
+
+ if (is_nd_pmem(dev) && nd_spa->nd_set)
+ /* pass, should be precluded by nd_region_visible */;
+ else
+ return -ENXIO;
+
+ return sprintf(buf, "%#llx\n", nd_spa->nd_set->cookie);
+}
+static DEVICE_ATTR_RO(set_cookie);
+
static ssize_t init_namespaces_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -154,12 +172,29 @@ static struct attribute *nd_region_attributes[] = {
&dev_attr_nstype.attr,
&dev_attr_mappings.attr,
&dev_attr_spa_index.attr,
+ &dev_attr_set_cookie.attr,
&dev_attr_init_namespaces.attr,
NULL,
};

+static umode_t nd_region_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+ struct device *dev = container_of(kobj, typeof(*dev), kobj);
+ struct nd_region *nd_region = to_nd_region(dev);
+ struct nd_spa *nd_spa = nd_region->nd_spa;
+
+ if (a != &dev_attr_set_cookie.attr)
+ return a->mode;
+
+ if (is_nd_pmem(dev) && nd_spa->nd_set)
+ return a->mode;
+
+ return 0;
+}
+
static struct attribute_group nd_region_attribute_group = {
.attrs = nd_region_attributes,
+ .is_visible = nd_region_visible,
};

/*
@@ -203,6 +238,147 @@ static struct nd_mem *nd_memdev_to_mem(struct nd_bus *nd_bus,
return NULL;
}

+/* enough info to uniquely specify an interleave set */
+struct nd_set_info {
+ struct nd_set_info_map {
+ u64 region_spa_offset;
+ u32 serial_number;
+ u32 pad;
+ } mapping[0];
+};
+
+static size_t sizeof_nd_set_info(int num_mappings)
+{
+ return sizeof(struct nd_set_info)
+ + num_mappings * sizeof(struct nd_set_info_map);
+}
+
+static int cmp_map(const void *m0, const void *m1)
+{
+ const struct nd_set_info_map *map0 = m0;
+ const struct nd_set_info_map *map1 = m1;
+
+ return memcmp(&map0->region_spa_offset, &map1->region_spa_offset,
+ sizeof(u64));
+}
+
+static int init_interleave_set(struct nd_bus *nd_bus,
+ struct nd_interleave_set *nd_set, struct nd_spa *nd_spa)
+{
+ u16 spa_index = readw(&nd_spa->nfit_spa->spa_index);
+ int num_mappings = num_nd_mem(nd_bus, spa_index);
+ struct nd_set_info *info;
+ int i;
+
+ info = kzalloc(sizeof_nd_set_info(num_mappings), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+ for (i = 0; i < num_mappings; i++) {
+ struct nd_set_info_map *map = &info->mapping[i];
+ struct nd_memdev *nd_memdev = nd_memdev_from_spa(nd_bus,
+ spa_index, i);
+ struct nd_mem *nd_mem = nd_memdev_to_mem(nd_bus, nd_memdev);
+
+ if (!nd_mem) {
+ dev_err(&nd_bus->dev, "%s: failed to find DCR\n",
+ __func__);
+ kfree(info);
+ return -ENODEV;
+ }
+
+ map->region_spa_offset = readl(
+ &nd_memdev->nfit_mem->region_spa_offset);
+ map->serial_number = readl(&nd_mem->nfit_dcr->serial_number);
+ }
+
+ sort(&info->mapping[0], num_mappings, sizeof(struct nd_set_info_map),
+ cmp_map, NULL);
+ nd_set->cookie = nd_fletcher64(info, sizeof_nd_set_info(num_mappings));
+
+ kfree(info);
+
+ return 0;
+}
+
+int nd_bus_init_interleave_sets(struct nd_bus *nd_bus)
+{
+ struct nd_spa *nd_spa;
+ int rc = 0;
+
+ /* PMEM interleave sets */
+ list_for_each_entry(nd_spa, &nd_bus->spas, list) {
+ u16 spa_index = readw(&nd_spa->nfit_spa->spa_index);
+ int spa_type = nfit_spa_type(nd_spa->nfit_spa);
+ struct nd_interleave_set *nd_set;
+
+ if (spa_type != NFIT_SPA_PM)
+ continue;
+ if (nd_memdev_from_spa(nd_bus, spa_index, 0) == NULL)
+ continue;
+ nd_set = kzalloc(sizeof(*nd_set), GFP_KERNEL);
+ if (!nd_set) {
+ rc = -ENOMEM;
+ break;
+ }
+ nd_spa->nd_set = nd_set;
+
+ rc = init_interleave_set(nd_bus, nd_set, nd_spa);
+ if (rc)
+ break;
+ }
+
+ return rc;
+}
+
+/*
+ * Upon successful probe/remove, take/release a reference on the
+ * associated interleave set (if present)
+ */
+static void nd_region_notify_driver_action(struct nd_bus *nd_bus,
+ struct device *dev, int rc, bool probe)
+{
+ if (rc)
+ return;
+
+ if (is_nd_pmem(dev) || is_nd_blk(dev)) {
+ struct nd_region *nd_region = to_nd_region(dev);
+ int i;
+
+ for (i = 0; i < nd_region->ndr_mappings; i++) {
+ struct nd_mapping *nd_mapping = &nd_region->mapping[i];
+ struct nd_dimm *nd_dimm = nd_mapping->nd_dimm;
+
+ if (probe)
+ atomic_inc(&nd_dimm->busy);
+ else
+ atomic_dec(&nd_dimm->busy);
+ }
+ }
+}
+
+void nd_region_probe_start(struct nd_bus *nd_bus, struct device *dev)
+{
+ nd_bus_lock(&nd_bus->dev);
+ nd_bus->probe_active++;
+ nd_bus_unlock(&nd_bus->dev);
+}
+
+void nd_region_probe_end(struct nd_bus *nd_bus, struct device *dev, int rc)
+{
+ nd_bus_lock(&nd_bus->dev);
+ nd_region_notify_driver_action(nd_bus, dev, rc, true);
+ if (--nd_bus->probe_active == 0)
+ wake_up(&nd_bus->probe_wait);
+ nd_bus_unlock(&nd_bus->dev);
+}
+
+void nd_region_notify_remove(struct nd_bus *nd_bus, struct device *dev, int rc)
+{
+ nd_bus_lock(dev);
+ nd_region_notify_driver_action(nd_bus, dev, rc, false);
+ nd_bus_unlock(dev);
+}
+
static ssize_t mappingN(struct device *dev, char *buf, int n)
{
struct nd_region *nd_region = to_nd_region(dev);

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/