libnvdimm, nfit: add interleave-set state-tracking infrastructure

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 is always 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.  It is the bus provider
implementation's responsibility to calculate the interleave set cookie
and attach it to a given region.

Cc: Neil Brown <neilb@suse.de>
Cc: <linux-acpi@vger.kernel.org>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

6 files changed, 172 insertions, 3 deletions

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 4b77665a6cc8..ffb43cada625 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -68,6 +68,21 @@ static struct module *to_bus_provider(struct device *dev)
         return NULL;
 }
 
+static void nvdimm_bus_probe_start(struct nvdimm_bus *nvdimm_bus)
+{
+        nvdimm_bus_lock(&nvdimm_bus->dev);
+        nvdimm_bus->probe_active++;
+        nvdimm_bus_unlock(&nvdimm_bus->dev);
+}
+
+static void nvdimm_bus_probe_end(struct nvdimm_bus *nvdimm_bus)
+{
+        nvdimm_bus_lock(&nvdimm_bus->dev);
+        if (--nvdimm_bus->probe_active == 0)
+                wake_up(&nvdimm_bus->probe_wait);
+        nvdimm_bus_unlock(&nvdimm_bus->dev);
+}
+
 static int nvdimm_bus_probe(struct device *dev)
 {
         struct nd_device_driver *nd_drv = to_nd_device_driver(dev->driver);
@@ -78,7 +93,12 @@ static int nvdimm_bus_probe(struct device *dev)
         if (!try_module_get(provider))
                 return -ENXIO;
 
+        nvdimm_bus_probe_start(nvdimm_bus);
         rc = nd_drv->probe(dev);
+        if (rc == 0)
+                nd_region_probe_success(nvdimm_bus, dev);
+        nvdimm_bus_probe_end(nvdimm_bus);
+
         dev_dbg(&nvdimm_bus->dev, "%s.probe(%s) = %d\n", dev->driver->name,
                         dev_name(dev), rc);
         if (rc != 0)
@@ -94,6 +114,8 @@ static int nvdimm_bus_remove(struct device *dev)
         int rc;
 
         rc = nd_drv->remove(dev);
+        nd_region_disable(nvdimm_bus, dev);
+
         dev_dbg(&nvdimm_bus->dev, "%s.remove(%s) = %d\n", dev->driver->name,
                         dev_name(dev), rc);
         module_put(provider);
@@ -359,6 +381,34 @@ u32 nd_cmd_out_size(struct nvdimm *nvdimm, int cmd,
 }
 EXPORT_SYMBOL_GPL(nd_cmd_out_size);
 
+static void wait_nvdimm_bus_probe_idle(struct nvdimm_bus *nvdimm_bus)
+{
+        do {
+                if (nvdimm_bus->probe_active == 0)
+                        break;
+                nvdimm_bus_unlock(&nvdimm_bus->dev);
+                wait_event(nvdimm_bus->probe_wait,
+                                nvdimm_bus->probe_active == 0);
+                nvdimm_bus_lock(&nvdimm_bus->dev);
+        } while (true);
+}
+
+/* set_config requires an idle interleave set */
+static int nd_cmd_clear_to_send(struct nvdimm *nvdimm, unsigned int cmd)
+{
+        struct nvdimm_bus *nvdimm_bus;
+
+        if (!nvdimm || cmd != ND_CMD_SET_CONFIG_DATA)
+                return 0;
+
+        nvdimm_bus = walk_to_nvdimm_bus(&nvdimm->dev);
+        wait_nvdimm_bus_probe_idle(nvdimm_bus);
+
+        if (atomic_read(&nvdimm->busy))
+                return -EBUSY;
+        return 0;
+}
+
 static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
                 int read_only, unsigned int ioctl_cmd, unsigned long arg)
 {
@@ -469,11 +519,18 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
                 goto out;
         }
 
+        nvdimm_bus_lock(&nvdimm_bus->dev);
+        rc = nd_cmd_clear_to_send(nvdimm, cmd);
+        if (rc)
+                goto out_unlock;
+
         rc = nd_desc->ndctl(nd_desc, nvdimm, cmd, buf, buf_len);
         if (rc < 0)
-                goto out;
+                goto out_unlock;
         if (copy_to_user(p, buf, buf_len))
                 rc = -EFAULT;
+ out_unlock:
+        nvdimm_bus_unlock(&nvdimm_bus->dev);
  out:
         vfree(buf);
         return rc;
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 1b6b15d11f54..7806eaaf4707 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -54,6 +54,22 @@ bool is_nvdimm_bus_locked(struct device *dev)
 }
 EXPORT_SYMBOL(is_nvdimm_bus_locked);
 
+u64 nd_fletcher64(void *addr, size_t len, bool le)
+{
+        u32 *buf = addr;
+        u32 lo32 = 0;
+        u64 hi32 = 0;
+        int i;
+
+        for (i = 0; i < len / sizeof(u32); i++) {
+                lo32 += le ? le32_to_cpu((__le32) buf[i]) : buf[i];
+                hi32 += lo32;
+        }
+
+        return hi32 << 32 | lo32;
+}
+EXPORT_SYMBOL_GPL(nd_fletcher64);
+
 static void nvdimm_bus_release(struct device *dev)
 {
         struct nvdimm_bus *nvdimm_bus;
@@ -175,6 +191,7 @@ struct nvdimm_bus *__nvdimm_bus_register(struct device *parent,
         if (!nvdimm_bus)
                 return NULL;
         INIT_LIST_HEAD(&nvdimm_bus->list);
+        init_waitqueue_head(&nvdimm_bus->probe_wait);
         nvdimm_bus->id = ida_simple_get(&nd_ida, 0, 0, GFP_KERNEL);
         mutex_init(&nvdimm_bus->reconfig_mutex);
         if (nvdimm_bus->id < 0) {
diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index b3ae86f2e1da..bdf8241b6525 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -185,7 +185,24 @@ 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 nvdimm *nvdimm = to_nvdimm(dev);
+
+        /*
+         * The state may be in the process of changing, userspace should
+         * quiesce probing if it wants a static answer
+         */
+        nvdimm_bus_lock(dev);
+        nvdimm_bus_unlock(dev);
+        return sprintf(buf, "%s\n", atomic_read(&nvdimm->busy)
+                        ? "active" : "idle");
+}
+static DEVICE_ATTR_RO(state);
+
 static struct attribute *nvdimm_attributes[] = {
+        &dev_attr_state.attr,
         &dev_attr_commands.attr,
         NULL,
 };
@@ -213,7 +230,7 @@ struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
         nvdimm->provider_data = provider_data;
         nvdimm->flags = flags;
         nvdimm->dsm_mask = dsm_mask;
-
+        atomic_set(&nvdimm->busy, 0);
         dev = &nvdimm->dev;
         dev_set_name(dev, "nmem%d", nvdimm->id);
         dev->parent = &nvdimm_bus->dev;
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index 0e9b41fd2546..6a4b2c066ee7 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -14,6 +14,9 @@
 #define __ND_CORE_H__
 #include <linux/libnvdimm.h>
 #include <linux/device.h>
+#include <linux/libnvdimm.h>
+#include <linux/sizes.h>
+#include <linux/mutex.h>
 
 extern struct list_head nvdimm_bus_list;
 extern struct mutex nvdimm_bus_list_mutex;
@@ -21,10 +24,11 @@ extern int nvdimm_major;
 
 struct nvdimm_bus {
         struct nvdimm_bus_descriptor *nd_desc;
+        wait_queue_head_t probe_wait;
         struct module *module;
         struct list_head list;
         struct device dev;
-        int id;
+        int id, probe_active;
         struct mutex reconfig_mutex;
 };
 
@@ -33,6 +37,7 @@ struct nvdimm {
         void *provider_data;
         unsigned long *dsm_mask;
         struct device dev;
+        atomic_t busy;
         int id;
 };
 
@@ -42,10 +47,13 @@ bool is_nd_pmem(struct device *dev);
 struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev);
 int __init nvdimm_bus_init(void);
 void nvdimm_bus_exit(void);
+void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev);
+void nd_region_disable(struct nvdimm_bus *nvdimm_bus, struct device *dev);
 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus);
 void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus);
 void nd_synchronize(void);
 int nvdimm_bus_register_dimms(struct nvdimm_bus *nvdimm_bus);
 int nvdimm_bus_register_regions(struct nvdimm_bus *nvdimm_bus);
+int nvdimm_bus_init_interleave_sets(struct nvdimm_bus *nvdimm_bus);
 int nd_match_dimm(struct device *dev, void *data);
 #endif /* __ND_CORE_H__ */
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index bc5a08e36a25..0285e4588b03 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -35,6 +35,7 @@ struct nd_region {
         u64 ndr_start;
         int id;
         void *provider_data;
+        struct nd_interleave_set *nd_set;
         struct nd_mapping mapping[0];
 };
 
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index b5c5b9095b28..1571424578f0 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/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-core.h"
 #include "nd.h"
@@ -133,6 +136,21 @@ 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_interleave_set *nd_set = nd_region->nd_set;
+
+        if (is_nd_pmem(dev) && nd_set)
+                /* pass, should be precluded by region_visible */;
+        else
+                return -ENXIO;
+
+        return sprintf(buf, "%#llx\n", nd_set->cookie);
+}
+static DEVICE_ATTR_RO(set_cookie);
+
 static ssize_t init_namespaces_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
 {
@@ -154,15 +172,65 @@ static struct attribute *nd_region_attributes[] = {
         &dev_attr_size.attr,
         &dev_attr_nstype.attr,
         &dev_attr_mappings.attr,
+        &dev_attr_set_cookie.attr,
         &dev_attr_init_namespaces.attr,
         NULL,
 };
 
+static umode_t 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_interleave_set *nd_set = nd_region->nd_set;
+
+        if (a != &dev_attr_set_cookie.attr)
+                return a->mode;
+
+        if (is_nd_pmem(dev) && nd_set)
+                        return a->mode;
+
+        return 0;
+}
+
 struct attribute_group nd_region_attribute_group = {
         .attrs = nd_region_attributes,
+        .is_visible = region_visible,
 };
 EXPORT_SYMBOL_GPL(nd_region_attribute_group);
 
+/*
+ * Upon successful probe/remove, take/release a reference on the
+ * associated interleave set (if present)
+ */
+static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
+                struct device *dev, bool probe)
+{
+        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 nvdimm *nvdimm = nd_mapping->nvdimm;
+
+                        if (probe)
+                                atomic_inc(&nvdimm->busy);
+                        else
+                                atomic_dec(&nvdimm->busy);
+                }
+        }
+}
+
+void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev)
+{
+        nd_region_notify_driver_action(nvdimm_bus, dev, true);
+}
+
+void nd_region_disable(struct nvdimm_bus *nvdimm_bus, struct device *dev)
+{
+        nd_region_notify_driver_action(nvdimm_bus, dev, false);
+}
+
 static ssize_t mappingN(struct device *dev, char *buf, int n)
 {
         struct nd_region *nd_region = to_nd_region(dev);
@@ -322,6 +390,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
         }
         nd_region->ndr_mappings = ndr_desc->num_mappings;
         nd_region->provider_data = ndr_desc->provider_data;
+        nd_region->nd_set = ndr_desc->nd_set;
         dev = &nd_region->dev;
         dev_set_name(dev, "region%d", nd_region->id);
         dev->parent = &nvdimm_bus->dev;