[PATCH v4 0/4] ARS rescanning triggered by latent errors or userspace

[PATCH v4 0/4] ARS rescanning triggered by latent errors or userspace

[Dan Williams]

Changes since v3 [1]:

1/ Fixed races of scrub_{store|show} versus driver shutdown.  We need to
   make sure the nvdimm_bus, nvdimm_bus_descriptor, and acpi_nfit_desc data
   structures for a given instance remain valid for the duration of an
   acpi_nfit_ars_rescan() submission.  Patch1 "libnvdimm: register
   nvdimm_bus devices with an nd_bus driver", which is new for v4, enables
   use of device_lock() to pin the nvdimm_bus active for this duration.

2/ Fixed races of scrub_{store|show} versus hotplug.  This was simply
   some missing acquisitions of acpi_desc->init_mutex.

3/ Enforce that scrub_store() only initiates a scrub when writing "1",
   other values are invalid.  This lets us introduce new values down the
   road to, for example, disable scrubs after machine checks or other scrub
   policies.

4/ Require all three ARS DSMs be available before the 'scrub' attribute
   becomes visible.

5/ Fix races of mce notifier chain vs driver shutdown by holding
   acpi_desc_lock over the acpi_nfit_destruct() event.

6/ Given ARM is now re-using the NFIT driver, move the x86 specific
   machine check code to its own conditionally-compiled file.  As a
   precursor to this change the nfit source was moved to its own
   sub-directory in Patch3 "nfit: move to nfit/ sub-directory".

[1]: https://lists.01.org/pipermail/linux-nvdimm/2016-July/006407.html

---
Initial cover letter from Vishal:

This series adds on-demand ARS scanning on both, discovery of
latent media errors, and a sysfs trigger from userspace.

The rescanning part is easy to test using the nfit_test framework
- create a namespace (this will by default have bad sectors in
the middle), clear the bad sectors by writing to them, trigger
the rescan through sysfs, and the bad sectors will reappear in
/sys/block/<pmemX>/badblocks.

For the mce handling, I've tested the notifier chain callback
being called with a mock struct mce (called via another sysfs
trigger - this isn't included in the patch obviously), which
has the address field set to a known address in a SPA range,
and the status field with the MCACOD flag set.

What I haven't easily been able to test is the same callback
path with a 'real world' mce, being called as part of the
x86_mce_decoder_chain notifier. I'd therefore appreciate a
closer look at the initial filtering done in nfit_handle_mce
(patch 3/3) from Tony or anyone more familiar with mce handling.

---

Dan Williams (2):
      libnvdimm: register nvdimm_bus devices with an nd_bus driver
      nfit: move to nfit/ sub-directory

Vishal Verma (2):
      nfit, libnvdimm: allow an ARS scrub to be triggered on demand
      nfit: do an ARS scrub on hitting a latent media error


 drivers/acpi/Kconfig             |   27 -----
 drivers/acpi/Makefile            |    2 
 drivers/acpi/nfit/Kconfig        |   26 +++++
 drivers/acpi/nfit/Makefile       |    3 +
 drivers/acpi/nfit/core.c         |  187 ++++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit/mce.c          |   89 ++++++++++++++++++
 drivers/acpi/nfit/nfit.h         |   24 +++++
 drivers/nvdimm/bus.c             |  188 +++++++++++++++++++++++++++++++++++++-
 drivers/nvdimm/core.c            |  128 +-------------------------
 include/linux/libnvdimm.h        |    1 
 tools/testing/nvdimm/Kbuild      |    5 +
 tools/testing/nvdimm/test/Kbuild |    2 
 12 files changed, 512 insertions(+), 170 deletions(-)
 create mode 100644 drivers/acpi/nfit/Kconfig
 create mode 100644 drivers/acpi/nfit/Makefile
 rename drivers/acpi/{nfit.c => nfit/core.c}
 create mode 100644 drivers/acpi/nfit/mce.c
 rename drivers/acpi/{nfit.h => nfit/nfit.h}

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[PATCH v4 0/4] ARS rescanning triggered by latent errors or userspace

[Dan Williams]

Changes since v3 [1]:

1/ Fixed races of scrub_{store|show} versus driver shutdown.  We need to
   make sure the nvdimm_bus, nvdimm_bus_descriptor, and acpi_nfit_desc data
   structures for a given instance remain valid for the duration of an
   acpi_nfit_ars_rescan() submission.  Patch1 "libnvdimm: register
   nvdimm_bus devices with an nd_bus driver", which is new for v4, enables
   use of device_lock() to pin the nvdimm_bus active for this duration.

2/ Fixed races of scrub_{store|show} versus hotplug.  This was simply
   some missing acquisitions of acpi_desc->init_mutex.

3/ Enforce that scrub_store() only initiates a scrub when writing "1",
   other values are invalid.  This lets us introduce new values down the
   road to, for example, disable scrubs after machine checks or other scrub
   policies.

4/ Require all three ARS DSMs be available before the 'scrub' attribute
   becomes visible.

5/ Fix races of mce notifier chain vs driver shutdown by holding
   acpi_desc_lock over the acpi_nfit_destruct() event.

6/ Given ARM is now re-using the NFIT driver, move the x86 specific
   machine check code to its own conditionally-compiled file.  As a
   precursor to this change the nfit source was moved to its own
   sub-directory in Patch3 "nfit: move to nfit/ sub-directory".

[1]: https://lists.01.org/pipermail/linux-nvdimm/2016-July/006407.html

---
Initial cover letter from Vishal:

This series adds on-demand ARS scanning on both, discovery of
latent media errors, and a sysfs trigger from userspace.

The rescanning part is easy to test using the nfit_test framework
- create a namespace (this will by default have bad sectors in
the middle), clear the bad sectors by writing to them, trigger
the rescan through sysfs, and the bad sectors will reappear in
/sys/block/<pmemX>/badblocks.

For the mce handling, I've tested the notifier chain callback
being called with a mock struct mce (called via another sysfs
trigger - this isn't included in the patch obviously), which
has the address field set to a known address in a SPA range,
and the status field with the MCACOD flag set.

What I haven't easily been able to test is the same callback
path with a 'real world' mce, being called as part of the
x86_mce_decoder_chain notifier. I'd therefore appreciate a
closer look at the initial filtering done in nfit_handle_mce
(patch 3/3) from Tony or anyone more familiar with mce handling.

---

Dan Williams (2):
      libnvdimm: register nvdimm_bus devices with an nd_bus driver
      nfit: move to nfit/ sub-directory

Vishal Verma (2):
      nfit, libnvdimm: allow an ARS scrub to be triggered on demand
      nfit: do an ARS scrub on hitting a latent media error


 drivers/acpi/Kconfig             |   27 -----
 drivers/acpi/Makefile            |    2 
 drivers/acpi/nfit/Kconfig        |   26 +++++
 drivers/acpi/nfit/Makefile       |    3 +
 drivers/acpi/nfit/core.c         |  187 ++++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit/mce.c          |   89 ++++++++++++++++++
 drivers/acpi/nfit/nfit.h         |   24 +++++
 drivers/nvdimm/bus.c             |  188 +++++++++++++++++++++++++++++++++++++-
 drivers/nvdimm/core.c            |  128 +-------------------------
 include/linux/libnvdimm.h        |    1 
 tools/testing/nvdimm/Kbuild      |    5 +
 tools/testing/nvdimm/test/Kbuild |    2 
 12 files changed, 512 insertions(+), 170 deletions(-)
 create mode 100644 drivers/acpi/nfit/Kconfig
 create mode 100644 drivers/acpi/nfit/Makefile
 rename drivers/acpi/{nfit.c => nfit/core.c}
 create mode 100644 drivers/acpi/nfit/mce.c
 rename drivers/acpi/{nfit.h => nfit/nfit.h}

[PATCH v4 0/4] ARS rescanning triggered by latent errors or userspace

[Dan Williams]

Changes since v3 [1]:

1/ Fixed races of scrub_{store|show} versus driver shutdown.  We need to
   make sure the nvdimm_bus, nvdimm_bus_descriptor, and acpi_nfit_desc data
   structures for a given instance remain valid for the duration of an
   acpi_nfit_ars_rescan() submission.  Patch1 "libnvdimm: register
   nvdimm_bus devices with an nd_bus driver", which is new for v4, enables
   use of device_lock() to pin the nvdimm_bus active for this duration.

2/ Fixed races of scrub_{store|show} versus hotplug.  This was simply
   some missing acquisitions of acpi_desc->init_mutex.

3/ Enforce that scrub_store() only initiates a scrub when writing "1",
   other values are invalid.  This lets us introduce new values down the
   road to, for example, disable scrubs after machine checks or other scrub
   policies.

4/ Require all three ARS DSMs be available before the 'scrub' attribute
   becomes visible.

5/ Fix races of mce notifier chain vs driver shutdown by holding
   acpi_desc_lock over the acpi_nfit_destruct() event.

6/ Given ARM is now re-using the NFIT driver, move the x86 specific
   machine check code to its own conditionally-compiled file.  As a
   precursor to this change the nfit source was moved to its own
   sub-directory in Patch3 "nfit: move to nfit/ sub-directory".

[1]: https://lists.01.org/pipermail/linux-nvdimm/2016-July/006407.html

---
Initial cover letter from Vishal:

This series adds on-demand ARS scanning on both, discovery of
latent media errors, and a sysfs trigger from userspace.

The rescanning part is easy to test using the nfit_test framework
- create a namespace (this will by default have bad sectors in
the middle), clear the bad sectors by writing to them, trigger
the rescan through sysfs, and the bad sectors will reappear in
/sys/block/<pmemX>/badblocks.

For the mce handling, I've tested the notifier chain callback
being called with a mock struct mce (called via another sysfs
trigger - this isn't included in the patch obviously), which
has the address field set to a known address in a SPA range,
and the status field with the MCACOD flag set.

What I haven't easily been able to test is the same callback
path with a 'real world' mce, being called as part of the
x86_mce_decoder_chain notifier. I'd therefore appreciate a
closer look at the initial filtering done in nfit_handle_mce
(patch 3/3) from Tony or anyone more familiar with mce handling.

---

Dan Williams (2):
      libnvdimm: register nvdimm_bus devices with an nd_bus driver
      nfit: move to nfit/ sub-directory

Vishal Verma (2):
      nfit, libnvdimm: allow an ARS scrub to be triggered on demand
      nfit: do an ARS scrub on hitting a latent media error


 drivers/acpi/Kconfig             |   27 -----
 drivers/acpi/Makefile            |    2 
 drivers/acpi/nfit/Kconfig        |   26 +++++
 drivers/acpi/nfit/Makefile       |    3 +
 drivers/acpi/nfit/core.c         |  187 ++++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit/mce.c          |   89 ++++++++++++++++++
 drivers/acpi/nfit/nfit.h         |   24 +++++
 drivers/nvdimm/bus.c             |  188 +++++++++++++++++++++++++++++++++++++-
 drivers/nvdimm/core.c            |  128 +-------------------------
 include/linux/libnvdimm.h        |    1 
 tools/testing/nvdimm/Kbuild      |    5 +
 tools/testing/nvdimm/test/Kbuild |    2 
 12 files changed, 512 insertions(+), 170 deletions(-)
 create mode 100644 drivers/acpi/nfit/Kconfig
 create mode 100644 drivers/acpi/nfit/Makefile
 rename drivers/acpi/{nfit.c => nfit/core.c}
 create mode 100644 drivers/acpi/nfit/mce.c
 rename drivers/acpi/{nfit.h => nfit/nfit.h}

[PATCH v4 1/4] libnvdimm: register nvdimm_bus devices with an nd_bus driver

[Dan Williams]

A recent effort to add a new nvdimm bus provider attribute highlighted a
race between interrogating nvdimm_bus->nd_desc and nvdimm_bus tear down.
The typical way to handle these races is to take the device_lock() in
the attribute method and validate that the device is still active.  In
order for a device to be 'active' it needs to be associated with a
driver.  So, we create the small boilerplate for a driver and register
nvdimm_bus devices on the 'nvdimm_bus_type' bus.

A result of this change is that ndbusX devices now appear under
/sys/bus/nd/devices.  In fact this makes /sys/class/nd somewhat
redundant, but removing that will need to take a long deprecation period
given its use by ndctl binaries in the field.

This change naturally pulls code from drivers/nvdimm/core.c to
drivers/nvdimm/bus.c, so it is a nice code organization clean-up as
well.

Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/bus.c  |  188 +++++++++++++++++++++++++++++++++++++++++++++++--
 drivers/nvdimm/core.c |  127 ---------------------------------
 2 files changed, 181 insertions(+), 134 deletions(-)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 275dd5c0a301..46d7e555b044 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -31,6 +31,7 @@
 int nvdimm_major;
 static int nvdimm_bus_major;
 static struct class *nd_class;
+static DEFINE_IDA(nd_ida);
 
 static int to_nd_device_type(struct device *dev)
 {
@@ -60,13 +61,6 @@ static int nvdimm_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 			to_nd_device_type(dev));
 }
 
-static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)
-{
-	struct nd_device_driver *nd_drv = to_nd_device_driver(drv);
-
-	return !!test_bit(to_nd_device_type(dev), &nd_drv->type);
-}
-
 static struct module *to_bus_provider(struct device *dev)
 {
 	/* pin bus providers while regions are enabled */
@@ -223,6 +217,8 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
 }
 EXPORT_SYMBOL_GPL(nvdimm_clear_poison);
 
+static int nvdimm_bus_match(struct device *dev, struct device_driver *drv);
+
 static struct bus_type nvdimm_bus_type = {
 	.name = "nd",
 	.uevent = nvdimm_bus_uevent,
@@ -232,6 +228,176 @@ static struct bus_type nvdimm_bus_type = {
 	.shutdown = nvdimm_bus_shutdown,
 };
 
+static void nvdimm_bus_release(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus;
+
+	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
+	ida_simple_remove(&nd_ida, nvdimm_bus->id);
+	kfree(nvdimm_bus);
+}
+
+static bool is_nvdimm_bus(struct device *dev)
+{
+	return dev->release == nvdimm_bus_release;
+}
+
+struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
+{
+	struct device *dev;
+
+	for (dev = nd_dev; dev; dev = dev->parent)
+		if (is_nvdimm_bus(dev))
+			break;
+	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");
+	if (dev)
+		return to_nvdimm_bus(dev);
+	return NULL;
+}
+
+struct nvdimm_bus *to_nvdimm_bus(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus;
+
+	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
+	WARN_ON(!is_nvdimm_bus(dev));
+	return nvdimm_bus;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_bus);
+
+struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
+		struct nvdimm_bus_descriptor *nd_desc)
+{
+	struct nvdimm_bus *nvdimm_bus;
+	int rc;
+
+	nvdimm_bus = kzalloc(sizeof(*nvdimm_bus), GFP_KERNEL);
+	if (!nvdimm_bus)
+		return NULL;
+	INIT_LIST_HEAD(&nvdimm_bus->list);
+	INIT_LIST_HEAD(&nvdimm_bus->mapping_list);
+	INIT_LIST_HEAD(&nvdimm_bus->poison_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) {
+		kfree(nvdimm_bus);
+		return NULL;
+	}
+	nvdimm_bus->nd_desc = nd_desc;
+	nvdimm_bus->dev.parent = parent;
+	nvdimm_bus->dev.release = nvdimm_bus_release;
+	nvdimm_bus->dev.groups = nd_desc->attr_groups;
+	nvdimm_bus->dev.bus = &nvdimm_bus_type;
+	dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);
+	rc = device_register(&nvdimm_bus->dev);
+	if (rc) {
+		dev_dbg(&nvdimm_bus->dev, "registration failed: %d\n", rc);
+		goto err;
+	}
+
+	return nvdimm_bus;
+ err:
+	put_device(&nvdimm_bus->dev);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_register);
+
+void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
+{
+	if (!nvdimm_bus)
+		return;
+	device_unregister(&nvdimm_bus->dev);
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);
+
+static int child_unregister(struct device *dev, void *data)
+{
+	/*
+	 * the singular ndctl class device per bus needs to be
+	 * "device_destroy"ed, so skip it here
+	 *
+	 * i.e. remove classless children
+	 */
+	if (dev->class)
+		/* pass */;
+	else
+		nd_device_unregister(dev, ND_SYNC);
+	return 0;
+}
+
+static void free_poison_list(struct list_head *poison_list)
+{
+	struct nd_poison *pl, *next;
+
+	list_for_each_entry_safe(pl, next, poison_list, list) {
+		list_del(&pl->list);
+		kfree(pl);
+	}
+	list_del_init(poison_list);
+}
+
+static int nd_bus_remove(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	mutex_lock(&nvdimm_bus_list_mutex);
+	list_del_init(&nvdimm_bus->list);
+	mutex_unlock(&nvdimm_bus_list_mutex);
+
+	nd_synchronize();
+	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);
+
+	nvdimm_bus_lock(&nvdimm_bus->dev);
+	free_poison_list(&nvdimm_bus->poison_list);
+	nvdimm_bus_unlock(&nvdimm_bus->dev);
+
+	nvdimm_bus_destroy_ndctl(nvdimm_bus);
+
+	return 0;
+}
+
+static int nd_bus_probe(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+	int rc;
+
+	rc = nvdimm_bus_create_ndctl(nvdimm_bus);
+	if (rc)
+		return rc;
+
+	mutex_lock(&nvdimm_bus_list_mutex);
+	list_add_tail(&nvdimm_bus->list, &nvdimm_bus_list);
+	mutex_unlock(&nvdimm_bus_list_mutex);
+
+	/* enable bus provider attributes to look up their local context */
+	dev_set_drvdata(dev, nvdimm_bus->nd_desc);
+
+	return 0;
+}
+
+static struct nd_device_driver nd_bus_driver = {
+	.probe = nd_bus_probe,
+	.remove = nd_bus_remove,
+	.drv = {
+		.name = "nd_bus",
+		.suppress_bind_attrs = true,
+		.bus = &nvdimm_bus_type,
+		.owner = THIS_MODULE,
+		.mod_name = KBUILD_MODNAME,
+	},
+};
+
+static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct nd_device_driver *nd_drv = to_nd_device_driver(drv);
+
+	if (is_nvdimm_bus(dev) && nd_drv == &nd_bus_driver)
+		return true;
+
+	return !!test_bit(to_nd_device_type(dev), &nd_drv->type);
+}
+
 static ASYNC_DOMAIN_EXCLUSIVE(nd_async_domain);
 
 void nd_synchronize(void)
@@ -864,8 +1030,14 @@ int __init nvdimm_bus_init(void)
 		goto err_class;
 	}
 
+	rc = driver_register(&nd_bus_driver.drv);
+	if (rc)
+		goto err_nd_bus;
+
 	return 0;
 
+ err_nd_bus:
+	class_destroy(nd_class);
  err_class:
 	unregister_chrdev(nvdimm_major, "dimmctl");
  err_dimm_chrdev:
@@ -878,8 +1050,10 @@ int __init nvdimm_bus_init(void)
 
 void nvdimm_bus_exit(void)
 {
+	driver_unregister(&nd_bus_driver.drv);
 	class_destroy(nd_class);
 	unregister_chrdev(nvdimm_bus_major, "ndctl");
 	unregister_chrdev(nvdimm_major, "dimmctl");
 	bus_unregister(&nvdimm_bus_type);
+	ida_destroy(&nd_ida);
 }
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index e8528756f54f..2c98f958fabb 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -26,7 +26,6 @@
 
 LIST_HEAD(nvdimm_bus_list);
 DEFINE_MUTEX(nvdimm_bus_list_mutex);
-static DEFINE_IDA(nd_ida);
 
 void nvdimm_bus_lock(struct device *dev)
 {
@@ -195,25 +194,6 @@ u64 nd_fletcher64(void *addr, size_t len, bool le)
 }
 EXPORT_SYMBOL_GPL(nd_fletcher64);
 
-static void nvdimm_bus_release(struct device *dev)
-{
-	struct nvdimm_bus *nvdimm_bus;
-
-	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
-	ida_simple_remove(&nd_ida, nvdimm_bus->id);
-	kfree(nvdimm_bus);
-}
-
-struct nvdimm_bus *to_nvdimm_bus(struct device *dev)
-{
-	struct nvdimm_bus *nvdimm_bus;
-
-	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
-	WARN_ON(nvdimm_bus->dev.release != nvdimm_bus_release);
-	return nvdimm_bus;
-}
-EXPORT_SYMBOL_GPL(to_nvdimm_bus);
-
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 {
 	/* struct nvdimm_bus definition is private to libnvdimm */
@@ -221,19 +201,6 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
-struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
-{
-	struct device *dev;
-
-	for (dev = nd_dev; dev; dev = dev->parent)
-		if (dev->release == nvdimm_bus_release)
-			break;
-	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");
-	if (dev)
-		return to_nvdimm_bus(dev);
-	return NULL;
-}
-
 static bool is_uuid_sep(char sep)
 {
 	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
@@ -447,51 +414,6 @@ struct attribute_group nvdimm_bus_attribute_group = {
 };
 EXPORT_SYMBOL_GPL(nvdimm_bus_attribute_group);
 
-struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
-		struct nvdimm_bus_descriptor *nd_desc)
-{
-	struct nvdimm_bus *nvdimm_bus;
-	int rc;
-
-	nvdimm_bus = kzalloc(sizeof(*nvdimm_bus), GFP_KERNEL);
-	if (!nvdimm_bus)
-		return NULL;
-	INIT_LIST_HEAD(&nvdimm_bus->list);
-	INIT_LIST_HEAD(&nvdimm_bus->mapping_list);
-	INIT_LIST_HEAD(&nvdimm_bus->poison_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) {
-		kfree(nvdimm_bus);
-		return NULL;
-	}
-	nvdimm_bus->nd_desc = nd_desc;
-	nvdimm_bus->dev.parent = parent;
-	nvdimm_bus->dev.release = nvdimm_bus_release;
-	nvdimm_bus->dev.groups = nd_desc->attr_groups;
-	dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);
-	rc = device_register(&nvdimm_bus->dev);
-	if (rc) {
-		dev_dbg(&nvdimm_bus->dev, "registration failed: %d\n", rc);
-		goto err;
-	}
-
-	rc = nvdimm_bus_create_ndctl(nvdimm_bus);
-	if (rc)
-		goto err;
-
-	mutex_lock(&nvdimm_bus_list_mutex);
-	list_add_tail(&nvdimm_bus->list, &nvdimm_bus_list);
-	mutex_unlock(&nvdimm_bus_list_mutex);
-
-	return nvdimm_bus;
- err:
-	put_device(&nvdimm_bus->dev);
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(nvdimm_bus_register);
-
 static void set_badblock(struct badblocks *bb, sector_t s, int num)
 {
 	dev_dbg(bb->dev, "Found a poison range (0x%llx, 0x%llx)\n",
@@ -667,54 +589,6 @@ int nvdimm_bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
 }
 EXPORT_SYMBOL_GPL(nvdimm_bus_add_poison);
 
-static void free_poison_list(struct list_head *poison_list)
-{
-	struct nd_poison *pl, *next;
-
-	list_for_each_entry_safe(pl, next, poison_list, list) {
-		list_del(&pl->list);
-		kfree(pl);
-	}
-	list_del_init(poison_list);
-}
-
-static int child_unregister(struct device *dev, void *data)
-{
-	/*
-	 * the singular ndctl class device per bus needs to be
-	 * "device_destroy"ed, so skip it here
-	 *
-	 * i.e. remove classless children
-	 */
-	if (dev->class)
-		/* pass */;
-	else
-		nd_device_unregister(dev, ND_SYNC);
-	return 0;
-}
-
-void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
-{
-	if (!nvdimm_bus)
-		return;
-
-	mutex_lock(&nvdimm_bus_list_mutex);
-	list_del_init(&nvdimm_bus->list);
-	mutex_unlock(&nvdimm_bus_list_mutex);
-
-	nd_synchronize();
-	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);
-
-	nvdimm_bus_lock(&nvdimm_bus->dev);
-	free_poison_list(&nvdimm_bus->poison_list);
-	nvdimm_bus_unlock(&nvdimm_bus->dev);
-
-	nvdimm_bus_destroy_ndctl(nvdimm_bus);
-
-	device_unregister(&nvdimm_bus->dev);
-}
-EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);
-
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)
 {
@@ -773,7 +647,6 @@ static __exit void libnvdimm_exit(void)
 	nvdimm_bus_exit();
 	nd_region_devs_exit();
 	nvdimm_devs_exit();
-	ida_destroy(&nd_ida);
 }
 
 MODULE_LICENSE("GPL v2");

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

[PATCH v4 1/4] libnvdimm: register nvdimm_bus devices with an nd_bus driver

[Dan Williams]

A recent effort to add a new nvdimm bus provider attribute highlighted a
race between interrogating nvdimm_bus->nd_desc and nvdimm_bus tear down.
The typical way to handle these races is to take the device_lock() in
the attribute method and validate that the device is still active.  In
order for a device to be 'active' it needs to be associated with a
driver.  So, we create the small boilerplate for a driver and register
nvdimm_bus devices on the 'nvdimm_bus_type' bus.

A result of this change is that ndbusX devices now appear under
/sys/bus/nd/devices.  In fact this makes /sys/class/nd somewhat
redundant, but removing that will need to take a long deprecation period
given its use by ndctl binaries in the field.

This change naturally pulls code from drivers/nvdimm/core.c to
drivers/nvdimm/bus.c, so it is a nice code organization clean-up as
well.

Cc: Vishal Verma <vishal.l.verma-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/nvdimm/bus.c  |  188 +++++++++++++++++++++++++++++++++++++++++++++++--
 drivers/nvdimm/core.c |  127 ---------------------------------
 2 files changed, 181 insertions(+), 134 deletions(-)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 275dd5c0a301..46d7e555b044 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -31,6 +31,7 @@
 int nvdimm_major;
 static int nvdimm_bus_major;
 static struct class *nd_class;
+static DEFINE_IDA(nd_ida);
 
 static int to_nd_device_type(struct device *dev)
 {
@@ -60,13 +61,6 @@ static int nvdimm_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 			to_nd_device_type(dev));
 }
 
-static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)
-{
-	struct nd_device_driver *nd_drv = to_nd_device_driver(drv);
-
-	return !!test_bit(to_nd_device_type(dev), &nd_drv->type);
-}
-
 static struct module *to_bus_provider(struct device *dev)
 {
 	/* pin bus providers while regions are enabled */
@@ -223,6 +217,8 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
 }
 EXPORT_SYMBOL_GPL(nvdimm_clear_poison);
 
+static int nvdimm_bus_match(struct device *dev, struct device_driver *drv);
+
 static struct bus_type nvdimm_bus_type = {
 	.name = "nd",
 	.uevent = nvdimm_bus_uevent,
@@ -232,6 +228,176 @@ static struct bus_type nvdimm_bus_type = {
 	.shutdown = nvdimm_bus_shutdown,
 };
 
+static void nvdimm_bus_release(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus;
+
+	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
+	ida_simple_remove(&nd_ida, nvdimm_bus->id);
+	kfree(nvdimm_bus);
+}
+
+static bool is_nvdimm_bus(struct device *dev)
+{
+	return dev->release == nvdimm_bus_release;
+}
+
+struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
+{
+	struct device *dev;
+
+	for (dev = nd_dev; dev; dev = dev->parent)
+		if (is_nvdimm_bus(dev))
+			break;
+	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");
+	if (dev)
+		return to_nvdimm_bus(dev);
+	return NULL;
+}
+
+struct nvdimm_bus *to_nvdimm_bus(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus;
+
+	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
+	WARN_ON(!is_nvdimm_bus(dev));
+	return nvdimm_bus;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_bus);
+
+struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
+		struct nvdimm_bus_descriptor *nd_desc)
+{
+	struct nvdimm_bus *nvdimm_bus;
+	int rc;
+
+	nvdimm_bus = kzalloc(sizeof(*nvdimm_bus), GFP_KERNEL);
+	if (!nvdimm_bus)
+		return NULL;
+	INIT_LIST_HEAD(&nvdimm_bus->list);
+	INIT_LIST_HEAD(&nvdimm_bus->mapping_list);
+	INIT_LIST_HEAD(&nvdimm_bus->poison_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) {
+		kfree(nvdimm_bus);
+		return NULL;
+	}
+	nvdimm_bus->nd_desc = nd_desc;
+	nvdimm_bus->dev.parent = parent;
+	nvdimm_bus->dev.release = nvdimm_bus_release;
+	nvdimm_bus->dev.groups = nd_desc->attr_groups;
+	nvdimm_bus->dev.bus = &nvdimm_bus_type;
+	dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);
+	rc = device_register(&nvdimm_bus->dev);
+	if (rc) {
+		dev_dbg(&nvdimm_bus->dev, "registration failed: %d\n", rc);
+		goto err;
+	}
+
+	return nvdimm_bus;
+ err:
+	put_device(&nvdimm_bus->dev);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_register);
+
+void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
+{
+	if (!nvdimm_bus)
+		return;
+	device_unregister(&nvdimm_bus->dev);
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);
+
+static int child_unregister(struct device *dev, void *data)
+{
+	/*
+	 * the singular ndctl class device per bus needs to be
+	 * "device_destroy"ed, so skip it here
+	 *
+	 * i.e. remove classless children
+	 */
+	if (dev->class)
+		/* pass */;
+	else
+		nd_device_unregister(dev, ND_SYNC);
+	return 0;
+}
+
+static void free_poison_list(struct list_head *poison_list)
+{
+	struct nd_poison *pl, *next;
+
+	list_for_each_entry_safe(pl, next, poison_list, list) {
+		list_del(&pl->list);
+		kfree(pl);
+	}
+	list_del_init(poison_list);
+}
+
+static int nd_bus_remove(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	mutex_lock(&nvdimm_bus_list_mutex);
+	list_del_init(&nvdimm_bus->list);
+	mutex_unlock(&nvdimm_bus_list_mutex);
+
+	nd_synchronize();
+	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);
+
+	nvdimm_bus_lock(&nvdimm_bus->dev);
+	free_poison_list(&nvdimm_bus->poison_list);
+	nvdimm_bus_unlock(&nvdimm_bus->dev);
+
+	nvdimm_bus_destroy_ndctl(nvdimm_bus);
+
+	return 0;
+}
+
+static int nd_bus_probe(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+	int rc;
+
+	rc = nvdimm_bus_create_ndctl(nvdimm_bus);
+	if (rc)
+		return rc;
+
+	mutex_lock(&nvdimm_bus_list_mutex);
+	list_add_tail(&nvdimm_bus->list, &nvdimm_bus_list);
+	mutex_unlock(&nvdimm_bus_list_mutex);
+
+	/* enable bus provider attributes to look up their local context */
+	dev_set_drvdata(dev, nvdimm_bus->nd_desc);
+
+	return 0;
+}
+
+static struct nd_device_driver nd_bus_driver = {
+	.probe = nd_bus_probe,
+	.remove = nd_bus_remove,
+	.drv = {
+		.name = "nd_bus",
+		.suppress_bind_attrs = true,
+		.bus = &nvdimm_bus_type,
+		.owner = THIS_MODULE,
+		.mod_name = KBUILD_MODNAME,
+	},
+};
+
+static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct nd_device_driver *nd_drv = to_nd_device_driver(drv);
+
+	if (is_nvdimm_bus(dev) && nd_drv == &nd_bus_driver)
+		return true;
+
+	return !!test_bit(to_nd_device_type(dev), &nd_drv->type);
+}
+
 static ASYNC_DOMAIN_EXCLUSIVE(nd_async_domain);
 
 void nd_synchronize(void)
@@ -864,8 +1030,14 @@ int __init nvdimm_bus_init(void)
 		goto err_class;
 	}
 
+	rc = driver_register(&nd_bus_driver.drv);
+	if (rc)
+		goto err_nd_bus;
+
 	return 0;
 
+ err_nd_bus:
+	class_destroy(nd_class);
  err_class:
 	unregister_chrdev(nvdimm_major, "dimmctl");
  err_dimm_chrdev:
@@ -878,8 +1050,10 @@ int __init nvdimm_bus_init(void)
 
 void nvdimm_bus_exit(void)
 {
+	driver_unregister(&nd_bus_driver.drv);
 	class_destroy(nd_class);
 	unregister_chrdev(nvdimm_bus_major, "ndctl");
 	unregister_chrdev(nvdimm_major, "dimmctl");
 	bus_unregister(&nvdimm_bus_type);
+	ida_destroy(&nd_ida);
 }
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index e8528756f54f..2c98f958fabb 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -26,7 +26,6 @@
 
 LIST_HEAD(nvdimm_bus_list);
 DEFINE_MUTEX(nvdimm_bus_list_mutex);
-static DEFINE_IDA(nd_ida);
 
 void nvdimm_bus_lock(struct device *dev)
 {
@@ -195,25 +194,6 @@ u64 nd_fletcher64(void *addr, size_t len, bool le)
 }
 EXPORT_SYMBOL_GPL(nd_fletcher64);
 
-static void nvdimm_bus_release(struct device *dev)
-{
-	struct nvdimm_bus *nvdimm_bus;
-
-	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
-	ida_simple_remove(&nd_ida, nvdimm_bus->id);
-	kfree(nvdimm_bus);
-}
-
-struct nvdimm_bus *to_nvdimm_bus(struct device *dev)
-{
-	struct nvdimm_bus *nvdimm_bus;
-
-	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
-	WARN_ON(nvdimm_bus->dev.release != nvdimm_bus_release);
-	return nvdimm_bus;
-}
-EXPORT_SYMBOL_GPL(to_nvdimm_bus);
-
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 {
 	/* struct nvdimm_bus definition is private to libnvdimm */
@@ -221,19 +201,6 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
-struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
-{
-	struct device *dev;
-
-	for (dev = nd_dev; dev; dev = dev->parent)
-		if (dev->release == nvdimm_bus_release)
-			break;
-	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");
-	if (dev)
-		return to_nvdimm_bus(dev);
-	return NULL;
-}
-
 static bool is_uuid_sep(char sep)
 {
 	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
@@ -447,51 +414,6 @@ struct attribute_group nvdimm_bus_attribute_group = {
 };
 EXPORT_SYMBOL_GPL(nvdimm_bus_attribute_group);
 
-struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
-		struct nvdimm_bus_descriptor *nd_desc)
-{
-	struct nvdimm_bus *nvdimm_bus;
-	int rc;
-
-	nvdimm_bus = kzalloc(sizeof(*nvdimm_bus), GFP_KERNEL);
-	if (!nvdimm_bus)
-		return NULL;
-	INIT_LIST_HEAD(&nvdimm_bus->list);
-	INIT_LIST_HEAD(&nvdimm_bus->mapping_list);
-	INIT_LIST_HEAD(&nvdimm_bus->poison_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) {
-		kfree(nvdimm_bus);
-		return NULL;
-	}
-	nvdimm_bus->nd_desc = nd_desc;
-	nvdimm_bus->dev.parent = parent;
-	nvdimm_bus->dev.release = nvdimm_bus_release;
-	nvdimm_bus->dev.groups = nd_desc->attr_groups;
-	dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);
-	rc = device_register(&nvdimm_bus->dev);
-	if (rc) {
-		dev_dbg(&nvdimm_bus->dev, "registration failed: %d\n", rc);
-		goto err;
-	}
-
-	rc = nvdimm_bus_create_ndctl(nvdimm_bus);
-	if (rc)
-		goto err;
-
-	mutex_lock(&nvdimm_bus_list_mutex);
-	list_add_tail(&nvdimm_bus->list, &nvdimm_bus_list);
-	mutex_unlock(&nvdimm_bus_list_mutex);
-
-	return nvdimm_bus;
- err:
-	put_device(&nvdimm_bus->dev);
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(nvdimm_bus_register);
-
 static void set_badblock(struct badblocks *bb, sector_t s, int num)
 {
 	dev_dbg(bb->dev, "Found a poison range (0x%llx, 0x%llx)\n",
@@ -667,54 +589,6 @@ int nvdimm_bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
 }
 EXPORT_SYMBOL_GPL(nvdimm_bus_add_poison);
 
-static void free_poison_list(struct list_head *poison_list)
-{
-	struct nd_poison *pl, *next;
-
-	list_for_each_entry_safe(pl, next, poison_list, list) {
-		list_del(&pl->list);
-		kfree(pl);
-	}
-	list_del_init(poison_list);
-}
-
-static int child_unregister(struct device *dev, void *data)
-{
-	/*
-	 * the singular ndctl class device per bus needs to be
-	 * "device_destroy"ed, so skip it here
-	 *
-	 * i.e. remove classless children
-	 */
-	if (dev->class)
-		/* pass */;
-	else
-		nd_device_unregister(dev, ND_SYNC);
-	return 0;
-}
-
-void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
-{
-	if (!nvdimm_bus)
-		return;
-
-	mutex_lock(&nvdimm_bus_list_mutex);
-	list_del_init(&nvdimm_bus->list);
-	mutex_unlock(&nvdimm_bus_list_mutex);
-
-	nd_synchronize();
-	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);
-
-	nvdimm_bus_lock(&nvdimm_bus->dev);
-	free_poison_list(&nvdimm_bus->poison_list);
-	nvdimm_bus_unlock(&nvdimm_bus->dev);
-
-	nvdimm_bus_destroy_ndctl(nvdimm_bus);
-
-	device_unregister(&nvdimm_bus->dev);
-}
-EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);
-
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)
 {
@@ -773,7 +647,6 @@ static __exit void libnvdimm_exit(void)
 	nvdimm_bus_exit();
 	nd_region_devs_exit();
 	nvdimm_devs_exit();
-	ida_destroy(&nd_ida);
 }
 
 MODULE_LICENSE("GPL v2");

[PATCH v4 1/4] libnvdimm: register nvdimm_bus devices with an nd_bus driver

[Dan Williams]

A recent effort to add a new nvdimm bus provider attribute highlighted a
race between interrogating nvdimm_bus->nd_desc and nvdimm_bus tear down.
The typical way to handle these races is to take the device_lock() in
the attribute method and validate that the device is still active.  In
order for a device to be 'active' it needs to be associated with a
driver.  So, we create the small boilerplate for a driver and register
nvdimm_bus devices on the 'nvdimm_bus_type' bus.

A result of this change is that ndbusX devices now appear under
/sys/bus/nd/devices.  In fact this makes /sys/class/nd somewhat
redundant, but removing that will need to take a long deprecation period
given its use by ndctl binaries in the field.

This change naturally pulls code from drivers/nvdimm/core.c to
drivers/nvdimm/bus.c, so it is a nice code organization clean-up as
well.

Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/bus.c  |  188 +++++++++++++++++++++++++++++++++++++++++++++++--
 drivers/nvdimm/core.c |  127 ---------------------------------
 2 files changed, 181 insertions(+), 134 deletions(-)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 275dd5c0a301..46d7e555b044 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -31,6 +31,7 @@
 int nvdimm_major;
 static int nvdimm_bus_major;
 static struct class *nd_class;
+static DEFINE_IDA(nd_ida);
 
 static int to_nd_device_type(struct device *dev)
 {
@@ -60,13 +61,6 @@ static int nvdimm_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 			to_nd_device_type(dev));
 }
 
-static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)
-{
-	struct nd_device_driver *nd_drv = to_nd_device_driver(drv);
-
-	return !!test_bit(to_nd_device_type(dev), &nd_drv->type);
-}
-
 static struct module *to_bus_provider(struct device *dev)
 {
 	/* pin bus providers while regions are enabled */
@@ -223,6 +217,8 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
 }
 EXPORT_SYMBOL_GPL(nvdimm_clear_poison);
 
+static int nvdimm_bus_match(struct device *dev, struct device_driver *drv);
+
 static struct bus_type nvdimm_bus_type = {
 	.name = "nd",
 	.uevent = nvdimm_bus_uevent,
@@ -232,6 +228,176 @@ static struct bus_type nvdimm_bus_type = {
 	.shutdown = nvdimm_bus_shutdown,
 };
 
+static void nvdimm_bus_release(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus;
+
+	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
+	ida_simple_remove(&nd_ida, nvdimm_bus->id);
+	kfree(nvdimm_bus);
+}
+
+static bool is_nvdimm_bus(struct device *dev)
+{
+	return dev->release == nvdimm_bus_release;
+}
+
+struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
+{
+	struct device *dev;
+
+	for (dev = nd_dev; dev; dev = dev->parent)
+		if (is_nvdimm_bus(dev))
+			break;
+	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");
+	if (dev)
+		return to_nvdimm_bus(dev);
+	return NULL;
+}
+
+struct nvdimm_bus *to_nvdimm_bus(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus;
+
+	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
+	WARN_ON(!is_nvdimm_bus(dev));
+	return nvdimm_bus;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_bus);
+
+struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
+		struct nvdimm_bus_descriptor *nd_desc)
+{
+	struct nvdimm_bus *nvdimm_bus;
+	int rc;
+
+	nvdimm_bus = kzalloc(sizeof(*nvdimm_bus), GFP_KERNEL);
+	if (!nvdimm_bus)
+		return NULL;
+	INIT_LIST_HEAD(&nvdimm_bus->list);
+	INIT_LIST_HEAD(&nvdimm_bus->mapping_list);
+	INIT_LIST_HEAD(&nvdimm_bus->poison_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) {
+		kfree(nvdimm_bus);
+		return NULL;
+	}
+	nvdimm_bus->nd_desc = nd_desc;
+	nvdimm_bus->dev.parent = parent;
+	nvdimm_bus->dev.release = nvdimm_bus_release;
+	nvdimm_bus->dev.groups = nd_desc->attr_groups;
+	nvdimm_bus->dev.bus = &nvdimm_bus_type;
+	dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);
+	rc = device_register(&nvdimm_bus->dev);
+	if (rc) {
+		dev_dbg(&nvdimm_bus->dev, "registration failed: %d\n", rc);
+		goto err;
+	}
+
+	return nvdimm_bus;
+ err:
+	put_device(&nvdimm_bus->dev);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_register);
+
+void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
+{
+	if (!nvdimm_bus)
+		return;
+	device_unregister(&nvdimm_bus->dev);
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);
+
+static int child_unregister(struct device *dev, void *data)
+{
+	/*
+	 * the singular ndctl class device per bus needs to be
+	 * "device_destroy"ed, so skip it here
+	 *
+	 * i.e. remove classless children
+	 */
+	if (dev->class)
+		/* pass */;
+	else
+		nd_device_unregister(dev, ND_SYNC);
+	return 0;
+}
+
+static void free_poison_list(struct list_head *poison_list)
+{
+	struct nd_poison *pl, *next;
+
+	list_for_each_entry_safe(pl, next, poison_list, list) {
+		list_del(&pl->list);
+		kfree(pl);
+	}
+	list_del_init(poison_list);
+}
+
+static int nd_bus_remove(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	mutex_lock(&nvdimm_bus_list_mutex);
+	list_del_init(&nvdimm_bus->list);
+	mutex_unlock(&nvdimm_bus_list_mutex);
+
+	nd_synchronize();
+	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);
+
+	nvdimm_bus_lock(&nvdimm_bus->dev);
+	free_poison_list(&nvdimm_bus->poison_list);
+	nvdimm_bus_unlock(&nvdimm_bus->dev);
+
+	nvdimm_bus_destroy_ndctl(nvdimm_bus);
+
+	return 0;
+}
+
+static int nd_bus_probe(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+	int rc;
+
+	rc = nvdimm_bus_create_ndctl(nvdimm_bus);
+	if (rc)
+		return rc;
+
+	mutex_lock(&nvdimm_bus_list_mutex);
+	list_add_tail(&nvdimm_bus->list, &nvdimm_bus_list);
+	mutex_unlock(&nvdimm_bus_list_mutex);
+
+	/* enable bus provider attributes to look up their local context */
+	dev_set_drvdata(dev, nvdimm_bus->nd_desc);
+
+	return 0;
+}
+
+static struct nd_device_driver nd_bus_driver = {
+	.probe = nd_bus_probe,
+	.remove = nd_bus_remove,
+	.drv = {
+		.name = "nd_bus",
+		.suppress_bind_attrs = true,
+		.bus = &nvdimm_bus_type,
+		.owner = THIS_MODULE,
+		.mod_name = KBUILD_MODNAME,
+	},
+};
+
+static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct nd_device_driver *nd_drv = to_nd_device_driver(drv);
+
+	if (is_nvdimm_bus(dev) && nd_drv == &nd_bus_driver)
+		return true;
+
+	return !!test_bit(to_nd_device_type(dev), &nd_drv->type);
+}
+
 static ASYNC_DOMAIN_EXCLUSIVE(nd_async_domain);
 
 void nd_synchronize(void)
@@ -864,8 +1030,14 @@ int __init nvdimm_bus_init(void)
 		goto err_class;
 	}
 
+	rc = driver_register(&nd_bus_driver.drv);
+	if (rc)
+		goto err_nd_bus;
+
 	return 0;
 
+ err_nd_bus:
+	class_destroy(nd_class);
  err_class:
 	unregister_chrdev(nvdimm_major, "dimmctl");
  err_dimm_chrdev:
@@ -878,8 +1050,10 @@ int __init nvdimm_bus_init(void)
 
 void nvdimm_bus_exit(void)
 {
+	driver_unregister(&nd_bus_driver.drv);
 	class_destroy(nd_class);
 	unregister_chrdev(nvdimm_bus_major, "ndctl");
 	unregister_chrdev(nvdimm_major, "dimmctl");
 	bus_unregister(&nvdimm_bus_type);
+	ida_destroy(&nd_ida);
 }
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index e8528756f54f..2c98f958fabb 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -26,7 +26,6 @@
 
 LIST_HEAD(nvdimm_bus_list);
 DEFINE_MUTEX(nvdimm_bus_list_mutex);
-static DEFINE_IDA(nd_ida);
 
 void nvdimm_bus_lock(struct device *dev)
 {
@@ -195,25 +194,6 @@ u64 nd_fletcher64(void *addr, size_t len, bool le)
 }
 EXPORT_SYMBOL_GPL(nd_fletcher64);
 
-static void nvdimm_bus_release(struct device *dev)
-{
-	struct nvdimm_bus *nvdimm_bus;
-
-	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
-	ida_simple_remove(&nd_ida, nvdimm_bus->id);
-	kfree(nvdimm_bus);
-}
-
-struct nvdimm_bus *to_nvdimm_bus(struct device *dev)
-{
-	struct nvdimm_bus *nvdimm_bus;
-
-	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
-	WARN_ON(nvdimm_bus->dev.release != nvdimm_bus_release);
-	return nvdimm_bus;
-}
-EXPORT_SYMBOL_GPL(to_nvdimm_bus);
-
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 {
 	/* struct nvdimm_bus definition is private to libnvdimm */
@@ -221,19 +201,6 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
-struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
-{
-	struct device *dev;
-
-	for (dev = nd_dev; dev; dev = dev->parent)
-		if (dev->release == nvdimm_bus_release)
-			break;
-	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");
-	if (dev)
-		return to_nvdimm_bus(dev);
-	return NULL;
-}
-
 static bool is_uuid_sep(char sep)
 {
 	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
@@ -447,51 +414,6 @@ struct attribute_group nvdimm_bus_attribute_group = {
 };
 EXPORT_SYMBOL_GPL(nvdimm_bus_attribute_group);
 
-struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
-		struct nvdimm_bus_descriptor *nd_desc)
-{
-	struct nvdimm_bus *nvdimm_bus;
-	int rc;
-
-	nvdimm_bus = kzalloc(sizeof(*nvdimm_bus), GFP_KERNEL);
-	if (!nvdimm_bus)
-		return NULL;
-	INIT_LIST_HEAD(&nvdimm_bus->list);
-	INIT_LIST_HEAD(&nvdimm_bus->mapping_list);
-	INIT_LIST_HEAD(&nvdimm_bus->poison_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) {
-		kfree(nvdimm_bus);
-		return NULL;
-	}
-	nvdimm_bus->nd_desc = nd_desc;
-	nvdimm_bus->dev.parent = parent;
-	nvdimm_bus->dev.release = nvdimm_bus_release;
-	nvdimm_bus->dev.groups = nd_desc->attr_groups;
-	dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);
-	rc = device_register(&nvdimm_bus->dev);
-	if (rc) {
-		dev_dbg(&nvdimm_bus->dev, "registration failed: %d\n", rc);
-		goto err;
-	}
-
-	rc = nvdimm_bus_create_ndctl(nvdimm_bus);
-	if (rc)
-		goto err;
-
-	mutex_lock(&nvdimm_bus_list_mutex);
-	list_add_tail(&nvdimm_bus->list, &nvdimm_bus_list);
-	mutex_unlock(&nvdimm_bus_list_mutex);
-
-	return nvdimm_bus;
- err:
-	put_device(&nvdimm_bus->dev);
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(nvdimm_bus_register);
-
 static void set_badblock(struct badblocks *bb, sector_t s, int num)
 {
 	dev_dbg(bb->dev, "Found a poison range (0x%llx, 0x%llx)\n",
@@ -667,54 +589,6 @@ int nvdimm_bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
 }
 EXPORT_SYMBOL_GPL(nvdimm_bus_add_poison);
 
-static void free_poison_list(struct list_head *poison_list)
-{
-	struct nd_poison *pl, *next;
-
-	list_for_each_entry_safe(pl, next, poison_list, list) {
-		list_del(&pl->list);
-		kfree(pl);
-	}
-	list_del_init(poison_list);
-}
-
-static int child_unregister(struct device *dev, void *data)
-{
-	/*
-	 * the singular ndctl class device per bus needs to be
-	 * "device_destroy"ed, so skip it here
-	 *
-	 * i.e. remove classless children
-	 */
-	if (dev->class)
-		/* pass */;
-	else
-		nd_device_unregister(dev, ND_SYNC);
-	return 0;
-}
-
-void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
-{
-	if (!nvdimm_bus)
-		return;
-
-	mutex_lock(&nvdimm_bus_list_mutex);
-	list_del_init(&nvdimm_bus->list);
-	mutex_unlock(&nvdimm_bus_list_mutex);
-
-	nd_synchronize();
-	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);
-
-	nvdimm_bus_lock(&nvdimm_bus->dev);
-	free_poison_list(&nvdimm_bus->poison_list);
-	nvdimm_bus_unlock(&nvdimm_bus->dev);
-
-	nvdimm_bus_destroy_ndctl(nvdimm_bus);
-
-	device_unregister(&nvdimm_bus->dev);
-}
-EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);
-
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)
 {
@@ -773,7 +647,6 @@ static __exit void libnvdimm_exit(void)
 	nvdimm_bus_exit();
 	nd_region_devs_exit();
 	nvdimm_devs_exit();
-	ida_destroy(&nd_ida);
 }
 
 MODULE_LICENSE("GPL v2");

[PATCH v4 2/4] nfit, libnvdimm: allow an ARS scrub to be triggered on demand

[Dan Williams]

From: Vishal Verma <vishal.l.verma@intel.com>

Normally, an ARS (Address Range Scrub) only happens at
boot/initialization time. There can however arise situations where a
bus-wide rescan is needed - notably, in the case of discovering a latent
media error, we should do a full rescan to figure out what other sectors
are bad, and thus potentially avoid triggering an mce on them in the
future. Also provide a sysfs trigger to start a bus-wide scrub.

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/nfit.c       |  167 +++++++++++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit.h       |    4 +
 drivers/nvdimm/core.c     |    7 ++
 include/linux/libnvdimm.h |    1 
 4 files changed, 171 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index be7c2fde16e7..2eaa03dc185a 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ndctl.h>
+#include <linux/sysfs.h>
 #include <linux/delay.h>
 #include <linux/list.h>
 #include <linux/acpi.h>
@@ -874,14 +875,87 @@ static ssize_t revision_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(revision);
 
+/*
+ * This shows the number of full Address Range Scrubs that have been
+ * completed since driver load time. Userspace can wait on this using
+ * select/poll etc. A '+' at the end indicates an ARS is in progress
+ */
+static ssize_t scrub_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc = -ENXIO;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
+				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+	}
+	device_unlock(dev);
+	return rc;
+}
+
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+static ssize_t scrub_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc;
+	long val;
+
+	rc = kstrtol(buf, 0, &val);
+	if (rc)
+		return rc;
+	if (val != 1)
+		return -EINVAL;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = acpi_nfit_ars_rescan(acpi_desc);
+	}
+	device_unlock(dev);
+	if (rc)
+		return rc;
+	return size;
+}
+static DEVICE_ATTR_RW(scrub);
+
+static bool ars_supported(struct nvdimm_bus *nvdimm_bus)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	const unsigned long mask = 1 << ND_CMD_ARS_CAP | 1 << ND_CMD_ARS_START
+		| 1 << ND_CMD_ARS_STATUS;
+
+	return (nd_desc->cmd_mask & mask) == mask;
+}
+
+static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	if (a == &dev_attr_scrub.attr && !ars_supported(nvdimm_bus))
+		return 0;
+	return a->mode;
+}
+
 static struct attribute *acpi_nfit_attributes[] = {
 	&dev_attr_revision.attr,
+	&dev_attr_scrub.attr,
 	NULL,
 };
 
 static struct attribute_group acpi_nfit_attribute_group = {
 	.name = "nfit",
 	.attrs = acpi_nfit_attributes,
+	.is_visible = nfit_visible,
 };
 
 static const struct attribute_group *acpi_nfit_attribute_groups[] = {
@@ -2054,7 +2128,7 @@ static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
 	unsigned int tmo = scrub_timeout;
 	int rc;
 
-	if (nfit_spa->ars_done || !nfit_spa->nd_region)
+	if (!nfit_spa->ars_required || !nfit_spa->nd_region)
 		return;
 
 	rc = ars_start(acpi_desc, nfit_spa);
@@ -2143,7 +2217,9 @@ static void acpi_nfit_scrub(struct work_struct *work)
 	 * firmware initiated scrubs to complete and then we go search for the
 	 * affected spa regions to mark them scanned.  In the second phase we
 	 * initiate a directed scrub for every range that was not scrubbed in
-	 * phase 1.
+	 * phase 1. If we're called for a 'rescan', we harmlessly pass through
+	 * the first phase, but really only care about running phase 2, where
+	 * regions can be notified of new poison.
 	 */
 
 	/* process platform firmware initiated scrubs */
@@ -2246,14 +2322,17 @@ static void acpi_nfit_scrub(struct work_struct *work)
 		 * Flag all the ranges that still need scrubbing, but
 		 * register them now to make data available.
 		 */
-		if (nfit_spa->nd_region)
-			nfit_spa->ars_done = 1;
-		else
+		if (!nfit_spa->nd_region) {
+			nfit_spa->ars_required = 1;
 			acpi_nfit_register_region(acpi_desc, nfit_spa);
+		}
 	}
 
 	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
 		acpi_nfit_async_scrub(acpi_desc, nfit_spa);
+	acpi_desc->scrub_count++;
+	if (acpi_desc->scrub_count_state)
+		sysfs_notify_dirent(acpi_desc->scrub_count_state);
 	mutex_unlock(&acpi_desc->init_mutex);
 }
 
@@ -2291,12 +2370,48 @@ static int acpi_nfit_check_deletions(struct acpi_nfit_desc *acpi_desc,
 	return 0;
 }
 
+static int acpi_nfit_desc_init_scrub_attr(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct kernfs_node *nfit;
+	struct device *bus_dev;
+
+	if (!ars_supported(acpi_desc->nvdimm_bus))
+		return 0;
+
+	bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+	nfit = sysfs_get_dirent(bus_dev->kobj.sd, "nfit");
+	if (!nfit) {
+		dev_err(dev, "sysfs_get_dirent 'nfit' failed\n");
+		return -ENODEV;
+	}
+	acpi_desc->scrub_count_state = sysfs_get_dirent(nfit, "scrub");
+	sysfs_put(nfit);
+	if (!acpi_desc->scrub_count_state) {
+		dev_err(dev, "sysfs_get_dirent 'scrub' failed\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
 static void acpi_nfit_destruct(void *data)
 {
 	struct acpi_nfit_desc *acpi_desc = data;
+	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
 
 	acpi_desc->cancel = 1;
+	/*
+	 * Bounce the nvdimm bus lock to make sure any in-flight
+	 * acpi_nfit_ars_rescan() submissions have had a chance to
+	 * either submit or see ->cancel set.
+	 */
+	device_lock(bus_dev);
+	device_unlock(bus_dev);
+
 	flush_workqueue(nfit_wq);
+	if (acpi_desc->scrub_count_state)
+		sysfs_put(acpi_desc->scrub_count_state);
 	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
 	acpi_desc->nvdimm_bus = NULL;
 }
@@ -2308,17 +2423,30 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	const void *end;
 	int rc;
 
+	acpi_nfit_init_dsms(acpi_desc);
+
 	if (!acpi_desc->nvdimm_bus) {
+		acpi_nfit_init_dsms(acpi_desc);
+
 		acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
 				&acpi_desc->nd_desc);
 		if (!acpi_desc->nvdimm_bus)
 			return -ENOMEM;
+
 		rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
 				acpi_desc);
 		if (rc)
 			return rc;
+
+		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+		if (rc)
+			return rc;
 	}
 
+	rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+	if (rc)
+		return rc;
+
 	mutex_lock(&acpi_desc->init_mutex);
 
 	INIT_LIST_HEAD(&prev.spas);
@@ -2360,8 +2488,6 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	if (rc)
 		goto out_unlock;
 
-	acpi_nfit_init_dsms(acpi_desc);
-
 	rc = acpi_nfit_register_dimms(acpi_desc);
 	if (rc)
 		goto out_unlock;
@@ -2429,6 +2555,33 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa;
+
+	if (work_busy(&acpi_desc->work))
+		return -EBUSY;
+
+	if (acpi_desc->cancel)
+		return 0;
+
+	mutex_lock(&acpi_desc->init_mutex);
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+		if (nfit_spa_type(spa) != NFIT_SPA_PM)
+			continue;
+
+		nfit_spa->ars_required = 1;
+	}
+	queue_work(nfit_wq, &acpi_desc->work);
+	dev_dbg(dev, "%s: ars_scan triggered\n", __func__);
+	mutex_unlock(&acpi_desc->init_mutex);
+
+	return 0;
+}
+
 void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 {
 	struct nvdimm_bus_descriptor *nd_desc;
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index b63a583a678f..6ecf337c97aa 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -80,7 +80,7 @@ enum {
 struct nfit_spa {
 	struct list_head list;
 	struct nd_region *nd_region;
-	unsigned int ars_done:1;
+	unsigned int ars_required:1;
 	u32 clear_err_unit;
 	u32 max_ars;
 	struct acpi_nfit_system_address spa[0];
@@ -148,6 +148,8 @@ struct acpi_nfit_desc {
 	struct nd_cmd_ars_status *ars_status;
 	size_t ars_status_size;
 	struct work_struct work;
+	struct kernfs_node *scrub_count_state;
+	unsigned int scrub_count;
 	unsigned int cancel:1;
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 2c98f958fabb..715583f69d28 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -201,6 +201,13 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
+{
+	/* struct nvdimm_bus definition is private to libnvdimm */
+	return &nvdimm_bus->dev;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);
+
 static bool is_uuid_sep(char sep)
 {
 	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 2ab869dece4a..b519e137b9b7 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -137,6 +137,7 @@ struct nvdimm *to_nvdimm(struct device *dev);
 struct nd_region *to_nd_region(struct device *dev);
 struct nd_blk_region *to_nd_blk_region(struct device *dev);
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus);
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus);
 const char *nvdimm_name(struct nvdimm *nvdimm);
 unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm);
 void *nvdimm_provider_data(struct nvdimm *nvdimm);

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

[PATCH v4 2/4] nfit, libnvdimm: allow an ARS scrub to be triggered on demand

[Dan Williams]

From: Vishal Verma <vishal.l.verma-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

Normally, an ARS (Address Range Scrub) only happens at
boot/initialization time. There can however arise situations where a
bus-wide rescan is needed - notably, in the case of discovering a latent
media error, we should do a full rescan to figure out what other sectors
are bad, and thus potentially avoid triggering an mce on them in the
future. Also provide a sysfs trigger to start a bus-wide scrub.

Cc: Rafael J. Wysocki <rafael.j.wysocki-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Vishal Verma <vishal.l.verma-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/acpi/nfit.c       |  167 +++++++++++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit.h       |    4 +
 drivers/nvdimm/core.c     |    7 ++
 include/linux/libnvdimm.h |    1 
 4 files changed, 171 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index be7c2fde16e7..2eaa03dc185a 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ndctl.h>
+#include <linux/sysfs.h>
 #include <linux/delay.h>
 #include <linux/list.h>
 #include <linux/acpi.h>
@@ -874,14 +875,87 @@ static ssize_t revision_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(revision);
 
+/*
+ * This shows the number of full Address Range Scrubs that have been
+ * completed since driver load time. Userspace can wait on this using
+ * select/poll etc. A '+' at the end indicates an ARS is in progress
+ */
+static ssize_t scrub_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc = -ENXIO;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
+				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+	}
+	device_unlock(dev);
+	return rc;
+}
+
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+static ssize_t scrub_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc;
+	long val;
+
+	rc = kstrtol(buf, 0, &val);
+	if (rc)
+		return rc;
+	if (val != 1)
+		return -EINVAL;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = acpi_nfit_ars_rescan(acpi_desc);
+	}
+	device_unlock(dev);
+	if (rc)
+		return rc;
+	return size;
+}
+static DEVICE_ATTR_RW(scrub);
+
+static bool ars_supported(struct nvdimm_bus *nvdimm_bus)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	const unsigned long mask = 1 << ND_CMD_ARS_CAP | 1 << ND_CMD_ARS_START
+		| 1 << ND_CMD_ARS_STATUS;
+
+	return (nd_desc->cmd_mask & mask) == mask;
+}
+
+static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	if (a == &dev_attr_scrub.attr && !ars_supported(nvdimm_bus))
+		return 0;
+	return a->mode;
+}
+
 static struct attribute *acpi_nfit_attributes[] = {
 	&dev_attr_revision.attr,
+	&dev_attr_scrub.attr,
 	NULL,
 };
 
 static struct attribute_group acpi_nfit_attribute_group = {
 	.name = "nfit",
 	.attrs = acpi_nfit_attributes,
+	.is_visible = nfit_visible,
 };
 
 static const struct attribute_group *acpi_nfit_attribute_groups[] = {
@@ -2054,7 +2128,7 @@ static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
 	unsigned int tmo = scrub_timeout;
 	int rc;
 
-	if (nfit_spa->ars_done || !nfit_spa->nd_region)
+	if (!nfit_spa->ars_required || !nfit_spa->nd_region)
 		return;
 
 	rc = ars_start(acpi_desc, nfit_spa);
@@ -2143,7 +2217,9 @@ static void acpi_nfit_scrub(struct work_struct *work)
 	 * firmware initiated scrubs to complete and then we go search for the
 	 * affected spa regions to mark them scanned.  In the second phase we
 	 * initiate a directed scrub for every range that was not scrubbed in
-	 * phase 1.
+	 * phase 1. If we're called for a 'rescan', we harmlessly pass through
+	 * the first phase, but really only care about running phase 2, where
+	 * regions can be notified of new poison.
 	 */
 
 	/* process platform firmware initiated scrubs */
@@ -2246,14 +2322,17 @@ static void acpi_nfit_scrub(struct work_struct *work)
 		 * Flag all the ranges that still need scrubbing, but
 		 * register them now to make data available.
 		 */
-		if (nfit_spa->nd_region)
-			nfit_spa->ars_done = 1;
-		else
+		if (!nfit_spa->nd_region) {
+			nfit_spa->ars_required = 1;
 			acpi_nfit_register_region(acpi_desc, nfit_spa);
+		}
 	}
 
 	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
 		acpi_nfit_async_scrub(acpi_desc, nfit_spa);
+	acpi_desc->scrub_count++;
+	if (acpi_desc->scrub_count_state)
+		sysfs_notify_dirent(acpi_desc->scrub_count_state);
 	mutex_unlock(&acpi_desc->init_mutex);
 }
 
@@ -2291,12 +2370,48 @@ static int acpi_nfit_check_deletions(struct acpi_nfit_desc *acpi_desc,
 	return 0;
 }
 
+static int acpi_nfit_desc_init_scrub_attr(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct kernfs_node *nfit;
+	struct device *bus_dev;
+
+	if (!ars_supported(acpi_desc->nvdimm_bus))
+		return 0;
+
+	bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+	nfit = sysfs_get_dirent(bus_dev->kobj.sd, "nfit");
+	if (!nfit) {
+		dev_err(dev, "sysfs_get_dirent 'nfit' failed\n");
+		return -ENODEV;
+	}
+	acpi_desc->scrub_count_state = sysfs_get_dirent(nfit, "scrub");
+	sysfs_put(nfit);
+	if (!acpi_desc->scrub_count_state) {
+		dev_err(dev, "sysfs_get_dirent 'scrub' failed\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
 static void acpi_nfit_destruct(void *data)
 {
 	struct acpi_nfit_desc *acpi_desc = data;
+	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
 
 	acpi_desc->cancel = 1;
+	/*
+	 * Bounce the nvdimm bus lock to make sure any in-flight
+	 * acpi_nfit_ars_rescan() submissions have had a chance to
+	 * either submit or see ->cancel set.
+	 */
+	device_lock(bus_dev);
+	device_unlock(bus_dev);
+
 	flush_workqueue(nfit_wq);
+	if (acpi_desc->scrub_count_state)
+		sysfs_put(acpi_desc->scrub_count_state);
 	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
 	acpi_desc->nvdimm_bus = NULL;
 }
@@ -2308,17 +2423,30 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	const void *end;
 	int rc;
 
+	acpi_nfit_init_dsms(acpi_desc);
+
 	if (!acpi_desc->nvdimm_bus) {
+		acpi_nfit_init_dsms(acpi_desc);
+
 		acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
 				&acpi_desc->nd_desc);
 		if (!acpi_desc->nvdimm_bus)
 			return -ENOMEM;
+
 		rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
 				acpi_desc);
 		if (rc)
 			return rc;
+
+		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+		if (rc)
+			return rc;
 	}
 
+	rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+	if (rc)
+		return rc;
+
 	mutex_lock(&acpi_desc->init_mutex);
 
 	INIT_LIST_HEAD(&prev.spas);
@@ -2360,8 +2488,6 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	if (rc)
 		goto out_unlock;
 
-	acpi_nfit_init_dsms(acpi_desc);
-
 	rc = acpi_nfit_register_dimms(acpi_desc);
 	if (rc)
 		goto out_unlock;
@@ -2429,6 +2555,33 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa;
+
+	if (work_busy(&acpi_desc->work))
+		return -EBUSY;
+
+	if (acpi_desc->cancel)
+		return 0;
+
+	mutex_lock(&acpi_desc->init_mutex);
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+		if (nfit_spa_type(spa) != NFIT_SPA_PM)
+			continue;
+
+		nfit_spa->ars_required = 1;
+	}
+	queue_work(nfit_wq, &acpi_desc->work);
+	dev_dbg(dev, "%s: ars_scan triggered\n", __func__);
+	mutex_unlock(&acpi_desc->init_mutex);
+
+	return 0;
+}
+
 void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 {
 	struct nvdimm_bus_descriptor *nd_desc;
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index b63a583a678f..6ecf337c97aa 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -80,7 +80,7 @@ enum {
 struct nfit_spa {
 	struct list_head list;
 	struct nd_region *nd_region;
-	unsigned int ars_done:1;
+	unsigned int ars_required:1;
 	u32 clear_err_unit;
 	u32 max_ars;
 	struct acpi_nfit_system_address spa[0];
@@ -148,6 +148,8 @@ struct acpi_nfit_desc {
 	struct nd_cmd_ars_status *ars_status;
 	size_t ars_status_size;
 	struct work_struct work;
+	struct kernfs_node *scrub_count_state;
+	unsigned int scrub_count;
 	unsigned int cancel:1;
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 2c98f958fabb..715583f69d28 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -201,6 +201,13 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
+{
+	/* struct nvdimm_bus definition is private to libnvdimm */
+	return &nvdimm_bus->dev;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);
+
 static bool is_uuid_sep(char sep)
 {
 	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 2ab869dece4a..b519e137b9b7 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -137,6 +137,7 @@ struct nvdimm *to_nvdimm(struct device *dev);
 struct nd_region *to_nd_region(struct device *dev);
 struct nd_blk_region *to_nd_blk_region(struct device *dev);
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus);
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus);
 const char *nvdimm_name(struct nvdimm *nvdimm);
 unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm);
 void *nvdimm_provider_data(struct nvdimm *nvdimm);

[PATCH v4 2/4] nfit, libnvdimm: allow an ARS scrub to be triggered on demand

[Dan Williams]

From: Vishal Verma <vishal.l.verma@intel.com>

Normally, an ARS (Address Range Scrub) only happens at
boot/initialization time. There can however arise situations where a
bus-wide rescan is needed - notably, in the case of discovering a latent
media error, we should do a full rescan to figure out what other sectors
are bad, and thus potentially avoid triggering an mce on them in the
future. Also provide a sysfs trigger to start a bus-wide scrub.

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/nfit.c       |  167 +++++++++++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit.h       |    4 +
 drivers/nvdimm/core.c     |    7 ++
 include/linux/libnvdimm.h |    1 
 4 files changed, 171 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index be7c2fde16e7..2eaa03dc185a 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ndctl.h>
+#include <linux/sysfs.h>
 #include <linux/delay.h>
 #include <linux/list.h>
 #include <linux/acpi.h>
@@ -874,14 +875,87 @@ static ssize_t revision_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(revision);
 
+/*
+ * This shows the number of full Address Range Scrubs that have been
+ * completed since driver load time. Userspace can wait on this using
+ * select/poll etc. A '+' at the end indicates an ARS is in progress
+ */
+static ssize_t scrub_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc = -ENXIO;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
+				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+	}
+	device_unlock(dev);
+	return rc;
+}
+
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+static ssize_t scrub_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc;
+	long val;
+
+	rc = kstrtol(buf, 0, &val);
+	if (rc)
+		return rc;
+	if (val != 1)
+		return -EINVAL;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = acpi_nfit_ars_rescan(acpi_desc);
+	}
+	device_unlock(dev);
+	if (rc)
+		return rc;
+	return size;
+}
+static DEVICE_ATTR_RW(scrub);
+
+static bool ars_supported(struct nvdimm_bus *nvdimm_bus)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	const unsigned long mask = 1 << ND_CMD_ARS_CAP | 1 << ND_CMD_ARS_START
+		| 1 << ND_CMD_ARS_STATUS;
+
+	return (nd_desc->cmd_mask & mask) == mask;
+}
+
+static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	if (a == &dev_attr_scrub.attr && !ars_supported(nvdimm_bus))
+		return 0;
+	return a->mode;
+}
+
 static struct attribute *acpi_nfit_attributes[] = {
 	&dev_attr_revision.attr,
+	&dev_attr_scrub.attr,
 	NULL,
 };
 
 static struct attribute_group acpi_nfit_attribute_group = {
 	.name = "nfit",
 	.attrs = acpi_nfit_attributes,
+	.is_visible = nfit_visible,
 };
 
 static const struct attribute_group *acpi_nfit_attribute_groups[] = {
@@ -2054,7 +2128,7 @@ static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
 	unsigned int tmo = scrub_timeout;
 	int rc;
 
-	if (nfit_spa->ars_done || !nfit_spa->nd_region)
+	if (!nfit_spa->ars_required || !nfit_spa->nd_region)
 		return;
 
 	rc = ars_start(acpi_desc, nfit_spa);
@@ -2143,7 +2217,9 @@ static void acpi_nfit_scrub(struct work_struct *work)
 	 * firmware initiated scrubs to complete and then we go search for the
 	 * affected spa regions to mark them scanned.  In the second phase we
 	 * initiate a directed scrub for every range that was not scrubbed in
-	 * phase 1.
+	 * phase 1. If we're called for a 'rescan', we harmlessly pass through
+	 * the first phase, but really only care about running phase 2, where
+	 * regions can be notified of new poison.
 	 */
 
 	/* process platform firmware initiated scrubs */
@@ -2246,14 +2322,17 @@ static void acpi_nfit_scrub(struct work_struct *work)
 		 * Flag all the ranges that still need scrubbing, but
 		 * register them now to make data available.
 		 */
-		if (nfit_spa->nd_region)
-			nfit_spa->ars_done = 1;
-		else
+		if (!nfit_spa->nd_region) {
+			nfit_spa->ars_required = 1;
 			acpi_nfit_register_region(acpi_desc, nfit_spa);
+		}
 	}
 
 	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
 		acpi_nfit_async_scrub(acpi_desc, nfit_spa);
+	acpi_desc->scrub_count++;
+	if (acpi_desc->scrub_count_state)
+		sysfs_notify_dirent(acpi_desc->scrub_count_state);
 	mutex_unlock(&acpi_desc->init_mutex);
 }
 
@@ -2291,12 +2370,48 @@ static int acpi_nfit_check_deletions(struct acpi_nfit_desc *acpi_desc,
 	return 0;
 }
 
+static int acpi_nfit_desc_init_scrub_attr(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct kernfs_node *nfit;
+	struct device *bus_dev;
+
+	if (!ars_supported(acpi_desc->nvdimm_bus))
+		return 0;
+
+	bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+	nfit = sysfs_get_dirent(bus_dev->kobj.sd, "nfit");
+	if (!nfit) {
+		dev_err(dev, "sysfs_get_dirent 'nfit' failed\n");
+		return -ENODEV;
+	}
+	acpi_desc->scrub_count_state = sysfs_get_dirent(nfit, "scrub");
+	sysfs_put(nfit);
+	if (!acpi_desc->scrub_count_state) {
+		dev_err(dev, "sysfs_get_dirent 'scrub' failed\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
 static void acpi_nfit_destruct(void *data)
 {
 	struct acpi_nfit_desc *acpi_desc = data;
+	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
 
 	acpi_desc->cancel = 1;
+	/*
+	 * Bounce the nvdimm bus lock to make sure any in-flight
+	 * acpi_nfit_ars_rescan() submissions have had a chance to
+	 * either submit or see ->cancel set.
+	 */
+	device_lock(bus_dev);
+	device_unlock(bus_dev);
+
 	flush_workqueue(nfit_wq);
+	if (acpi_desc->scrub_count_state)
+		sysfs_put(acpi_desc->scrub_count_state);
 	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
 	acpi_desc->nvdimm_bus = NULL;
 }
@@ -2308,17 +2423,30 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	const void *end;
 	int rc;
 
+	acpi_nfit_init_dsms(acpi_desc);
+
 	if (!acpi_desc->nvdimm_bus) {
+		acpi_nfit_init_dsms(acpi_desc);
+
 		acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
 				&acpi_desc->nd_desc);
 		if (!acpi_desc->nvdimm_bus)
 			return -ENOMEM;
+
 		rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
 				acpi_desc);
 		if (rc)
 			return rc;
+
+		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+		if (rc)
+			return rc;
 	}
 
+	rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+	if (rc)
+		return rc;
+
 	mutex_lock(&acpi_desc->init_mutex);
 
 	INIT_LIST_HEAD(&prev.spas);
@@ -2360,8 +2488,6 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	if (rc)
 		goto out_unlock;
 
-	acpi_nfit_init_dsms(acpi_desc);
-
 	rc = acpi_nfit_register_dimms(acpi_desc);
 	if (rc)
 		goto out_unlock;
@@ -2429,6 +2555,33 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa;
+
+	if (work_busy(&acpi_desc->work))
+		return -EBUSY;
+
+	if (acpi_desc->cancel)
+		return 0;
+
+	mutex_lock(&acpi_desc->init_mutex);
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+		if (nfit_spa_type(spa) != NFIT_SPA_PM)
+			continue;
+
+		nfit_spa->ars_required = 1;
+	}
+	queue_work(nfit_wq, &acpi_desc->work);
+	dev_dbg(dev, "%s: ars_scan triggered\n", __func__);
+	mutex_unlock(&acpi_desc->init_mutex);
+
+	return 0;
+}
+
 void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 {
 	struct nvdimm_bus_descriptor *nd_desc;
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index b63a583a678f..6ecf337c97aa 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -80,7 +80,7 @@ enum {
 struct nfit_spa {
 	struct list_head list;
 	struct nd_region *nd_region;
-	unsigned int ars_done:1;
+	unsigned int ars_required:1;
 	u32 clear_err_unit;
 	u32 max_ars;
 	struct acpi_nfit_system_address spa[0];
@@ -148,6 +148,8 @@ struct acpi_nfit_desc {
 	struct nd_cmd_ars_status *ars_status;
 	size_t ars_status_size;
 	struct work_struct work;
+	struct kernfs_node *scrub_count_state;
+	unsigned int scrub_count;
 	unsigned int cancel:1;
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 2c98f958fabb..715583f69d28 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -201,6 +201,13 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
+{
+	/* struct nvdimm_bus definition is private to libnvdimm */
+	return &nvdimm_bus->dev;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);
+
 static bool is_uuid_sep(char sep)
 {
 	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 2ab869dece4a..b519e137b9b7 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -137,6 +137,7 @@ struct nvdimm *to_nvdimm(struct device *dev);
 struct nd_region *to_nd_region(struct device *dev);
 struct nd_blk_region *to_nd_blk_region(struct device *dev);
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus);
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus);
 const char *nvdimm_name(struct nvdimm *nvdimm);
 unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm);
 void *nvdimm_provider_data(struct nvdimm *nvdimm);

[PATCH v4 3/4] nfit: move to nfit/ sub-directory

[Dan Williams]

With the arrival of x86-machine-check support the nfit driver will add a
(conditionally-compiled) source file.  Prepare for this by moving all
nfit source to drivers/acpi/nfit/.  This is pure code movement, no
functional changes.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/Kconfig             |   27 +--------------------------
 drivers/acpi/Makefile            |    2 +-
 drivers/acpi/nfit/Kconfig        |   26 ++++++++++++++++++++++++++
 drivers/acpi/nfit/Makefile       |    2 ++
 drivers/acpi/nfit/core.c         |    0 
 drivers/acpi/nfit/nfit.h         |    0 
 tools/testing/nvdimm/Kbuild      |    4 ++--
 tools/testing/nvdimm/test/Kbuild |    2 +-
 8 files changed, 33 insertions(+), 30 deletions(-)
 create mode 100644 drivers/acpi/nfit/Kconfig
 create mode 100644 drivers/acpi/nfit/Makefile
 rename drivers/acpi/{nfit.c => nfit/core.c} (100%)
 rename drivers/acpi/{nfit.h => nfit/nfit.h} (100%)

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index b7e2e776397d..415b148a8698 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -447,32 +447,7 @@ config ACPI_REDUCED_HARDWARE_ONLY
 
 	  If you are unsure what to do, do not enable this option.
 
-config ACPI_NFIT
-	tristate "ACPI NVDIMM Firmware Interface Table (NFIT)"
-	depends on PHYS_ADDR_T_64BIT
-	depends on BLK_DEV
-	depends on ARCH_HAS_MMIO_FLUSH
-	select LIBNVDIMM
-	help
-	  Infrastructure to probe ACPI 6 compliant platforms for
-	  NVDIMMs (NFIT) and register a libnvdimm device tree.  In
-	  addition to storage devices this also enables libnvdimm to pass
-	  ACPI._DSM messages for platform/dimm configuration.
-
-	  To compile this driver as a module, choose M here:
-	  the module will be called nfit.
-
-config ACPI_NFIT_DEBUG
-	bool "NFIT DSM debug"
-	depends on ACPI_NFIT
-	depends on DYNAMIC_DEBUG
-	default n
-	help
-	  Enabling this option causes the nfit driver to dump the
-	  input and output buffers of _DSM operations on the ACPI0012
-	  device and its children.  This can be very verbose, so leave
-	  it disabled unless you are debugging a hardware / firmware
-	  issue.
+source "drivers/acpi/nfit/Kconfig"
 
 source "drivers/acpi/apei/Kconfig"
 
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 251ce85a66fb..64a575a6f7ef 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -70,7 +70,7 @@ obj-$(CONFIG_ACPI_PCI_SLOT)	+= pci_slot.o
 obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
 obj-$(CONFIG_ACPI)		+= container.o
 obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
-obj-$(CONFIG_ACPI_NFIT)		+= nfit.o
+obj-$(CONFIG_ACPI_NFIT)		+= nfit/
 obj-$(CONFIG_ACPI)		+= acpi_memhotplug.o
 obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
 obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
diff --git a/drivers/acpi/nfit/Kconfig b/drivers/acpi/nfit/Kconfig
new file mode 100644
index 000000000000..dd0d53c52552
--- /dev/null
+++ b/drivers/acpi/nfit/Kconfig
@@ -0,0 +1,26 @@
+config ACPI_NFIT
+	tristate "ACPI NVDIMM Firmware Interface Table (NFIT)"
+	depends on PHYS_ADDR_T_64BIT
+	depends on BLK_DEV
+	depends on ARCH_HAS_MMIO_FLUSH
+	select LIBNVDIMM
+	help
+	  Infrastructure to probe ACPI 6 compliant platforms for
+	  NVDIMMs (NFIT) and register a libnvdimm device tree.  In
+	  addition to storage devices this also enables libnvdimm to pass
+	  ACPI._DSM messages for platform/dimm configuration.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called nfit.
+
+config ACPI_NFIT_DEBUG
+	bool "NFIT DSM debug"
+	depends on ACPI_NFIT
+	depends on DYNAMIC_DEBUG
+	default n
+	help
+	  Enabling this option causes the nfit driver to dump the
+	  input and output buffers of _DSM operations on the ACPI0012
+	  device and its children.  This can be very verbose, so leave
+	  it disabled unless you are debugging a hardware / firmware
+	  issue.
diff --git a/drivers/acpi/nfit/Makefile b/drivers/acpi/nfit/Makefile
new file mode 100644
index 000000000000..eb95c5aff83b
--- /dev/null
+++ b/drivers/acpi/nfit/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_ACPI_NFIT) := nfit.o
+nfit-y := core.o
diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit/core.c
similarity index 100%
rename from drivers/acpi/nfit.c
rename to drivers/acpi/nfit/core.c
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit/nfit.h
similarity index 100%
rename from drivers/acpi/nfit.h
rename to drivers/acpi/nfit/nfit.h
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index 62d5ac3c988e..0dca8ff7557b 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -16,7 +16,7 @@ ldflags-y += --wrap=remove_resource
 
 DRIVERS := ../../../drivers
 NVDIMM_SRC := $(DRIVERS)/nvdimm
-ACPI_SRC := $(DRIVERS)/acpi
+ACPI_SRC := $(DRIVERS)/acpi/nfit
 DAX_SRC := $(DRIVERS)/dax
 ccflags-y := -I$(src)/$(NVDIMM_SRC)/
 
@@ -29,7 +29,7 @@ obj-$(CONFIG_ACPI_NFIT) += nfit.o
 obj-$(CONFIG_DEV_DAX) += dax.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
-nfit-y := $(ACPI_SRC)/nfit.o
+nfit-y := $(ACPI_SRC)/core.o
 nfit-y += config_check.o
 
 nd_pmem-y := $(NVDIMM_SRC)/pmem.o
diff --git a/tools/testing/nvdimm/test/Kbuild b/tools/testing/nvdimm/test/Kbuild
index 9241064970fe..d32f25bba42a 100644
--- a/tools/testing/nvdimm/test/Kbuild
+++ b/tools/testing/nvdimm/test/Kbuild
@@ -1,5 +1,5 @@
 ccflags-y := -I$(src)/../../../../drivers/nvdimm/
-ccflags-y += -I$(src)/../../../../drivers/acpi/
+ccflags-y += -I$(src)/../../../../drivers/acpi/nfit/
 
 obj-m += nfit_test.o
 obj-m += nfit_test_iomap.o

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

[PATCH v4 3/4] nfit: move to nfit/ sub-directory

[Dan Williams]

With the arrival of x86-machine-check support the nfit driver will add a
(conditionally-compiled) source file.  Prepare for this by moving all
nfit source to drivers/acpi/nfit/.  This is pure code movement, no
functional changes.

Signed-off-by: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/acpi/Kconfig             |   27 +--------------------------
 drivers/acpi/Makefile            |    2 +-
 drivers/acpi/nfit/Kconfig        |   26 ++++++++++++++++++++++++++
 drivers/acpi/nfit/Makefile       |    2 ++
 drivers/acpi/nfit/core.c         |    0 
 drivers/acpi/nfit/nfit.h         |    0 
 tools/testing/nvdimm/Kbuild      |    4 ++--
 tools/testing/nvdimm/test/Kbuild |    2 +-
 8 files changed, 33 insertions(+), 30 deletions(-)
 create mode 100644 drivers/acpi/nfit/Kconfig
 create mode 100644 drivers/acpi/nfit/Makefile
 rename drivers/acpi/{nfit.c => nfit/core.c} (100%)
 rename drivers/acpi/{nfit.h => nfit/nfit.h} (100%)

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index b7e2e776397d..415b148a8698 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -447,32 +447,7 @@ config ACPI_REDUCED_HARDWARE_ONLY
 
 	  If you are unsure what to do, do not enable this option.
 
-config ACPI_NFIT
-	tristate "ACPI NVDIMM Firmware Interface Table (NFIT)"
-	depends on PHYS_ADDR_T_64BIT
-	depends on BLK_DEV
-	depends on ARCH_HAS_MMIO_FLUSH
-	select LIBNVDIMM
-	help
-	  Infrastructure to probe ACPI 6 compliant platforms for
-	  NVDIMMs (NFIT) and register a libnvdimm device tree.  In
-	  addition to storage devices this also enables libnvdimm to pass
-	  ACPI._DSM messages for platform/dimm configuration.
-
-	  To compile this driver as a module, choose M here:
-	  the module will be called nfit.
-
-config ACPI_NFIT_DEBUG
-	bool "NFIT DSM debug"
-	depends on ACPI_NFIT
-	depends on DYNAMIC_DEBUG
-	default n
-	help
-	  Enabling this option causes the nfit driver to dump the
-	  input and output buffers of _DSM operations on the ACPI0012
-	  device and its children.  This can be very verbose, so leave
-	  it disabled unless you are debugging a hardware / firmware
-	  issue.
+source "drivers/acpi/nfit/Kconfig"
 
 source "drivers/acpi/apei/Kconfig"
 
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 251ce85a66fb..64a575a6f7ef 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -70,7 +70,7 @@ obj-$(CONFIG_ACPI_PCI_SLOT)	+= pci_slot.o
 obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
 obj-$(CONFIG_ACPI)		+= container.o
 obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
-obj-$(CONFIG_ACPI_NFIT)		+= nfit.o
+obj-$(CONFIG_ACPI_NFIT)		+= nfit/
 obj-$(CONFIG_ACPI)		+= acpi_memhotplug.o
 obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
 obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
diff --git a/drivers/acpi/nfit/Kconfig b/drivers/acpi/nfit/Kconfig
new file mode 100644
index 000000000000..dd0d53c52552
--- /dev/null
+++ b/drivers/acpi/nfit/Kconfig
@@ -0,0 +1,26 @@
+config ACPI_NFIT
+	tristate "ACPI NVDIMM Firmware Interface Table (NFIT)"
+	depends on PHYS_ADDR_T_64BIT
+	depends on BLK_DEV
+	depends on ARCH_HAS_MMIO_FLUSH
+	select LIBNVDIMM
+	help
+	  Infrastructure to probe ACPI 6 compliant platforms for
+	  NVDIMMs (NFIT) and register a libnvdimm device tree.  In
+	  addition to storage devices this also enables libnvdimm to pass
+	  ACPI._DSM messages for platform/dimm configuration.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called nfit.
+
+config ACPI_NFIT_DEBUG
+	bool "NFIT DSM debug"
+	depends on ACPI_NFIT
+	depends on DYNAMIC_DEBUG
+	default n
+	help
+	  Enabling this option causes the nfit driver to dump the
+	  input and output buffers of _DSM operations on the ACPI0012
+	  device and its children.  This can be very verbose, so leave
+	  it disabled unless you are debugging a hardware / firmware
+	  issue.
diff --git a/drivers/acpi/nfit/Makefile b/drivers/acpi/nfit/Makefile
new file mode 100644
index 000000000000..eb95c5aff83b
--- /dev/null
+++ b/drivers/acpi/nfit/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_ACPI_NFIT) := nfit.o
+nfit-y := core.o
diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit/core.c
similarity index 100%
rename from drivers/acpi/nfit.c
rename to drivers/acpi/nfit/core.c
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit/nfit.h
similarity index 100%
rename from drivers/acpi/nfit.h
rename to drivers/acpi/nfit/nfit.h
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index 62d5ac3c988e..0dca8ff7557b 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -16,7 +16,7 @@ ldflags-y += --wrap=remove_resource
 
 DRIVERS := ../../../drivers
 NVDIMM_SRC := $(DRIVERS)/nvdimm
-ACPI_SRC := $(DRIVERS)/acpi
+ACPI_SRC := $(DRIVERS)/acpi/nfit
 DAX_SRC := $(DRIVERS)/dax
 ccflags-y := -I$(src)/$(NVDIMM_SRC)/
 
@@ -29,7 +29,7 @@ obj-$(CONFIG_ACPI_NFIT) += nfit.o
 obj-$(CONFIG_DEV_DAX) += dax.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
-nfit-y := $(ACPI_SRC)/nfit.o
+nfit-y := $(ACPI_SRC)/core.o
 nfit-y += config_check.o
 
 nd_pmem-y := $(NVDIMM_SRC)/pmem.o
diff --git a/tools/testing/nvdimm/test/Kbuild b/tools/testing/nvdimm/test/Kbuild
index 9241064970fe..d32f25bba42a 100644
--- a/tools/testing/nvdimm/test/Kbuild
+++ b/tools/testing/nvdimm/test/Kbuild
@@ -1,5 +1,5 @@
 ccflags-y := -I$(src)/../../../../drivers/nvdimm/
-ccflags-y += -I$(src)/../../../../drivers/acpi/
+ccflags-y += -I$(src)/../../../../drivers/acpi/nfit/
 
 obj-m += nfit_test.o
 obj-m += nfit_test_iomap.o

[PATCH v4 3/4] nfit: move to nfit/ sub-directory

[Dan Williams]

With the arrival of x86-machine-check support the nfit driver will add a
(conditionally-compiled) source file.  Prepare for this by moving all
nfit source to drivers/acpi/nfit/.  This is pure code movement, no
functional changes.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/Kconfig             |   27 +--------------------------
 drivers/acpi/Makefile            |    2 +-
 drivers/acpi/nfit/Kconfig        |   26 ++++++++++++++++++++++++++
 drivers/acpi/nfit/Makefile       |    2 ++
 drivers/acpi/nfit/core.c         |    0 
 drivers/acpi/nfit/nfit.h         |    0 
 tools/testing/nvdimm/Kbuild      |    4 ++--
 tools/testing/nvdimm/test/Kbuild |    2 +-
 8 files changed, 33 insertions(+), 30 deletions(-)
 create mode 100644 drivers/acpi/nfit/Kconfig
 create mode 100644 drivers/acpi/nfit/Makefile
 rename drivers/acpi/{nfit.c => nfit/core.c} (100%)
 rename drivers/acpi/{nfit.h => nfit/nfit.h} (100%)

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index b7e2e776397d..415b148a8698 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -447,32 +447,7 @@ config ACPI_REDUCED_HARDWARE_ONLY
 
 	  If you are unsure what to do, do not enable this option.
 
-config ACPI_NFIT
-	tristate "ACPI NVDIMM Firmware Interface Table (NFIT)"
-	depends on PHYS_ADDR_T_64BIT
-	depends on BLK_DEV
-	depends on ARCH_HAS_MMIO_FLUSH
-	select LIBNVDIMM
-	help
-	  Infrastructure to probe ACPI 6 compliant platforms for
-	  NVDIMMs (NFIT) and register a libnvdimm device tree.  In
-	  addition to storage devices this also enables libnvdimm to pass
-	  ACPI._DSM messages for platform/dimm configuration.
-
-	  To compile this driver as a module, choose M here:
-	  the module will be called nfit.
-
-config ACPI_NFIT_DEBUG
-	bool "NFIT DSM debug"
-	depends on ACPI_NFIT
-	depends on DYNAMIC_DEBUG
-	default n
-	help
-	  Enabling this option causes the nfit driver to dump the
-	  input and output buffers of _DSM operations on the ACPI0012
-	  device and its children.  This can be very verbose, so leave
-	  it disabled unless you are debugging a hardware / firmware
-	  issue.
+source "drivers/acpi/nfit/Kconfig"
 
 source "drivers/acpi/apei/Kconfig"
 
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 251ce85a66fb..64a575a6f7ef 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -70,7 +70,7 @@ obj-$(CONFIG_ACPI_PCI_SLOT)	+= pci_slot.o
 obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
 obj-$(CONFIG_ACPI)		+= container.o
 obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
-obj-$(CONFIG_ACPI_NFIT)		+= nfit.o
+obj-$(CONFIG_ACPI_NFIT)		+= nfit/
 obj-$(CONFIG_ACPI)		+= acpi_memhotplug.o
 obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
 obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
diff --git a/drivers/acpi/nfit/Kconfig b/drivers/acpi/nfit/Kconfig
new file mode 100644
index 000000000000..dd0d53c52552
--- /dev/null
+++ b/drivers/acpi/nfit/Kconfig
@@ -0,0 +1,26 @@
+config ACPI_NFIT
+	tristate "ACPI NVDIMM Firmware Interface Table (NFIT)"
+	depends on PHYS_ADDR_T_64BIT
+	depends on BLK_DEV
+	depends on ARCH_HAS_MMIO_FLUSH
+	select LIBNVDIMM
+	help
+	  Infrastructure to probe ACPI 6 compliant platforms for
+	  NVDIMMs (NFIT) and register a libnvdimm device tree.  In
+	  addition to storage devices this also enables libnvdimm to pass
+	  ACPI._DSM messages for platform/dimm configuration.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called nfit.
+
+config ACPI_NFIT_DEBUG
+	bool "NFIT DSM debug"
+	depends on ACPI_NFIT
+	depends on DYNAMIC_DEBUG
+	default n
+	help
+	  Enabling this option causes the nfit driver to dump the
+	  input and output buffers of _DSM operations on the ACPI0012
+	  device and its children.  This can be very verbose, so leave
+	  it disabled unless you are debugging a hardware / firmware
+	  issue.
diff --git a/drivers/acpi/nfit/Makefile b/drivers/acpi/nfit/Makefile
new file mode 100644
index 000000000000..eb95c5aff83b
--- /dev/null
+++ b/drivers/acpi/nfit/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_ACPI_NFIT) := nfit.o
+nfit-y := core.o
diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit/core.c
similarity index 100%
rename from drivers/acpi/nfit.c
rename to drivers/acpi/nfit/core.c
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit/nfit.h
similarity index 100%
rename from drivers/acpi/nfit.h
rename to drivers/acpi/nfit/nfit.h
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index 62d5ac3c988e..0dca8ff7557b 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -16,7 +16,7 @@ ldflags-y += --wrap=remove_resource
 
 DRIVERS := ../../../drivers
 NVDIMM_SRC := $(DRIVERS)/nvdimm
-ACPI_SRC := $(DRIVERS)/acpi
+ACPI_SRC := $(DRIVERS)/acpi/nfit
 DAX_SRC := $(DRIVERS)/dax
 ccflags-y := -I$(src)/$(NVDIMM_SRC)/
 
@@ -29,7 +29,7 @@ obj-$(CONFIG_ACPI_NFIT) += nfit.o
 obj-$(CONFIG_DEV_DAX) += dax.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
-nfit-y := $(ACPI_SRC)/nfit.o
+nfit-y := $(ACPI_SRC)/core.o
 nfit-y += config_check.o
 
 nd_pmem-y := $(NVDIMM_SRC)/pmem.o
diff --git a/tools/testing/nvdimm/test/Kbuild b/tools/testing/nvdimm/test/Kbuild
index 9241064970fe..d32f25bba42a 100644
--- a/tools/testing/nvdimm/test/Kbuild
+++ b/tools/testing/nvdimm/test/Kbuild
@@ -1,5 +1,5 @@
 ccflags-y := -I$(src)/../../../../drivers/nvdimm/
-ccflags-y += -I$(src)/../../../../drivers/acpi/
+ccflags-y += -I$(src)/../../../../drivers/acpi/nfit/
 
 obj-m += nfit_test.o
 obj-m += nfit_test_iomap.o

[PATCH v4 4/4] nfit: do an ARS scrub on hitting a latent media error

[Dan Williams]

From: Vishal Verma <vishal.l.verma@intel.com>

When a latent (unknown to 'badblocks') error is encountered, it will
trigger a machine check exception. On a system with machine check
recovery, this will only SIGBUS the process(es) which had the bad page
mapped (as opposed to a kernel panic on platforms without machine
check recovery features). In the former case, we want to trigger a full
rescan of that nvdimm bus. This will allow any additional, new errors
to be captured in the block devices' badblocks lists, and offending
operations on them can be trapped early, avoiding machine checks.

This is done by registering a callback function with the
x86_mce_decoder_chain and calling the new ars_rescan functionality with
the address in the mce notificatiion.

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/nfit/Makefile  |    1 
 drivers/acpi/nfit/core.c    |   26 +++++++++++--
 drivers/acpi/nfit/mce.c     |   89 +++++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/nfit/nfit.h    |   20 ++++++++++
 tools/testing/nvdimm/Kbuild |    1 
 5 files changed, 133 insertions(+), 4 deletions(-)
 create mode 100644 drivers/acpi/nfit/mce.c

diff --git a/drivers/acpi/nfit/Makefile b/drivers/acpi/nfit/Makefile
index eb95c5aff83b..a407e769f103 100644
--- a/drivers/acpi/nfit/Makefile
+++ b/drivers/acpi/nfit/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_ACPI_NFIT) := nfit.o
 nfit-y := core.o
+nfit-$(CONFIG_X86_MCE) += mce.o
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 2eaa03dc185a..686837e8358f 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -51,6 +51,9 @@ module_param(disable_vendor_specific, bool, S_IRUGO);
 MODULE_PARM_DESC(disable_vendor_specific,
 		"Limit commands to the publicly specified set\n");
 
+LIST_HEAD(acpi_descs);
+DEFINE_MUTEX(acpi_desc_lock);
+
 static struct workqueue_struct *nfit_wq;
 
 struct nfit_table_prev {
@@ -361,7 +364,7 @@ static const char *spa_type_name(u16 type)
 	return to_name[type];
 }
 
-static int nfit_spa_type(struct acpi_nfit_system_address *spa)
+int nfit_spa_type(struct acpi_nfit_system_address *spa)
 {
 	int i;
 
@@ -898,8 +901,6 @@ static ssize_t scrub_show(struct device *dev,
 	return rc;
 }
 
-static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
-
 static ssize_t scrub_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t size)
 {
@@ -2400,6 +2401,11 @@ static void acpi_nfit_destruct(void *data)
 	struct acpi_nfit_desc *acpi_desc = data;
 	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
 
+	/*
+	 * Destruct under acpi_desc_lock so that nfit_handle_mce does not
+	 * race teardown
+	 */
+	mutex_lock(&acpi_desc_lock);
 	acpi_desc->cancel = 1;
 	/*
 	 * Bounce the nvdimm bus lock to make sure any in-flight
@@ -2414,6 +2420,8 @@ static void acpi_nfit_destruct(void *data)
 		sysfs_put(acpi_desc->scrub_count_state);
 	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
 	acpi_desc->nvdimm_bus = NULL;
+	list_del(&acpi_desc->list);
+	mutex_unlock(&acpi_desc_lock);
 }
 
 int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
@@ -2441,6 +2449,11 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
 		if (rc)
 			return rc;
+
+		/* register this acpi_desc for mce notifications */
+		mutex_lock(&acpi_desc_lock);
+		list_add_tail(&acpi_desc->list, &acpi_descs);
+		mutex_unlock(&acpi_desc_lock);
 	}
 
 	rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
@@ -2555,7 +2568,7 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
-static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
 {
 	struct device *dev = acpi_desc->dev;
 	struct nfit_spa *nfit_spa;
@@ -2604,6 +2617,7 @@ void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 	INIT_LIST_HEAD(&acpi_desc->flushes);
 	INIT_LIST_HEAD(&acpi_desc->memdevs);
 	INIT_LIST_HEAD(&acpi_desc->dimms);
+	INIT_LIST_HEAD(&acpi_desc->list);
 	mutex_init(&acpi_desc->init_mutex);
 	INIT_WORK(&acpi_desc->work, acpi_nfit_scrub);
 }
@@ -2756,13 +2770,17 @@ static __init int nfit_init(void)
 	if (!nfit_wq)
 		return -ENOMEM;
 
+	nfit_mce_register();
+
 	return acpi_bus_register_driver(&acpi_nfit_driver);
 }
 
 static __exit void nfit_exit(void)
 {
+	nfit_mce_unregister();
 	acpi_bus_unregister_driver(&acpi_nfit_driver);
 	destroy_workqueue(nfit_wq);
+	WARN_ON(!list_empty(&acpi_descs));
 }
 
 module_init(nfit_init);
diff --git a/drivers/acpi/nfit/mce.c b/drivers/acpi/nfit/mce.c
new file mode 100644
index 000000000000..4c745bf389fe
--- /dev/null
+++ b/drivers/acpi/nfit/mce.c
@@ -0,0 +1,89 @@
+/*
+ * NFIT - Machine Check Handler
+ *
+ * Copyright(c) 2013-2016 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#include <linux/notifier.h>
+#include <linux/acpi.h>
+#include <asm/mce.h>
+#include "nfit.h"
+
+static int nfit_handle_mce(struct notifier_block *nb, unsigned long val,
+			void *data)
+{
+	struct mce *mce = (struct mce *)data;
+	struct acpi_nfit_desc *acpi_desc;
+	struct nfit_spa *nfit_spa;
+
+	/* We only care about memory errors */
+	if (!(mce->status & MCACOD))
+		return NOTIFY_DONE;
+
+	/*
+	 * mce->addr contains the physical addr accessed that caused the
+	 * machine check. We need to walk through the list of NFITs, and see
+	 * if any of them matches that address, and only then start a scrub.
+	 */
+	mutex_lock(&acpi_desc_lock);
+	list_for_each_entry(acpi_desc, &acpi_descs, list) {
+		struct device *dev = acpi_desc->dev;
+		int found_match = 0;
+
+		mutex_lock(&acpi_desc->init_mutex);
+		list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+			struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+			if (nfit_spa_type(spa) == NFIT_SPA_PM)
+				continue;
+			/* find the spa that covers the mce addr */
+			if (spa->address > mce->addr)
+				continue;
+			if ((spa->address + spa->length - 1) < mce->addr)
+				continue;
+			found_match = 1;
+			dev_dbg(dev, "%s: addr in SPA %d (0x%llx, 0x%llx)\n",
+				__func__, spa->range_index, spa->address,
+				spa->length);
+			/*
+			 * We can break at the first match because we're going
+			 * to rescan all the SPA ranges. There shouldn't be any
+			 * aliasing anyway.
+			 */
+			break;
+		}
+		mutex_unlock(&acpi_desc->init_mutex);
+
+		/*
+		 * We can ignore an -EBUSY here because if an ARS is already
+		 * in progress, just let that be the last authoritative one
+		 */
+		if (found_match)
+			acpi_nfit_ars_rescan(acpi_desc);
+	}
+
+	mutex_unlock(&acpi_desc_lock);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block nfit_mce_dec = {
+	.notifier_call	= nfit_handle_mce,
+};
+
+void nfit_mce_register(void)
+{
+	mce_register_decode_chain(&nfit_mce_dec);
+}
+
+void nfit_mce_unregister(void)
+{
+	mce_unregister_decode_chain(&nfit_mce_dec);
+}
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index 6ecf337c97aa..ba6074a06958 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -16,6 +16,7 @@
 #define __NFIT_H__
 #include <linux/workqueue.h>
 #include <linux/libnvdimm.h>
+#include <linux/ndctl.h>
 #include <linux/types.h>
 #include <linux/uuid.h>
 #include <linux/acpi.h>
@@ -148,6 +149,7 @@ struct acpi_nfit_desc {
 	struct nd_cmd_ars_status *ars_status;
 	size_t ars_status_size;
 	struct work_struct work;
+	struct list_head list;
 	struct kernfs_node *scrub_count_state;
 	unsigned int scrub_count;
 	unsigned int cancel:1;
@@ -187,6 +189,24 @@ struct nfit_blk {
 	u32 dimm_flags;
 };
 
+extern struct list_head acpi_descs;
+extern struct mutex acpi_desc_lock;
+int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+#ifdef CONFIG_X86_MCE
+void nfit_mce_register(void);
+void nfit_mce_unregister(void);
+#else
+static inline void nfit_mce_register(void)
+{
+}
+static inline void nfit_mce_unregister(void)
+{
+}
+#endif
+
+int nfit_spa_type(struct acpi_nfit_system_address *spa);
+
 static inline struct acpi_nfit_memory_map *__to_nfit_memdev(
 		struct nfit_mem *nfit_mem)
 {
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index 0dca8ff7557b..ad6dd0543019 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -30,6 +30,7 @@ obj-$(CONFIG_DEV_DAX) += dax.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
 nfit-y := $(ACPI_SRC)/core.o
+nfit-$(CONFIG_X86_MCE) += $(ACPI_SRC)/mce.o
 nfit-y += config_check.o
 
 nd_pmem-y := $(NVDIMM_SRC)/pmem.o

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

[PATCH v4 4/4] nfit: do an ARS scrub on hitting a latent media error

[Dan Williams]

From: Vishal Verma <vishal.l.verma-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

When a latent (unknown to 'badblocks') error is encountered, it will
trigger a machine check exception. On a system with machine check
recovery, this will only SIGBUS the process(es) which had the bad page
mapped (as opposed to a kernel panic on platforms without machine
check recovery features). In the former case, we want to trigger a full
rescan of that nvdimm bus. This will allow any additional, new errors
to be captured in the block devices' badblocks lists, and offending
operations on them can be trapped early, avoiding machine checks.

This is done by registering a callback function with the
x86_mce_decoder_chain and calling the new ars_rescan functionality with
the address in the mce notificatiion.

Cc: Rafael J. Wysocki <rafael.j.wysocki-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: Tony Luck <tony.luck-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Vishal Verma <vishal.l.verma-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/acpi/nfit/Makefile  |    1 
 drivers/acpi/nfit/core.c    |   26 +++++++++++--
 drivers/acpi/nfit/mce.c     |   89 +++++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/nfit/nfit.h    |   20 ++++++++++
 tools/testing/nvdimm/Kbuild |    1 
 5 files changed, 133 insertions(+), 4 deletions(-)
 create mode 100644 drivers/acpi/nfit/mce.c

diff --git a/drivers/acpi/nfit/Makefile b/drivers/acpi/nfit/Makefile
index eb95c5aff83b..a407e769f103 100644
--- a/drivers/acpi/nfit/Makefile
+++ b/drivers/acpi/nfit/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_ACPI_NFIT) := nfit.o
 nfit-y := core.o
+nfit-$(CONFIG_X86_MCE) += mce.o
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 2eaa03dc185a..686837e8358f 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -51,6 +51,9 @@ module_param(disable_vendor_specific, bool, S_IRUGO);
 MODULE_PARM_DESC(disable_vendor_specific,
 		"Limit commands to the publicly specified set\n");
 
+LIST_HEAD(acpi_descs);
+DEFINE_MUTEX(acpi_desc_lock);
+
 static struct workqueue_struct *nfit_wq;
 
 struct nfit_table_prev {
@@ -361,7 +364,7 @@ static const char *spa_type_name(u16 type)
 	return to_name[type];
 }
 
-static int nfit_spa_type(struct acpi_nfit_system_address *spa)
+int nfit_spa_type(struct acpi_nfit_system_address *spa)
 {
 	int i;
 
@@ -898,8 +901,6 @@ static ssize_t scrub_show(struct device *dev,
 	return rc;
 }
 
-static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
-
 static ssize_t scrub_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t size)
 {
@@ -2400,6 +2401,11 @@ static void acpi_nfit_destruct(void *data)
 	struct acpi_nfit_desc *acpi_desc = data;
 	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
 
+	/*
+	 * Destruct under acpi_desc_lock so that nfit_handle_mce does not
+	 * race teardown
+	 */
+	mutex_lock(&acpi_desc_lock);
 	acpi_desc->cancel = 1;
 	/*
 	 * Bounce the nvdimm bus lock to make sure any in-flight
@@ -2414,6 +2420,8 @@ static void acpi_nfit_destruct(void *data)
 		sysfs_put(acpi_desc->scrub_count_state);
 	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
 	acpi_desc->nvdimm_bus = NULL;
+	list_del(&acpi_desc->list);
+	mutex_unlock(&acpi_desc_lock);
 }
 
 int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
@@ -2441,6 +2449,11 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
 		if (rc)
 			return rc;
+
+		/* register this acpi_desc for mce notifications */
+		mutex_lock(&acpi_desc_lock);
+		list_add_tail(&acpi_desc->list, &acpi_descs);
+		mutex_unlock(&acpi_desc_lock);
 	}
 
 	rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
@@ -2555,7 +2568,7 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
-static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
 {
 	struct device *dev = acpi_desc->dev;
 	struct nfit_spa *nfit_spa;
@@ -2604,6 +2617,7 @@ void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 	INIT_LIST_HEAD(&acpi_desc->flushes);
 	INIT_LIST_HEAD(&acpi_desc->memdevs);
 	INIT_LIST_HEAD(&acpi_desc->dimms);
+	INIT_LIST_HEAD(&acpi_desc->list);
 	mutex_init(&acpi_desc->init_mutex);
 	INIT_WORK(&acpi_desc->work, acpi_nfit_scrub);
 }
@@ -2756,13 +2770,17 @@ static __init int nfit_init(void)
 	if (!nfit_wq)
 		return -ENOMEM;
 
+	nfit_mce_register();
+
 	return acpi_bus_register_driver(&acpi_nfit_driver);
 }
 
 static __exit void nfit_exit(void)
 {
+	nfit_mce_unregister();
 	acpi_bus_unregister_driver(&acpi_nfit_driver);
 	destroy_workqueue(nfit_wq);
+	WARN_ON(!list_empty(&acpi_descs));
 }
 
 module_init(nfit_init);
diff --git a/drivers/acpi/nfit/mce.c b/drivers/acpi/nfit/mce.c
new file mode 100644
index 000000000000..4c745bf389fe
--- /dev/null
+++ b/drivers/acpi/nfit/mce.c
@@ -0,0 +1,89 @@
+/*
+ * NFIT - Machine Check Handler
+ *
+ * Copyright(c) 2013-2016 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#include <linux/notifier.h>
+#include <linux/acpi.h>
+#include <asm/mce.h>
+#include "nfit.h"
+
+static int nfit_handle_mce(struct notifier_block *nb, unsigned long val,
+			void *data)
+{
+	struct mce *mce = (struct mce *)data;
+	struct acpi_nfit_desc *acpi_desc;
+	struct nfit_spa *nfit_spa;
+
+	/* We only care about memory errors */
+	if (!(mce->status & MCACOD))
+		return NOTIFY_DONE;
+
+	/*
+	 * mce->addr contains the physical addr accessed that caused the
+	 * machine check. We need to walk through the list of NFITs, and see
+	 * if any of them matches that address, and only then start a scrub.
+	 */
+	mutex_lock(&acpi_desc_lock);
+	list_for_each_entry(acpi_desc, &acpi_descs, list) {
+		struct device *dev = acpi_desc->dev;
+		int found_match = 0;
+
+		mutex_lock(&acpi_desc->init_mutex);
+		list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+			struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+			if (nfit_spa_type(spa) == NFIT_SPA_PM)
+				continue;
+			/* find the spa that covers the mce addr */
+			if (spa->address > mce->addr)
+				continue;
+			if ((spa->address + spa->length - 1) < mce->addr)
+				continue;
+			found_match = 1;
+			dev_dbg(dev, "%s: addr in SPA %d (0x%llx, 0x%llx)\n",
+				__func__, spa->range_index, spa->address,
+				spa->length);
+			/*
+			 * We can break at the first match because we're going
+			 * to rescan all the SPA ranges. There shouldn't be any
+			 * aliasing anyway.
+			 */
+			break;
+		}
+		mutex_unlock(&acpi_desc->init_mutex);
+
+		/*
+		 * We can ignore an -EBUSY here because if an ARS is already
+		 * in progress, just let that be the last authoritative one
+		 */
+		if (found_match)
+			acpi_nfit_ars_rescan(acpi_desc);
+	}
+
+	mutex_unlock(&acpi_desc_lock);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block nfit_mce_dec = {
+	.notifier_call	= nfit_handle_mce,
+};
+
+void nfit_mce_register(void)
+{
+	mce_register_decode_chain(&nfit_mce_dec);
+}
+
+void nfit_mce_unregister(void)
+{
+	mce_unregister_decode_chain(&nfit_mce_dec);
+}
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index 6ecf337c97aa..ba6074a06958 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -16,6 +16,7 @@
 #define __NFIT_H__
 #include <linux/workqueue.h>
 #include <linux/libnvdimm.h>
+#include <linux/ndctl.h>
 #include <linux/types.h>
 #include <linux/uuid.h>
 #include <linux/acpi.h>
@@ -148,6 +149,7 @@ struct acpi_nfit_desc {
 	struct nd_cmd_ars_status *ars_status;
 	size_t ars_status_size;
 	struct work_struct work;
+	struct list_head list;
 	struct kernfs_node *scrub_count_state;
 	unsigned int scrub_count;
 	unsigned int cancel:1;
@@ -187,6 +189,24 @@ struct nfit_blk {
 	u32 dimm_flags;
 };
 
+extern struct list_head acpi_descs;
+extern struct mutex acpi_desc_lock;
+int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+#ifdef CONFIG_X86_MCE
+void nfit_mce_register(void);
+void nfit_mce_unregister(void);
+#else
+static inline void nfit_mce_register(void)
+{
+}
+static inline void nfit_mce_unregister(void)
+{
+}
+#endif
+
+int nfit_spa_type(struct acpi_nfit_system_address *spa);
+
 static inline struct acpi_nfit_memory_map *__to_nfit_memdev(
 		struct nfit_mem *nfit_mem)
 {
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index 0dca8ff7557b..ad6dd0543019 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -30,6 +30,7 @@ obj-$(CONFIG_DEV_DAX) += dax.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
 nfit-y := $(ACPI_SRC)/core.o
+nfit-$(CONFIG_X86_MCE) += $(ACPI_SRC)/mce.o
 nfit-y += config_check.o
 
 nd_pmem-y := $(NVDIMM_SRC)/pmem.o

[PATCH v4 4/4] nfit: do an ARS scrub on hitting a latent media error

[Dan Williams]

From: Vishal Verma <vishal.l.verma@intel.com>

When a latent (unknown to 'badblocks') error is encountered, it will
trigger a machine check exception. On a system with machine check
recovery, this will only SIGBUS the process(es) which had the bad page
mapped (as opposed to a kernel panic on platforms without machine
check recovery features). In the former case, we want to trigger a full
rescan of that nvdimm bus. This will allow any additional, new errors
to be captured in the block devices' badblocks lists, and offending
operations on them can be trapped early, avoiding machine checks.

This is done by registering a callback function with the
x86_mce_decoder_chain and calling the new ars_rescan functionality with
the address in the mce notificatiion.

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/nfit/Makefile  |    1 
 drivers/acpi/nfit/core.c    |   26 +++++++++++--
 drivers/acpi/nfit/mce.c     |   89 +++++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/nfit/nfit.h    |   20 ++++++++++
 tools/testing/nvdimm/Kbuild |    1 
 5 files changed, 133 insertions(+), 4 deletions(-)
 create mode 100644 drivers/acpi/nfit/mce.c

diff --git a/drivers/acpi/nfit/Makefile b/drivers/acpi/nfit/Makefile
index eb95c5aff83b..a407e769f103 100644
--- a/drivers/acpi/nfit/Makefile
+++ b/drivers/acpi/nfit/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_ACPI_NFIT) := nfit.o
 nfit-y := core.o
+nfit-$(CONFIG_X86_MCE) += mce.o
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 2eaa03dc185a..686837e8358f 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -51,6 +51,9 @@ module_param(disable_vendor_specific, bool, S_IRUGO);
 MODULE_PARM_DESC(disable_vendor_specific,
 		"Limit commands to the publicly specified set\n");
 
+LIST_HEAD(acpi_descs);
+DEFINE_MUTEX(acpi_desc_lock);
+
 static struct workqueue_struct *nfit_wq;
 
 struct nfit_table_prev {
@@ -361,7 +364,7 @@ static const char *spa_type_name(u16 type)
 	return to_name[type];
 }
 
-static int nfit_spa_type(struct acpi_nfit_system_address *spa)
+int nfit_spa_type(struct acpi_nfit_system_address *spa)
 {
 	int i;
 
@@ -898,8 +901,6 @@ static ssize_t scrub_show(struct device *dev,
 	return rc;
 }
 
-static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
-
 static ssize_t scrub_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t size)
 {
@@ -2400,6 +2401,11 @@ static void acpi_nfit_destruct(void *data)
 	struct acpi_nfit_desc *acpi_desc = data;
 	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
 
+	/*
+	 * Destruct under acpi_desc_lock so that nfit_handle_mce does not
+	 * race teardown
+	 */
+	mutex_lock(&acpi_desc_lock);
 	acpi_desc->cancel = 1;
 	/*
 	 * Bounce the nvdimm bus lock to make sure any in-flight
@@ -2414,6 +2420,8 @@ static void acpi_nfit_destruct(void *data)
 		sysfs_put(acpi_desc->scrub_count_state);
 	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
 	acpi_desc->nvdimm_bus = NULL;
+	list_del(&acpi_desc->list);
+	mutex_unlock(&acpi_desc_lock);
 }
 
 int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
@@ -2441,6 +2449,11 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
 		if (rc)
 			return rc;
+
+		/* register this acpi_desc for mce notifications */
+		mutex_lock(&acpi_desc_lock);
+		list_add_tail(&acpi_desc->list, &acpi_descs);
+		mutex_unlock(&acpi_desc_lock);
 	}
 
 	rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
@@ -2555,7 +2568,7 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
-static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
 {
 	struct device *dev = acpi_desc->dev;
 	struct nfit_spa *nfit_spa;
@@ -2604,6 +2617,7 @@ void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 	INIT_LIST_HEAD(&acpi_desc->flushes);
 	INIT_LIST_HEAD(&acpi_desc->memdevs);
 	INIT_LIST_HEAD(&acpi_desc->dimms);
+	INIT_LIST_HEAD(&acpi_desc->list);
 	mutex_init(&acpi_desc->init_mutex);
 	INIT_WORK(&acpi_desc->work, acpi_nfit_scrub);
 }
@@ -2756,13 +2770,17 @@ static __init int nfit_init(void)
 	if (!nfit_wq)
 		return -ENOMEM;
 
+	nfit_mce_register();
+
 	return acpi_bus_register_driver(&acpi_nfit_driver);
 }
 
 static __exit void nfit_exit(void)
 {
+	nfit_mce_unregister();
 	acpi_bus_unregister_driver(&acpi_nfit_driver);
 	destroy_workqueue(nfit_wq);
+	WARN_ON(!list_empty(&acpi_descs));
 }
 
 module_init(nfit_init);
diff --git a/drivers/acpi/nfit/mce.c b/drivers/acpi/nfit/mce.c
new file mode 100644
index 000000000000..4c745bf389fe
--- /dev/null
+++ b/drivers/acpi/nfit/mce.c
@@ -0,0 +1,89 @@
+/*
+ * NFIT - Machine Check Handler
+ *
+ * Copyright(c) 2013-2016 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#include <linux/notifier.h>
+#include <linux/acpi.h>
+#include <asm/mce.h>
+#include "nfit.h"
+
+static int nfit_handle_mce(struct notifier_block *nb, unsigned long val,
+			void *data)
+{
+	struct mce *mce = (struct mce *)data;
+	struct acpi_nfit_desc *acpi_desc;
+	struct nfit_spa *nfit_spa;
+
+	/* We only care about memory errors */
+	if (!(mce->status & MCACOD))
+		return NOTIFY_DONE;
+
+	/*
+	 * mce->addr contains the physical addr accessed that caused the
+	 * machine check. We need to walk through the list of NFITs, and see
+	 * if any of them matches that address, and only then start a scrub.
+	 */
+	mutex_lock(&acpi_desc_lock);
+	list_for_each_entry(acpi_desc, &acpi_descs, list) {
+		struct device *dev = acpi_desc->dev;
+		int found_match = 0;
+
+		mutex_lock(&acpi_desc->init_mutex);
+		list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+			struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+			if (nfit_spa_type(spa) == NFIT_SPA_PM)
+				continue;
+			/* find the spa that covers the mce addr */
+			if (spa->address > mce->addr)
+				continue;
+			if ((spa->address + spa->length - 1) < mce->addr)
+				continue;
+			found_match = 1;
+			dev_dbg(dev, "%s: addr in SPA %d (0x%llx, 0x%llx)\n",
+				__func__, spa->range_index, spa->address,
+				spa->length);
+			/*
+			 * We can break at the first match because we're going
+			 * to rescan all the SPA ranges. There shouldn't be any
+			 * aliasing anyway.
+			 */
+			break;
+		}
+		mutex_unlock(&acpi_desc->init_mutex);
+
+		/*
+		 * We can ignore an -EBUSY here because if an ARS is already
+		 * in progress, just let that be the last authoritative one
+		 */
+		if (found_match)
+			acpi_nfit_ars_rescan(acpi_desc);
+	}
+
+	mutex_unlock(&acpi_desc_lock);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block nfit_mce_dec = {
+	.notifier_call	= nfit_handle_mce,
+};
+
+void nfit_mce_register(void)
+{
+	mce_register_decode_chain(&nfit_mce_dec);
+}
+
+void nfit_mce_unregister(void)
+{
+	mce_unregister_decode_chain(&nfit_mce_dec);
+}
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index 6ecf337c97aa..ba6074a06958 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -16,6 +16,7 @@
 #define __NFIT_H__
 #include <linux/workqueue.h>
 #include <linux/libnvdimm.h>
+#include <linux/ndctl.h>
 #include <linux/types.h>
 #include <linux/uuid.h>
 #include <linux/acpi.h>
@@ -148,6 +149,7 @@ struct acpi_nfit_desc {
 	struct nd_cmd_ars_status *ars_status;
 	size_t ars_status_size;
 	struct work_struct work;
+	struct list_head list;
 	struct kernfs_node *scrub_count_state;
 	unsigned int scrub_count;
 	unsigned int cancel:1;
@@ -187,6 +189,24 @@ struct nfit_blk {
 	u32 dimm_flags;
 };
 
+extern struct list_head acpi_descs;
+extern struct mutex acpi_desc_lock;
+int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+#ifdef CONFIG_X86_MCE
+void nfit_mce_register(void);
+void nfit_mce_unregister(void);
+#else
+static inline void nfit_mce_register(void)
+{
+}
+static inline void nfit_mce_unregister(void)
+{
+}
+#endif
+
+int nfit_spa_type(struct acpi_nfit_system_address *spa);
+
 static inline struct acpi_nfit_memory_map *__to_nfit_memdev(
 		struct nfit_mem *nfit_mem)
 {
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index 0dca8ff7557b..ad6dd0543019 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -30,6 +30,7 @@ obj-$(CONFIG_DEV_DAX) += dax.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
 nfit-y := $(ACPI_SRC)/core.o
+nfit-$(CONFIG_X86_MCE) += $(ACPI_SRC)/mce.o
 nfit-y += config_check.o
 
 nd_pmem-y := $(NVDIMM_SRC)/pmem.o

Re: [PATCH v4 2/4] nfit, libnvdimm: allow an ARS scrub to be triggered on demand

[Dan Williams]

On Sat, Jul 23, 2016 at 10:26 PM, Dan Williams <dan.j.williams@intel.com> wrote:
> From: Vishal Verma <vishal.l.verma@intel.com>
>
> Normally, an ARS (Address Range Scrub) only happens at
> boot/initialization time. There can however arise situations where a
> bus-wide rescan is needed - notably, in the case of discovering a latent
> media error, we should do a full rescan to figure out what other sectors
> are bad, and thus potentially avoid triggering an mce on them in the
> future. Also provide a sysfs trigger to start a bus-wide scrub.
>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  drivers/acpi/nfit.c       |  167 +++++++++++++++++++++++++++++++++++++++++++--
>  drivers/acpi/nfit.h       |    4 +
>  drivers/nvdimm/core.c     |    7 ++
>  include/linux/libnvdimm.h |    1
>  4 files changed, 171 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
> index be7c2fde16e7..2eaa03dc185a 100644
> --- a/drivers/acpi/nfit.c
> +++ b/drivers/acpi/nfit.c
[..]
> @@ -2308,17 +2423,30 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
>         const void *end;
>         int rc;
>
> +       acpi_nfit_init_dsms(acpi_desc);
> +
>         if (!acpi_desc->nvdimm_bus) {
> +               acpi_nfit_init_dsms(acpi_desc);
> +
>                 acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
>                                 &acpi_desc->nd_desc);
>                 if (!acpi_desc->nvdimm_bus)
>                         return -ENOMEM;
> +
>                 rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
>                                 acpi_desc);
>                 if (rc)
>                         return rc;
> +
> +               rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
> +               if (rc)
> +                       return rc;
>         }
>
> +       rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
> +       if (rc)
> +               return rc;
> +

Whoops, rebase error.  I was moving acpi_nfit_init_dsms() and
acpi_nfit_desc_init_scrub_attr() to only run at the initial call to
acpi_nfit_init().
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

Re: [PATCH v4 2/4] nfit, libnvdimm: allow an ARS scrub to be triggered on demand

[Dan Williams]

On Sat, Jul 23, 2016 at 10:26 PM, Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> wrote:
> From: Vishal Verma <vishal.l.verma-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>
> Normally, an ARS (Address Range Scrub) only happens at
> boot/initialization time. There can however arise situations where a
> bus-wide rescan is needed - notably, in the case of discovering a latent
> media error, we should do a full rescan to figure out what other sectors
> are bad, and thus potentially avoid triggering an mce on them in the
> future. Also provide a sysfs trigger to start a bus-wide scrub.
>
> Cc: Rafael J. Wysocki <rafael.j.wysocki-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Vishal Verma <vishal.l.verma-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/acpi/nfit.c       |  167 +++++++++++++++++++++++++++++++++++++++++++--
>  drivers/acpi/nfit.h       |    4 +
>  drivers/nvdimm/core.c     |    7 ++
>  include/linux/libnvdimm.h |    1
>  4 files changed, 171 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
> index be7c2fde16e7..2eaa03dc185a 100644
> --- a/drivers/acpi/nfit.c
> +++ b/drivers/acpi/nfit.c
[..]
> @@ -2308,17 +2423,30 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
>         const void *end;
>         int rc;
>
> +       acpi_nfit_init_dsms(acpi_desc);
> +
>         if (!acpi_desc->nvdimm_bus) {
> +               acpi_nfit_init_dsms(acpi_desc);
> +
>                 acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
>                                 &acpi_desc->nd_desc);
>                 if (!acpi_desc->nvdimm_bus)
>                         return -ENOMEM;
> +
>                 rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
>                                 acpi_desc);
>                 if (rc)
>                         return rc;
> +
> +               rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
> +               if (rc)
> +                       return rc;
>         }
>
> +       rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
> +       if (rc)
> +               return rc;
> +

Whoops, rebase error.  I was moving acpi_nfit_init_dsms() and
acpi_nfit_desc_init_scrub_attr() to only run at the initial call to
acpi_nfit_init().

Re: [PATCH v4 2/4] nfit, libnvdimm: allow an ARS scrub to be triggered on demand

[Dan Williams]

On Sat, Jul 23, 2016 at 10:26 PM, Dan Williams <dan.j.williams@intel.com> wrote:
> From: Vishal Verma <vishal.l.verma@intel.com>
>
> Normally, an ARS (Address Range Scrub) only happens at
> boot/initialization time. There can however arise situations where a
> bus-wide rescan is needed - notably, in the case of discovering a latent
> media error, we should do a full rescan to figure out what other sectors
> are bad, and thus potentially avoid triggering an mce on them in the
> future. Also provide a sysfs trigger to start a bus-wide scrub.
>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  drivers/acpi/nfit.c       |  167 +++++++++++++++++++++++++++++++++++++++++++--
>  drivers/acpi/nfit.h       |    4 +
>  drivers/nvdimm/core.c     |    7 ++
>  include/linux/libnvdimm.h |    1
>  4 files changed, 171 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
> index be7c2fde16e7..2eaa03dc185a 100644
> --- a/drivers/acpi/nfit.c
> +++ b/drivers/acpi/nfit.c
[..]
> @@ -2308,17 +2423,30 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
>         const void *end;
>         int rc;
>
> +       acpi_nfit_init_dsms(acpi_desc);
> +
>         if (!acpi_desc->nvdimm_bus) {
> +               acpi_nfit_init_dsms(acpi_desc);
> +
>                 acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
>                                 &acpi_desc->nd_desc);
>                 if (!acpi_desc->nvdimm_bus)
>                         return -ENOMEM;
> +
>                 rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
>                                 acpi_desc);
>                 if (rc)
>                         return rc;
> +
> +               rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
> +               if (rc)
> +                       return rc;
>         }
>
> +       rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
> +       if (rc)
> +               return rc;
> +

Whoops, rebase error.  I was moving acpi_nfit_init_dsms() and
acpi_nfit_desc_init_scrub_attr() to only run at the initial call to
acpi_nfit_init().

[PATCH v5] nfit, libnvdimm: allow an ARS scrub to be triggered on demand

[Dan Williams]

From: Vishal Verma <vishal.l.verma@intel.com>

Normally, an ARS (Address Range Scrub) only happens at
boot/initialization time. There can however arise situations where a
bus-wide rescan is needed - notably, in the case of discovering a latent
media error, we should do a full rescan to figure out what other sectors
are bad, and thus potentially avoid triggering an mce on them in the
future. Also provide a sysfs trigger to start a bus-wide scrub.

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/nfit.c       |  161 +++++++++++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit.h       |    4 +
 drivers/nvdimm/core.c     |    7 ++
 include/linux/libnvdimm.h |    1 
 4 files changed, 165 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index be7c2fde16e7..19d0dfdf9633 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ndctl.h>
+#include <linux/sysfs.h>
 #include <linux/delay.h>
 #include <linux/list.h>
 #include <linux/acpi.h>
@@ -874,14 +875,87 @@ static ssize_t revision_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(revision);
 
+/*
+ * This shows the number of full Address Range Scrubs that have been
+ * completed since driver load time. Userspace can wait on this using
+ * select/poll etc. A '+' at the end indicates an ARS is in progress
+ */
+static ssize_t scrub_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc = -ENXIO;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
+				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+	}
+	device_unlock(dev);
+	return rc;
+}
+
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+static ssize_t scrub_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc;
+	long val;
+
+	rc = kstrtol(buf, 0, &val);
+	if (rc)
+		return rc;
+	if (val != 1)
+		return -EINVAL;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = acpi_nfit_ars_rescan(acpi_desc);
+	}
+	device_unlock(dev);
+	if (rc)
+		return rc;
+	return size;
+}
+static DEVICE_ATTR_RW(scrub);
+
+static bool ars_supported(struct nvdimm_bus *nvdimm_bus)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	const unsigned long mask = 1 << ND_CMD_ARS_CAP | 1 << ND_CMD_ARS_START
+		| 1 << ND_CMD_ARS_STATUS;
+
+	return (nd_desc->cmd_mask & mask) == mask;
+}
+
+static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	if (a == &dev_attr_scrub.attr && !ars_supported(nvdimm_bus))
+		return 0;
+	return a->mode;
+}
+
 static struct attribute *acpi_nfit_attributes[] = {
 	&dev_attr_revision.attr,
+	&dev_attr_scrub.attr,
 	NULL,
 };
 
 static struct attribute_group acpi_nfit_attribute_group = {
 	.name = "nfit",
 	.attrs = acpi_nfit_attributes,
+	.is_visible = nfit_visible,
 };
 
 static const struct attribute_group *acpi_nfit_attribute_groups[] = {
@@ -2054,7 +2128,7 @@ static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
 	unsigned int tmo = scrub_timeout;
 	int rc;
 
-	if (nfit_spa->ars_done || !nfit_spa->nd_region)
+	if (!nfit_spa->ars_required || !nfit_spa->nd_region)
 		return;
 
 	rc = ars_start(acpi_desc, nfit_spa);
@@ -2143,7 +2217,9 @@ static void acpi_nfit_scrub(struct work_struct *work)
 	 * firmware initiated scrubs to complete and then we go search for the
 	 * affected spa regions to mark them scanned.  In the second phase we
 	 * initiate a directed scrub for every range that was not scrubbed in
-	 * phase 1.
+	 * phase 1. If we're called for a 'rescan', we harmlessly pass through
+	 * the first phase, but really only care about running phase 2, where
+	 * regions can be notified of new poison.
 	 */
 
 	/* process platform firmware initiated scrubs */
@@ -2246,14 +2322,17 @@ static void acpi_nfit_scrub(struct work_struct *work)
 		 * Flag all the ranges that still need scrubbing, but
 		 * register them now to make data available.
 		 */
-		if (nfit_spa->nd_region)
-			nfit_spa->ars_done = 1;
-		else
+		if (!nfit_spa->nd_region) {
+			nfit_spa->ars_required = 1;
 			acpi_nfit_register_region(acpi_desc, nfit_spa);
+		}
 	}
 
 	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
 		acpi_nfit_async_scrub(acpi_desc, nfit_spa);
+	acpi_desc->scrub_count++;
+	if (acpi_desc->scrub_count_state)
+		sysfs_notify_dirent(acpi_desc->scrub_count_state);
 	mutex_unlock(&acpi_desc->init_mutex);
 }
 
@@ -2291,12 +2370,48 @@ static int acpi_nfit_check_deletions(struct acpi_nfit_desc *acpi_desc,
 	return 0;
 }
 
+static int acpi_nfit_desc_init_scrub_attr(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct kernfs_node *nfit;
+	struct device *bus_dev;
+
+	if (!ars_supported(acpi_desc->nvdimm_bus))
+		return 0;
+
+	bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+	nfit = sysfs_get_dirent(bus_dev->kobj.sd, "nfit");
+	if (!nfit) {
+		dev_err(dev, "sysfs_get_dirent 'nfit' failed\n");
+		return -ENODEV;
+	}
+	acpi_desc->scrub_count_state = sysfs_get_dirent(nfit, "scrub");
+	sysfs_put(nfit);
+	if (!acpi_desc->scrub_count_state) {
+		dev_err(dev, "sysfs_get_dirent 'scrub' failed\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
 static void acpi_nfit_destruct(void *data)
 {
 	struct acpi_nfit_desc *acpi_desc = data;
+	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
 
 	acpi_desc->cancel = 1;
+	/*
+	 * Bounce the nvdimm bus lock to make sure any in-flight
+	 * acpi_nfit_ars_rescan() submissions have had a chance to
+	 * either submit or see ->cancel set.
+	 */
+	device_lock(bus_dev);
+	device_unlock(bus_dev);
+
 	flush_workqueue(nfit_wq);
+	if (acpi_desc->scrub_count_state)
+		sysfs_put(acpi_desc->scrub_count_state);
 	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
 	acpi_desc->nvdimm_bus = NULL;
 }
@@ -2309,14 +2424,21 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	int rc;
 
 	if (!acpi_desc->nvdimm_bus) {
+		acpi_nfit_init_dsms(acpi_desc);
+
 		acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
 				&acpi_desc->nd_desc);
 		if (!acpi_desc->nvdimm_bus)
 			return -ENOMEM;
+
 		rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
 				acpi_desc);
 		if (rc)
 			return rc;
+
+		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+		if (rc)
+			return rc;
 	}
 
 	mutex_lock(&acpi_desc->init_mutex);
@@ -2360,8 +2482,6 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	if (rc)
 		goto out_unlock;
 
-	acpi_nfit_init_dsms(acpi_desc);
-
 	rc = acpi_nfit_register_dimms(acpi_desc);
 	if (rc)
 		goto out_unlock;
@@ -2429,6 +2549,33 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa;
+
+	if (work_busy(&acpi_desc->work))
+		return -EBUSY;
+
+	if (acpi_desc->cancel)
+		return 0;
+
+	mutex_lock(&acpi_desc->init_mutex);
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+		if (nfit_spa_type(spa) != NFIT_SPA_PM)
+			continue;
+
+		nfit_spa->ars_required = 1;
+	}
+	queue_work(nfit_wq, &acpi_desc->work);
+	dev_dbg(dev, "%s: ars_scan triggered\n", __func__);
+	mutex_unlock(&acpi_desc->init_mutex);
+
+	return 0;
+}
+
 void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 {
 	struct nvdimm_bus_descriptor *nd_desc;
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index b63a583a678f..6ecf337c97aa 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -80,7 +80,7 @@ enum {
 struct nfit_spa {
 	struct list_head list;
 	struct nd_region *nd_region;
-	unsigned int ars_done:1;
+	unsigned int ars_required:1;
 	u32 clear_err_unit;
 	u32 max_ars;
 	struct acpi_nfit_system_address spa[0];
@@ -148,6 +148,8 @@ struct acpi_nfit_desc {
 	struct nd_cmd_ars_status *ars_status;
 	size_t ars_status_size;
 	struct work_struct work;
+	struct kernfs_node *scrub_count_state;
+	unsigned int scrub_count;
 	unsigned int cancel:1;
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 2c98f958fabb..715583f69d28 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -201,6 +201,13 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
+{
+	/* struct nvdimm_bus definition is private to libnvdimm */
+	return &nvdimm_bus->dev;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);
+
 static bool is_uuid_sep(char sep)
 {
 	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 2ab869dece4a..b519e137b9b7 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -137,6 +137,7 @@ struct nvdimm *to_nvdimm(struct device *dev);
 struct nd_region *to_nd_region(struct device *dev);
 struct nd_blk_region *to_nd_blk_region(struct device *dev);
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus);
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus);
 const char *nvdimm_name(struct nvdimm *nvdimm);
 unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm);
 void *nvdimm_provider_data(struct nvdimm *nvdimm);

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

[PATCH v5] nfit, libnvdimm: allow an ARS scrub to be triggered on demand

[Dan Williams]

From: Vishal Verma <vishal.l.verma-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

Normally, an ARS (Address Range Scrub) only happens at
boot/initialization time. There can however arise situations where a
bus-wide rescan is needed - notably, in the case of discovering a latent
media error, we should do a full rescan to figure out what other sectors
are bad, and thus potentially avoid triggering an mce on them in the
future. Also provide a sysfs trigger to start a bus-wide scrub.

Cc: Rafael J. Wysocki <rafael.j.wysocki-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Vishal Verma <vishal.l.verma-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/acpi/nfit.c       |  161 +++++++++++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit.h       |    4 +
 drivers/nvdimm/core.c     |    7 ++
 include/linux/libnvdimm.h |    1 
 4 files changed, 165 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index be7c2fde16e7..19d0dfdf9633 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ndctl.h>
+#include <linux/sysfs.h>
 #include <linux/delay.h>
 #include <linux/list.h>
 #include <linux/acpi.h>
@@ -874,14 +875,87 @@ static ssize_t revision_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(revision);
 
+/*
+ * This shows the number of full Address Range Scrubs that have been
+ * completed since driver load time. Userspace can wait on this using
+ * select/poll etc. A '+' at the end indicates an ARS is in progress
+ */
+static ssize_t scrub_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc = -ENXIO;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
+				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+	}
+	device_unlock(dev);
+	return rc;
+}
+
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+static ssize_t scrub_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc;
+	long val;
+
+	rc = kstrtol(buf, 0, &val);
+	if (rc)
+		return rc;
+	if (val != 1)
+		return -EINVAL;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = acpi_nfit_ars_rescan(acpi_desc);
+	}
+	device_unlock(dev);
+	if (rc)
+		return rc;
+	return size;
+}
+static DEVICE_ATTR_RW(scrub);
+
+static bool ars_supported(struct nvdimm_bus *nvdimm_bus)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	const unsigned long mask = 1 << ND_CMD_ARS_CAP | 1 << ND_CMD_ARS_START
+		| 1 << ND_CMD_ARS_STATUS;
+
+	return (nd_desc->cmd_mask & mask) == mask;
+}
+
+static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	if (a == &dev_attr_scrub.attr && !ars_supported(nvdimm_bus))
+		return 0;
+	return a->mode;
+}
+
 static struct attribute *acpi_nfit_attributes[] = {
 	&dev_attr_revision.attr,
+	&dev_attr_scrub.attr,
 	NULL,
 };
 
 static struct attribute_group acpi_nfit_attribute_group = {
 	.name = "nfit",
 	.attrs = acpi_nfit_attributes,
+	.is_visible = nfit_visible,
 };
 
 static const struct attribute_group *acpi_nfit_attribute_groups[] = {
@@ -2054,7 +2128,7 @@ static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
 	unsigned int tmo = scrub_timeout;
 	int rc;
 
-	if (nfit_spa->ars_done || !nfit_spa->nd_region)
+	if (!nfit_spa->ars_required || !nfit_spa->nd_region)
 		return;
 
 	rc = ars_start(acpi_desc, nfit_spa);
@@ -2143,7 +2217,9 @@ static void acpi_nfit_scrub(struct work_struct *work)
 	 * firmware initiated scrubs to complete and then we go search for the
 	 * affected spa regions to mark them scanned.  In the second phase we
 	 * initiate a directed scrub for every range that was not scrubbed in
-	 * phase 1.
+	 * phase 1. If we're called for a 'rescan', we harmlessly pass through
+	 * the first phase, but really only care about running phase 2, where
+	 * regions can be notified of new poison.
 	 */
 
 	/* process platform firmware initiated scrubs */
@@ -2246,14 +2322,17 @@ static void acpi_nfit_scrub(struct work_struct *work)
 		 * Flag all the ranges that still need scrubbing, but
 		 * register them now to make data available.
 		 */
-		if (nfit_spa->nd_region)
-			nfit_spa->ars_done = 1;
-		else
+		if (!nfit_spa->nd_region) {
+			nfit_spa->ars_required = 1;
 			acpi_nfit_register_region(acpi_desc, nfit_spa);
+		}
 	}
 
 	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
 		acpi_nfit_async_scrub(acpi_desc, nfit_spa);
+	acpi_desc->scrub_count++;
+	if (acpi_desc->scrub_count_state)
+		sysfs_notify_dirent(acpi_desc->scrub_count_state);
 	mutex_unlock(&acpi_desc->init_mutex);
 }
 
@@ -2291,12 +2370,48 @@ static int acpi_nfit_check_deletions(struct acpi_nfit_desc *acpi_desc,
 	return 0;
 }
 
+static int acpi_nfit_desc_init_scrub_attr(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct kernfs_node *nfit;
+	struct device *bus_dev;
+
+	if (!ars_supported(acpi_desc->nvdimm_bus))
+		return 0;
+
+	bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+	nfit = sysfs_get_dirent(bus_dev->kobj.sd, "nfit");
+	if (!nfit) {
+		dev_err(dev, "sysfs_get_dirent 'nfit' failed\n");
+		return -ENODEV;
+	}
+	acpi_desc->scrub_count_state = sysfs_get_dirent(nfit, "scrub");
+	sysfs_put(nfit);
+	if (!acpi_desc->scrub_count_state) {
+		dev_err(dev, "sysfs_get_dirent 'scrub' failed\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
 static void acpi_nfit_destruct(void *data)
 {
 	struct acpi_nfit_desc *acpi_desc = data;
+	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
 
 	acpi_desc->cancel = 1;
+	/*
+	 * Bounce the nvdimm bus lock to make sure any in-flight
+	 * acpi_nfit_ars_rescan() submissions have had a chance to
+	 * either submit or see ->cancel set.
+	 */
+	device_lock(bus_dev);
+	device_unlock(bus_dev);
+
 	flush_workqueue(nfit_wq);
+	if (acpi_desc->scrub_count_state)
+		sysfs_put(acpi_desc->scrub_count_state);
 	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
 	acpi_desc->nvdimm_bus = NULL;
 }
@@ -2309,14 +2424,21 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	int rc;
 
 	if (!acpi_desc->nvdimm_bus) {
+		acpi_nfit_init_dsms(acpi_desc);
+
 		acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
 				&acpi_desc->nd_desc);
 		if (!acpi_desc->nvdimm_bus)
 			return -ENOMEM;
+
 		rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
 				acpi_desc);
 		if (rc)
 			return rc;
+
+		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+		if (rc)
+			return rc;
 	}
 
 	mutex_lock(&acpi_desc->init_mutex);
@@ -2360,8 +2482,6 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	if (rc)
 		goto out_unlock;
 
-	acpi_nfit_init_dsms(acpi_desc);
-
 	rc = acpi_nfit_register_dimms(acpi_desc);
 	if (rc)
 		goto out_unlock;
@@ -2429,6 +2549,33 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa;
+
+	if (work_busy(&acpi_desc->work))
+		return -EBUSY;
+
+	if (acpi_desc->cancel)
+		return 0;
+
+	mutex_lock(&acpi_desc->init_mutex);
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+		if (nfit_spa_type(spa) != NFIT_SPA_PM)
+			continue;
+
+		nfit_spa->ars_required = 1;
+	}
+	queue_work(nfit_wq, &acpi_desc->work);
+	dev_dbg(dev, "%s: ars_scan triggered\n", __func__);
+	mutex_unlock(&acpi_desc->init_mutex);
+
+	return 0;
+}
+
 void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 {
 	struct nvdimm_bus_descriptor *nd_desc;
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index b63a583a678f..6ecf337c97aa 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -80,7 +80,7 @@ enum {
 struct nfit_spa {
 	struct list_head list;
 	struct nd_region *nd_region;
-	unsigned int ars_done:1;
+	unsigned int ars_required:1;
 	u32 clear_err_unit;
 	u32 max_ars;
 	struct acpi_nfit_system_address spa[0];
@@ -148,6 +148,8 @@ struct acpi_nfit_desc {
 	struct nd_cmd_ars_status *ars_status;
 	size_t ars_status_size;
 	struct work_struct work;
+	struct kernfs_node *scrub_count_state;
+	unsigned int scrub_count;
 	unsigned int cancel:1;
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 2c98f958fabb..715583f69d28 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -201,6 +201,13 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
+{
+	/* struct nvdimm_bus definition is private to libnvdimm */
+	return &nvdimm_bus->dev;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);
+
 static bool is_uuid_sep(char sep)
 {
 	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 2ab869dece4a..b519e137b9b7 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -137,6 +137,7 @@ struct nvdimm *to_nvdimm(struct device *dev);
 struct nd_region *to_nd_region(struct device *dev);
 struct nd_blk_region *to_nd_blk_region(struct device *dev);
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus);
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus);
 const char *nvdimm_name(struct nvdimm *nvdimm);
 unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm);
 void *nvdimm_provider_data(struct nvdimm *nvdimm);

[PATCH v5] nfit, libnvdimm: allow an ARS scrub to be triggered on demand

[Dan Williams]

From: Vishal Verma <vishal.l.verma@intel.com>

Normally, an ARS (Address Range Scrub) only happens at
boot/initialization time. There can however arise situations where a
bus-wide rescan is needed - notably, in the case of discovering a latent
media error, we should do a full rescan to figure out what other sectors
are bad, and thus potentially avoid triggering an mce on them in the
future. Also provide a sysfs trigger to start a bus-wide scrub.

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/nfit.c       |  161 +++++++++++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit.h       |    4 +
 drivers/nvdimm/core.c     |    7 ++
 include/linux/libnvdimm.h |    1 
 4 files changed, 165 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index be7c2fde16e7..19d0dfdf9633 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ndctl.h>
+#include <linux/sysfs.h>
 #include <linux/delay.h>
 #include <linux/list.h>
 #include <linux/acpi.h>
@@ -874,14 +875,87 @@ static ssize_t revision_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(revision);
 
+/*
+ * This shows the number of full Address Range Scrubs that have been
+ * completed since driver load time. Userspace can wait on this using
+ * select/poll etc. A '+' at the end indicates an ARS is in progress
+ */
+static ssize_t scrub_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc = -ENXIO;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
+				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+	}
+	device_unlock(dev);
+	return rc;
+}
+
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+static ssize_t scrub_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc;
+	long val;
+
+	rc = kstrtol(buf, 0, &val);
+	if (rc)
+		return rc;
+	if (val != 1)
+		return -EINVAL;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = acpi_nfit_ars_rescan(acpi_desc);
+	}
+	device_unlock(dev);
+	if (rc)
+		return rc;
+	return size;
+}
+static DEVICE_ATTR_RW(scrub);
+
+static bool ars_supported(struct nvdimm_bus *nvdimm_bus)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	const unsigned long mask = 1 << ND_CMD_ARS_CAP | 1 << ND_CMD_ARS_START
+		| 1 << ND_CMD_ARS_STATUS;
+
+	return (nd_desc->cmd_mask & mask) == mask;
+}
+
+static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	if (a == &dev_attr_scrub.attr && !ars_supported(nvdimm_bus))
+		return 0;
+	return a->mode;
+}
+
 static struct attribute *acpi_nfit_attributes[] = {
 	&dev_attr_revision.attr,
+	&dev_attr_scrub.attr,
 	NULL,
 };
 
 static struct attribute_group acpi_nfit_attribute_group = {
 	.name = "nfit",
 	.attrs = acpi_nfit_attributes,
+	.is_visible = nfit_visible,
 };
 
 static const struct attribute_group *acpi_nfit_attribute_groups[] = {
@@ -2054,7 +2128,7 @@ static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
 	unsigned int tmo = scrub_timeout;
 	int rc;
 
-	if (nfit_spa->ars_done || !nfit_spa->nd_region)
+	if (!nfit_spa->ars_required || !nfit_spa->nd_region)
 		return;
 
 	rc = ars_start(acpi_desc, nfit_spa);
@@ -2143,7 +2217,9 @@ static void acpi_nfit_scrub(struct work_struct *work)
 	 * firmware initiated scrubs to complete and then we go search for the
 	 * affected spa regions to mark them scanned.  In the second phase we
 	 * initiate a directed scrub for every range that was not scrubbed in
-	 * phase 1.
+	 * phase 1. If we're called for a 'rescan', we harmlessly pass through
+	 * the first phase, but really only care about running phase 2, where
+	 * regions can be notified of new poison.
 	 */
 
 	/* process platform firmware initiated scrubs */
@@ -2246,14 +2322,17 @@ static void acpi_nfit_scrub(struct work_struct *work)
 		 * Flag all the ranges that still need scrubbing, but
 		 * register them now to make data available.
 		 */
-		if (nfit_spa->nd_region)
-			nfit_spa->ars_done = 1;
-		else
+		if (!nfit_spa->nd_region) {
+			nfit_spa->ars_required = 1;
 			acpi_nfit_register_region(acpi_desc, nfit_spa);
+		}
 	}
 
 	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
 		acpi_nfit_async_scrub(acpi_desc, nfit_spa);
+	acpi_desc->scrub_count++;
+	if (acpi_desc->scrub_count_state)
+		sysfs_notify_dirent(acpi_desc->scrub_count_state);
 	mutex_unlock(&acpi_desc->init_mutex);
 }
 
@@ -2291,12 +2370,48 @@ static int acpi_nfit_check_deletions(struct acpi_nfit_desc *acpi_desc,
 	return 0;
 }
 
+static int acpi_nfit_desc_init_scrub_attr(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct kernfs_node *nfit;
+	struct device *bus_dev;
+
+	if (!ars_supported(acpi_desc->nvdimm_bus))
+		return 0;
+
+	bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+	nfit = sysfs_get_dirent(bus_dev->kobj.sd, "nfit");
+	if (!nfit) {
+		dev_err(dev, "sysfs_get_dirent 'nfit' failed\n");
+		return -ENODEV;
+	}
+	acpi_desc->scrub_count_state = sysfs_get_dirent(nfit, "scrub");
+	sysfs_put(nfit);
+	if (!acpi_desc->scrub_count_state) {
+		dev_err(dev, "sysfs_get_dirent 'scrub' failed\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
 static void acpi_nfit_destruct(void *data)
 {
 	struct acpi_nfit_desc *acpi_desc = data;
+	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
 
 	acpi_desc->cancel = 1;
+	/*
+	 * Bounce the nvdimm bus lock to make sure any in-flight
+	 * acpi_nfit_ars_rescan() submissions have had a chance to
+	 * either submit or see ->cancel set.
+	 */
+	device_lock(bus_dev);
+	device_unlock(bus_dev);
+
 	flush_workqueue(nfit_wq);
+	if (acpi_desc->scrub_count_state)
+		sysfs_put(acpi_desc->scrub_count_state);
 	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
 	acpi_desc->nvdimm_bus = NULL;
 }
@@ -2309,14 +2424,21 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	int rc;
 
 	if (!acpi_desc->nvdimm_bus) {
+		acpi_nfit_init_dsms(acpi_desc);
+
 		acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
 				&acpi_desc->nd_desc);
 		if (!acpi_desc->nvdimm_bus)
 			return -ENOMEM;
+
 		rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
 				acpi_desc);
 		if (rc)
 			return rc;
+
+		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+		if (rc)
+			return rc;
 	}
 
 	mutex_lock(&acpi_desc->init_mutex);
@@ -2360,8 +2482,6 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 	if (rc)
 		goto out_unlock;
 
-	acpi_nfit_init_dsms(acpi_desc);
-
 	rc = acpi_nfit_register_dimms(acpi_desc);
 	if (rc)
 		goto out_unlock;
@@ -2429,6 +2549,33 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa;
+
+	if (work_busy(&acpi_desc->work))
+		return -EBUSY;
+
+	if (acpi_desc->cancel)
+		return 0;
+
+	mutex_lock(&acpi_desc->init_mutex);
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+		if (nfit_spa_type(spa) != NFIT_SPA_PM)
+			continue;
+
+		nfit_spa->ars_required = 1;
+	}
+	queue_work(nfit_wq, &acpi_desc->work);
+	dev_dbg(dev, "%s: ars_scan triggered\n", __func__);
+	mutex_unlock(&acpi_desc->init_mutex);
+
+	return 0;
+}
+
 void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 {
 	struct nvdimm_bus_descriptor *nd_desc;
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index b63a583a678f..6ecf337c97aa 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -80,7 +80,7 @@ enum {
 struct nfit_spa {
 	struct list_head list;
 	struct nd_region *nd_region;
-	unsigned int ars_done:1;
+	unsigned int ars_required:1;
 	u32 clear_err_unit;
 	u32 max_ars;
 	struct acpi_nfit_system_address spa[0];
@@ -148,6 +148,8 @@ struct acpi_nfit_desc {
 	struct nd_cmd_ars_status *ars_status;
 	size_t ars_status_size;
 	struct work_struct work;
+	struct kernfs_node *scrub_count_state;
+	unsigned int scrub_count;
 	unsigned int cancel:1;
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 2c98f958fabb..715583f69d28 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -201,6 +201,13 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
+{
+	/* struct nvdimm_bus definition is private to libnvdimm */
+	return &nvdimm_bus->dev;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);
+
 static bool is_uuid_sep(char sep)
 {
 	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 2ab869dece4a..b519e137b9b7 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -137,6 +137,7 @@ struct nvdimm *to_nvdimm(struct device *dev);
 struct nd_region *to_nd_region(struct device *dev);
 struct nd_blk_region *to_nd_blk_region(struct device *dev);
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus);
+struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus);
 const char *nvdimm_name(struct nvdimm *nvdimm);
 unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm);
 void *nvdimm_provider_data(struct nvdimm *nvdimm);