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Commit 87a30e1f authored by Dan Williams's avatar Dan Williams
Browse files

driver-core, libnvdimm: Let device subsystems add local lockdep coverage 



For good reason, the standard device_lock() is marked
lockdep_set_novalidate_class() because there is simply no sane way to
describe the myriad ways the device_lock() ordered with other locks.
However, that leaves subsystems that know their own local device_lock()
ordering rules to find lock ordering mistakes manually. Instead,
introduce an optional / additional lockdep-enabled lock that a subsystem
can acquire in all the same paths that the device_lock() is acquired.

A conversion of the NFIT driver and NVDIMM subsystem to a
lockdep-validate device_lock() scheme is included. The
debug_nvdimm_lock() implementation implements the correct lock-class and
stacking order for the libnvdimm device topology hierarchy.

Yes, this is a hack, but hopefully it is a useful hack for other
subsystems device_lock() debug sessions. Quoting Greg:

    "Yeah, it feels a bit hacky but it's really up to a subsystem to mess up
     using it as much as anything else, so user beware :)

     I don't object to it if it makes things easier for you to debug."

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/156341210661.292348.7014034644265455704.stgit@dwillia2-desk3.amr.corp.intel.com
parent ca6bf264

drivers/acpi/nfit/core.c

+14 −14
Original line number Diff line number Diff line
@@ -1282,7 +1282,7 @@ static ssize_t hw_error_scrub_store(struct device *dev, 
	if (rc)

		return rc;



	device_lock(dev);

	nfit_device_lock(dev);

	nd_desc = dev_get_drvdata(dev);

	if (nd_desc) {

		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
@@ -1299,7 +1299,7 @@ static ssize_t hw_error_scrub_store(struct device *dev, 
			break;

		}

	}

	device_unlock(dev);

	nfit_device_unlock(dev);

	if (rc)

		return rc;

	return size;
@@ -1319,7 +1319,7 @@ static ssize_t scrub_show(struct device *dev, 
	ssize_t rc = -ENXIO;

	bool busy;



	device_lock(dev);

	nfit_device_lock(dev);

	nd_desc = dev_get_drvdata(dev);

	if (!nd_desc) {

		device_unlock(dev);
@@ -1339,7 +1339,7 @@ static ssize_t scrub_show(struct device *dev, 
	}



	mutex_unlock(&acpi_desc->init_mutex);

	device_unlock(dev);

	nfit_device_unlock(dev);

	return rc;

}
@@ -1356,14 +1356,14 @@ static ssize_t scrub_store(struct device *dev, 
	if (val != 1)

		return -EINVAL;



	device_lock(dev);

	nfit_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, ARS_REQ_LONG);

	}

	device_unlock(dev);

	nfit_device_unlock(dev);

	if (rc)

		return rc;

	return size;
@@ -1749,9 +1749,9 @@ static void acpi_nvdimm_notify(acpi_handle handle, u32 event, void *data) 
	struct acpi_device *adev = data;

	struct device *dev = &adev->dev;



	device_lock(dev->parent);

	nfit_device_lock(dev->parent);

	__acpi_nvdimm_notify(dev, event);

	device_unlock(dev->parent);

	nfit_device_unlock(dev->parent);

}



static bool acpi_nvdimm_has_method(struct acpi_device *adev, char *method)
@@ -3457,8 +3457,8 @@ static int acpi_nfit_flush_probe(struct nvdimm_bus_descriptor *nd_desc) 
	struct device *dev = acpi_desc->dev;



	/* Bounce the device lock to flush acpi_nfit_add / acpi_nfit_notify */

	device_lock(dev);

	device_unlock(dev);

	nfit_device_lock(dev);

	nfit_device_unlock(dev);



	/* Bounce the init_mutex to complete initial registration */

	mutex_lock(&acpi_desc->init_mutex);
@@ -3602,8 +3602,8 @@ void acpi_nfit_shutdown(void *data) 
	 * acpi_nfit_ars_rescan() submissions have had a chance to

	 * either submit or see ->cancel set.

	 */

	device_lock(bus_dev);

	device_unlock(bus_dev);

	nfit_device_lock(bus_dev);

	nfit_device_unlock(bus_dev);



	flush_workqueue(nfit_wq);

}
@@ -3746,9 +3746,9 @@ EXPORT_SYMBOL_GPL(__acpi_nfit_notify); 


static void acpi_nfit_notify(struct acpi_device *adev, u32 event)

{

	device_lock(&adev->dev);

	nfit_device_lock(&adev->dev);

	__acpi_nfit_notify(&adev->dev, adev->handle, event);

	device_unlock(&adev->dev);

	nfit_device_unlock(&adev->dev);

}



static const struct acpi_device_id acpi_nfit_ids[] = {

drivers/acpi/nfit/nfit.h

+24 −0
Original line number Diff line number Diff line
@@ -312,6 +312,30 @@ static inline struct acpi_nfit_desc *to_acpi_desc( 
	return container_of(nd_desc, struct acpi_nfit_desc, nd_desc);

}



#ifdef CONFIG_PROVE_LOCKING

static inline void nfit_device_lock(struct device *dev)

{

	device_lock(dev);

	mutex_lock(&dev->lockdep_mutex);

}



static inline void nfit_device_unlock(struct device *dev)

{

	mutex_unlock(&dev->lockdep_mutex);

	device_unlock(dev);

}

#else

static inline void nfit_device_lock(struct device *dev)

{

	device_lock(dev);

}



static inline void nfit_device_unlock(struct device *dev)

{

	device_unlock(dev);

}

#endif



const guid_t *to_nfit_uuid(enum nfit_uuids id);

int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *nfit, acpi_size sz);

void acpi_nfit_shutdown(void *data);

drivers/base/core.c

+3 −0
Original line number Diff line number Diff line
@@ -1663,6 +1663,9 @@ void device_initialize(struct device *dev) 
	kobject_init(&dev->kobj, &device_ktype);

	INIT_LIST_HEAD(&dev->dma_pools);

	mutex_init(&dev->mutex);

#ifdef CONFIG_PROVE_LOCKING

	mutex_init(&dev->lockdep_mutex);

#endif

	lockdep_set_novalidate_class(&dev->mutex);

	spin_lock_init(&dev->devres_lock);

	INIT_LIST_HEAD(&dev->devres_head);

drivers/nvdimm/btt_devs.c

+8 −8
Original line number Diff line number Diff line
@@ -62,14 +62,14 @@ static ssize_t sector_size_store(struct device *dev, 
	struct nd_btt *nd_btt = to_nd_btt(dev);

	ssize_t rc;



	device_lock(dev);

	nd_device_lock(dev);

	nvdimm_bus_lock(dev);

	rc = nd_size_select_store(dev, buf, &nd_btt->lbasize,

			btt_lbasize_supported);

	dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,

			buf[len - 1] == '\n' ? "" : "\n");

	nvdimm_bus_unlock(dev);

	device_unlock(dev);

	nd_device_unlock(dev);



	return rc ? rc : len;

}
@@ -91,11 +91,11 @@ static ssize_t uuid_store(struct device *dev, 
	struct nd_btt *nd_btt = to_nd_btt(dev);

	ssize_t rc;



	device_lock(dev);

	nd_device_lock(dev);

	rc = nd_uuid_store(dev, &nd_btt->uuid, buf, len);

	dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,

			buf[len - 1] == '\n' ? "" : "\n");

	device_unlock(dev);

	nd_device_unlock(dev);



	return rc ? rc : len;

}
@@ -120,13 +120,13 @@ static ssize_t namespace_store(struct device *dev, 
	struct nd_btt *nd_btt = to_nd_btt(dev);

	ssize_t rc;



	device_lock(dev);

	nd_device_lock(dev);

	nvdimm_bus_lock(dev);

	rc = nd_namespace_store(dev, &nd_btt->ndns, buf, len);

	dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,

			buf[len - 1] == '\n' ? "" : "\n");

	nvdimm_bus_unlock(dev);

	device_unlock(dev);

	nd_device_unlock(dev);



	return rc;

}
@@ -138,14 +138,14 @@ static ssize_t size_show(struct device *dev, 
	struct nd_btt *nd_btt = to_nd_btt(dev);

	ssize_t rc;



	device_lock(dev);

	nd_device_lock(dev);

	if (dev->driver)

		rc = sprintf(buf, "%llu\n", nd_btt->size);

	else {

		/* no size to convey if the btt instance is disabled */

		rc = -ENXIO;

	}

	device_unlock(dev);

	nd_device_unlock(dev);



	return rc;

}

drivers/nvdimm/bus.c

+17 −11
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ 


int nvdimm_major;

static int nvdimm_bus_major;

static struct class *nd_class;

struct class *nd_class;

static DEFINE_IDA(nd_ida);



static int to_nd_device_type(struct device *dev)
@@ -91,7 +91,10 @@ static int nvdimm_bus_probe(struct device *dev) 
			dev->driver->name, dev_name(dev));



	nvdimm_bus_probe_start(nvdimm_bus);

	debug_nvdimm_lock(dev);

	rc = nd_drv->probe(dev);

	debug_nvdimm_unlock(dev);



	if (rc == 0)

		nd_region_probe_success(nvdimm_bus, dev);

	else
@@ -113,8 +116,11 @@ static int nvdimm_bus_remove(struct device *dev) 
	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);

	int rc = 0;



	if (nd_drv->remove)

	if (nd_drv->remove) {

		debug_nvdimm_lock(dev);

		rc = nd_drv->remove(dev);

		debug_nvdimm_unlock(dev);

	}

	nd_region_disable(nvdimm_bus, dev);



	dev_dbg(&nvdimm_bus->dev, "%s.remove(%s) = %d\n", dev->driver->name,
@@ -140,7 +146,7 @@ static void nvdimm_bus_shutdown(struct device *dev) 


void nd_device_notify(struct device *dev, enum nvdimm_event event)

{

	device_lock(dev);

	nd_device_lock(dev);

	if (dev->driver) {

		struct nd_device_driver *nd_drv;
@@ -148,7 +154,7 @@ void nd_device_notify(struct device *dev, enum nvdimm_event event) 
		if (nd_drv->notify)

			nd_drv->notify(dev, event);

	}

	device_unlock(dev);

	nd_device_unlock(dev);

}

EXPORT_SYMBOL(nd_device_notify);
@@ -296,7 +302,7 @@ static void nvdimm_bus_release(struct device *dev) 
	kfree(nvdimm_bus);

}



static bool is_nvdimm_bus(struct device *dev)

bool is_nvdimm_bus(struct device *dev)

{

	return dev->release == nvdimm_bus_release;

}
@@ -575,9 +581,9 @@ void nd_device_unregister(struct device *dev, enum nd_async_mode mode) 
		 * or otherwise let the async path handle it if the

		 * unregistration was already queued.

		 */

		device_lock(dev);

		nd_device_lock(dev);

		killed = kill_device(dev);

		device_unlock(dev);

		nd_device_unlock(dev);



		if (!killed)

			return;
@@ -888,10 +894,10 @@ void wait_nvdimm_bus_probe_idle(struct device *dev) 
		if (nvdimm_bus->probe_active == 0)

			break;

		nvdimm_bus_unlock(dev);

		device_unlock(dev);

		nd_device_unlock(dev);

		wait_event(nvdimm_bus->wait,

				nvdimm_bus->probe_active == 0);

		device_lock(dev);

		nd_device_lock(dev);

		nvdimm_bus_lock(dev);

	} while (true);

}
@@ -1107,7 +1113,7 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 
		goto out;

	}



	device_lock(dev);

	nd_device_lock(dev);

	nvdimm_bus_lock(dev);

	rc = nd_cmd_clear_to_send(nvdimm_bus, nvdimm, func, buf);

	if (rc)
@@ -1129,7 +1135,7 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 


out_unlock:

	nvdimm_bus_unlock(dev);

	device_unlock(dev);

	nd_device_unlock(dev);

out:

	kfree(in_env);

	kfree(out_env);