Commit 3750d013 authored by Dan Williams's avatar Dan Williams
Browse files

cxl: Replace lockdep_mutex with local lock classes 

In response to an attempt to expand dev->lockdep_mutex for device_lock()
validation [1], Peter points out [2] that the lockdep API already has
the ability to assign a dedicated lock class per subsystem device-type.

Use lockdep_set_class() to override the default device_lock()
'__lockdep_no_validate__' class for each CXL subsystem device-type. This
enables lockdep to detect deadlocks and recursive locking within the
device-driver core and the subsystem. The
lockdep_set_class_and_subclass() API is used for port objects that
recursively lock the 'cxl_port_key' class by hierarchical topology
depth.

Link: https://lore.kernel.org/r/164982968798.684294.15817853329823976469.stgit@dwillia2-desk3.amr.corp.intel.com [1]
Link: https://lore.kernel.org/r/Ylf0dewci8myLvoW@hirez.programming.kicks-ass.net

 [2]
Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Ben Widawsky <ben.widawsky@intel.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/165055519317.3745911.7342499516839702840.stgit@dwillia2-desk3.amr.corp.intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 56368029

drivers/cxl/core/memdev.c

+3 −0
Original line number Diff line number Diff line
@@ -228,6 +228,8 @@ static void detach_memdev(struct work_struct *work) 
	put_device(&cxlmd->dev);

}



static struct lock_class_key cxl_memdev_key;



static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds,

					   const struct file_operations *fops)

{
@@ -247,6 +249,7 @@ static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds, 


	dev = &cxlmd->dev;

	device_initialize(dev);

	lockdep_set_class(&dev->mutex, &cxl_memdev_key);

	dev->parent = cxlds->dev;

	dev->bus = &cxl_bus_type;

	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);

drivers/cxl/core/pmem.c

+6 −0
Original line number Diff line number Diff line
@@ -80,6 +80,8 @@ struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_nvdimm *cxl_nvd) 
}

EXPORT_SYMBOL_NS_GPL(cxl_find_nvdimm_bridge, CXL);



static struct lock_class_key cxl_nvdimm_bridge_key;



static struct cxl_nvdimm_bridge *cxl_nvdimm_bridge_alloc(struct cxl_port *port)

{

	struct cxl_nvdimm_bridge *cxl_nvb;
@@ -99,6 +101,7 @@ static struct cxl_nvdimm_bridge *cxl_nvdimm_bridge_alloc(struct cxl_port *port) 
	cxl_nvb->port = port;

	cxl_nvb->state = CXL_NVB_NEW;

	device_initialize(dev);

	lockdep_set_class(&dev->mutex, &cxl_nvdimm_bridge_key);

	device_set_pm_not_required(dev);

	dev->parent = &port->dev;

	dev->bus = &cxl_bus_type;
@@ -214,6 +217,8 @@ struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev) 
}

EXPORT_SYMBOL_NS_GPL(to_cxl_nvdimm, CXL);



static struct lock_class_key cxl_nvdimm_key;



static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_memdev *cxlmd)

{

	struct cxl_nvdimm *cxl_nvd;
@@ -226,6 +231,7 @@ static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_memdev *cxlmd) 
	dev = &cxl_nvd->dev;

	cxl_nvd->cxlmd = cxlmd;

	device_initialize(dev);

	lockdep_set_class(&dev->mutex, &cxl_nvdimm_key);

	device_set_pm_not_required(dev);

	dev->parent = &cxlmd->dev;

	dev->bus = &cxl_bus_type;

drivers/cxl/core/port.c

+9 −4
Original line number Diff line number Diff line
@@ -391,6 +391,8 @@ static int devm_cxl_link_uport(struct device *host, struct cxl_port *port) 
	return devm_add_action_or_reset(host, cxl_unlink_uport, port);

}



static struct lock_class_key cxl_port_key;



static struct cxl_port *cxl_port_alloc(struct device *uport,

				       resource_size_t component_reg_phys,

				       struct cxl_port *parent_port)
@@ -415,9 +417,10 @@ static struct cxl_port *cxl_port_alloc(struct device *uport, 
	 * description.

	 */

	dev = &port->dev;

	if (parent_port)

	if (parent_port) {

		dev->parent = &parent_port->dev;

	else

		port->depth = parent_port->depth + 1;

	} else

		dev->parent = uport;



	port->uport = uport;
@@ -427,6 +430,7 @@ static struct cxl_port *cxl_port_alloc(struct device *uport, 
	INIT_LIST_HEAD(&port->endpoints);



	device_initialize(dev);

	lockdep_set_class_and_subclass(&dev->mutex, &cxl_port_key, port->depth);

	device_set_pm_not_required(dev);

	dev->bus = &cxl_bus_type;

	dev->type = &cxl_port_type;
@@ -457,8 +461,6 @@ struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport, 
	if (IS_ERR(port))

		return port;



	if (parent_port)

		port->depth = parent_port->depth + 1;

	dev = &port->dev;

	if (is_cxl_memdev(uport))

		rc = dev_set_name(dev, "endpoint%d", port->id);
@@ -1173,6 +1175,8 @@ static int decoder_populate_targets(struct cxl_decoder *cxld, 
	return rc;

}



static struct lock_class_key cxl_decoder_key;



/**

 * cxl_decoder_alloc - Allocate a new CXL decoder

 * @port: owning port of this decoder
@@ -1214,6 +1218,7 @@ static struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, 
	seqlock_init(&cxld->target_lock);

	dev = &cxld->dev;

	device_initialize(dev);

	lockdep_set_class(&dev->mutex, &cxl_decoder_key);

	device_set_pm_not_required(dev);

	dev->parent = &port->dev;

	dev->bus = &cxl_bus_type;