cxl: Drop cxl_device_lock()

Now that all CXL subsystem locking is validated with custom lock
classes, there is no need for the custom usage of the lockdep_mutex.

Cc: Alison Schofield <[e-mail]>
Cc: Vishal Verma <[e-mail]>
Cc: Ira Weiny <[e-mail]>
Cc: Ben Widawsky <[e-mail]>
Cc: Jonathan Cameron <[e-mail]>
Reviewed-by: Ira Weiny <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dan Williams <[e-mail]>

drivers/cxl/core/pmem.c

···
 	 * work to flush. Once the state has been changed to 'dead' then no new
 	 * work can be queued by user-triggered bind.
 	 */
-	cxl_device_lock(&cxl_nvb->dev);
+	device_lock(&cxl_nvb->dev);
 	flush = cxl_nvb->state != CXL_NVB_NEW;
 	cxl_nvb->state = CXL_NVB_DEAD;
-	cxl_device_unlock(&cxl_nvb->dev);
+	device_unlock(&cxl_nvb->dev);
 
 	/*
 	 * Even though the device core will trigger device_release_driver()

drivers/cxl/core/port.c

···
 	struct cxl_port *port = to_cxl_port(dev);
 	struct cxl_ep *ep, *_e;
 
-	cxl_device_lock(dev);
+	device_lock(dev);
 	list_for_each_entry_safe(ep, _e, &port->endpoints, list)
 		cxl_ep_release(ep);
-	cxl_device_unlock(dev);
+	device_unlock(dev);
 	ida_free(&cxl_port_ida, port->id);
 	kfree(port);
 }
···
 		return 0;
 
 	port = to_cxl_port(dev);
-	cxl_device_lock(dev);
+	device_lock(dev);
 	list_for_each_entry(dport, &port->dports, list) {
 		iter = match;
 		while (iter) {
···
 		}
 	}
 out:
-	cxl_device_unlock(dev);
+	device_unlock(dev);
 
 	return !!iter;
 }
···
 static void cond_cxl_root_lock(struct cxl_port *port)
 {
 	if (is_cxl_root(port))
-		cxl_device_lock(&port->dev);
+		device_lock(&port->dev);
 }
 
 static void cond_cxl_root_unlock(struct cxl_port *port)
 {
 	if (is_cxl_root(port))
-		cxl_device_unlock(&port->dev);
+		device_unlock(&port->dev);
 }
 
 static void cxl_dport_remove(void *data)
···
 {
 	struct cxl_ep *dup;
 
-	cxl_device_lock(&port->dev);
+	device_lock(&port->dev);
 	if (port->dead) {
-		cxl_device_unlock(&port->dev);
+		device_unlock(&port->dev);
 		return -ENXIO;
 	}
 	dup = find_ep(port, new->ep);
 	if (!dup)
 		list_add_tail(&new->list, &port->endpoints);
-	cxl_device_unlock(&port->dev);
+	device_unlock(&port->dev);
 
 	return dup ? -EEXIST : 0;
 }
···
 		goto out;
 	parent = &parent_port->dev;
 
-	cxl_device_lock(parent);
+	device_lock(parent);
 	if (parent->driver && endpoint->uport) {
 		devm_release_action(parent, cxl_unlink_uport, endpoint);
 		devm_release_action(parent, unregister_port, endpoint);
 	}
-	cxl_device_unlock(parent);
+	device_unlock(parent);
 	put_device(parent);
 out:
 	put_device(&endpoint->dev);
···
 		}
 
 		parent_port = to_cxl_port(port->dev.parent);
-		cxl_device_lock(&parent_port->dev);
+		device_lock(&parent_port->dev);
 		if (!parent_port->dev.driver) {
 			/*
 			 * The bottom-up race to delete the port lost to a
···
 			 * parent_port ->remove() will have cleaned up all
 			 * descendants.
 			 */
-			cxl_device_unlock(&parent_port->dev);
+			device_unlock(&parent_port->dev);
 			put_device(&port->dev);
 			continue;
 		}
 
-		cxl_device_lock(&port->dev);
+		device_lock(&port->dev);
 		ep = find_ep(port, &cxlmd->dev);
 		dev_dbg(&cxlmd->dev, "disconnect %s from %s\n",
 			ep ? dev_name(ep->ep) : "", dev_name(&port->dev));
···
 			port->dead = true;
 			list_splice_init(&port->dports, &reap_dports);
 		}
-		cxl_device_unlock(&port->dev);
+		device_unlock(&port->dev);
 
 		if (!list_empty(&reap_dports)) {
 			dev_dbg(&cxlmd->dev, "delete %s\n",
···
 			delete_switch_port(port, &reap_dports);
 		}
 		put_device(&port->dev);
-		cxl_device_unlock(&parent_port->dev);
+		device_unlock(&parent_port->dev);
 	}
 }
 
···
 		return -EAGAIN;
 	}
 
-	cxl_device_lock(&parent_port->dev);
+	device_lock(&parent_port->dev);
 	if (!parent_port->dev.driver) {
 		dev_warn(&cxlmd->dev,
 			 "port %s:%s disabled, failed to enumerate CXL.mem\n",
···
 			get_device(&port->dev);
 	}
 out:
-	cxl_device_unlock(&parent_port->dev);
+	device_unlock(&parent_port->dev);
 
 	if (IS_ERR(port))
 		rc = PTR_ERR(port);
···
 {
 	struct cxl_dport *dport;
 
-	cxl_device_lock(&port->dev);
+	device_lock(&port->dev);
 	list_for_each_entry(dport, &port->dports, list)
 		if (dport->dport == dev) {
-			cxl_device_unlock(&port->dev);
+			device_unlock(&port->dev);
 			return dport;
 		}
 
-	cxl_device_unlock(&port->dev);
+	device_unlock(&port->dev);
 	return NULL;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_find_dport_by_dev, CXL);
···
 
 	port = to_cxl_port(cxld->dev.parent);
 
-	cxl_device_lock(&port->dev);
+	device_lock(&port->dev);
 	rc = cxl_decoder_add_locked(cxld, target_map);
-	cxl_device_unlock(&port->dev);
+	device_unlock(&port->dev);
 
 	return rc;
 }
···
 {
 	int rc;
 
-	/*
-	 * Take the CXL nested lock since the driver core only holds
-	 * @dev->mutex and not @dev->lockdep_mutex.
-	 */
-	cxl_nested_lock(dev);
 	rc = to_cxl_drv(dev->driver)->probe(dev);
-	cxl_nested_unlock(dev);
-
 	dev_dbg(dev, "probe: %d\n", rc);
 	return rc;
 }
···
 {
 	struct cxl_driver *cxl_drv = to_cxl_drv(dev->driver);
 
-	cxl_nested_lock(dev);
 	if (cxl_drv->remove)
 		cxl_drv->remove(dev);
-	cxl_nested_unlock(dev);
 }
 
 static struct workqueue_struct *cxl_bus_wq;

drivers/cxl/cxl.h

···
 #define __mock static
 #endif
 
-#ifdef CONFIG_PROVE_CXL_LOCKING
-enum cxl_lock_class {
-	CXL_ANON_LOCK,
-	CXL_NVDIMM_LOCK,
-	CXL_NVDIMM_BRIDGE_LOCK,
-	CXL_PORT_LOCK,
-	/*
-	 * Be careful to add new lock classes here, CXL_PORT_LOCK is
-	 * extended by the port depth, so a maximum CXL port topology
-	 * depth would need to be defined first.
-	 */
-};
-
-static inline void cxl_nested_lock(struct device *dev)
-{
-	if (is_cxl_port(dev)) {
-		struct cxl_port *port = to_cxl_port(dev);
-
-		mutex_lock_nested(&dev->lockdep_mutex,
-				  CXL_PORT_LOCK + port->depth);
-	} else if (is_cxl_decoder(dev)) {
-		struct cxl_port *port = to_cxl_port(dev->parent);
-
-		/*
-		 * A decoder is the immediate child of a port, so set
-		 * its lock class equal to other child device siblings.
-		 */
-		mutex_lock_nested(&dev->lockdep_mutex,
-				  CXL_PORT_LOCK + port->depth + 1);
-	} else if (is_cxl_nvdimm_bridge(dev))
-		mutex_lock_nested(&dev->lockdep_mutex, CXL_NVDIMM_BRIDGE_LOCK);
-	else if (is_cxl_nvdimm(dev))
-		mutex_lock_nested(&dev->lockdep_mutex, CXL_NVDIMM_LOCK);
-	else
-		mutex_lock_nested(&dev->lockdep_mutex, CXL_ANON_LOCK);
-}
-
-static inline void cxl_nested_unlock(struct device *dev)
-{
-	mutex_unlock(&dev->lockdep_mutex);
-}
-
-static inline void cxl_device_lock(struct device *dev)
-{
-	/*
-	 * For double lock errors the lockup will happen before lockdep
-	 * warns at cxl_nested_lock(), so assert explicitly.
-	 */
-	lockdep_assert_not_held(&dev->lockdep_mutex);
-
-	device_lock(dev);
-	cxl_nested_lock(dev);
-}
-
-static inline void cxl_device_unlock(struct device *dev)
-{
-	cxl_nested_unlock(dev);
-	device_unlock(dev);
-}
-#else
-static inline void cxl_nested_lock(struct device *dev)
-{
-}
-
-static inline void cxl_nested_unlock(struct device *dev)
-{
-}
-
-static inline void cxl_device_lock(struct device *dev)
-{
-	device_lock(dev);
-}
-
-static inline void cxl_device_unlock(struct device *dev)
-{
-	device_unlock(dev);
-}
-#endif
 #endif /* __CXL_H__ */

drivers/cxl/mem.c

···
 		return -ENXIO;
 	}
 
-	cxl_device_lock(&parent_port->dev);
+	device_lock(&parent_port->dev);
 	if (!parent_port->dev.driver) {
 		dev_err(dev, "CXL port topology %s not enabled\n",
 			dev_name(&parent_port->dev));
···
 
 	rc = create_endpoint(cxlmd, parent_port);
 out:
-	cxl_device_unlock(&parent_port->dev);
+	device_unlock(&parent_port->dev);
 	put_device(&parent_port->dev);
 
 	/*

drivers/cxl/pmem.c

···
 	if (!cxl_nvb)
 		return -ENXIO;
 
-	cxl_device_lock(&cxl_nvb->dev);
+	device_lock(&cxl_nvb->dev);
 	if (!cxl_nvb->nvdimm_bus) {
 		rc = -ENXIO;
 		goto out;
···
 	dev_set_drvdata(dev, nvdimm);
 	rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm);
 out:
-	cxl_device_unlock(&cxl_nvb->dev);
+	device_unlock(&cxl_nvb->dev);
 	put_device(&cxl_nvb->dev);
 
 	return rc;
···
 	struct nvdimm_bus *victim_bus = NULL;
 	bool release = false, rescan = false;
 
-	cxl_device_lock(&cxl_nvb->dev);
+	device_lock(&cxl_nvb->dev);
 	switch (cxl_nvb->state) {
 	case CXL_NVB_ONLINE:
 		if (!online_nvdimm_bus(cxl_nvb)) {
···
 	default:
 		break;
 	}
-	cxl_device_unlock(&cxl_nvb->dev);
+	device_unlock(&cxl_nvb->dev);
 
 	if (release)
 		device_release_driver(&cxl_nvb->dev);
···
 		return 0;
 
 	cxl_nvb = to_cxl_nvdimm_bridge(dev);
-	cxl_device_lock(dev);
+	device_lock(dev);
 	cxl_nvb->state = CXL_NVB_NEW;
-	cxl_device_unlock(dev);
+	device_unlock(dev);
 
 	return 0;
 }

lib/Kconfig.debug

···
 	help
 	  Enable lockdep to validate nd_device_lock() usage.
 
-config PROVE_CXL_LOCKING
-	bool "CXL"
-	depends on CXL_BUS
-	help
-	  Enable lockdep to validate cxl_device_lock() usage.
-
 endchoice
 
 endmenu # lock debugging