linux-kernel - [PATCH 5.10 10/25] gpu: host1x: Use different lock classes for each client

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Message-Id: <20210415144413.493750270@linuxfoundation.org>
Date:   Thu, 15 Apr 2021 16:48:04 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Mikko Perttunen <mperttunen@...dia.com>,
        Thierry Reding <treding@...dia.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 10/25] gpu: host1x: Use different lock classes for each client

From: Mikko Perttunen <mperttunen@...dia.com>

[ Upstream commit a24f98176d1efae2c37d3438c57a624d530d9c33 ]

To avoid false lockdep warnings, give each client lock a different
lock class, passed from the initialization site by macro.

Signed-off-by: Mikko Perttunen <mperttunen@...dia.com>
Signed-off-by: Thierry Reding <treding@...dia.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/host1x/bus.c | 10 ++++++----
 include/linux/host1x.h   |  9 ++++++++-
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
index e201f62d62c0..9e2cb6968819 100644
--- a/drivers/gpu/host1x/bus.c
+++ b/drivers/gpu/host1x/bus.c
@@ -704,8 +704,9 @@ void host1x_driver_unregister(struct host1x_driver *driver)
 EXPORT_SYMBOL(host1x_driver_unregister);
 
 /**
- * host1x_client_register() - register a host1x client
+ * __host1x_client_register() - register a host1x client
  * @client: host1x client
+ * @key: lock class key for the client-specific mutex
  *
  * Registers a host1x client with each host1x controller instance. Note that
  * each client will only match their parent host1x controller and will only be
@@ -714,13 +715,14 @@ EXPORT_SYMBOL(host1x_driver_unregister);
  * device and call host1x_device_init(), which will in turn call each client's
  * &host1x_client_ops.init implementation.
  */
-int host1x_client_register(struct host1x_client *client)
+int __host1x_client_register(struct host1x_client *client,
+			     struct lock_class_key *key)
 {
 	struct host1x *host1x;
 	int err;
 
 	INIT_LIST_HEAD(&client->list);
-	mutex_init(&client->lock);
+	__mutex_init(&client->lock, "host1x client lock", key);
 	client->usecount = 0;
 
 	mutex_lock(&devices_lock);
@@ -741,7 +743,7 @@ int host1x_client_register(struct host1x_client *client)
 
 	return 0;
 }
-EXPORT_SYMBOL(host1x_client_register);
+EXPORT_SYMBOL(__host1x_client_register);
 
 /**
  * host1x_client_unregister() - unregister a host1x client
diff --git a/include/linux/host1x.h b/include/linux/host1x.h
index ce59a6a6a008..9eb77c87a83b 100644
--- a/include/linux/host1x.h
+++ b/include/linux/host1x.h
@@ -320,7 +320,14 @@ static inline struct host1x_device *to_host1x_device(struct device *dev)
 int host1x_device_init(struct host1x_device *device);
 int host1x_device_exit(struct host1x_device *device);
 
-int host1x_client_register(struct host1x_client *client);
+int __host1x_client_register(struct host1x_client *client,
+			     struct lock_class_key *key);
+#define host1x_client_register(class) \
+	({ \
+		static struct lock_class_key __key; \
+		__host1x_client_register(class, &__key); \
+	})
+
 int host1x_client_unregister(struct host1x_client *client);
 
 int host1x_client_suspend(struct host1x_client *client);
-- 
2.30.2