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Commit 77ed74da authored by Jean Delvare's avatar Jean Delvare Committed by Linus Torvalds
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[PATCH] i2c: Prevent deadlock on i2c client registration 



Delay the call to adapter->client_register() until after we are
certain that the client registration is a success. At this point the
client is fully initialized and we no longer hold the adapter->clist
mutex, so this should prevent the deadlocks if the client_register()
callback needs to take that mutex too, as is the case for the bttv
driver.

This fixes bug #7234.

Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 5ffd1a6a

drivers/i2c/i2c-core.c

+13 −12
Original line number Original line Diff line number Diff line
@@ -420,14 +420,6 @@ int i2c_attach_client(struct i2c_client *client) 
	}

	}

	list_add_tail(&client->list,&adapter->clients);

	list_add_tail(&client->list,&adapter->clients);

	

	

	if (adapter->client_register)  {

		if (adapter->client_register(client))  {

			dev_dbg(&adapter->dev, "client_register "

				"failed for client [%s] at 0x%02x\n",

				client->name, client->addr);

		}

	}



	client->usage_count = 0;

	client->usage_count = 0;





	client->dev.parent = &client->adapter->dev;

	client->dev.parent = &client->adapter->dev;
@@ -445,10 +437,17 @@ int i2c_attach_client(struct i2c_client *client) 
	res = device_create_file(&client->dev, &dev_attr_client_name);

	res = device_create_file(&client->dev, &dev_attr_client_name);

	if (res)

	if (res)

		goto out_unregister;

		goto out_unregister;



out_unlock:

	mutex_unlock(&adapter->clist_lock);

	mutex_unlock(&adapter->clist_lock);

	return res;



	if (adapter->client_register)  {

		if (adapter->client_register(client)) {

			dev_dbg(&adapter->dev, "client_register "

				"failed for client [%s] at 0x%02x\n",

				client->name, client->addr);

		}

	}



	return 0;





out_unregister:

out_unregister:

	init_completion(&client->released); /* Needed? */

	init_completion(&client->released); /* Needed? */
@@ -458,7 +457,9 @@ int i2c_attach_client(struct i2c_client *client) 
	list_del(&client->list);

	list_del(&client->list);

	dev_err(&adapter->dev, "Failed to attach i2c client %s at 0x%02x "

	dev_err(&adapter->dev, "Failed to attach i2c client %s at 0x%02x "

		"(%d)\n", client->name, client->addr, res);

		"(%d)\n", client->name, client->addr, res);

	goto out_unlock;

out_unlock:

	mutex_unlock(&adapter->clist_lock);

	return res;

}

}