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Commit a0d78193 authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Greg Kroah-Hartman
Browse files

IB/ucm: utilize new cdev_device_add helper function 



The use after free is not triggerable here because the cdev holds
the module lock and the only device_unregister is only triggered by
module unload, however make the change for consistency.

To make this work the cdev_del needs to move out of the struct device
release function.

This cleans up the error path significantly and thus also fixes a minor
bug where the devnum would not be released if cdev_add failed.

Signed-off-by: default avatarJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1c1d152c

drivers/infiniband/core/ucm.c

+18 −17
Original line number Diff line number Diff line
@@ -1205,12 +1205,15 @@ static void ib_ucm_release_dev(struct device *dev) 
	struct ib_ucm_device *ucm_dev;



	ucm_dev = container_of(dev, struct ib_ucm_device, dev);

	cdev_del(&ucm_dev->cdev);

	kfree(ucm_dev);

}



static void ib_ucm_free_dev(struct ib_ucm_device *ucm_dev)

{

	if (ucm_dev->devnum < IB_UCM_MAX_DEVICES)

		clear_bit(ucm_dev->devnum, dev_map);

	else

		clear_bit(ucm_dev->devnum - IB_UCM_MAX_DEVICES, overflow_map);

	kfree(ucm_dev);

}



static const struct file_operations ucm_fops = {
@@ -1266,7 +1269,9 @@ static void ib_ucm_add_one(struct ib_device *device) 
	if (!ucm_dev)

		return;



	device_initialize(&ucm_dev->dev);

	ucm_dev->ib_dev = device;

	ucm_dev->dev.release = ib_ucm_release_dev;



	devnum = find_first_zero_bit(dev_map, IB_UCM_MAX_DEVICES);

	if (devnum >= IB_UCM_MAX_DEVICES) {
@@ -1286,16 +1291,14 @@ static void ib_ucm_add_one(struct ib_device *device) 
	cdev_init(&ucm_dev->cdev, &ucm_fops);

	ucm_dev->cdev.owner = THIS_MODULE;

	kobject_set_name(&ucm_dev->cdev.kobj, "ucm%d", ucm_dev->devnum);

	if (cdev_add(&ucm_dev->cdev, base, 1))

		goto err;



	ucm_dev->dev.class = &cm_class;

	ucm_dev->dev.parent = device->dev.parent;

	ucm_dev->dev.devt = ucm_dev->cdev.dev;

	ucm_dev->dev.release = ib_ucm_release_dev;

	ucm_dev->dev.devt = base;



	dev_set_name(&ucm_dev->dev, "ucm%d", ucm_dev->devnum);

	if (device_register(&ucm_dev->dev))

		goto err_cdev;

	if (cdev_device_add(&ucm_dev->cdev, &ucm_dev->dev))

		goto err_devnum;



	if (device_create_file(&ucm_dev->dev, &dev_attr_ibdev))

		goto err_dev;
@@ -1304,15 +1307,11 @@ static void ib_ucm_add_one(struct ib_device *device) 
	return;



err_dev:

	device_unregister(&ucm_dev->dev);

err_cdev:

	cdev_del(&ucm_dev->cdev);

	if (ucm_dev->devnum < IB_UCM_MAX_DEVICES)

		clear_bit(devnum, dev_map);

	else

		clear_bit(devnum, overflow_map);

	cdev_device_del(&ucm_dev->cdev, &ucm_dev->dev);

err_devnum:

	ib_ucm_free_dev(ucm_dev);

err:

	kfree(ucm_dev);

	put_device(&ucm_dev->dev);

	return;

}
@@ -1323,7 +1322,9 @@ static void ib_ucm_remove_one(struct ib_device *device, void *client_data) 
	if (!ucm_dev)

		return;



	device_unregister(&ucm_dev->dev);

	cdev_device_del(&ucm_dev->cdev, &ucm_dev->dev);

	ib_ucm_free_dev(ucm_dev);

	put_device(&ucm_dev->dev);

}



static CLASS_ATTR_STRING(abi_version, S_IRUGO,