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Commit daa91358 authored by Alexander Chiang's avatar Alexander Chiang Committed by Roland Dreier
Browse files

IB/ucm: Increase maximum devices supported 



Some large systems may support more than IB_UCM_MAX_DEVICES
(currently 32).

This change allows us to support more devices in a backwards-compatible
manner. the first IB_UCM_MAX_DEVICES keep the same major/minor device
numbers they've always had.

If there are more than IB_UCM_MAX_DEVICES, then we dynamically request
a new major device number (new minors start at 0).

Signed-off-by: default avatarAlex Chiang <achiang@hp.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 31d14b6e

drivers/infiniband/core/ucm.c

+45 −8
Original line number Diff line number Diff line
@@ -1215,7 +1215,10 @@ static void ib_ucm_release_dev(struct device *dev) 


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

	cdev_del(&ucm_dev->cdev);

	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, dev_map);

	kfree(ucm_dev);

}
@@ -1237,6 +1240,28 @@ static ssize_t show_ibdev(struct device *dev, struct device_attribute *attr, 
}

static DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);



static dev_t overflow_maj;

static DECLARE_BITMAP(overflow_map, IB_UCM_MAX_DEVICES);

static int find_overflow_devnum(void)

{

	int ret;



	if (!overflow_maj) {

		ret = alloc_chrdev_region(&overflow_maj, 0, IB_UCM_MAX_DEVICES,

					  "infiniband_cm");

		if (ret) {

			printk(KERN_ERR "ucm: couldn't register dynamic device number\n");

			return ret;

		}

	}



	ret = find_first_zero_bit(overflow_map, IB_UCM_MAX_DEVICES);

	if (ret >= IB_UCM_MAX_DEVICES)

		return -1;



	return ret;

}



static void ib_ucm_add_one(struct ib_device *device)

{

	int devnum;
@@ -1254,12 +1279,19 @@ static void ib_ucm_add_one(struct ib_device *device) 
	ucm_dev->ib_dev = device;



	devnum = find_first_zero_bit(dev_map, IB_UCM_MAX_DEVICES);

	if (devnum >= IB_UCM_MAX_DEVICES)

	if (devnum >= IB_UCM_MAX_DEVICES) {

		devnum = find_overflow_devnum();

		if (devnum < 0)

			goto err;



		ucm_dev->devnum = devnum + IB_UCM_MAX_DEVICES;

		base = devnum + overflow_maj;

		set_bit(devnum, overflow_map);

	} else {

		ucm_dev->devnum = devnum;

		base = devnum + IB_UCM_BASE_DEV;

		set_bit(devnum, dev_map);

	}



	cdev_init(&ucm_dev->cdev, &ucm_fops);

	ucm_dev->cdev.owner = THIS_MODULE;
@@ -1285,7 +1317,10 @@ 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);

err:

	kfree(ucm_dev);

	return;
@@ -1344,6 +1379,8 @@ static void __exit ib_ucm_cleanup(void) 
	ib_unregister_client(&ucm_client);

	class_remove_file(&cm_class, &class_attr_abi_version);

	unregister_chrdev_region(IB_UCM_BASE_DEV, IB_UCM_MAX_DEVICES);

	if (overflow_maj)

		unregister_chrdev_region(overflow_maj, IB_UCM_MAX_DEVICES);

	idr_destroy(&ctx_id_table);

}