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Commit 8698d3fe authored by Alexander Chiang's avatar Alexander Chiang Committed by Roland Dreier
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IB/umad: Increase maximum devices supported 



Some large systems may support more than IB_UMAD_MAX_PORTS
(currently 64).

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

If there are more than IB_UMAD_MAX_PORTS, we then 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 dc2ed5e3

drivers/infiniband/core/user_mad.c

+44 −6
Original line number Diff line number Diff line
@@ -971,6 +971,28 @@ static ssize_t show_abi_version(struct class *class, char *buf) 
}

static CLASS_ATTR(abi_version, S_IRUGO, show_abi_version, NULL);



static dev_t overflow_maj;

static DECLARE_BITMAP(overflow_map, IB_UMAD_MAX_PORTS);

static int find_overflow_devnum(void)

{

	int ret;



	if (!overflow_maj) {

		ret = alloc_chrdev_region(&overflow_maj, 0, IB_UMAD_MAX_PORTS * 2,

					  "infiniband_mad");

		if (ret) {

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

			return ret;

		}

	}



	ret = find_first_zero_bit(overflow_map, IB_UMAD_MAX_PORTS);

	if (ret >= IB_UMAD_MAX_PORTS)

		return -1;



	return ret;

}



static int ib_umad_init_port(struct ib_device *device, int port_num,

			     struct ib_umad_port *port)

{
@@ -981,11 +1003,19 @@ static int ib_umad_init_port(struct ib_device *device, int port_num, 
	devnum = find_first_zero_bit(dev_map, IB_UMAD_MAX_PORTS);

	if (devnum >= IB_UMAD_MAX_PORTS) {

		spin_unlock(&port_lock);

		devnum = find_overflow_devnum();

		if (devnum < 0)

			return -1;

	}



		spin_lock(&port_lock);

		port->dev_num = devnum + IB_UMAD_MAX_PORTS;

		base = devnum + overflow_maj;

		set_bit(devnum, overflow_map);

	} else {

		port->dev_num = devnum;

		base = devnum + base_dev;

		set_bit(devnum, dev_map);

	}

	spin_unlock(&port_lock);



	port->ib_dev   = device;
@@ -1042,7 +1072,10 @@ err_dev: 


err_cdev:

	cdev_del(&port->cdev);

	if (port->dev_num < IB_UMAD_MAX_PORTS)

		clear_bit(devnum, dev_map);

	else

		clear_bit(devnum, overflow_map);



	return -1;

}
@@ -1079,7 +1112,10 @@ static void ib_umad_kill_port(struct ib_umad_port *port) 


	mutex_unlock(&port->file_mutex);



	if (port->dev_num < IB_UMAD_MAX_PORTS)

		clear_bit(port->dev_num, dev_map);

	else

		clear_bit(port->dev_num - IB_UMAD_MAX_PORTS, overflow_map);

}



static void ib_umad_add_one(struct ib_device *device)
@@ -1187,6 +1223,8 @@ static void __exit ib_umad_cleanup(void) 
	ib_unregister_client(&umad_client);

	class_destroy(umad_class);

	unregister_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2);

	if (overflow_maj)

		unregister_chrdev_region(overflow_maj, IB_UMAD_MAX_PORTS * 2);

}



module_init(ib_umad_init);