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IB/umad: Increase maximum devices supported

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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: Alex Chiang <achiang@hp.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Alexander Chiang 2010-02-02 19:08:45 +00:00 committed by Roland Dreier
parent dc2ed5e3c9
commit 8698d3fecc
1 changed files with 44 additions and 6 deletions
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50
drivers/infiniband/core/user_mad.c
View file

@ -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);
return -1;
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);
}
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);
clear_bit(devnum, dev_map);
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);
clear_bit(port->dev_num, dev_map);
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);