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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: Alex Chiang <achiang@hp.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Alexander Chiang 2010-02-02 19:09:06 +00:00 committed by Roland Dreier
parent 31d14b6e10
commit daa913580e
1 changed files with 44 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
drivers/infiniband/core/ucm.c
View File

@ -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);
clear_bit(ucm_dev->devnum, dev_map);
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)
goto err;
if (devnum >= IB_UCM_MAX_DEVICES) {
devnum = find_overflow_devnum();
if (devnum < 0)
goto err;
ucm_dev->devnum = devnum;
base = devnum + IB_UCM_BASE_DEV;
set_bit(devnum, dev_map);
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);
clear_bit(devnum, dev_map);
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);
}