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IB/uverbs: Increase maximum devices supported 

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

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

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

This change increases the maximum number of HCAs to 64 (from 32).

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 19:08:09 +00:00 committed by Roland Dreier
parent ddbd688301
commit 6d6a0e71ee
1 changed files with 50 additions and 6 deletions
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56
drivers/infiniband/core/uverbs_main.c
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@ -728,6 +728,34 @@ 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_UVERBS_MAX_DEVICES);
/*
* If we have more than IB_UVERBS_MAX_DEVICES, dynamically overflow by
* requesting a new major number and doubling the number of max devices we
* support. It's stupid, but simple.
*/
static int find_overflow_devnum(void)
{
int ret;
if (!overflow_maj) {
ret = alloc_chrdev_region(&overflow_maj, 0, IB_UVERBS_MAX_DEVICES,
"infiniband_verbs");
if (ret) {
printk(KERN_ERR "user_verbs: couldn't register dynamic device number\n");
return ret;
}
}
ret = find_first_zero_bit(overflow_map, IB_UVERBS_MAX_DEVICES);
if (ret >= IB_UVERBS_MAX_DEVICES)
return -1;
return ret;
}
static void ib_uverbs_add_one(struct ib_device *device)
{
int devnum;
@ -748,11 +776,19 @@ static void ib_uverbs_add_one(struct ib_device *device)
devnum = find_first_zero_bit(dev_map, IB_UVERBS_MAX_DEVICES);
if (devnum >= IB_UVERBS_MAX_DEVICES) {
spin_unlock(&map_lock);
goto err;
devnum = find_overflow_devnum();
if (devnum < 0)
goto err;
spin_lock(&map_lock);
uverbs_dev->devnum = devnum + IB_UVERBS_MAX_DEVICES;
base = devnum + overflow_maj;
set_bit(devnum, overflow_map);
} else {
uverbs_dev->devnum = devnum;
base = devnum + IB_UVERBS_BASE_DEV;
set_bit(devnum, dev_map);
}
uverbs_dev->devnum = devnum;
base = devnum + IB_UVERBS_BASE_DEV;
set_bit(devnum, dev_map);
spin_unlock(&map_lock);
uverbs_dev->ib_dev = device;
@ -785,7 +821,10 @@ err_class:
err_cdev:
cdev_del(&uverbs_dev->cdev);
clear_bit(devnum, dev_map);
if (uverbs_dev->devnum < IB_UVERBS_MAX_DEVICES)
clear_bit(devnum, dev_map);
else
clear_bit(devnum, overflow_map);
err:
kref_put(&uverbs_dev->ref, ib_uverbs_release_dev);
@ -805,7 +844,10 @@ static void ib_uverbs_remove_one(struct ib_device *device)
device_destroy(uverbs_class, uverbs_dev->cdev.dev);
cdev_del(&uverbs_dev->cdev);
clear_bit(uverbs_dev->devnum, dev_map);
if (uverbs_dev->devnum < IB_UVERBS_MAX_DEVICES)
clear_bit(uverbs_dev->devnum, dev_map);
else
clear_bit(uverbs_dev->devnum - IB_UVERBS_MAX_DEVICES, overflow_map);
kref_put(&uverbs_dev->ref, ib_uverbs_release_dev);
wait_for_completion(&uverbs_dev->comp);
@ -895,6 +937,8 @@ static void __exit ib_uverbs_cleanup(void)
unregister_filesystem(&uverbs_event_fs);
class_destroy(uverbs_class);
unregister_chrdev_region(IB_UVERBS_BASE_DEV, IB_UVERBS_MAX_DEVICES);
if (overflow_maj)
unregister_chrdev_region(overflow_maj, IB_UVERBS_MAX_DEVICES);
idr_destroy(&ib_uverbs_pd_idr);
idr_destroy(&ib_uverbs_mr_idr);
idr_destroy(&ib_uverbs_mw_idr);