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Commit 6d6a0e71 authored by Alexander Chiang's avatar Alexander Chiang Committed by Roland Dreier
Browse files

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: default avatarAlex Chiang <achiang@hp.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent ddbd6883

drivers/infiniband/core/uverbs_main.c

+50 −6
Original line number Diff line number Diff line
@@ -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);

		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);

	}

	spin_unlock(&map_lock);



	uverbs_dev->ib_dev           = device;
@@ -785,7 +821,10 @@ static void ib_uverbs_add_one(struct ib_device *device) 


err_cdev:

	cdev_del(&uverbs_dev->cdev);

	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);



	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);