IB/uverbs: BKL is not needed for ib_uverbs_open()

#include <linux/file.h>

#include <linux/mount.h>

#include <linux/cdev.h>

#include <linux/smp_lock.h>

#include <asm/uaccess.h>

		return file->device->ib_dev->mmap(file->ucontext, vma);

}

/*

 * ib_uverbs_open() does not need the BKL:

 *

 *  - dev_table[] accesses are protected by map_lock, the

 *    ib_uverbs_device structures are properly reference counted, and

 *    everything else is purely local to the file being created, so

 *    races against other open calls are not a problem;

 *  - there is no ioctl method to race against;

 *  - the device is added to dev_table[] as the last part of module

 *    initialization, the open method will either immediately run

 *    -ENXIO, or all required initialization will be done.

 */

static int ib_uverbs_open(struct inode *inode, struct file *filp)

{

	struct ib_uverbs_device *dev;

	struct ib_uverbs_file *file;

	int ret;

	lock_kernel();

	spin_lock(&map_lock);

	dev = dev_table[iminor(inode) - IB_UVERBS_BASE_MINOR];

	if (dev)

		kref_get(&dev->ref);

	spin_unlock(&map_lock);

	if (!dev) {

		unlock_kernel();

	if (!dev)

		return -ENXIO;

	}

	if (!try_module_get(dev->ib_dev->owner)) {

		ret = -ENODEV;

	filp->private_data = file;

	unlock_kernel();

	return 0;

err_module:

err:

	kref_put(&dev->ref, ib_uverbs_release_dev);

	unlock_kernel();

	return ret;

}