IB/umad: BKL is not needed for ib_umad_open()

#include <linux/kref.h>

#include <linux/compat.h>

#include <linux/semaphore.h>

#include <linux/smp_lock.h>

#include <asm/uaccess.h>

}

#endif

/*

 * ib_umad_open() does not need the BKL:

 *

 *  - umad_port[] accesses are protected by port_lock, the

 *    ib_umad_port 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;

 *  - the ioctl method does not affect any global state outside of the

 *    file structure being operated on;

 *  - the port is added to umad_port[] as the last part of module

 *    initialization so the open method will either immediately run

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

 */

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

{

	struct ib_umad_port *port;

	struct ib_umad_file *file;

	int ret = 0;

	lock_kernel();

	spin_lock(&port_lock);

	port = umad_port[iminor(inode) - IB_UMAD_MINOR_BASE];

	if (port)

		kref_get(&port->umad_dev->ref);

	spin_unlock(&port_lock);

	if (!port) {

		unlock_kernel();

	if (!port)

		return -ENXIO;

	}

	mutex_lock(&port->file_mutex);

out:

	mutex_unlock(&port->file_mutex);

	unlock_kernel();

	return ret;

}