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kernel/linux-rt-4.4.41/drivers/misc/mic/scif/scif_ports.c 2.8 KB
5113f6f70   김현기   kernel add
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  /*
   * Intel MIC Platform Software Stack (MPSS)
   *
   * Copyright(c) 2014 Intel Corporation.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License, version 2, as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   * General Public License for more details.
   *
   * Intel SCIF driver.
   *
   */
  #include <linux/idr.h>
  
  #include "scif_main.h"
  
  #define SCIF_PORT_COUNT	0x10000	/* Ports available */
  
  struct idr scif_ports;
  
  /*
   * struct scif_port - SCIF port information
   *
   * @ref_cnt - Reference count since there can be multiple endpoints
   *		created via scif_accept(..) simultaneously using a port.
   */
  struct scif_port {
  	int ref_cnt;
  };
  
  /**
   * __scif_get_port - Reserve a specified port # for SCIF and add it
   * to the global list.
   * @port : port # to be reserved.
   *
   * @return : Allocated SCIF port #, or -ENOSPC if port unavailable.
   *		On memory allocation failure, returns -ENOMEM.
   */
  static int __scif_get_port(int start, int end)
  {
  	int id;
  	struct scif_port *port = kzalloc(sizeof(*port), GFP_ATOMIC);
  
  	if (!port)
  		return -ENOMEM;
  	spin_lock(&scif_info.port_lock);
  	id = idr_alloc(&scif_ports, port, start, end, GFP_ATOMIC);
  	if (id >= 0)
  		port->ref_cnt++;
  	spin_unlock(&scif_info.port_lock);
  	return id;
  }
  
  /**
   * scif_rsrv_port - Reserve a specified port # for SCIF.
   * @port : port # to be reserved.
   *
   * @return : Allocated SCIF port #, or -ENOSPC if port unavailable.
   *		On memory allocation failure, returns -ENOMEM.
   */
  int scif_rsrv_port(u16 port)
  {
  	return __scif_get_port(port, port + 1);
  }
  
  /**
   * scif_get_new_port - Get and reserve any port # for SCIF in the range
   *			SCIF_PORT_RSVD + 1 to SCIF_PORT_COUNT - 1.
   *
   * @return : Allocated SCIF port #, or -ENOSPC if no ports available.
   *		On memory allocation failure, returns -ENOMEM.
   */
  int scif_get_new_port(void)
  {
  	return __scif_get_port(SCIF_PORT_RSVD + 1, SCIF_PORT_COUNT);
  }
  
  /**
   * scif_get_port - Increment the reference count for a SCIF port
   * @id : SCIF port
   *
   * @return : None
   */
  void scif_get_port(u16 id)
  {
  	struct scif_port *port;
  
  	if (!id)
  		return;
  	spin_lock(&scif_info.port_lock);
  	port = idr_find(&scif_ports, id);
  	if (port)
  		port->ref_cnt++;
  	spin_unlock(&scif_info.port_lock);
  }
  
  /**
   * scif_put_port - Release a reserved SCIF port
   * @id : SCIF port to be released.
   *
   * @return : None
   */
  void scif_put_port(u16 id)
  {
  	struct scif_port *port;
  
  	if (!id)
  		return;
  	spin_lock(&scif_info.port_lock);
  	port = idr_find(&scif_ports, id);
  	if (port) {
  		port->ref_cnt--;
  		if (!port->ref_cnt) {
  			idr_remove(&scif_ports, id);
  			kfree(port);
  		}
  	}
  	spin_unlock(&scif_info.port_lock);
  }