drivers/misc/mic/scif/scif_ports.c

   1 /*
   2  * Intel MIC Platform Software Stack (MPSS)
   3  *
   4  * Copyright(c) 2014 Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * Intel SCIF driver.
  16  *
  17  */
  18 #include <linux/idr.h>
  19
  20 #include "scif_main.h"
  21
  22 #define SCIF_PORT_COUNT 0x10000 /* Ports available */
  23
  24 struct idr scif_ports;
  25
  26 /*
  27  * struct scif_port - SCIF port information
  28  *
  29  * @ref_cnt - Reference count since there can be multiple endpoints
  30  *              created via scif_accept(..) simultaneously using a port.
  31  */
  32 struct scif_port {
  33         int ref_cnt;
  34 };
  35
  36 /**
  37  * __scif_get_port - Reserve a specified port # for SCIF and add it
  38  * to the global list.
  39  * @port : port # to be reserved.
  40  *
  41  * @return : Allocated SCIF port #, or -ENOSPC if port unavailable.
  42  *              On memory allocation failure, returns -ENOMEM.
  43  */
  44 static int __scif_get_port(int start, int end)
  45 {
  46         int id;
  47         struct scif_port *port = kzalloc(sizeof(*port), GFP_ATOMIC);
  48
  49         if (!port)
  50                 return -ENOMEM;
  51         spin_lock(&scif_info.port_lock);
  52         id = idr_alloc(&scif_ports, port, start, end, GFP_ATOMIC);
  53         if (id >= 0)
  54                 port->ref_cnt++;
  55         spin_unlock(&scif_info.port_lock);
  56         return id;
  57 }
  58
  59 /**
  60  * scif_rsrv_port - Reserve a specified port # for SCIF.
  61  * @port : port # to be reserved.
  62  *
  63  * @return : Allocated SCIF port #, or -ENOSPC if port unavailable.
  64  *              On memory allocation failure, returns -ENOMEM.
  65  */
  66 int scif_rsrv_port(u16 port)
  67 {
  68         return __scif_get_port(port, port + 1);
  69 }
  70
  71 /**
  72  * scif_get_new_port - Get and reserve any port # for SCIF in the range
  73  *                      SCIF_PORT_RSVD + 1 to SCIF_PORT_COUNT - 1.
  74  *
  75  * @return : Allocated SCIF port #, or -ENOSPC if no ports available.
  76  *              On memory allocation failure, returns -ENOMEM.
  77  */
  78 int scif_get_new_port(void)
  79 {
  80         return __scif_get_port(SCIF_PORT_RSVD + 1, SCIF_PORT_COUNT);
  81 }
  82
  83 /**
  84  * scif_get_port - Increment the reference count for a SCIF port
  85  * @id : SCIF port
  86  *
  87  * @return : None
  88  */
  89 void scif_get_port(u16 id)
  90 {
  91         struct scif_port *port;
  92
  93         if (!id)
  94                 return;
  95         spin_lock(&scif_info.port_lock);
  96         port = idr_find(&scif_ports, id);
  97         if (port)
  98                 port->ref_cnt++;
  99         spin_unlock(&scif_info.port_lock);
 100 }
 101
 102 /**
 103  * scif_put_port - Release a reserved SCIF port
 104  * @id : SCIF port to be released.
 105  *
 106  * @return : None
 107  */
 108 void scif_put_port(u16 id)
 109 {
 110         struct scif_port *port;
 111
 112         if (!id)
 113                 return;
 114         spin_lock(&scif_info.port_lock);
 115         port = idr_find(&scif_ports, id);
 116         if (port) {
 117                 port->ref_cnt--;
 118                 if (!port->ref_cnt) {
 119                         idr_remove(&scif_ports, id);
 120                         kfree(port);
 121                 }
 122         }
 123         spin_unlock(&scif_info.port_lock);
 124 }