drivers/misc/mic/scif/scif_ports.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Intel MIC Platform Software Stack (MPSS)
   4  *
   5  * Copyright(c) 2014 Intel Corporation.
   6  *
   7  * Intel SCIF driver.
   8  */
   9 #include <linux/idr.h>
  10
  11 #include "scif_main.h"
  12
  13 #define SCIF_PORT_COUNT 0x10000 /* Ports available */
  14
  15 struct idr scif_ports;
  16
  17 /*
  18  * struct scif_port - SCIF port information
  19  *
  20  * @ref_cnt - Reference count since there can be multiple endpoints
  21  *              created via scif_accept(..) simultaneously using a port.
  22  */
  23 struct scif_port {
  24         int ref_cnt;
  25 };
  26
  27 /**
  28  * __scif_get_port - Reserve a specified port # for SCIF and add it
  29  * to the global list.
  30  * @port : port # to be reserved.
  31  *
  32  * @return : Allocated SCIF port #, or -ENOSPC if port unavailable.
  33  *              On memory allocation failure, returns -ENOMEM.
  34  */
  35 static int __scif_get_port(int start, int end)
  36 {
  37         int id;
  38         struct scif_port *port = kzalloc(sizeof(*port), GFP_ATOMIC);
  39
  40         if (!port)
  41                 return -ENOMEM;
  42         spin_lock(&scif_info.port_lock);
  43         id = idr_alloc(&scif_ports, port, start, end, GFP_ATOMIC);
  44         if (id >= 0)
  45                 port->ref_cnt++;
  46         spin_unlock(&scif_info.port_lock);
  47         return id;
  48 }
  49
  50 /**
  51  * scif_rsrv_port - Reserve a specified port # for SCIF.
  52  * @port : port # to be reserved.
  53  *
  54  * @return : Allocated SCIF port #, or -ENOSPC if port unavailable.
  55  *              On memory allocation failure, returns -ENOMEM.
  56  */
  57 int scif_rsrv_port(u16 port)
  58 {
  59         return __scif_get_port(port, port + 1);
  60 }
  61
  62 /**
  63  * scif_get_new_port - Get and reserve any port # for SCIF in the range
  64  *                      SCIF_PORT_RSVD + 1 to SCIF_PORT_COUNT - 1.
  65  *
  66  * @return : Allocated SCIF port #, or -ENOSPC if no ports available.
  67  *              On memory allocation failure, returns -ENOMEM.
  68  */
  69 int scif_get_new_port(void)
  70 {
  71         return __scif_get_port(SCIF_PORT_RSVD + 1, SCIF_PORT_COUNT);
  72 }
  73
  74 /**
  75  * scif_get_port - Increment the reference count for a SCIF port
  76  * @id : SCIF port
  77  *
  78  * @return : None
  79  */
  80 void scif_get_port(u16 id)
  81 {
  82         struct scif_port *port;
  83
  84         if (!id)
  85                 return;
  86         spin_lock(&scif_info.port_lock);
  87         port = idr_find(&scif_ports, id);
  88         if (port)
  89                 port->ref_cnt++;
  90         spin_unlock(&scif_info.port_lock);
  91 }
  92
  93 /**
  94  * scif_put_port - Release a reserved SCIF port
  95  * @id : SCIF port to be released.
  96  *
  97  * @return : None
  98  */
  99 void scif_put_port(u16 id)
 100 {
 101         struct scif_port *port;
 102
 103         if (!id)
 104                 return;
 105         spin_lock(&scif_info.port_lock);
 106         port = idr_find(&scif_ports, id);
 107         if (port) {
 108                 port->ref_cnt--;
 109                 if (!port->ref_cnt) {
 110                         idr_remove(&scif_ports, id);
 111                         kfree(port);
 112                 }
 113         }
 114         spin_unlock(&scif_info.port_lock);
 115 }