src/add-ons/kernel/bus_managers/scsi/queuing.h

   1 /*
   2 ** Copyright 2002/03, Thomas Kurschel. All rights reserved.
   3 ** Distributed under the terms of the MIT License.
   4 */
   5
   6 /*
   7         Part of Open SCSI bus manager
   8
   9         Handling of bus/device blocking. Inline functions defined
  10         here don't wake service thread if required and don't lock bus, so
  11         everyone using them must take care of that himself.
  12 */
  13
  14 #ifndef __BLOCKING_H__
  15 #define __BLOCKING_H__
  16
  17 #include "dl_list.h"
  18
  19 void scsi_add_queued_request( scsi_ccb *request );
  20 void scsi_add_queued_request_first( scsi_ccb *request );
  21 void scsi_remove_queued_request( scsi_ccb *request );
  22
  23
  24 static inline void scsi_add_req_queue_first( scsi_ccb *request )
  25 {
  26         scsi_device_info *device = request->device;
  27
  28         SHOW_FLOW( 3, "request=%p", request );
  29
  30         ADD_CDL_LIST_HEAD( request, scsi_ccb, device->queued_reqs, );
  31 }
  32
  33 static inline void scsi_add_req_queue_last( scsi_ccb *request )
  34 {
  35         scsi_device_info *device = request->device;
  36
  37         SHOW_FLOW( 3, "request=%p", request );
  38
  39         ADD_CDL_LIST_TAIL( request, scsi_ccb, device->queued_reqs, );
  40 }
  41
  42 static inline void scsi_remove_req_queue( scsi_ccb *request )
  43 {
  44         scsi_device_info *device = request->device;
  45
  46         SHOW_FLOW( 3, "request=%p", request );
  47
  48         REMOVE_CDL_LIST( request, device->queued_reqs, );
  49 }
  50
  51 // ignored, if device is already queued
  52 static inline void scsi_add_device_queue_first( scsi_device_info *device )
  53 {
  54         SHOW_FLOW0( 3, "" );
  55
  56         if( DEVICE_IN_WAIT_QUEUE( device ))
  57                 return;
  58
  59         SHOW_FLOW0( 3, "was not in wait queue - adding" );
  60
  61         ADD_CDL_LIST_HEAD( device, scsi_device_info, device->bus->waiting_devices, waiting_ );
  62 }
  63
  64 // ignored, if device is already queued
  65 static inline void scsi_add_device_queue_last( scsi_device_info *device )
  66 {
  67         SHOW_FLOW0( 3, "" );
  68
  69         if( DEVICE_IN_WAIT_QUEUE( device ))
  70                 return;
  71
  72         SHOW_FLOW0( 3, "was not in wait queue - adding" );
  73
  74         ADD_CDL_LIST_TAIL( device, scsi_device_info, device->bus->waiting_devices, waiting_ );
  75 }
  76
  77 // ignored, if device is not in queue
  78 static inline void scsi_remove_device_queue( scsi_device_info *device )
  79 {
  80         SHOW_FLOW0( 3, "" );
  81
  82         if( !DEVICE_IN_WAIT_QUEUE( device ))
  83                 return;
  84
  85         SHOW_FLOW0( 3, "was in wait queue - removing from it" );
  86
  87         REMOVE_CDL_LIST( device, device->bus->waiting_devices, waiting_ );
  88
  89         // reset next link so we can see that it's not in device queue
  90         device->waiting_next = NULL;
  91 }
  92
  93 // set overflow bit of device; this will not remove device from bus queue!
  94 // (multiple calls are ignored gracefully)
  95 static inline void scsi_set_device_overflow( scsi_device_info *device )
  96 {
  97         device->lock_count += device->sim_overflow ^ 1;
  98         device->sim_overflow = 1;
  99 }
 100
 101 // set overflow bit of bus
 102 // (multiple calls are ignored gracefully)
 103 static inline void scsi_set_bus_overflow( scsi_bus_info *bus )
 104 {
 105         bus->lock_count += bus->sim_overflow ^ 1;
 106         bus->sim_overflow = 1;
 107 }
 108
 109 // clear overflow bit of device; this will not add device to bus queue!
 110 // (multiple calls are ignored gracefully)
 111 static inline void scsi_clear_device_overflow( scsi_device_info *device )
 112 {
 113         device->lock_count -= device->sim_overflow;
 114         device->sim_overflow = 0;
 115 }
 116
 117 // clear overflow bit of bus
 118 // (multiple calls are ignored gracefully)
 119 static inline void scsi_clear_bus_overflow( scsi_bus_info *bus )
 120 {
 121         bus->lock_count -= bus->sim_overflow;
 122         bus->sim_overflow = 0;
 123 }
 124
 125 // check whether bus has some pending requests it can process now
 126 static inline bool scsi_can_service_bus( scsi_bus_info *bus )
 127 {
 128         // bus must not be blocked and requests pending
 129         return (bus->lock_count == 0) & (bus->waiting_devices != NULL);
 130 }
 131
 132 // unblock bus
 133 // lock must be hold; service thread is not informed
 134 static inline void scsi_unblock_bus_noresume( scsi_bus_info *bus, bool by_SIM )
 135 {
 136         if( bus->blocked[by_SIM] > 0 ) {
 137                 --bus->blocked[by_SIM];
 138                 --bus->lock_count;
 139         } else {
 140                 panic( "Tried to unblock bus %d which wasn't blocked",
 141                         bus->path_id );
 142         }
 143 }
 144
 145
 146 // unblock device
 147 // lock must be hold; device is not added to queue and service thread is not informed
 148 static inline void scsi_unblock_device_noresume( scsi_device_info *device, bool by_SIM )
 149 {
 150         if( device->blocked[by_SIM] > 0 ) {
 151                 --device->blocked[by_SIM];
 152                 --device->lock_count;
 153         } else {
 154                 panic( "Tried to unblock device %d/%d/%d which wasn't blocked",
 155                         device->bus->path_id, device->target_id, device->target_lun );
 156         }
 157 }
 158
 159
 160 // block bus
 161 // lock must be hold
 162 static inline void scsi_block_bus_nolock( scsi_bus_info *bus, bool by_SIM )
 163 {
 164         ++bus->blocked[by_SIM];
 165         ++bus->lock_count;
 166 }
 167
 168
 169 // block device
 170 // lock must be hold
 171 static inline void scsi_block_device_nolock( scsi_device_info *device, bool by_SIM )
 172 {
 173         ++device->blocked[by_SIM];
 174         ++device->lock_count;
 175
 176         // remove device from bus queue as it cannot be processed anymore
 177         scsi_remove_device_queue( device );
 178 }
 179
 180
 181 void scsi_block_bus( scsi_bus_info *bus );
 182 void scsi_unblock_bus( scsi_bus_info *bus );
 183 void scsi_block_device( scsi_device_info *device );
 184 void scsi_unblock_device( scsi_device_info *device );
 185
 186 void scsi_cont_send_bus( scsi_bus_info *bus );
 187 void scsi_cont_send_device( scsi_device_info *device );
 188
 189 #endif