src/add-ons/kernel/bus_managers/scsi/dpc.cpp

   1 /*
   2 ** Copyright 2002/03, Thomas Kurschel. All rights reserved.
   3 ** Distributed under the terms of the Haiku License.
   4 */
   5
   6 /*
   7         Part of Open SCSI bus manager
   8
   9         DPC handling (deferred procedure calls).
  10
  11         DPC are executed by the service thread of the bus
  12         (see busses.c).
  13 */
  14
  15 #include "scsi_internal.h"
  16
  17 #include <string.h>
  18 #include <stdlib.h>
  19
  20
  21 status_t
  22 scsi_alloc_dpc(scsi_dpc_info **dpc)
  23 {
  24         SHOW_FLOW0(3, "");
  25
  26         *dpc = (scsi_dpc_info *)malloc(sizeof(scsi_dpc_info));
  27         if (*dpc == NULL)
  28                 return B_NO_MEMORY;
  29
  30         memset(*dpc, 0, sizeof(scsi_dpc_info));
  31         return B_OK;
  32 }
  33
  34
  35 status_t
  36 scsi_free_dpc(scsi_dpc_info *dpc)
  37 {
  38         SHOW_FLOW0(3, "");
  39
  40         free(dpc);
  41         return B_OK;
  42 }
  43
  44
  45 status_t
  46 scsi_schedule_dpc(scsi_bus_info *bus, scsi_dpc_info *dpc, /*int flags,*/
  47         void (*func)(void *arg), void *arg)
  48 {
  49         SHOW_FLOW(3, "bus=%p, dpc=%p", bus, dpc);
  50         acquire_spinlock_irq(&bus->dpc_lock);
  51
  52         dpc->func = func;
  53         dpc->arg = arg;
  54
  55         if (!dpc->registered) {
  56                 dpc->registered = true;
  57                 dpc->next = bus->dpc_list;
  58                 bus->dpc_list = dpc;
  59         } else
  60                 SHOW_FLOW0(3, "already registered - ignored");
  61
  62         release_spinlock_irq(&bus->dpc_lock);
  63
  64         // this is called in IRQ context, so scheduler is not allowed
  65         release_sem_etc(bus->start_service, 1, B_DO_NOT_RESCHEDULE);
  66         return B_OK;
  67 }
  68
  69
  70 /** execute pending DPCs */
  71
  72 bool
  73 scsi_check_exec_dpc(scsi_bus_info *bus)
  74 {
  75         SHOW_FLOW(3, "bus=%p, dpc_list=%p", bus, bus->dpc_list);
  76         acquire_spinlock_irq(&bus->dpc_lock);
  77
  78         if (bus->dpc_list) {
  79                 scsi_dpc_info *dpc;
  80                 void (*dpc_func)(void *);
  81                 void *dpc_arg;
  82
  83                 dpc = bus->dpc_list;
  84                 bus->dpc_list = dpc->next;
  85
  86                 dpc_func = dpc->func;
  87                 dpc_arg = dpc->arg;
  88                 dpc->registered = false;
  89
  90                 release_spinlock_irq(&bus->dpc_lock);
  91
  92                 dpc_func(dpc_arg);
  93                 return true;
  94         }
  95
  96         release_spinlock_irq(&bus->dpc_lock);
  97         return false;
  98 }
  99