src/add-ons/kernel/bus_managers/scsi/scsi_lock.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         Special locks
  10
  11         The only one defined herein is a spinlock that automatically
  12         disabled IRQs on enter and restores them on leave. Probably,
  13         this should be made public as it's quite basic.
  14 */
  15
  16 #ifndef __SCSI_LOCK_H__
  17 #define __SCSI_LOCK_H__
  18
  19 #include <KernelExport.h>
  20
  21
  22 // enhanced spinlock that automatically disables irqs when lock is hold
  23 typedef struct spinlock_irq {
  24         spinlock        lock;                           // normal spinlock
  25         cpu_status      prev_irq_state;         // irq state before spinlock was entered
  26 } spinlock_irq;
  27
  28
  29 static inline void
  30 spinlock_irq_init(spinlock_irq *lock)
  31 {
  32         B_INITIALIZE_SPINLOCK(&lock->lock);
  33 }
  34
  35 static inline void
  36 acquire_spinlock_irq(spinlock_irq *lock)
  37 {
  38         cpu_status prev_irq_state = disable_interrupts();
  39
  40         acquire_spinlock(&lock->lock);
  41         lock->prev_irq_state = prev_irq_state;
  42 }
  43
  44 static inline void
  45 release_spinlock_irq(spinlock_irq *lock)
  46 {
  47         cpu_status prev_irq_state = lock->prev_irq_state;
  48
  49         release_spinlock(&lock->lock);
  50         restore_interrupts(prev_irq_state);
  51 }
  52
  53 #endif