sema.h 1.5 KB

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  1. /*
  2. * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
  3. * All Rights Reserved.
  4. *
  5. * This program is free software; you can redistribute it and/or
  6. * modify it under the terms of the GNU General Public License as
  7. * published by the Free Software Foundation.
  8. *
  9. * This program is distributed in the hope that it would be useful,
  10. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12. * GNU General Public License for more details.
  13. *
  14. * You should have received a copy of the GNU General Public License
  15. * along with this program; if not, write the Free Software Foundation,
  16. * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  17. */
  18. #ifndef __XFS_SUPPORT_SEMA_H__
  19. #define __XFS_SUPPORT_SEMA_H__
  20. #include <linux/time.h>
  21. #include <linux/wait.h>
  22. #include <asm/atomic.h>
  23. #include <asm/semaphore.h>
  24. /*
  25. * sema_t structure just maps to struct semaphore in Linux kernel.
  26. */
  27. typedef struct semaphore sema_t;
  28. #define initnsema(sp, val, name) sema_init(sp, val)
  29. #define psema(sp, b) down(sp)
  30. #define vsema(sp) up(sp)
  31. #define freesema(sema) do { } while (0)
  32. static inline int issemalocked(sema_t *sp)
  33. {
  34. return down_trylock(sp) || (up(sp), 0);
  35. }
  36. /*
  37. * Map cpsema (try to get the sema) to down_trylock. We need to switch
  38. * the return values since cpsema returns 1 (acquired) 0 (failed) and
  39. * down_trylock returns the reverse 0 (acquired) 1 (failed).
  40. */
  41. static inline int cpsema(sema_t *sp)
  42. {
  43. return down_trylock(sp) ? 0 : 1;
  44. }
  45. #endif /* __XFS_SUPPORT_SEMA_H__ */