include/linux/rwsem_compat.h

   1 /*
   2  *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
   3  *  Copyright (C) 2007 The Regents of the University of California.
   4  *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
   5  *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
   6  *  UCRL-CODE-235197
   7  *
   8  *  This file is part of the SPL, Solaris Porting Layer.
   9  *  For details, see <http://zfsonlinux.org/>.
  10  *
  11  *  The SPL is free software; you can redistribute it and/or modify it
  12  *  under the terms of the GNU General Public License as published by the
  13  *  Free Software Foundation; either version 2 of the License, or (at your
  14  *  option) any later version.
  15  *
  16  *  The SPL is distributed in the hope that it will be useful, but WITHOUT
  17  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  19  *  for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License along
  22  *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24
  25 #ifndef _SPL_RWSEM_COMPAT_H
  26 #define _SPL_RWSEM_COMPAT_H
  27
  28 #include <linux/rwsem.h>
  29
  30 #if defined(CONFIG_PREEMPT_RT_FULL)
  31 #define SPL_RWSEM_SINGLE_READER_VALUE   (1)
  32 #define SPL_RWSEM_SINGLE_WRITER_VALUE   (0)
  33 #elif defined(CONFIG_RWSEM_GENERIC_SPINLOCK)
  34 #define SPL_RWSEM_SINGLE_READER_VALUE   (1)
  35 #define SPL_RWSEM_SINGLE_WRITER_VALUE   (-1)
  36 #else
  37 #define SPL_RWSEM_SINGLE_READER_VALUE   (RWSEM_ACTIVE_READ_BIAS)
  38 #define SPL_RWSEM_SINGLE_WRITER_VALUE   (RWSEM_ACTIVE_WRITE_BIAS)
  39 #endif
  40
  41 /* Linux 3.16 changed activity to count for rwsem-spinlock */
  42 #if defined(CONFIG_PREEMPT_RT_FULL)
  43 #define RWSEM_COUNT(sem)        sem->read_depth
  44 #elif defined(HAVE_RWSEM_ACTIVITY)
  45 #define RWSEM_COUNT(sem)        sem->activity
  46 /* Linux 4.8 changed count to an atomic_long_t for !rwsem-spinlock */
  47 #elif defined(HAVE_RWSEM_ATOMIC_LONG_COUNT)
  48 #define RWSEM_COUNT(sem)        atomic_long_read(&(sem)->count)
  49 #else
  50 #define RWSEM_COUNT(sem)        sem->count
  51 #endif
  52
  53 int rwsem_tryupgrade(struct rw_semaphore *rwsem);
  54
  55 #if defined(RWSEM_SPINLOCK_IS_RAW)
  56 #define spl_rwsem_lock_irqsave(lk, fl)          raw_spin_lock_irqsave(lk, fl)
  57 #define spl_rwsem_unlock_irqrestore(lk, fl)     \
  58     raw_spin_unlock_irqrestore(lk, fl)
  59 #define spl_rwsem_trylock_irqsave(lk, fl)       raw_spin_trylock_irqsave(lk, fl)
  60 #else
  61 #define spl_rwsem_lock_irqsave(lk, fl)          spin_lock_irqsave(lk, fl)
  62 #define spl_rwsem_unlock_irqrestore(lk, fl)     spin_unlock_irqrestore(lk, fl)
  63 #define spl_rwsem_trylock_irqsave(lk, fl)       spin_trylock_irqsave(lk, fl)
  64 #endif /* RWSEM_SPINLOCK_IS_RAW */
  65
  66 #define spl_rwsem_is_locked(rwsem)              rwsem_is_locked(rwsem)
  67
  68 #endif /* _SPL_RWSEM_COMPAT_H */