mirror of
https://git.proxmox.com/git/mirror_zfs
synced 2025-11-03 23:46:39 +00:00
3d6af2dd6d
Update links to refer to the official ZFS on Linux website instead of @behlendorf's personal fork on github. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
215 lines
8.7 KiB
C
215 lines
8.7 KiB
C
/*****************************************************************************\
|
|
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
|
|
* Copyright (C) 2007 The Regents of the University of California.
|
|
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
|
|
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
|
|
* UCRL-CODE-235197
|
|
*
|
|
* This file is part of the SPL, Solaris Porting Layer.
|
|
* For details, see <http://zfsonlinux.org/>.
|
|
*
|
|
* The SPL is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the
|
|
* Free Software Foundation; either version 2 of the License, or (at your
|
|
* option) any later version.
|
|
*
|
|
* The SPL is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
|
|
\*****************************************************************************/
|
|
|
|
#ifndef _SPL_RWLOCK_H
|
|
#define _SPL_RWLOCK_H
|
|
|
|
#include <sys/types.h>
|
|
#include <linux/rwsem.h>
|
|
#include <linux/rwsem_compat.h>
|
|
|
|
typedef enum {
|
|
RW_DRIVER = 2,
|
|
RW_DEFAULT = 4
|
|
} krw_type_t;
|
|
|
|
typedef enum {
|
|
RW_NONE = 0,
|
|
RW_WRITER = 1,
|
|
RW_READER = 2
|
|
} krw_t;
|
|
|
|
typedef struct {
|
|
struct rw_semaphore rw_rwlock;
|
|
kthread_t *rw_owner;
|
|
} krwlock_t;
|
|
|
|
#define SEM(rwp) ((struct rw_semaphore *)(rwp))
|
|
|
|
static inline void
|
|
spl_rw_set_owner(krwlock_t *rwp)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, flags);
|
|
rwp->rw_owner = current;
|
|
spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
|
|
}
|
|
|
|
static inline void
|
|
spl_rw_clear_owner(krwlock_t *rwp)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, flags);
|
|
rwp->rw_owner = NULL;
|
|
spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
|
|
}
|
|
|
|
static inline kthread_t *
|
|
rw_owner(krwlock_t *rwp)
|
|
{
|
|
unsigned long flags;
|
|
kthread_t *owner;
|
|
|
|
spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, flags);
|
|
owner = rwp->rw_owner;
|
|
spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
|
|
|
|
return owner;
|
|
}
|
|
|
|
static inline int
|
|
RW_READ_HELD(krwlock_t *rwp)
|
|
{
|
|
return (spl_rwsem_is_locked(SEM(rwp)) &&
|
|
rw_owner(rwp) == NULL);
|
|
}
|
|
|
|
static inline int
|
|
RW_WRITE_HELD(krwlock_t *rwp)
|
|
{
|
|
return (spl_rwsem_is_locked(SEM(rwp)) &&
|
|
rw_owner(rwp) == current);
|
|
}
|
|
|
|
static inline int
|
|
RW_LOCK_HELD(krwlock_t *rwp)
|
|
{
|
|
return spl_rwsem_is_locked(SEM(rwp));
|
|
}
|
|
|
|
/*
|
|
* The following functions must be a #define and not static inline.
|
|
* This ensures that the native linux semaphore functions (down/up)
|
|
* will be correctly located in the users code which is important
|
|
* for the built in kernel lock analysis tools
|
|
*/
|
|
#define rw_init(rwp, name, type, arg) \
|
|
({ \
|
|
static struct lock_class_key __key; \
|
|
\
|
|
__init_rwsem(SEM(rwp), #rwp, &__key); \
|
|
spl_rw_clear_owner(rwp); \
|
|
})
|
|
|
|
#define rw_destroy(rwp) \
|
|
({ \
|
|
VERIFY(!RW_LOCK_HELD(rwp)); \
|
|
})
|
|
|
|
#define rw_tryenter(rwp, rw) \
|
|
({ \
|
|
int _rc_ = 0; \
|
|
\
|
|
switch (rw) { \
|
|
case RW_READER: \
|
|
_rc_ = down_read_trylock(SEM(rwp)); \
|
|
break; \
|
|
case RW_WRITER: \
|
|
if ((_rc_ = down_write_trylock(SEM(rwp)))) \
|
|
spl_rw_set_owner(rwp); \
|
|
break; \
|
|
default: \
|
|
VERIFY(0); \
|
|
} \
|
|
_rc_; \
|
|
})
|
|
|
|
#define rw_enter(rwp, rw) \
|
|
({ \
|
|
switch (rw) { \
|
|
case RW_READER: \
|
|
down_read(SEM(rwp)); \
|
|
break; \
|
|
case RW_WRITER: \
|
|
down_write(SEM(rwp)); \
|
|
spl_rw_set_owner(rwp); \
|
|
break; \
|
|
default: \
|
|
VERIFY(0); \
|
|
} \
|
|
})
|
|
|
|
#define rw_exit(rwp) \
|
|
({ \
|
|
if (RW_WRITE_HELD(rwp)) { \
|
|
spl_rw_clear_owner(rwp); \
|
|
up_write(SEM(rwp)); \
|
|
} else { \
|
|
ASSERT(RW_READ_HELD(rwp)); \
|
|
up_read(SEM(rwp)); \
|
|
} \
|
|
})
|
|
|
|
#define rw_downgrade(rwp) \
|
|
({ \
|
|
spl_rw_clear_owner(rwp); \
|
|
downgrade_write(SEM(rwp)); \
|
|
})
|
|
|
|
#if defined(CONFIG_RWSEM_GENERIC_SPINLOCK)
|
|
/*
|
|
* For the generic implementations of rw-semaphores the following is
|
|
* true. If your semaphore implementation internally represents the
|
|
* semaphore state differently then special case handling is required.
|
|
* - if activity/count is 0 then there are no active readers or writers
|
|
* - if activity/count is +ve then that is the number of active readers
|
|
* - if activity/count is -1 then there is one active writer
|
|
*/
|
|
|
|
extern void __up_read_locked(struct rw_semaphore *);
|
|
extern int __down_write_trylock_locked(struct rw_semaphore *);
|
|
|
|
#define rw_tryupgrade(rwp) \
|
|
({ \
|
|
unsigned long _flags_; \
|
|
int _rc_ = 0; \
|
|
\
|
|
spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, _flags_); \
|
|
if ((list_empty(&SEM(rwp)->wait_list)) && \
|
|
(SEM(rwp)->activity == 1)) { \
|
|
__up_read_locked(SEM(rwp)); \
|
|
VERIFY(_rc_ = __down_write_trylock_locked(SEM(rwp))); \
|
|
(rwp)->rw_owner = current; \
|
|
} \
|
|
spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, _flags_); \
|
|
_rc_; \
|
|
})
|
|
#else
|
|
/*
|
|
* rw_tryupgrade() can be implemented correctly but for each supported
|
|
* arch we will need a custom implementation. For the x86 implementation
|
|
* it looks like a custom cmpxchg() to atomically check and promote the
|
|
* rwsem would be safe. For now that's not worth the trouble so in this
|
|
* case rw_tryupgrade() has just been disabled.
|
|
*/
|
|
#define rw_tryupgrade(rwp) ({ 0; })
|
|
#endif
|
|
|
|
int spl_rw_init(void);
|
|
void spl_rw_fini(void);
|
|
|
|
#endif /* _SPL_RWLOCK_H */
|