+++ /dev/null
-/*****************************************************************************\
- * 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,
- RW_NOLOCKDEP = 5
-} krw_type_t;
-
-typedef enum {
- RW_NONE = 0,
- RW_WRITER = 1,
- RW_READER = 2
-} krw_t;
-
-/*
- * If CONFIG_RWSEM_SPIN_ON_OWNER is defined, rw_semaphore will have an owner
- * field, so we don't need our own.
- */
-typedef struct {
- struct rw_semaphore rw_rwlock;
-#ifndef CONFIG_RWSEM_SPIN_ON_OWNER
- kthread_t *rw_owner;
-#endif
-#ifdef CONFIG_LOCKDEP
- krw_type_t rw_type;
-#endif /* CONFIG_LOCKDEP */
-} krwlock_t;
-
-#define SEM(rwp) (&(rwp)->rw_rwlock)
-
-static inline void
-spl_rw_set_owner(krwlock_t *rwp)
-{
-/*
- * If CONFIG_RWSEM_SPIN_ON_OWNER is defined, down_write, up_write,
- * downgrade_write and __init_rwsem will set/clear owner for us.
- */
-#ifndef CONFIG_RWSEM_SPIN_ON_OWNER
- rwp->rw_owner = current;
-#endif
-}
-
-static inline void
-spl_rw_clear_owner(krwlock_t *rwp)
-{
-#ifndef CONFIG_RWSEM_SPIN_ON_OWNER
- rwp->rw_owner = NULL;
-#endif
-}
-
-static inline kthread_t *
-rw_owner(krwlock_t *rwp)
-{
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
- return SEM(rwp)->owner;
-#else
- return rwp->rw_owner;
-#endif
-}
-
-#ifdef CONFIG_LOCKDEP
-static inline void
-spl_rw_set_type(krwlock_t *rwp, krw_type_t type)
-{
- rwp->rw_type = type;
-}
-static inline void
-spl_rw_lockdep_off_maybe(krwlock_t *rwp) \
-{ \
- if (rwp && rwp->rw_type == RW_NOLOCKDEP) \
- lockdep_off(); \
-}
-static inline void
-spl_rw_lockdep_on_maybe(krwlock_t *rwp) \
-{ \
- if (rwp && rwp->rw_type == RW_NOLOCKDEP) \
- lockdep_on(); \
-}
-#else /* CONFIG_LOCKDEP */
-#define spl_rw_set_type(rwp, type)
-#define spl_rw_lockdep_off_maybe(rwp)
-#define spl_rw_lockdep_on_maybe(rwp)
-#endif /* CONFIG_LOCKDEP */
-
-static inline int
-RW_READ_HELD(krwlock_t *rwp)
-{
- /*
- * Linux 4.8 will set owner to 1 when read held instead of leave it
- * NULL. So we check whether owner <= 1.
- */
- return (spl_rwsem_is_locked(SEM(rwp)) &&
- (unsigned long)rw_owner(rwp) <= 1);
-}
-
-static inline int
-RW_WRITE_HELD(krwlock_t *rwp)
-{
- return (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; \
- ASSERT(type == RW_DEFAULT || type == RW_NOLOCKDEP); \
- \
- __init_rwsem(SEM(rwp), #rwp, &__key); \
- spl_rw_clear_owner(rwp); \
- spl_rw_set_type(rwp, type); \
-})
-
-#define rw_destroy(rwp) \
-({ \
- VERIFY(!RW_LOCK_HELD(rwp)); \
-})
-
-#define rw_tryenter(rwp, rw) \
-({ \
- int _rc_ = 0; \
- \
- spl_rw_lockdep_off_maybe(rwp); \
- 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); \
- } \
- spl_rw_lockdep_on_maybe(rwp); \
- _rc_; \
-})
-
-#define rw_enter(rwp, rw) \
-({ \
- spl_rw_lockdep_off_maybe(rwp); \
- 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); \
- } \
- spl_rw_lockdep_on_maybe(rwp); \
-})
-
-#define rw_exit(rwp) \
-({ \
- spl_rw_lockdep_off_maybe(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)); \
- } \
- spl_rw_lockdep_on_maybe(rwp); \
-})
-
-#define rw_downgrade(rwp) \
-({ \
- spl_rw_lockdep_off_maybe(rwp); \
- spl_rw_clear_owner(rwp); \
- downgrade_write(SEM(rwp)); \
- spl_rw_lockdep_on_maybe(rwp); \
-})
-
-#define rw_tryupgrade(rwp) \
-({ \
- int _rc_ = 0; \
- \
- if (RW_WRITE_HELD(rwp)) { \
- _rc_ = 1; \
- } else { \
- spl_rw_lockdep_off_maybe(rwp); \
- if ((_rc_ = rwsem_tryupgrade(SEM(rwp)))) \
- spl_rw_set_owner(rwp); \
- spl_rw_lockdep_on_maybe(rwp); \
- } \
- _rc_; \
-})
-
-int spl_rw_init(void);
-void spl_rw_fini(void);
-
-#endif /* _SPL_RWLOCK_H */
projects / mirror_ubuntu-bionic-kernel.git / blobdiff