12249b3441
The rwsem initializers and related macros and functions are mostly the
same. Some of them lack the lockdep initializer, but having it in
place does not matter for architectures which do not support lockdep.
powerpc, sparc, x86: No functional change
sh, s390: Removes the duplicate init_rwsem (inline and #define)
alpha, ia64, xtensa: Use the lockdep capable init function in
lib/rwsem.c which is just uninlining the init
function for the LOCKDEP=n case
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: David Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.771812729@linutronix.de>
46 lines
1.5 KiB
C
46 lines
1.5 KiB
C
/* rwsem-spinlock.h: fallback C implementation
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*
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* Copyright (c) 2001 David Howells (dhowells@redhat.com).
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* - Derived partially from ideas by Andrea Arcangeli <andrea@suse.de>
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* - Derived also from comments by Linus
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*/
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#ifndef _LINUX_RWSEM_SPINLOCK_H
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#define _LINUX_RWSEM_SPINLOCK_H
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#ifndef _LINUX_RWSEM_H
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#error "please don't include linux/rwsem-spinlock.h directly, use linux/rwsem.h instead"
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#endif
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#ifdef __KERNEL__
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/*
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* the rw-semaphore definition
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* - if activity is 0 then there are no active readers or writers
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* - if activity is +ve then that is the number of active readers
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* - if activity is -1 then there is one active writer
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* - if wait_list is not empty, then there are processes waiting for the semaphore
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*/
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struct rw_semaphore {
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__s32 activity;
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spinlock_t wait_lock;
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struct list_head wait_list;
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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struct lockdep_map dep_map;
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#endif
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};
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#define RWSEM_UNLOCKED_VALUE 0x00000000
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extern void __down_read(struct rw_semaphore *sem);
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extern int __down_read_trylock(struct rw_semaphore *sem);
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extern void __down_write(struct rw_semaphore *sem);
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extern void __down_write_nested(struct rw_semaphore *sem, int subclass);
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extern int __down_write_trylock(struct rw_semaphore *sem);
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extern void __up_read(struct rw_semaphore *sem);
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extern void __up_write(struct rw_semaphore *sem);
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extern void __downgrade_write(struct rw_semaphore *sem);
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extern int rwsem_is_locked(struct rw_semaphore *sem);
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#endif /* __KERNEL__ */
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#endif /* _LINUX_RWSEM_SPINLOCK_H */
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