aboutsummaryrefslogtreecommitdiffstats
path: root/arch/ia64/include/asm/mutex.h
diff options
context:
space:
mode:
authorTony Luck <tony.luck@intel.com>2008-08-01 13:13:32 -0400
committerTony Luck <tony.luck@intel.com>2008-08-01 13:21:21 -0400
commit7f30491ccd28627742e37899453ae20e3da8e18f (patch)
tree7291c0a26ed3a31acf9542857af3981d278f5de8 /arch/ia64/include/asm/mutex.h
parent94ad374a0751f40d25e22e036c37f7263569d24c (diff)
[IA64] Move include/asm-ia64 to arch/ia64/include/asm
After moving the the include files there were a few clean-ups: 1) Some files used #include <asm-ia64/xyz.h>, changed to <asm/xyz.h> 2) Some comments alerted maintainers to look at various header files to make matching updates if certain code were to be changed. Updated these comments to use the new include paths. 3) Some header files mentioned their own names in initial comments. Just deleted these self references. Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/include/asm/mutex.h')
-rw-r--r--arch/ia64/include/asm/mutex.h92
1 files changed, 92 insertions, 0 deletions
diff --git a/arch/ia64/include/asm/mutex.h b/arch/ia64/include/asm/mutex.h
new file mode 100644
index 000000000000..bed73a643a56
--- /dev/null
+++ b/arch/ia64/include/asm/mutex.h
@@ -0,0 +1,92 @@
1/*
2 * ia64 implementation of the mutex fastpath.
3 *
4 * Copyright (C) 2006 Ken Chen <kenneth.w.chen@intel.com>
5 *
6 */
7
8#ifndef _ASM_MUTEX_H
9#define _ASM_MUTEX_H
10
11/**
12 * __mutex_fastpath_lock - try to take the lock by moving the count
13 * from 1 to a 0 value
14 * @count: pointer of type atomic_t
15 * @fail_fn: function to call if the original value was not 1
16 *
17 * Change the count from 1 to a value lower than 1, and call <fail_fn> if
18 * it wasn't 1 originally. This function MUST leave the value lower than
19 * 1 even when the "1" assertion wasn't true.
20 */
21static inline void
22__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
23{
24 if (unlikely(ia64_fetchadd4_acq(count, -1) != 1))
25 fail_fn(count);
26}
27
28/**
29 * __mutex_fastpath_lock_retval - try to take the lock by moving the count
30 * from 1 to a 0 value
31 * @count: pointer of type atomic_t
32 * @fail_fn: function to call if the original value was not 1
33 *
34 * Change the count from 1 to a value lower than 1, and call <fail_fn> if
35 * it wasn't 1 originally. This function returns 0 if the fastpath succeeds,
36 * or anything the slow path function returns.
37 */
38static inline int
39__mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
40{
41 if (unlikely(ia64_fetchadd4_acq(count, -1) != 1))
42 return fail_fn(count);
43 return 0;
44}
45
46/**
47 * __mutex_fastpath_unlock - try to promote the count from 0 to 1
48 * @count: pointer of type atomic_t
49 * @fail_fn: function to call if the original value was not 0
50 *
51 * Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
52 * In the failure case, this function is allowed to either set the value to
53 * 1, or to set it to a value lower than 1.
54 *
55 * If the implementation sets it to a value of lower than 1, then the
56 * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
57 * to return 0 otherwise.
58 */
59static inline void
60__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
61{
62 int ret = ia64_fetchadd4_rel(count, 1);
63 if (unlikely(ret < 0))
64 fail_fn(count);
65}
66
67#define __mutex_slowpath_needs_to_unlock() 1
68
69/**
70 * __mutex_fastpath_trylock - try to acquire the mutex, without waiting
71 *
72 * @count: pointer of type atomic_t
73 * @fail_fn: fallback function
74 *
75 * Change the count from 1 to a value lower than 1, and return 0 (failure)
76 * if it wasn't 1 originally, or return 1 (success) otherwise. This function
77 * MUST leave the value lower than 1 even when the "1" assertion wasn't true.
78 * Additionally, if the value was < 0 originally, this function must not leave
79 * it to 0 on failure.
80 *
81 * If the architecture has no effective trylock variant, it should call the
82 * <fail_fn> spinlock-based trylock variant unconditionally.
83 */
84static inline int
85__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
86{
87 if (cmpxchg_acq(count, 1, 0) == 1)
88 return 1;
89 return 0;
90}
91
92#endif