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authorLinus Torvalds <torvalds@linux-foundation.org>2008-04-18 11:25:29 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-18 11:25:29 -0400
commitd7bb545d86825e635cab33a1dd81ca0ad7b92887 (patch)
tree34da4139ef06ceab6549aea3906639c7413978c8 /arch/s390/kernel
parent75e98b34155264d943aa53edce465e87f3ccbadf (diff)
parent2342e51ba2b52a7f5b78227e6faa4603ed3632a0 (diff)
Merge branch 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc
* 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc: Remove DEBUG_SEMAPHORE from Kconfig Improve semaphore documentation Simplify semaphore implementation Add down_timeout and change ACPI to use it Introduce down_killable() Generic semaphore implementation Add semaphore.h to kernel_lock.c Fix quota.h includes
Diffstat (limited to 'arch/s390/kernel')
-rw-r--r--arch/s390/kernel/Makefile2
-rw-r--r--arch/s390/kernel/s390_ksyms.c7
-rw-r--r--arch/s390/kernel/semaphore.c108
3 files changed, 1 insertions, 116 deletions
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index ef2b2470c25c..77051cd27925 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -11,7 +11,7 @@ CFLAGS_smp.o := -Wno-nonnull
11 11
12obj-y := bitmap.o traps.o time.o process.o base.o early.o \ 12obj-y := bitmap.o traps.o time.o process.o base.o early.o \
13 setup.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o \ 13 setup.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o \
14 semaphore.o s390_ext.o debug.o irq.o ipl.o dis.o diag.o 14 s390_ext.o debug.o irq.o ipl.o dis.o diag.o
15 15
16obj-y += $(if $(CONFIG_64BIT),entry64.o,entry.o) 16obj-y += $(if $(CONFIG_64BIT),entry64.o,entry.o)
17obj-y += $(if $(CONFIG_64BIT),reipl64.o,reipl.o) 17obj-y += $(if $(CONFIG_64BIT),reipl64.o,reipl.o)
diff --git a/arch/s390/kernel/s390_ksyms.c b/arch/s390/kernel/s390_ksyms.c
index 7234c737f825..48238a114ce9 100644
--- a/arch/s390/kernel/s390_ksyms.c
+++ b/arch/s390/kernel/s390_ksyms.c
@@ -27,13 +27,6 @@ EXPORT_SYMBOL(_zb_findmap);
27EXPORT_SYMBOL(_sb_findmap); 27EXPORT_SYMBOL(_sb_findmap);
28 28
29/* 29/*
30 * semaphore ops
31 */
32EXPORT_SYMBOL(__up);
33EXPORT_SYMBOL(__down);
34EXPORT_SYMBOL(__down_interruptible);
35
36/*
37 * binfmt_elf loader 30 * binfmt_elf loader
38 */ 31 */
39extern int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs); 32extern int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs);
diff --git a/arch/s390/kernel/semaphore.c b/arch/s390/kernel/semaphore.c
deleted file mode 100644
index 191303f6c1d8..000000000000
--- a/arch/s390/kernel/semaphore.c
+++ /dev/null
@@ -1,108 +0,0 @@
1/*
2 * linux/arch/s390/kernel/semaphore.c
3 *
4 * S390 version
5 * Copyright (C) 1998-2000 IBM Corporation
6 * Author(s): Martin Schwidefsky
7 *
8 * Derived from "linux/arch/i386/kernel/semaphore.c
9 * Copyright (C) 1999, Linus Torvalds
10 *
11 */
12#include <linux/sched.h>
13#include <linux/errno.h>
14#include <linux/init.h>
15
16#include <asm/semaphore.h>
17
18/*
19 * Atomically update sem->count. Equivalent to:
20 * old_val = sem->count.counter;
21 * new_val = ((old_val >= 0) ? old_val : 0) + incr;
22 * sem->count.counter = new_val;
23 * return old_val;
24 */
25static inline int __sem_update_count(struct semaphore *sem, int incr)
26{
27 int old_val, new_val;
28
29 asm volatile(
30 " l %0,0(%3)\n"
31 "0: ltr %1,%0\n"
32 " jhe 1f\n"
33 " lhi %1,0\n"
34 "1: ar %1,%4\n"
35 " cs %0,%1,0(%3)\n"
36 " jl 0b\n"
37 : "=&d" (old_val), "=&d" (new_val), "=m" (sem->count)
38 : "a" (&sem->count), "d" (incr), "m" (sem->count)
39 : "cc");
40 return old_val;
41}
42
43/*
44 * The inline function up() incremented count but the result
45 * was <= 0. This indicates that some process is waiting on
46 * the semaphore. The semaphore is free and we'll wake the
47 * first sleeping process, so we set count to 1 unless some
48 * other cpu has called up in the meantime in which case
49 * we just increment count by 1.
50 */
51void __up(struct semaphore *sem)
52{
53 __sem_update_count(sem, 1);
54 wake_up(&sem->wait);
55}
56
57/*
58 * The inline function down() decremented count and the result
59 * was < 0. The wait loop will atomically test and update the
60 * semaphore counter following the rules:
61 * count > 0: decrement count, wake up queue and exit.
62 * count <= 0: set count to -1, go to sleep.
63 */
64void __sched __down(struct semaphore * sem)
65{
66 struct task_struct *tsk = current;
67 DECLARE_WAITQUEUE(wait, tsk);
68
69 __set_task_state(tsk, TASK_UNINTERRUPTIBLE);
70 add_wait_queue_exclusive(&sem->wait, &wait);
71 while (__sem_update_count(sem, -1) <= 0) {
72 schedule();
73 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
74 }
75 remove_wait_queue(&sem->wait, &wait);
76 __set_task_state(tsk, TASK_RUNNING);
77 wake_up(&sem->wait);
78}
79
80/*
81 * Same as __down() with an additional test for signals.
82 * If a signal is pending the count is updated as follows:
83 * count > 0: wake up queue and exit.
84 * count <= 0: set count to 0, wake up queue and exit.
85 */
86int __sched __down_interruptible(struct semaphore * sem)
87{
88 int retval = 0;
89 struct task_struct *tsk = current;
90 DECLARE_WAITQUEUE(wait, tsk);
91
92 __set_task_state(tsk, TASK_INTERRUPTIBLE);
93 add_wait_queue_exclusive(&sem->wait, &wait);
94 while (__sem_update_count(sem, -1) <= 0) {
95 if (signal_pending(current)) {
96 __sem_update_count(sem, 0);
97 retval = -EINTR;
98 break;
99 }
100 schedule();
101 set_task_state(tsk, TASK_INTERRUPTIBLE);
102 }
103 remove_wait_queue(&sem->wait, &wait);
104 __set_task_state(tsk, TASK_RUNNING);
105 wake_up(&sem->wait);
106 return retval;
107}
108