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authorDavid S. Miller <davem@davemloft.net>2005-09-15 00:47:01 -0400
committerDavid S. Miller <davem@davemloft.net>2005-09-15 00:47:01 -0400
commit4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f (patch)
tree87a00c97e02a77cdfec517398caa3f1d8f6a2f0d /arch/ia64/lib
parent4a805e863d6b9466baf7084e1d6fdbe6e0628d8e (diff)
[LIB]: Consolidate _atomic_dec_and_lock()
Several implementations were essentialy a common piece of C code using the cmpxchg() macro. Put the implementation in one spot that everyone can share, and convert sparc64 over to using this. Alpha is the lone arch-specific implementation, which codes up a special fast path for the common case in order to avoid GP reloading which a pure C version would require. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/ia64/lib')
-rw-r--r--arch/ia64/lib/Makefile1
-rw-r--r--arch/ia64/lib/dec_and_lock.c42
2 files changed, 0 insertions, 43 deletions
diff --git a/arch/ia64/lib/Makefile b/arch/ia64/lib/Makefile
index 799407e7726f..cb1af597370b 100644
--- a/arch/ia64/lib/Makefile
+++ b/arch/ia64/lib/Makefile
@@ -15,7 +15,6 @@ lib-$(CONFIG_ITANIUM) += copy_page.o copy_user.o memcpy.o
15lib-$(CONFIG_MCKINLEY) += copy_page_mck.o memcpy_mck.o 15lib-$(CONFIG_MCKINLEY) += copy_page_mck.o memcpy_mck.o
16lib-$(CONFIG_PERFMON) += carta_random.o 16lib-$(CONFIG_PERFMON) += carta_random.o
17lib-$(CONFIG_MD_RAID5) += xor.o 17lib-$(CONFIG_MD_RAID5) += xor.o
18lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o
19 18
20AFLAGS___divdi3.o = 19AFLAGS___divdi3.o =
21AFLAGS___udivdi3.o = -DUNSIGNED 20AFLAGS___udivdi3.o = -DUNSIGNED
diff --git a/arch/ia64/lib/dec_and_lock.c b/arch/ia64/lib/dec_and_lock.c
deleted file mode 100644
index c7ce92f968f1..000000000000
--- a/arch/ia64/lib/dec_and_lock.c
+++ /dev/null
@@ -1,42 +0,0 @@
1/*
2 * Copyright (C) 2003 Jerome Marchand, Bull S.A.
3 * Cleaned up by David Mosberger-Tang <davidm@hpl.hp.com>
4 *
5 * This file is released under the GPLv2, or at your option any later version.
6 *
7 * ia64 version of "atomic_dec_and_lock()" using the atomic "cmpxchg" instruction. This
8 * code is an adaptation of the x86 version of "atomic_dec_and_lock()".
9 */
10
11#include <linux/compiler.h>
12#include <linux/module.h>
13#include <linux/spinlock.h>
14#include <asm/atomic.h>
15
16/*
17 * Decrement REFCOUNT and if the count reaches zero, acquire the spinlock. Both of these
18 * operations have to be done atomically, so that the count doesn't drop to zero without
19 * acquiring the spinlock first.
20 */
21int
22_atomic_dec_and_lock (atomic_t *refcount, spinlock_t *lock)
23{
24 int old, new;
25
26 do {
27 old = atomic_read(refcount);
28 new = old - 1;
29
30 if (unlikely (old == 1)) {
31 /* oops, we may be decrementing to zero, do it the slow way... */
32 spin_lock(lock);
33 if (atomic_dec_and_test(refcount))
34 return 1;
35 spin_unlock(lock);
36 return 0;
37 }
38 } while (cmpxchg(&refcount->counter, old, new) != old);
39 return 0;
40}
41
42EXPORT_SYMBOL(_atomic_dec_and_lock);