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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/mips
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/mips')
-rw-r--r--arch/mips/Kconfig4
-rw-r--r--arch/mips/lib/Makefile2
-rw-r--r--arch/mips/lib/dec_and_lock.c47
3 files changed, 1 insertions, 52 deletions
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 0eb71ac303af..4cd724c05700 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1009,10 +1009,6 @@ config GENERIC_CALIBRATE_DELAY
1009 bool 1009 bool
1010 default y 1010 default y
1011 1011
1012config HAVE_DEC_LOCK
1013 bool
1014 default y
1015
1016# 1012#
1017# Select some configuration options automatically based on user selections. 1013# Select some configuration options automatically based on user selections.
1018# 1014#
diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index 21b92b9dd013..037303412909 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -2,7 +2,7 @@
2# Makefile for MIPS-specific library files.. 2# Makefile for MIPS-specific library files..
3# 3#
4 4
5lib-y += csum_partial_copy.o dec_and_lock.o memcpy.o promlib.o \ 5lib-y += csum_partial_copy.o memcpy.o promlib.o \
6 strlen_user.o strncpy_user.o strnlen_user.o 6 strlen_user.o strncpy_user.o strnlen_user.o
7 7
8obj-y += iomap.o 8obj-y += iomap.o
diff --git a/arch/mips/lib/dec_and_lock.c b/arch/mips/lib/dec_and_lock.c
deleted file mode 100644
index fd82c84a93b7..000000000000
--- a/arch/mips/lib/dec_and_lock.c
+++ /dev/null
@@ -1,47 +0,0 @@
1/*
2 * MIPS version of atomic_dec_and_lock() using cmpxchg
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9
10#include <linux/module.h>
11#include <linux/spinlock.h>
12#include <asm/atomic.h>
13#include <asm/system.h>
14
15/*
16 * This is an implementation of the notion of "decrement a
17 * reference count, and return locked if it decremented to zero".
18 *
19 * This implementation can be used on any architecture that
20 * has a cmpxchg, and where atomic->value is an int holding
21 * the value of the atomic (i.e. the high bits aren't used
22 * for a lock or anything like that).
23 */
24int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
25{
26 int counter;
27 int newcount;
28
29 for (;;) {
30 counter = atomic_read(atomic);
31 newcount = counter - 1;
32 if (!newcount)
33 break; /* do it the slow way */
34
35 newcount = cmpxchg(&atomic->counter, counter, newcount);
36 if (newcount == counter)
37 return 0;
38 }
39
40 spin_lock(lock);
41 if (atomic_dec_and_test(atomic))
42 return 1;
43 spin_unlock(lock);
44 return 0;
45}
46
47EXPORT_SYMBOL(_atomic_dec_and_lock);