[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>

3 files changed, 0 insertions, 48 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index ed25d66c8d50..945c15a0722b 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -298,11 +298,6 @@ config PREEMPT
 
 source "mm/Kconfig"
 
-config HAVE_DEC_LOCK
-        bool
-        depends on (SMP || PREEMPT)
-        default y
-
 config IA32_SUPPORT
         bool "Support for Linux/x86 binaries"
         help
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-$(CONFIG_ITANIUM)	+= copy_page.o copy_user.o memcpy.o
 lib-$(CONFIG_MCKINLEY)  += copy_page_mck.o memcpy_mck.o
 lib-$(CONFIG_PERFMON)   += carta_random.o
 lib-$(CONFIG_MD_RAID5)  += xor.o
-lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o
 
 AFLAGS___divdi3.o       =
 AFLAGS___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 @@
-/*
- * Copyright (C) 2003 Jerome Marchand, Bull S.A.
- *      Cleaned up by David Mosberger-Tang <davidm@hpl.hp.com>
- *
- * This file is released under the GPLv2, or at your option any later version.
- *
- * ia64 version of "atomic_dec_and_lock()" using the atomic "cmpxchg" instruction.  This
- * code is an adaptation of the x86 version of "atomic_dec_and_lock()".
- */
-
-#include <linux/compiler.h>
-#include <linux/module.h>
-#include <linux/spinlock.h>
-#include <asm/atomic.h>
-
-/*
- * Decrement REFCOUNT and if the count reaches zero, acquire the spinlock.  Both of these
- * operations have to be done atomically, so that the count doesn't drop to zero without
- * acquiring the spinlock first.
- */
-int
-_atomic_dec_and_lock (atomic_t *refcount, spinlock_t *lock)
-{
-        int old, new;
-
-        do {
-                old = atomic_read(refcount);
-                new = old - 1;
-
-                if (unlikely (old == 1)) {
-                        /* oops, we may be decrementing to zero, do it the slow way... */
-                        spin_lock(lock);
-                        if (atomic_dec_and_test(refcount))
-                                return 1;
-                        spin_unlock(lock);
-                        return 0;
-                }
-        } while (cmpxchg(&refcount->counter, old, new) != old);
-        return 0;
-}
-
-EXPORT_SYMBOL(_atomic_dec_and_lock);