[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>

2 files changed, 1 insertions, 48 deletions

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 @@
 # Makefile for MIPS-specific library files..
 #
 
-lib-y   += csum_partial_copy.o dec_and_lock.o memcpy.o promlib.o \
+lib-y   += csum_partial_copy.o memcpy.o promlib.o \
            strlen_user.o strncpy_user.o strnlen_user.o
 
 obj-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 @@
-/*
- * MIPS version of atomic_dec_and_lock() using cmpxchg
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-
-#include <linux/module.h>
-#include <linux/spinlock.h>
-#include <asm/atomic.h>
-#include <asm/system.h>
-
-/*
- * This is an implementation of the notion of "decrement a
- * reference count, and return locked if it decremented to zero".
- *
- * This implementation can be used on any architecture that
- * has a cmpxchg, and where atomic->value is an int holding
- * the value of the atomic (i.e. the high bits aren't used
- * for a lock or anything like that).
- */
-int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
-{
-        int counter;
-        int newcount;
-
-        for (;;) {
-                counter = atomic_read(atomic);
-                newcount = counter - 1;
-                if (!newcount)
-                        break;          /* do it the slow way */
-
-                newcount = cmpxchg(&atomic->counter, counter, newcount);
-                if (newcount == counter)
-                        return 0;
-        }
-
-        spin_lock(lock);
-        if (atomic_dec_and_test(atomic))
-                return 1;
-        spin_unlock(lock);
-        return 0;
-}
-
-EXPORT_SYMBOL(_atomic_dec_and_lock);