[PATCH] atomic_long_t & include/asm-generic/atomic.h V2

Several counters already have the need to use 64 atomic variables on 64 bit
platforms (see mm_counter_t in sched.h).  We have to do ugly ifdefs to fall
back to 32 bit atomic on 32 bit platforms.

The VM statistics patch that I am working on will also make more extensive
use of atomic64.

This patch introduces a new type atomic_long_t by providing definitions in
asm-generic/atomic.h that works similar to the c "long" type.  Its 32 bits
on 32 bit platforms and 64 bits on 64 bit platforms.

Also cleans up the determination of the mm_counter_t in sched.h.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/asm-generic/atomic.h

@@ -0,0 +1,116 @@
+#ifndef _ASM_GENERIC_ATOMIC_H
+#define _ASM_GENERIC_ATOMIC_H
+/*
+ * Copyright (C) 2005 Silicon Graphics, Inc.
+ *	Christoph Lameter <clameter@sgi.com>
+ *
+ * Allows to provide arch independent atomic definitions without the need to
+ * edit all arch specific atomic.h files.
+ */
+
+
+/*
+ * Suppport for atomic_long_t
+ *
+ * Casts for parameters are avoided for existing atomic functions in order to
+ * avoid issues with cast-as-lval under gcc 4.x and other limitations that the
+ * macros of a platform may have.
+ */
+
+#if BITS_PER_LONG == 64
+
+typedef atomic64_t atomic_long_t;
+
+#define ATOMIC_LONG_INIT(i)	ATOMIC64_INIT(i)
+
+static inline long atomic_long_read(atomic_long_t *l)
+{
+	atomic64_t *v = (atomic64_t *)l;
+
+	return (long)atomic64_read(v);
+}
+
+static inline void atomic_long_set(atomic_long_t *l, long i)
+{
+	atomic64_t *v = (atomic64_t *)l;
+
+	atomic_set(v, i);
+}
+
+static inline void atomic_long_inc(atomic_long_t *l)
+{
+	atomic64_t *v = (atomic64_t *)l;
+
+	atomic64_inc(v);
+}
+
+static inline void atomic_long_dec(atomic_long_t *l)
+{
+	atomic64_t *v = (atomic64_t *)l;
+
+	atomic64_dec(v);
+}
+
+static inline void atomic_long_add(long i, atomic_long_t *l)
+{
+	atomic64_t *v = (atomic64_t *)l;
+
+	atomic64_add(i, v);
+}
+
+static inline void atomic_long_sub(long i, atomic_long_t *l)
+{
+	atomic64_t *v = (atomic64_t *)l;
+
+	atomic64_sub(i, v);
+}
+
+#else
+
+typedef atomic_t atomic_long_t;
+
+#define ATOMIC_LONG_INIT(i)	ATOMIC_INIT(i)
+static inline long atomic_long_read(atomic_long_t *l)
+{
+	atomic_t *v = (atomic_t *)l;
+
+	return (long)atomic_read(v);
+}
+
+static inline void atomic_long_set(atomic_long_t *l, long i)
+{
+	atomic_t *v = (atomic_t *)l;
+
+	atomic_set(v, i);
+}
+
+static inline void atomic_long_inc(atomic_long_t *l)
+{
+	atomic_t *v = (atomic_t *)l;
+
+	atomic_inc(v);
+}
+
+static inline void atomic_long_dec(atomic_long_t *l)
+{
+	atomic_t *v = (atomic_t *)l;
+
+	atomic_dec(v);
+}
+
+static inline void atomic_long_add(long i, atomic_long_t *l)
+{
+	atomic_t *v = (atomic_t *)l;
+
+	atomic_add(i, v);
+}
+
+static inline void atomic_long_sub(long i, atomic_long_t *l)
+{
+	atomic_t *v = (atomic_t *)l;
+
+	atomic_sub(i, v);
+}
+
+#endif
+#endif