[PATCH] s390: atomic primitives

      Hugh Dickins <hugh@veritas.com>

Fix the broken atomic_cmpxchg primitive.  Add atomic_sub_and_test,
atomic64_sub_return, atomic64_sub_and_test, atomic64_cmpxchg,
atomic64_add_unless and atomic64_inc_not_zero.  Replace old style
atomic_compare_and_swap by atomic_cmpxchg.  Shorten the whole header by
defining most primitives with the two inline functions atomic_add_return and
atomic_sub_return.

In addition this patch contains the s390 related fixes of Hugh's "mm: fill
arch atomic64 gaps" patch.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 70 insertions, 103 deletions

diff --git a/include/asm-s390/atomic.h b/include/asm-s390/atomic.h
index 6d07c7df4b40..d82aedf616fe 100644
--- a/include/asm-s390/atomic.h
+++ b/include/asm-s390/atomic.h
@@ -5,7 +5,7 @@
  *  include/asm-s390/atomic.h
  *
  *  S390 version
- *    Copyright (C) 1999-2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Copyright (C) 1999-2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
  *               Denis Joseph Barrow,
  *               Arnd Bergmann (arndb@de.ibm.com)
@@ -45,59 +45,57 @@ typedef struct {
 #define atomic_read(v)          ((v)->counter)
 #define atomic_set(v,i)         (((v)->counter) = (i))
 
-static __inline__ void atomic_add(int i, atomic_t * v)
-{
-               __CS_LOOP(v, i, "ar");
-}
 static __inline__ int atomic_add_return(int i, atomic_t * v)
 {
         return __CS_LOOP(v, i, "ar");
 }
-static __inline__ int atomic_add_negative(int i, atomic_t * v)
-{
-        return __CS_LOOP(v, i, "ar") < 0;
-}
-static __inline__ void atomic_sub(int i, atomic_t * v)
-{
-               __CS_LOOP(v, i, "sr");
-}
+#define atomic_add(_i, _v)              atomic_add_return(_i, _v)
+#define atomic_add_negative(_i, _v)     (atomic_add_return(_i, _v) < 0)
+#define atomic_inc(_v)                  atomic_add_return(1, _v)
+#define atomic_inc_return(_v)           atomic_add_return(1, _v)
+#define atomic_inc_and_test(_v)         (atomic_add_return(1, _v) == 0)
+
 static __inline__ int atomic_sub_return(int i, atomic_t * v)
 {
         return __CS_LOOP(v, i, "sr");
 }
-static __inline__ void atomic_inc(volatile atomic_t * v)
-{
-               __CS_LOOP(v, 1, "ar");
-}
-static __inline__ int atomic_inc_return(volatile atomic_t * v)
-{
-        return __CS_LOOP(v, 1, "ar");
-}
+#define atomic_sub(_i, _v)              atomic_sub_return(_i, _v)
+#define atomic_sub_and_test(_i, _v)     (atomic_sub_return(_i, _v) == 0)
+#define atomic_dec(_v)                  atomic_sub_return(1, _v)
+#define atomic_dec_return(_v)           atomic_sub_return(1, _v)
+#define atomic_dec_and_test(_v)         (atomic_sub_return(1, _v) == 0)
 
-static __inline__ int atomic_inc_and_test(volatile atomic_t * v)
-{
-        return __CS_LOOP(v, 1, "ar") == 0;
-}
-static __inline__ void atomic_dec(volatile atomic_t * v)
-{
-               __CS_LOOP(v, 1, "sr");
-}
-static __inline__ int atomic_dec_return(volatile atomic_t * v)
-{
-        return __CS_LOOP(v, 1, "sr");
-}
-static __inline__ int atomic_dec_and_test(volatile atomic_t * v)
-{
-        return __CS_LOOP(v, 1, "sr") == 0;
-}
 static __inline__ void atomic_clear_mask(unsigned long mask, atomic_t * v)
 {
                __CS_LOOP(v, ~mask, "nr");
 }
+
 static __inline__ void atomic_set_mask(unsigned long mask, atomic_t * v)
 {
                __CS_LOOP(v, mask, "or");
 }
+
+static __inline__ int atomic_cmpxchg(atomic_t *v, int old, int new)
+{
+        __asm__ __volatile__("  cs   %0,%3,0(%2)\n"
+                             : "+d" (old), "=m" (v->counter)
+                             : "a" (v), "d" (new), "m" (v->counter)
+                             : "cc", "memory" );
+        return old;
+}
+
+static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
+{
+        int c, old;
+
+        c = atomic_read(v);
+        while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c)
+                c = old;
+        return c != u;
+}
+
+#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+
 #undef __CS_LOOP
 
 #ifdef __s390x__
@@ -123,92 +121,61 @@ typedef struct {
 #define atomic64_read(v)          ((v)->counter)
 #define atomic64_set(v,i)         (((v)->counter) = (i))
 
-static __inline__ void atomic64_add(long long i, atomic64_t * v)
-{
-               __CSG_LOOP(v, i, "agr");
-}
 static __inline__ long long atomic64_add_return(long long i, atomic64_t * v)
 {
         return __CSG_LOOP(v, i, "agr");
 }
-static __inline__ long long atomic64_add_negative(long long i, atomic64_t * v)
-{
-        return __CSG_LOOP(v, i, "agr") < 0;
-}
-static __inline__ void atomic64_sub(long long i, atomic64_t * v)
-{
-               __CSG_LOOP(v, i, "sgr");
-}
-static __inline__ void atomic64_inc(volatile atomic64_t * v)
-{
-               __CSG_LOOP(v, 1, "agr");
-}
-static __inline__ long long atomic64_inc_return(volatile atomic64_t * v)
-{
-        return __CSG_LOOP(v, 1, "agr");
-}
-static __inline__ long long atomic64_inc_and_test(volatile atomic64_t * v)
-{
-        return __CSG_LOOP(v, 1, "agr") == 0;
-}
-static __inline__ void atomic64_dec(volatile atomic64_t * v)
-{
-               __CSG_LOOP(v, 1, "sgr");
-}
-static __inline__ long long atomic64_dec_return(volatile atomic64_t * v)
-{
-        return __CSG_LOOP(v, 1, "sgr");
-}
-static __inline__ long long atomic64_dec_and_test(volatile atomic64_t * v)
+#define atomic64_add(_i, _v)            atomic64_add_return(_i, _v)
+#define atomic64_add_negative(_i, _v)   (atomic64_add_return(_i, _v) < 0)
+#define atomic64_inc(_v)                atomic64_add_return(1, _v)
+#define atomic64_inc_return(_v)         atomic64_add_return(1, _v)
+#define atomic64_inc_and_test(_v)       (atomic64_add_return(1, _v) == 0)
+
+static __inline__ long long atomic64_sub_return(long long i, atomic64_t * v)
 {
-        return __CSG_LOOP(v, 1, "sgr") == 0;
+        return __CSG_LOOP(v, i, "sgr");
 }
+#define atomic64_sub(_i, _v)            atomic64_sub_return(_i, _v)
+#define atomic64_sub_and_test(_i, _v)   (atomic64_sub_return(_i, _v) == 0)
+#define atomic64_dec(_v)                atomic64_sub_return(1, _v)
+#define atomic64_dec_return(_v)         atomic64_sub_return(1, _v)
+#define atomic64_dec_and_test(_v)       (atomic64_sub_return(1, _v) == 0)
+
 static __inline__ void atomic64_clear_mask(unsigned long mask, atomic64_t * v)
 {
                __CSG_LOOP(v, ~mask, "ngr");
 }
+
 static __inline__ void atomic64_set_mask(unsigned long mask, atomic64_t * v)
 {
                __CSG_LOOP(v, mask, "ogr");
 }
 
-#undef __CSG_LOOP
-#endif
-
-/*
-  returns 0  if expected_oldval==value in *v ( swap was successful )
-  returns 1  if unsuccessful.
+static __inline__ long long atomic64_cmpxchg(atomic64_t *v,
+                                             long long old, long long new)
+{
+        __asm__ __volatile__("  csg  %0,%3,0(%2)\n"
+                             : "+d" (old), "=m" (v->counter)
+                             : "a" (v), "d" (new), "m" (v->counter)
+                             : "cc", "memory" );
+        return old;
+}
 
-  This is non-portable, use bitops or spinlocks instead!
-*/
-static __inline__ int
-atomic_compare_and_swap(int expected_oldval,int new_val,atomic_t *v)
+static __inline__ int atomic64_add_unless(atomic64_t *v,
+                                          long long a, long long u)
 {
-        int retval;
-
-        __asm__ __volatile__(
-                "  lr   %0,%3\n"
-                "  cs   %0,%4,0(%2)\n"
-                "  ipm  %0\n"
-                "  srl  %0,28\n"
-                "0:"
-                : "=&d" (retval), "=m" (v->counter)
-                : "a" (v), "d" (expected_oldval) , "d" (new_val),
-                  "m" (v->counter) : "cc", "memory" );
-        return retval;
+        long long c, old;
+
+        c = atomic64_read(v);
+        while (c != u && (old = atomic64_cmpxchg(v, c, c + a)) != c)
+                c = old;
+        return c != u;
 }
 
-#define atomic_cmpxchg(v, o, n) (atomic_compare_and_swap((o), (n), &((v)->counter)))
+#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 
-#define atomic_add_unless(v, a, u)                              \
-({                                                              \
-        int c, old;                                             \
-        c = atomic_read(v);                                     \
-        while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
-                c = old;                                        \
-        c != (u);                                               \
-})
-#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#undef __CSG_LOOP
+#endif
 
 #define smp_mb__before_atomic_dec()     smp_mb()
 #define smp_mb__after_atomic_dec()      smp_mb()