sh: consolidate atomic_cmpxchg()/atomic_add_unless() definitions.

The LL/SC and IRQ versions were using generic stubs while the GRB version
was just reimplementing what it already had for the standard cmpxchg()
code. As we have optimized cmpxchg() implementations that are decoupled
from the atomic code, simply falling back on the generic wrapper does the
right thing. With this in place the GRB case is unaffected while the
LL/SC case gets to use its optimized cmpxchg().

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 29 insertions, 44 deletions

diff --git a/arch/sh/include/asm/atomic.h b/arch/sh/include/asm/atomic.h
index b16388d71954..275a448ae8c2 100644
--- a/arch/sh/include/asm/atomic.h
+++ b/arch/sh/include/asm/atomic.h
@@ -25,58 +25,43 @@
 #endif
 
 #define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
+#define atomic_dec_return(v)            atomic_sub_return(1, (v))
+#define atomic_inc_return(v)            atomic_add_return(1, (v))
+#define atomic_inc_and_test(v)          (atomic_inc_return(v) == 0)
+#define atomic_sub_and_test(i,v)        (atomic_sub_return((i), (v)) == 0)
+#define atomic_dec_and_test(v)          (atomic_sub_return(1, (v)) == 0)
+#define atomic_inc_not_zero(v)          atomic_add_unless((v), 1, 0)
 
-#define atomic_dec_return(v) atomic_sub_return(1,(v))
-#define atomic_inc_return(v) atomic_add_return(1,(v))
+#define atomic_inc(v)                   atomic_add(1, (v))
+#define atomic_dec(v)                   atomic_sub(1, (v))
 
-/*
- * atomic_inc_and_test - increment and test
+#define atomic_xchg(v, new)             (xchg(&((v)->counter), new))
+#define atomic_cmpxchg(v, o, n)         (cmpxchg(&((v)->counter), (o), (n)))
+
+/**
+ * atomic_add_unless - add unless the number is a given value
  * @v: pointer of type atomic_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
  *
- * Atomically increments @v by 1
- * and returns true if the result is zero, or false for all
- * other cases.
+ * Atomically adds @a to @v, so long as it was not @u.
+ * Returns non-zero if @v was not @u, and zero otherwise.
  */
-#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
-
-#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
-#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
-
-#define atomic_inc(v) atomic_add(1,(v))
-#define atomic_dec(v) atomic_sub(1,(v))
-
-#if !defined(CONFIG_GUSA_RB) && !defined(CONFIG_CPU_SH4A)
-static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
-{
-        int ret;
-        unsigned long flags;
-
-        local_irq_save(flags);
-        ret = v->counter;
-        if (likely(ret == old))
-                v->counter = new;
-        local_irq_restore(flags);
-
-        return ret;
-}
-
 static inline int atomic_add_unless(atomic_t *v, int a, int u)
 {
-        int ret;
-        unsigned long flags;
-
-        local_irq_save(flags);
-        ret = v->counter;
-        if (ret != u)
-                v->counter += a;
-        local_irq_restore(flags);
-
-        return ret != u;
+        int c, old;
+        c = atomic_read(v);
+        for (;;) {
+                if (unlikely(c == (u)))
+                        break;
+                old = atomic_cmpxchg((v), c, c + (a));
+                if (likely(old == c))
+                        break;
+                c = old;
+        }
+
+        return c != (u);
 }
-#endif /* !CONFIG_GUSA_RB && !CONFIG_CPU_SH4A */
-
-#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
-#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 
 #define smp_mb__before_atomic_dec()     smp_mb()
 #define smp_mb__after_atomic_dec()      smp_mb()