fedora core 6 1.2949 + vserver 2.2.0

[linux-2.6.git] / include / asm-i386 / local.h

diff --git a/include/asm-i386/local.h b/include/asm-i386/local.h
index 0177da8..12060e2 100644 (file)
--- a/include/asm-i386/local.h
+++ b/include/asm-i386/local.h
@@ -5,7 +5,7 @@
 
 typedef struct
 {
-       volatile unsigned long counter;
+       volatile long counter;
 } local_t;
 
 #define LOCAL_INIT(i)  { (i) }
@@ -17,32 +17,30 @@ static __inline__ void local_inc(local_t *v)
 {
        __asm__ __volatile__(
                "incl %0"
-               :"=m" (v->counter)
-               :"m" (v->counter));
+               :"+m" (v->counter));
 }
 
 static __inline__ void local_dec(local_t *v)
 {
        __asm__ __volatile__(
                "decl %0"
-               :"=m" (v->counter)
-               :"m" (v->counter));
+               :"+m" (v->counter));
 }
 
-static __inline__ void local_add(unsigned long i, local_t *v)
+static __inline__ void local_add(long i, local_t *v)
 {
        __asm__ __volatile__(
                "addl %1,%0"
-               :"=m" (v->counter)
-               :"ir" (i), "m" (v->counter));
+               :"+m" (v->counter)
+               :"ir" (i));
 }
 
-static __inline__ void local_sub(unsigned long i, local_t *v)
+static __inline__ void local_sub(long i, local_t *v)
 {
        __asm__ __volatile__(
                "subl %1,%0"
-               :"=m" (v->counter)
-               :"ir" (i), "m" (v->counter));
+               :"+m" (v->counter)
+               :"ir" (i));
 }
 
 /* On x86, these are no better than the atomic variants. */
@@ -55,12 +53,26 @@ static __inline__ void local_sub(unsigned long i, local_t *v)
  * much more efficient than these naive implementations.  Note they take
  * a variable, not an address.
  */
-#define cpu_local_read(v)      local_read(&__get_cpu_var(v))
-#define cpu_local_set(v, i)    local_set(&__get_cpu_var(v), (i))
-#define cpu_local_inc(v)       local_inc(&__get_cpu_var(v))
-#define cpu_local_dec(v)       local_dec(&__get_cpu_var(v))
-#define cpu_local_add(i, v)    local_add((i), &__get_cpu_var(v))
-#define cpu_local_sub(i, v)    local_sub((i), &__get_cpu_var(v))
+
+/* Need to disable preemption for the cpu local counters otherwise we could
+   still access a variable of a previous CPU in a non atomic way. */
+#define cpu_local_wrap_v(v)            \
+       ({ local_t res__;               \
+          preempt_disable();           \
+          res__ = (v);                 \
+          preempt_enable();            \
+          res__; })
+#define cpu_local_wrap(v)              \
+       ({ preempt_disable();           \
+          v;                           \
+          preempt_enable(); })         \
+
+#define cpu_local_read(v)    cpu_local_wrap_v(local_read(&__get_cpu_var(v)))
+#define cpu_local_set(v, i)  cpu_local_wrap(local_set(&__get_cpu_var(v), (i)))
+#define cpu_local_inc(v)     cpu_local_wrap(local_inc(&__get_cpu_var(v)))
+#define cpu_local_dec(v)     cpu_local_wrap(local_dec(&__get_cpu_var(v)))
+#define cpu_local_add(i, v)  cpu_local_wrap(local_add((i), &__get_cpu_var(v)))
+#define cpu_local_sub(i, v)  cpu_local_wrap(local_sub((i), &__get_cpu_var(v)))
 
 #define __cpu_local_inc(v)     cpu_local_inc(v)
 #define __cpu_local_dec(v)     cpu_local_dec(v)