typedef struct
{
- volatile unsigned long counter;
+ volatile long counter;
} local_t;
#define LOCAL_INIT(i) { (i) }
{
__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. */
* 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)