1 files changed, 61 insertions, 0 deletions

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
new file mode 100644
index 000000000000..5451eb1e781d
--- /dev/null
+++ b/include/linux/percpu.h
@@ -0,0 +1,61 @@
+#ifndef __LINUX_PERCPU_H
+#define __LINUX_PERCPU_H
+#include <linux/spinlock.h> /* For preempt_disable() */
+#include <linux/slab.h> /* For kmalloc() */
+#include <linux/smp.h>
+#include <linux/string.h> /* For memset() */
+#include <asm/percpu.h>
+
+/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
+#ifndef PERCPU_ENOUGH_ROOM
+#define PERCPU_ENOUGH_ROOM 32768
+#endif
+
+/* Must be an lvalue. */
+#define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); }))
+#define put_cpu_var(var) preempt_enable()
+
+#ifdef CONFIG_SMP
+
+struct percpu_data {
+        void *ptrs[NR_CPUS];
+        void *blkp;
+};
+
+/* 
+ * Use this to get to a cpu's version of the per-cpu object allocated using
+ * alloc_percpu.  Non-atomic access to the current CPU's version should
+ * probably be combined with get_cpu()/put_cpu().
+ */ 
+#define per_cpu_ptr(ptr, cpu)                   \
+({                                              \
+        struct percpu_data *__p = (struct percpu_data *)~(unsigned long)(ptr); \
+        (__typeof__(ptr))__p->ptrs[(cpu)];      \
+})
+
+extern void *__alloc_percpu(size_t size, size_t align);
+extern void free_percpu(const void *);
+
+#else /* CONFIG_SMP */
+
+#define per_cpu_ptr(ptr, cpu) (ptr)
+
+static inline void *__alloc_percpu(size_t size, size_t align)
+{
+        void *ret = kmalloc(size, GFP_KERNEL);
+        if (ret)
+                memset(ret, 0, size);
+        return ret;
+}
+static inline void free_percpu(const void *ptr)
+{       
+        kfree(ptr);
+}
+
+#endif /* CONFIG_SMP */
+
+/* Simple wrapper for the common case: zeros memory. */
+#define alloc_percpu(type) \
+        ((type *)(__alloc_percpu(sizeof(type), __alignof__(type))))
+
+#endif /* __LINUX_PERCPU_H */