ida: Move ida_bitmap to a percpu variable

When we preload the IDA, we allocate an IDA bitmap.  Instead of storing
that preallocated bitmap in the IDA, we store it in a percpu variable.
Generally there are more IDAs in the system than CPUs, so this cuts down
on the number of preallocated bitmaps that are unused, and about half
of the IDA users did not call ida_destroy() so they were leaking IDA
bitmaps.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>

tools/testing/radix-tree/linux/kernel.h

@@ -24,6 +24,4 @@
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 
-#define xchg(ptr, x)	uatomic_xchg(ptr, x)
-
 #endif /* _KERNEL_H */

tools/testing/radix-tree/linux/percpu.h

@@ -1,7 +1,10 @@
-
+#define DECLARE_PER_CPU(type, val) extern type val
 #define DEFINE_PER_CPU(type, val) type val
 
 #define __get_cpu_var(var)	var
 #define this_cpu_ptr(var)	var
+#define this_cpu_read(var)	var
+#define this_cpu_xchg(var, val)		uatomic_xchg(&var, val)
+#define this_cpu_cmpxchg(var, old, new)	uatomic_cmpxchg(&var, old, new)
 #define per_cpu_ptr(ptr, cpu)   ({ (void)(cpu); (ptr); })
 #define per_cpu(var, cpu)	(*per_cpu_ptr(&(var), cpu))