mm/damon: modify damon_rand() macro to static inline function

damon_rand() cannot be implemented as a macro.

Example:
	damon_rand(a++, b);

The value of 'a' will be incremented twice, This is obviously
unreasonable, So there fix it.

Link: https://lkml.kernel.org/r/110ffcd4e420c86c42b41ce2bc9f0fe6a4f32cd3.1638795127.git.xhao@linux.alibaba.com
Fixes: b9a6ac4 ("mm/damon: adaptively adjust regions")
Signed-off-by: Xin Hao <[email protected]>
Reported-by: Andrew Morton <[email protected]>
Reviewed-by: SeongJae Park <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: Xin Hao

include/linux/damon.h

@@ -19,7 +19,10 @@
 #define DAMOS_MAX_SCORE		(99)
 
 /* Get a random number in [l, r) */
-#define damon_rand(l, r) (l + prandom_u32_max(r - l))
+static inline unsigned long damon_rand(unsigned long l, unsigned long r)
+{
+	return l + prandom_u32_max(r - l);
+}
 
 /**
  * struct damon_addr_range - Represents an address region of [@start, @end).