mm/damon: convert macro functions to static inline functions

Patch series "mm/damon: Misc cleanups".

This patchset contains miscellaneous cleanups for DAMON's macro
functions and documentation.

This patch (of 6):

This commit converts macro functions in DAMON to static inline functions,
for better type checking, code documentation, etc[1].

[1] https://lore.kernel.org/linux-mm/20211202151213.6ec830863342220da4141bc5@linux-foundation.org/

Link: https://lkml.kernel.org/r/20211209131806.19317-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20211209131806.19317-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/damon.h

@@ -399,14 +399,20 @@ struct damon_ctx {
 	struct list_head schemes;
 };
 
-#define damon_next_region(r) \
-	(container_of(r->list.next, struct damon_region, list))
+static inline struct damon_region *damon_next_region(struct damon_region *r)
+{
+	return container_of(r->list.next, struct damon_region, list);
+}
 
-#define damon_prev_region(r) \
-	(container_of(r->list.prev, struct damon_region, list))
+static inline struct damon_region *damon_prev_region(struct damon_region *r)
+{
+	return container_of(r->list.prev, struct damon_region, list);
+}
 
-#define damon_last_region(t) \
-	(list_last_entry(&t->regions_list, struct damon_region, list))
+static inline struct damon_region *damon_last_region(struct damon_target *t)
+{
+	return list_last_entry(&t->regions_list, struct damon_region, list);
+}
 
 #define damon_for_each_region(r, t) \
 	list_for_each_entry(r, &t->regions_list, list)

mm/damon/core.c

@@ -729,7 +729,10 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
 	}
 }
 
-#define sz_damon_region(r) (r->ar.end - r->ar.start)
+static inline unsigned long sz_damon_region(struct damon_region *r)
+{
+	return r->ar.end - r->ar.start;
+}
 
 /*
  * Merge two adjacent regions into one region

mm/damon/vaddr.c

@@ -26,8 +26,10 @@
  * 't->id' should be the pointer to the relevant 'struct pid' having reference
  * count.  Caller must put the returned task, unless it is NULL.
  */
-#define damon_get_task_struct(t) \
-	(get_pid_task((struct pid *)t->id, PIDTYPE_PID))
+static inline struct task_struct *damon_get_task_struct(struct damon_target *t)
+{
+	return get_pid_task((struct pid *)t->id, PIDTYPE_PID);
+}
 
 /*
  * Get the mm_struct of the given target