1 files changed, 42 insertions, 24 deletions

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 5ba82ab4943b..26e9ad80f9ea 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -297,59 +297,77 @@ static bool damon_intersect(struct damon_region *r,
 }
 
 /*
- * Update damon regions for the three big regions of the given target
+ * damon_set_regions() - Set regions of a target for given address ranges.
+ * @t:		the given target.
+ * @ranges:	array of new monitoring target ranges.
+ * @nr_ranges:	length of @ranges.
  *
- * t		the given target
- * bregions	the three big regions of the target
+ * This function adds new regions to, or modify existing regions of a
+ * monitoring target to fit in specific ranges.
+ *
+ * Return: 0 if success, or negative error code otherwise.
  */
-static void damon_va_apply_three_regions(struct damon_target *t,
-		struct damon_addr_range bregions[3])
+static int damon_set_regions(struct damon_target *t,
+		struct damon_addr_range *ranges, unsigned int nr_ranges)
 {
 	struct damon_region *r, *next;
 	unsigned int i;
 
-	/* Remove regions which are not in the three big regions now */
+	/* Remove regions which are not in the new ranges */
 	damon_for_each_region_safe(r, next, t) {
-		for (i = 0; i < 3; i++) {
-			if (damon_intersect(r, &bregions[i]))
+		for (i = 0; i < nr_ranges; i++) {
+			if (damon_intersect(r, &ranges[i]))
 				break;
 		}
-		if (i == 3)
+		if (i == nr_ranges)
 			damon_destroy_region(r, t);
 	}
 
-	/* Adjust intersecting regions to fit with the three big regions */
-	for (i = 0; i < 3; i++) {
-		struct damon_region *first = NULL, *last;
-		struct damon_region *newr;
-		struct damon_addr_range *br;
+	/* Add new regions or resize existing regions to fit in the ranges */
+	for (i = 0; i < nr_ranges; i++) {
+		struct damon_region *first = NULL, *last, *newr;
+		struct damon_addr_range *range;
 
-		br = &bregions[i];
-		/* Get the first and last regions which intersects with br */
+		range = &ranges[i];
+		/* Get the first/last regions intersecting with the range */
 		damon_for_each_region(r, t) {
-			if (damon_intersect(r, br)) {
+			if (damon_intersect(r, range)) {
 				if (!first)
 					first = r;
 				last = r;
 			}
-			if (r->ar.start >= br->end)
+			if (r->ar.start >= range->end)
 				break;
 		}
 		if (!first) {
-			/* no damon_region intersects with this big region */
+			/* no region intersects with this range */
 			newr = damon_new_region(
-					ALIGN_DOWN(br->start,
+					ALIGN_DOWN(range->start,
 						DAMON_MIN_REGION),
-					ALIGN(br->end, DAMON_MIN_REGION));
+					ALIGN(range->end, DAMON_MIN_REGION));
 			if (!newr)
-				continue;
+				return -ENOMEM;
 			damon_insert_region(newr, damon_prev_region(r), r, t);
 		} else {
-			first->ar.start = ALIGN_DOWN(br->start,
+			/* resize intersecting regions to fit in this range */
+			first->ar.start = ALIGN_DOWN(range->start,
 					DAMON_MIN_REGION);
-			last->ar.end = ALIGN(br->end, DAMON_MIN_REGION);
+			last->ar.end = ALIGN(range->end, DAMON_MIN_REGION);
 		}
 	}
+	return 0;
+}
+
+/*
+ * Update damon regions for the three big regions of the given target
+ *
+ * t		the given target
+ * bregions	the three big regions of the target
+ */
+static void damon_va_apply_three_regions(struct damon_target *t,
+		struct damon_addr_range bregions[3])
+{
+	damon_set_regions(t, bregions, 3);
 }
 
 /*