mm/damon/core: factor out 'damos_quota' private fileds initialization

The 'struct damos' creation function, 'damon_new_scheme()', does
initialization of private fileds of 'struct damos_quota' in it.  As its
verbose and makes the function unnecessarily long, this commit factors it
out to separate function.

Link: https://lkml.kernel.org/r/20220913174449.50645-5-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core.c

@@ -263,6 +263,19 @@ int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
 	return 0;
 }
 
+/* initialize private fields of damos_quota and return the pointer */
+static struct damos_quota *damos_quota_init_priv(struct damos_quota *quota)
+{
+	quota->total_charged_sz = 0;
+	quota->total_charged_ns = 0;
+	quota->esz = 0;
+	quota->charged_sz = 0;
+	quota->charged_from = 0;
+	quota->charge_target_from = NULL;
+	quota->charge_addr_from = 0;
+	return quota;
+}
+
 struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
 			enum damos_action action, struct damos_quota *quota,
 			struct damos_watermarks *wmarks)
@@ -277,15 +290,7 @@ struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
 	scheme->stat = (struct damos_stat){};
 	INIT_LIST_HEAD(&scheme->list);
 
-	scheme->quota = *quota;
-	/* caller might not zero-initialized the private fileds */
-	scheme->quota.total_charged_sz = 0;
-	scheme->quota.total_charged_ns = 0;
-	scheme->quota.esz = 0;
-	scheme->quota.charged_sz = 0;
-	scheme->quota.charged_from = 0;
-	scheme->quota.charge_target_from = NULL;
-	scheme->quota.charge_addr_from = 0;
+	scheme->quota = *(damos_quota_init_priv(quota));
 
 	scheme->wmarks = *wmarks;
 	scheme->wmarks.activated = true;