[RFC PATCH v2 3/8] mm/damon/core: return an error from damos_commit_filter_arg()

[SJ Park <sj@kernel.org>]

damos_commit_filter_arg() is supposed to always succeed.  It may not in
future, for example, if the given filter is invalid.  Prepare the case
by modifying its signature to return an error when it failed.  Also pipe
the return value to its callers and let them handle the error.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/core.c | 41 ++++++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 3d7a973ea8b6f..ea7d8d5a4abf6 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1317,7 +1317,7 @@ static struct damos_filter *damos_nth_ops_filter(int n, struct damos *s)
 	return NULL;
 }
 
-static void damos_commit_filter_arg(
+static int damos_commit_filter_arg(
 		struct damos_filter *dst, struct damos_filter *src)
 {
 	switch (dst->type) {
@@ -1340,28 +1340,32 @@ static void damos_commit_filter_arg(
 	default:
 		break;
 	}
+	return 0;
 }
 
-static void damos_commit_filter(
+static int damos_commit_filter(
 		struct damos_filter *dst, struct damos_filter *src)
 {
 	dst->type = src->type;
 	dst->matching = src->matching;
 	dst->allow = src->allow;
-	damos_commit_filter_arg(dst, src);
+	return damos_commit_filter_arg(dst, src);
 }
 
 static int damos_commit_core_filters(struct damos *dst, struct damos *src)
 {
 	struct damos_filter *dst_filter, *next, *src_filter, *new_filter;
-	int i = 0, j = 0;
+	int i = 0, j = 0, err;
 
 	damos_for_each_core_filter_safe(dst_filter, next, dst) {
 		src_filter = damos_nth_core_filter(i++, src);
-		if (src_filter)
-			damos_commit_filter(dst_filter, src_filter);
-		else
+		if (src_filter) {
+			err = damos_commit_filter(dst_filter, src_filter);
+			if (err)
+				return err;
+		} else {
 			damos_destroy_filter(dst_filter);
+		}
 	}
 
 	damos_for_each_core_filter_safe(src_filter, next, src) {
@@ -1373,7 +1377,11 @@ static int damos_commit_core_filters(struct damos *dst, struct damos *src)
 				src_filter->allow);
 		if (!new_filter)
 			return -ENOMEM;
-		damos_commit_filter_arg(new_filter, src_filter);
+		err = damos_commit_filter_arg(new_filter, src_filter);
+		if (err) {
+			damos_destroy_filter(new_filter);
+			return err;
+		}
 		damos_add_filter(dst, new_filter);
 	}
 	return 0;
@@ -1382,14 +1390,17 @@ static int damos_commit_core_filters(struct damos *dst, struct damos *src)
 static int damos_commit_ops_filters(struct damos *dst, struct damos *src)
 {
 	struct damos_filter *dst_filter, *next, *src_filter, *new_filter;
-	int i = 0, j = 0;
+	int i = 0, j = 0, err;
 
 	damos_for_each_ops_filter_safe(dst_filter, next, dst) {
 		src_filter = damos_nth_ops_filter(i++, src);
-		if (src_filter)
-			damos_commit_filter(dst_filter, src_filter);
-		else
+		if (src_filter) {
+			err = damos_commit_filter(dst_filter, src_filter);
+			if (err)
+				return err;
+		} else {
 			damos_destroy_filter(dst_filter);
+		}
 	}
 
 	damos_for_each_ops_filter_safe(src_filter, next, src) {
@@ -1401,7 +1412,11 @@ static int damos_commit_ops_filters(struct damos *dst, struct damos *src)
 				src_filter->allow);
 		if (!new_filter)
 			return -ENOMEM;
-		damos_commit_filter_arg(new_filter, src_filter);
+		err = damos_commit_filter_arg(new_filter, src_filter);
+		if (err) {
+			damos_destroy_filter(new_filter);
+			return err;
+		}
 		damos_add_filter(dst, new_filter);
 	}
 	return 0;
-- 
2.47.3