From: SeongJae Park <sj@kernel.org>
Date: Wed, 5 Mar 2025 22:27:31 +0000 (-0800)
Subject: mm/damon/sysfs-schemes: return error when for attempts to install filters on wrong... 
X-Git-Tag: v6.15-rc1~81^2~103
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ae8fd5b6666b0d99f485748b2b2259de1a7458dc;p=thirdparty%2Fkernel%2Flinux.git

mm/damon/sysfs-schemes: return error when for attempts to install filters on wrong sysfs directory

Return error if the user tries to install a DAMOS filter on DAMOS filters
sysfs directory that assumed to be used for filters that handled by a
DAMON layer that not same to that for the installing filter.

Link: https://lkml.kernel.org/r/20250305222733.59089-7-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>
---

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index e4e36c34ec0e5..1895d2d2c2950 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -362,6 +362,23 @@ static ssize_t type_show(struct kobject *kobj,
 			damon_sysfs_scheme_filter_type_strs[filter->type]);
 }
 
+static bool damos_sysfs_scheme_filter_valid_type(
+		enum damos_sysfs_filter_handle_layer layer,
+		enum damos_filter_type type)
+{
+	switch (layer) {
+	case DAMOS_SYSFS_FILTER_HANDLE_LAYER_BOTH:
+		return true;
+	case DAMOS_SYSFS_FILTER_HANDLE_LAYER_CORE:
+		return !damos_filter_for_ops(type);
+	case DAMOS_SYSFS_FILTER_HANDLE_LAYER_OPS:
+		return damos_filter_for_ops(type);
+	default:
+		break;
+	}
+	return false;
+}
+
 static ssize_t type_store(struct kobject *kobj,
 		struct kobj_attribute *attr, const char *buf, size_t count)
 {
@@ -373,6 +390,9 @@ static ssize_t type_store(struct kobject *kobj,
 	for (type = 0; type < NR_DAMOS_FILTER_TYPES; type++) {
 		if (sysfs_streq(buf, damon_sysfs_scheme_filter_type_strs[
 					type])) {
+			if (!damos_sysfs_scheme_filter_valid_type(
+						filter->handle_layer, type))
+				break;
 			filter->type = type;
 			ret = count;
 			break;