mm/damon/sysfs-schemes: add a file for setting damos_filter->allow

Only kernel-space DAMON API users can use inclusive DAMOS filters.  Add a
sysfs file named 'allow' under DAMOS filter directory of DAMON sysfs
interface, to let the user-space users use inclusive DAMOS filters.

Link: https://lkml.kernel.org/r/20250109175126.57878-7-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 9a883e8..98f93ae 100644 (file)
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -313,6 +313,7 @@ struct damon_sysfs_scheme_filter {
        struct kobject kobj;
        enum damos_filter_type type;
        bool matching;
+       bool allow;
        char *memcg_path;
        struct damon_addr_range addr_range;
        int target_idx;
@@ -385,6 +386,30 @@ static ssize_t matching_store(struct kobject *kobj,
        return count;
 }
 
+static ssize_t allow_show(struct kobject *kobj,
+               struct kobj_attribute *attr, char *buf)
+{
+       struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+                       struct damon_sysfs_scheme_filter, kobj);
+
+       return sysfs_emit(buf, "%c\n", filter->allow ? 'Y' : 'N');
+}
+
+static ssize_t allow_store(struct kobject *kobj,
+               struct kobj_attribute *attr, const char *buf, size_t count)
+{
+       struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+                       struct damon_sysfs_scheme_filter, kobj);
+       bool allow;
+       int err = kstrtobool(buf, &allow);
+
+       if (err)
+               return err;
+
+       filter->allow = allow;
+       return count;
+}
+
 static ssize_t memcg_path_show(struct kobject *kobj,
                struct kobj_attribute *attr, char *buf)
 {
@@ -482,6 +507,9 @@ static struct kobj_attribute damon_sysfs_scheme_filter_type_attr =
 static struct kobj_attribute damon_sysfs_scheme_filter_matching_attr =
                __ATTR_RW_MODE(matching, 0600);
 
+static struct kobj_attribute damon_sysfs_scheme_filter_allow_attr =
+               __ATTR_RW_MODE(allow, 0600);
+
 static struct kobj_attribute damon_sysfs_scheme_filter_memcg_path_attr =
                __ATTR_RW_MODE(memcg_path, 0600);
 
@@ -497,6 +525,7 @@ static struct kobj_attribute damon_sysfs_scheme_filter_damon_target_idx_attr =
 static struct attribute *damon_sysfs_scheme_filter_attrs[] = {
        &damon_sysfs_scheme_filter_type_attr.attr,
        &damon_sysfs_scheme_filter_matching_attr.attr,
+       &damon_sysfs_scheme_filter_allow_attr.attr,
        &damon_sysfs_scheme_filter_memcg_path_attr.attr,
        &damon_sysfs_scheme_filter_addr_start_attr.attr,
        &damon_sysfs_scheme_filter_addr_end_attr.attr,
@@ -1901,7 +1930,8 @@ static int damon_sysfs_add_scheme_filters(struct damos *scheme,
                        sysfs_filters->filters_arr[i];
                struct damos_filter *filter =
                        damos_new_filter(sysfs_filter->type,
-                                       sysfs_filter->matching, false);
+                                       sysfs_filter->matching,
+                                       sysfs_filter->allow);
                int err;
 
                if (!filter)