mm/damon/sysfs: implement filters directory

Implement a directory for letting users to install data probe filters.

Link: https://lore.kernel.org/20260518234119.97569-12-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 6cef3eaa4431ea42604871a3266c346ec4d41684..dad4985a826dba9618e0147af5b496287928c929 100644 (file)
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -747,12 +747,42 @@ static const struct kobj_type damon_sysfs_intervals_ktype = {
        .default_groups = damon_sysfs_intervals_groups,
 };
 
+/*
+ * filters directory
+ */
+
+struct damon_sysfs_filters {
+       struct kobject kobj;
+};
+
+static struct damon_sysfs_filters *damon_sysfs_filters_alloc(void)
+{
+       return kzalloc_obj(struct damon_sysfs_filters);
+}
+
+static void damon_sysfs_filters_release(struct kobject *kobj)
+{
+       kfree(container_of(kobj, struct damon_sysfs_filters, kobj));
+}
+
+static struct attribute *damon_sysfs_filters_attrs[] = {
+       NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_filters);
+
+static const struct kobj_type damon_sysfs_filters_ktype = {
+       .release = damon_sysfs_filters_release,
+       .sysfs_ops = &kobj_sysfs_ops,
+       .default_groups = damon_sysfs_filters_groups,
+};
+
 /*
  * probe directory
  */
 
 struct damon_sysfs_probe {
        struct kobject kobj;
+       struct damon_sysfs_filters *filters;
 };
 
 static struct damon_sysfs_probe *damon_sysfs_probe_alloc(void)
@@ -760,6 +790,30 @@ static struct damon_sysfs_probe *damon_sysfs_probe_alloc(void)
        return kzalloc_obj(struct damon_sysfs_probe);
 }
 
+static int damon_sysfs_probe_add_dirs(struct damon_sysfs_probe *attr)
+{
+       struct damon_sysfs_filters *filters;
+       int err;
+
+       filters = damon_sysfs_filters_alloc();
+       if (!filters)
+               return -ENOMEM;
+       attr->filters = filters;
+
+       err = kobject_init_and_add(&filters->kobj, &damon_sysfs_filters_ktype,
+                       &attr->kobj, "filters");
+       if (err) {
+               kobject_put(&filters->kobj);
+               attr->filters = NULL;
+       }
+       return err;
+}
+
+static void damon_sysfs_probe_rm_dirs(struct damon_sysfs_probe *attr)
+{
+       kobject_put(&attr->filters->kobj);
+}
+
 static void damon_sysfs_probe_release(struct kobject *kobj)
 {
        kfree(container_of(kobj, struct damon_sysfs_probe, kobj));
@@ -797,8 +851,10 @@ static void damon_sysfs_probes_rm_dirs(
        struct damon_sysfs_probe **probes_arr = probes->probes_arr;
        int i;
 
-       for (i = 0; i < probes->nr; i++)
+       for (i = 0; i < probes->nr; i++) {
+               damon_sysfs_probe_rm_dirs(probes_arr[i]);
                kobject_put(&probes_arr[i]->kobj);
+       }
        probes->nr = 0;
        kfree(probes_arr);
        probes->probes_arr = NULL;
@@ -836,6 +892,13 @@ static int damon_sysfs_probes_add_dirs(
                        return err;
                }
 
+               err = damon_sysfs_probe_add_dirs(probe);
+               if (err) {
+                       kobject_put(&probe->kobj);
+                       damon_sysfs_probes_rm_dirs(probes);
+                       return err;
+               }
+
                probes_arr[i] = probe;
                probes->nr++;
        }