mm/damon/sysfs: decouple from damon_ops_id

Decouple DAMON sysfs interface from damon_ops_id.  For this, define and
use new mm/damon/sysfs.c internal data structure that maps the user-space
keywords and damon_ops_id, instead of having the implicit and unflexible
array index rule.

Link: https://lkml.kernel.org/r/20250622213759.50930-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 1af6aff35d84a09de69fbfdd45ed31b519dbec14..1b1476b79cdbada707736818f02689285c422dbb 100644 (file)
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -811,11 +811,24 @@ static const struct kobj_type damon_sysfs_attrs_ktype = {
  * context directory
  */
 
-/* This should match with enum damon_ops_id */
-static const char * const damon_sysfs_ops_strs[] = {
-       "vaddr",
-       "fvaddr",
-       "paddr",
+struct damon_sysfs_ops_name {
+       enum damon_ops_id ops_id;
+       char *name;
+};
+
+static const struct damon_sysfs_ops_name damon_sysfs_ops_names[] = {
+       {
+               .ops_id = DAMON_OPS_VADDR,
+               .name = "vaddr",
+       },
+       {
+               .ops_id = DAMON_OPS_FVADDR,
+               .name = "fvaddr",
+       },
+       {
+               .ops_id = DAMON_OPS_PADDR,
+               .name = "paddr",
+       },
 };
 
 struct damon_sysfs_context {
@@ -934,14 +947,16 @@ static void damon_sysfs_context_rm_dirs(struct damon_sysfs_context *context)
 static ssize_t avail_operations_show(struct kobject *kobj,
                struct kobj_attribute *attr, char *buf)
 {
-       enum damon_ops_id id;
        int len = 0;
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(damon_sysfs_ops_names); i++) {
+               const struct damon_sysfs_ops_name *ops_name;
 
-       for (id = 0; id < NR_DAMON_OPS; id++) {
-               if (!damon_is_registered_ops(id))
+               ops_name = &damon_sysfs_ops_names[i];
+               if (!damon_is_registered_ops(ops_name->ops_id))
                        continue;
-               len += sysfs_emit_at(buf, len, "%s\n",
-                               damon_sysfs_ops_strs[id]);
+               len += sysfs_emit_at(buf, len, "%s\n", ops_name->name);
        }
        return len;
 }
@@ -951,8 +966,16 @@ static ssize_t operations_show(struct kobject *kobj,
 {
        struct damon_sysfs_context *context = container_of(kobj,
                        struct damon_sysfs_context, kobj);
+       int i;
 
-       return sysfs_emit(buf, "%s\n", damon_sysfs_ops_strs[context->ops_id]);
+       for (i = 0; i < ARRAY_SIZE(damon_sysfs_ops_names); i++) {
+               const struct damon_sysfs_ops_name *ops_name;
+
+               ops_name = &damon_sysfs_ops_names[i];
+               if (ops_name->ops_id == context->ops_id)
+                       return sysfs_emit(buf, "%s\n", ops_name->name);
+       }
+       return -EINVAL;
 }
 
 static ssize_t operations_store(struct kobject *kobj,
@@ -960,11 +983,14 @@ static ssize_t operations_store(struct kobject *kobj,
 {
        struct damon_sysfs_context *context = container_of(kobj,
                        struct damon_sysfs_context, kobj);
-       enum damon_ops_id id;
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(damon_sysfs_ops_names); i++) {
+               const struct damon_sysfs_ops_name *ops_name;
 
-       for (id = 0; id < NR_DAMON_OPS; id++) {
-               if (sysfs_streq(buf, damon_sysfs_ops_strs[id])) {
-                       context->ops_id = id;
+               ops_name = &damon_sysfs_ops_names[i];
+               if (sysfs_streq(buf, ops_name->name)) {
+                       context->ops_id = ops_name->ops_id;
                        return count;
                }
        }