mm/damon/sysfs: use damon_commit_ctx()

DAMON_SYSFS manually manipulates DAMON context structs for online
parameters update.  Since the struct contains not only input parameters
but also internal status and operation results, it is not that simple. 
Indeed, we found and fixed a few bugs in the code.  Now DAMON core layer
provides a function for the usage, namely damon_commit_ctx().  Replace the
manual manipulation logic with the function.  The core layer function
could have its own bugs, but this change removes a source of bugs.

Link: https://lkml.kernel.org/r/20240618181809.82078-4-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/sysfs.c

@@ -1345,6 +1345,9 @@ static int damon_sysfs_apply_inputs(struct damon_ctx *ctx,
 	return damon_sysfs_set_schemes(ctx, sys_ctx->schemes);
 }
 
+static struct damon_ctx *damon_sysfs_build_ctx(
+		struct damon_sysfs_context *sys_ctx);
+
 /*
  * damon_sysfs_commit_input() - Commit user inputs to a running kdamond.
  * @kdamond:	The kobject wrapper for the associated kdamond.
@@ -1353,14 +1356,22 @@ static int damon_sysfs_apply_inputs(struct damon_ctx *ctx,
  */
 static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond)
 {
+	struct damon_ctx *param_ctx;
+	int err;
+
 	if (!damon_sysfs_kdamond_running(kdamond))
 		return -EINVAL;
 	/* TODO: Support multiple contexts per kdamond */
 	if (kdamond->contexts->nr != 1)
 		return -EINVAL;
 
-	return damon_sysfs_apply_inputs(kdamond->damon_ctx,
-			kdamond->contexts->contexts_arr[0]);
+	param_ctx = damon_sysfs_build_ctx(kdamond->contexts->contexts_arr[0]);
+	if (IS_ERR(param_ctx))
+		return PTR_ERR(param_ctx);
+	err = damon_commit_ctx(kdamond->damon_ctx, param_ctx);
+	damon_sysfs_destroy_targets(param_ctx);
+	damon_destroy_ctx(param_ctx);
+	return err;
 }
 
 static int damon_sysfs_commit_schemes_quota_goals(