[PATCH 1/3] mm/damon/sysfs: check error from damon_sysfs_update_target()

[SeongJae Park]

damon_sysfs_update_target() returns error code for failures, but its
caller, damon_sysfs_set_targets() is ignoring that.  The update function
seems making no critical change in case of such failures, but the
behavior will look like DAMON sysfs is silently ignoring or only
partially accepting the user input.  Fix it.

Fixes: 19467a950b49 ("mm/damon/sysfs: remove requested targets when online-commit inputs")
Cc: <stable@xxxxxxxxxxxxxxx> # 5.19.x
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---

Note that yet another fix[1] should be applied before this.

[1] https://lore.kernel.org/all/739e6aaf-a634-4e33-98a8-16546379ec9f@moroto.mountain/

 mm/damon/sysfs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 1dfa96d4de99..7472404456aa 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1203,8 +1203,10 @@ static int damon_sysfs_set_targets(struct damon_ctx *ctx,
 
 	damon_for_each_target_safe(t, next, ctx) {
 		if (i < sysfs_targets->nr) {
-			damon_sysfs_update_target(t, ctx,
+			err = damon_sysfs_update_target(t, ctx,
 					sysfs_targets->targets_arr[i]);
+			if (err)
+				return err;
 		} else {
 			if (damon_target_has_pid(ctx))
 				put_pid(t->pid);
-- 
2.34.1