devlink: avoid potential loop in devlink_rel_nested_in_notify_work()

In case devlink_rel_nested_in_notify_work() can not take the devlink
lock mutex. Convert the work to delayed work and in case of reschedule
do it jiffie later and avoid potential looping.

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Fixes: c137743bce02 ("devlink: introduce object and nested devlink relationship infra")
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240205171114.338679-1-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/devlink/core.c b/net/devlink/core.c
index 4275a2b..6a58342 100644 (file)
--- a/net/devlink/core.c
+++ b/net/devlink/core.c
@@ -46,7 +46,7 @@ struct devlink_rel {
                u32 obj_index;
                devlink_rel_notify_cb_t *notify_cb;
                devlink_rel_cleanup_cb_t *cleanup_cb;
-               struct work_struct notify_work;
+               struct delayed_work notify_work;
        } nested_in;
 };
 
@@ -70,7 +70,7 @@ static void __devlink_rel_put(struct devlink_rel *rel)
 static void devlink_rel_nested_in_notify_work(struct work_struct *work)
 {
        struct devlink_rel *rel = container_of(work, struct devlink_rel,
-                                              nested_in.notify_work);
+                                              nested_in.notify_work.work);
        struct devlink *devlink;
 
        devlink = devlinks_xa_get(rel->nested_in.devlink_index);
@@ -96,13 +96,13 @@ rel_put:
        return;
 
 reschedule_work:
-       schedule_work(&rel->nested_in.notify_work);
+       schedule_delayed_work(&rel->nested_in.notify_work, 1);
 }
 
 static void devlink_rel_nested_in_notify_work_schedule(struct devlink_rel *rel)
 {
        __devlink_rel_get(rel);
-       schedule_work(&rel->nested_in.notify_work);
+       schedule_delayed_work(&rel->nested_in.notify_work, 0);
 }
 
 static struct devlink_rel *devlink_rel_alloc(void)
@@ -123,8 +123,8 @@ static struct devlink_rel *devlink_rel_alloc(void)
        }
 
        refcount_set(&rel->refcount, 1);
-       INIT_WORK(&rel->nested_in.notify_work,
-                 &devlink_rel_nested_in_notify_work);
+       INIT_DELAYED_WORK(&rel->nested_in.notify_work,
+                         &devlink_rel_nested_in_notify_work);
        return rel;
 }