Revert "staging: vchiq_arm: Create keep-alive thread during probe"

The commit 86bc882 ("staging: vchiq_arm: Create keep-alive thread
during probe") introduced a regression for certain configurations,
which doesn't have a VCHIQ user. This results in a unused and hanging
keep-alive thread:

  INFO: task vchiq-keep/0:85 blocked for more than 120 seconds.
        Not tainted 6.12.34-v8-+ #13
  "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  task:vchiq-keep/0    state:D stack:0 pid:85    tgid:85    ppid:2
  Call trace:
   __switch_to+0x188/0x230
   __schedule+0xa54/0xb28
   schedule+0x80/0x120
   schedule_preempt_disabled+0x30/0x50
   kthread+0xd4/0x1a0
   ret_from_fork+0x10/0x20

Fixes: 86bc882 ("staging: vchiq_arm: Create keep-alive thread during probe")
Reported-by: Maíra Canal <mcanal@igalia.com>
Closes: https://lore.kernel.org/linux-staging/ba35b960-a981-4671-9f7f-060da10feaa1@usp.br/
Cc: stable@kernel.org
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Link: https://lore.kernel.org/r/20250715161108.3411-3-wahrenst@gmx.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: lategoodbye

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c

@@ -280,6 +280,29 @@ static int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state
 	return 0;
 }
 
+int
+vchiq_platform_init_state(struct vchiq_state *state)
+{
+	struct vchiq_arm_state *platform_state;
+
+	platform_state = devm_kzalloc(state->dev, sizeof(*platform_state), GFP_KERNEL);
+	if (!platform_state)
+		return -ENOMEM;
+
+	rwlock_init(&platform_state->susp_res_lock);
+
+	init_completion(&platform_state->ka_evt);
+	atomic_set(&platform_state->ka_use_count, 0);
+	atomic_set(&platform_state->ka_use_ack_count, 0);
+	atomic_set(&platform_state->ka_release_count, 0);
+
+	platform_state->state = state;
+
+	state->platform_state = (struct opaque_platform_state *)platform_state;
+
+	return 0;
+}
+
 static struct vchiq_arm_state *vchiq_platform_get_arm_state(struct vchiq_state *state)
 {
 	return (struct vchiq_arm_state *)state->platform_state;
@@ -988,39 +1011,6 @@ vchiq_keepalive_thread_func(void *v)
 	return 0;
 }
 
-int
-vchiq_platform_init_state(struct vchiq_state *state)
-{
-	struct vchiq_arm_state *platform_state;
-	char threadname[16];
-
-	platform_state = devm_kzalloc(state->dev, sizeof(*platform_state), GFP_KERNEL);
-	if (!platform_state)
-		return -ENOMEM;
-
-	snprintf(threadname, sizeof(threadname), "vchiq-keep/%d",
-		 state->id);
-	platform_state->ka_thread = kthread_create(&vchiq_keepalive_thread_func,
-						   (void *)state, threadname);
-	if (IS_ERR(platform_state->ka_thread)) {
-		dev_err(state->dev, "couldn't create thread %s\n", threadname);
-		return PTR_ERR(platform_state->ka_thread);
-	}
-
-	rwlock_init(&platform_state->susp_res_lock);
-
-	init_completion(&platform_state->ka_evt);
-	atomic_set(&platform_state->ka_use_count, 0);
-	atomic_set(&platform_state->ka_use_ack_count, 0);
-	atomic_set(&platform_state->ka_release_count, 0);
-
-	platform_state->state = state;
-
-	state->platform_state = (struct opaque_platform_state *)platform_state;
-
-	return 0;
-}
-
 int
 vchiq_use_internal(struct vchiq_state *state, struct vchiq_service *service,
 		   enum USE_TYPE_E use_type)
@@ -1341,6 +1331,7 @@ void vchiq_platform_conn_state_changed(struct vchiq_state *state,
 				       enum vchiq_connstate newstate)
 {
 	struct vchiq_arm_state *arm_state = vchiq_platform_get_arm_state(state);
+	char threadname[16];
 
 	dev_dbg(state->dev, "suspend: %d: %s->%s\n",
 		state->id, get_conn_state_name(oldstate), get_conn_state_name(newstate));
@@ -1355,7 +1346,17 @@ void vchiq_platform_conn_state_changed(struct vchiq_state *state,
 
 	arm_state->first_connect = 1;
 	write_unlock_bh(&arm_state->susp_res_lock);
-	wake_up_process(arm_state->ka_thread);
+	snprintf(threadname, sizeof(threadname), "vchiq-keep/%d",
+		 state->id);
+	arm_state->ka_thread = kthread_create(&vchiq_keepalive_thread_func,
+					      (void *)state,
+					      threadname);
+	if (IS_ERR(arm_state->ka_thread)) {
+		dev_err(state->dev, "suspend: Couldn't create thread %s\n",
+			threadname);
+	} else {
+		wake_up_process(arm_state->ka_thread);
+	}
 }
 
 static const struct of_device_id vchiq_of_match[] = {