scx: Fix maximal BPF selftest prog

maximal.bpf.c is still dispatching to and consuming from SCX_DSQ_GLOBAL.
Let's have it use its own DSQ to avoid any runtime errors.

Signed-off-by: David Vernet <void@manifault.com>
Tested-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Author: Byte-Lab

tools/testing/selftests/sched_ext/maximal.bpf.c

@@ -12,6 +12,8 @@
 
 char _license[] SEC("license") = "GPL";
 
+#define DSQ_ID 0
+
 s32 BPF_STRUCT_OPS(maximal_select_cpu, struct task_struct *p, s32 prev_cpu,
 		   u64 wake_flags)
 {
@@ -20,15 +22,15 @@ s32 BPF_STRUCT_OPS(maximal_select_cpu, struct task_struct *p, s32 prev_cpu,
 
 void BPF_STRUCT_OPS(maximal_enqueue, struct task_struct *p, u64 enq_flags)
 {
-	scx_bpf_dsq_insert(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
+	scx_bpf_dsq_insert(p, DSQ_ID, SCX_SLICE_DFL, enq_flags);
 }
 
 void BPF_STRUCT_OPS(maximal_dequeue, struct task_struct *p, u64 deq_flags)
 {}
 
 void BPF_STRUCT_OPS(maximal_dispatch, s32 cpu, struct task_struct *prev)
 {
-	scx_bpf_dsq_move_to_local(SCX_DSQ_GLOBAL);
+	scx_bpf_dsq_move_to_local(DSQ_ID);
 }
 
 void BPF_STRUCT_OPS(maximal_runnable, struct task_struct *p, u64 enq_flags)
@@ -123,7 +125,7 @@ void BPF_STRUCT_OPS(maximal_cgroup_set_weight, struct cgroup *cgrp, u32 weight)
 
 s32 BPF_STRUCT_OPS_SLEEPABLE(maximal_init)
 {
-	return 0;
+	return scx_bpf_create_dsq(DSQ_ID, -1);
 }
 
 void BPF_STRUCT_OPS(maximal_exit, struct scx_exit_info *info)