sched_ext: Remove deprecated scx_bpf_cpu_rq()

scx_bpf_cpu_rq() exposes rq pointers without requiring the rq lock and
has emitted a deprecation warning since commit
5c48d88fe004 ("sched_ext: deprecation warn for scx_bpf_cpu_rq()").
The supported replacements cover the intended uses:
scx_bpf_locked_rq() for locked rq access and
scx_bpf_cpu_curr() for remote curr lookup.

Remove the kfunc, its BTF registrations, the deprecation warning
state, and the BPF-side prototype and compat fallback.

Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Hongyan Xia <hongyan.xia@transsion.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

2 files changed, 2 insertions, 20 deletions

diff --git a/tools/sched_ext/include/scx/common.bpf.h b/tools/sched_ext/include/scx/common.bpf.h
index 9591a6e778ce..bd51986c4c42 100644
--- a/tools/sched_ext/include/scx/common.bpf.h
+++ b/tools/sched_ext/include/scx/common.bpf.h
@@ -96,7 +96,6 @@ s32 scx_bpf_pick_any_cpu_node(const cpumask_t *cpus_allowed, int node, u64 flags
 s32 scx_bpf_pick_any_cpu(const cpumask_t *cpus_allowed, u64 flags) __ksym;
 bool scx_bpf_task_running(const struct task_struct *p) __ksym;
 s32 scx_bpf_task_cpu(const struct task_struct *p) __ksym;
-struct rq *scx_bpf_cpu_rq(s32 cpu) __ksym;
 struct rq *scx_bpf_locked_rq(void) __ksym;
 struct task_struct *scx_bpf_cpu_curr(s32 cpu) __ksym __weak;
 struct task_struct *scx_bpf_tid_to_task(u64 tid) __ksym __weak;
@@ -983,8 +982,8 @@ extern struct irqtime___local cpu_irqtime __ksym __weak;
 static inline struct rq___local *get_current_rq(u32 cpu)
 {
 	/*
-	 * This is a workaround to get an rq pointer since we decided to
-	 * deprecate scx_bpf_cpu_rq().
+	 * This is a workaround to get an rq pointer now that
+	 * scx_bpf_cpu_rq() has been removed.
 	 *
 	 * WARNING: The caller must hold the rq lock for @cpu. This is
 	 * guaranteed when called from scheduling callbacks (ops.running,
diff --git a/tools/sched_ext/include/scx/compat.bpf.h b/tools/sched_ext/include/scx/compat.bpf.h
index 87f15f296234..133058578668 100644
--- a/tools/sched_ext/include/scx/compat.bpf.h
+++ b/tools/sched_ext/include/scx/compat.bpf.h
@@ -234,23 +234,6 @@ static inline bool __COMPAT_is_enq_cpu_selected(u64 enq_flags)
 	 scx_bpf_pick_any_cpu(cpus_allowed, flags))
 
 /*
- * v6.18: Add a helper to retrieve the current task running on a CPU.
- *
- * Keep this helper available until v6.20 for compatibility.
- */
-static inline struct task_struct *__COMPAT_scx_bpf_cpu_curr(int cpu)
-{
-	struct rq *rq;
-
-	if (bpf_ksym_exists(scx_bpf_cpu_curr))
-		return scx_bpf_cpu_curr(cpu);
-
-	rq = scx_bpf_cpu_rq(cpu);
-
-	return rq ? rq->curr : NULL;
-}
-
-/*
  * v6.19: To work around BPF maximum parameter limit, the following kfuncs are
  * replaced with variants that pack scalar arguments in a struct. Wrappers are
  * provided to maintain source compatibility.