sched_ext: Remove runtime kfunc mask enforcement

Now that scx_kfunc_context_filter enforces context-sensitive kfunc
restrictions at BPF load time, the per-task runtime enforcement via
scx_kf_mask is redundant. Remove it entirely:

 - Delete enum scx_kf_mask, the kf_mask field on sched_ext_entity, and
   the scx_kf_allow()/scx_kf_disallow()/scx_kf_allowed() helpers along
   with the higher_bits()/highest_bit() helpers they used.
 - Strip the @mask parameter (and the BUILD_BUG_ON checks) from the
   SCX_CALL_OP[_RET]/SCX_CALL_OP_TASK[_RET]/SCX_CALL_OP_2TASKS_RET
   macros and update every call site. Reflow call sites that were
   wrapped only to fit the old 5-arg form and now collapse onto a single
   line under ~100 cols.
 - Remove the in-kfunc scx_kf_allowed() runtime checks from
   scx_dsq_insert_preamble(), scx_dsq_move(), scx_bpf_dispatch_nr_slots(),
   scx_bpf_dispatch_cancel(), scx_bpf_dsq_move_to_local___v2(),
   scx_bpf_sub_dispatch(), scx_bpf_reenqueue_local(), and the per-call
   guard inside select_cpu_from_kfunc().

scx_bpf_task_cgroup() and scx_kf_allowed_on_arg_tasks() were already
cleaned up in the "drop redundant rq-locked check" patch.
scx_kf_allowed_if_unlocked() was rewritten in the preceding "decouple"
patch. No further changes to those helpers here.

Co-developed-by: Juntong Deng <juntong.deng@outlook.com>
Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
Signed-off-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h
index 602dc83cab367a838321d3574c3439c82dc3ebad..1a3af2ea2a794ab2031691413f36a19538ca3617 100644 (file)
--- a/include/linux/sched/ext.h
+++ b/include/linux/sched/ext.h
@@ -147,33 +147,6 @@ enum scx_ent_dsq_flags {
        SCX_TASK_DSQ_ON_PRIQ    = 1 << 0, /* task is queued on the priority queue of a dsq */
 };
 
-/*
- * Mask bits for scx_entity.kf_mask. Not all kfuncs can be called from
- * everywhere and the following bits track which kfunc sets are currently
- * allowed for %current. This simple per-task tracking works because SCX ops
- * nest in a limited way. BPF will likely implement a way to allow and disallow
- * kfuncs depending on the calling context which will replace this manual
- * mechanism. See scx_kf_allow().
- */
-enum scx_kf_mask {
-       SCX_KF_UNLOCKED         = 0,      /* sleepable and not rq locked */
-       /* ENQUEUE and DISPATCH may be nested inside CPU_RELEASE */
-       SCX_KF_CPU_RELEASE      = 1 << 0, /* ops.cpu_release() */
-       /*
-        * ops.dispatch() may release rq lock temporarily and thus ENQUEUE and
-        * SELECT_CPU may be nested inside. ops.dequeue (in REST) may also be
-        * nested inside DISPATCH.
-        */
-       SCX_KF_DISPATCH         = 1 << 1, /* ops.dispatch() */
-       SCX_KF_ENQUEUE          = 1 << 2, /* ops.enqueue() and ops.select_cpu() */
-       SCX_KF_SELECT_CPU       = 1 << 3, /* ops.select_cpu() */
-       SCX_KF_REST             = 1 << 4, /* other rq-locked operations */
-
-       __SCX_KF_RQ_LOCKED      = SCX_KF_CPU_RELEASE | SCX_KF_DISPATCH |
-                                 SCX_KF_ENQUEUE | SCX_KF_SELECT_CPU | SCX_KF_REST,
-       __SCX_KF_TERMINAL       = SCX_KF_ENQUEUE | SCX_KF_SELECT_CPU | SCX_KF_REST,
-};
-
 enum scx_dsq_lnode_flags {
        SCX_DSQ_LNODE_ITER_CURSOR = 1 << 0,
 
@@ -221,7 +194,6 @@ struct sched_ext_entity {
        s32                     sticky_cpu;
        s32                     holding_cpu;
        s32                     selected_cpu;
-       u32                     kf_mask;        /* see scx_kf_mask above */
        struct task_struct      *kf_tasks[2];   /* see SCX_CALL_OP_TASK() */
 
        struct list_head        runnable_node;  /* rq->scx.runnable_list */

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index edf51d91bab2a974759aa28fd6bfa1fd7121d42e..d37418a684e965af0f8de36d14a86d68099c0740 100644 (file)
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -229,19 +229,6 @@ static long jiffies_delta_msecs(unsigned long at, unsigned long now)
                return -(long)jiffies_to_msecs(now - at);
 }
 
-/* if the highest set bit is N, return a mask with bits [N+1, 31] set */
-static u32 higher_bits(u32 flags)
-{
-       return ~((1 << fls(flags)) - 1);
-}
-
-/* return the mask with only the highest bit set */
-static u32 highest_bit(u32 flags)
-{
-       int bit = fls(flags);
-       return ((u64)1 << bit) >> 1;
-}
-
 static bool u32_before(u32 a, u32 b)
 {
        return (s32)(a - b) < 0;
@@ -462,30 +449,6 @@ static bool rq_is_open(struct rq *rq, u64 enq_flags)
        return false;
 }
 
-/*
- * scx_kf_mask enforcement. Some kfuncs can only be called from specific SCX
- * ops. When invoking SCX ops, SCX_CALL_OP[_RET]() should be used to indicate
- * the allowed kfuncs and those kfuncs should use scx_kf_allowed() to check
- * whether it's running from an allowed context.
- *
- * @mask is constant, always inline to cull the mask calculations.
- */
-static __always_inline void scx_kf_allow(u32 mask)
-{
-       /* nesting is allowed only in increasing scx_kf_mask order */
-       WARN_ONCE((mask | higher_bits(mask)) & current->scx.kf_mask,
-                 "invalid nesting current->scx.kf_mask=0x%x mask=0x%x\n",
-                 current->scx.kf_mask, mask);
-       current->scx.kf_mask |= mask;
-       barrier();
-}
-
-static void scx_kf_disallow(u32 mask)
-{
-       barrier();
-       current->scx.kf_mask &= ~mask;
-}
-
 /*
  * Track the rq currently locked.
  *
@@ -506,34 +469,22 @@ static inline void update_locked_rq(struct rq *rq)
        __this_cpu_write(scx_locked_rq_state, rq);
 }
 
-#define SCX_CALL_OP(sch, mask, op, rq, args...)                                        \
+#define SCX_CALL_OP(sch, op, rq, args...)                                      \
 do {                                                                           \
        if (rq)                                                                 \
                update_locked_rq(rq);                                           \
-       if (mask) {                                                             \
-               scx_kf_allow(mask);                                             \
-               (sch)->ops.op(args);                                            \
-               scx_kf_disallow(mask);                                          \
-       } else {                                                                \
-               (sch)->ops.op(args);                                            \
-       }                                                                       \
+       (sch)->ops.op(args);                                                    \
        if (rq)                                                                 \
                update_locked_rq(NULL);                                         \
 } while (0)
 
-#define SCX_CALL_OP_RET(sch, mask, op, rq, args...)                            \
+#define SCX_CALL_OP_RET(sch, op, rq, args...)                                  \
 ({                                                                             \
        __typeof__((sch)->ops.op(args)) __ret;                                  \
                                                                                \
        if (rq)                                                                 \
                update_locked_rq(rq);                                           \
-       if (mask) {                                                             \
-               scx_kf_allow(mask);                                             \
-               __ret = (sch)->ops.op(args);                                    \
-               scx_kf_disallow(mask);                                          \
-       } else {                                                                \
-               __ret = (sch)->ops.op(args);                                    \
-       }                                                                       \
+       __ret = (sch)->ops.op(args);                                            \
        if (rq)                                                                 \
                update_locked_rq(NULL);                                         \
        __ret;                                                                  \
@@ -553,67 +504,33 @@ do {                                                                              \
  *
  * These macros only work for non-nesting ops since kf_tasks[] is not stacked.
  */
-#define SCX_CALL_OP_TASK(sch, mask, op, rq, task, args...)                     \
+#define SCX_CALL_OP_TASK(sch, op, rq, task, args...)                           \
 do {                                                                           \
-       BUILD_BUG_ON((mask) & ~__SCX_KF_TERMINAL);                              \
        current->scx.kf_tasks[0] = task;                                        \
-       SCX_CALL_OP((sch), mask, op, rq, task, ##args);                         \
+       SCX_CALL_OP((sch), op, rq, task, ##args);                               \
        current->scx.kf_tasks[0] = NULL;                                        \
 } while (0)
 
-#define SCX_CALL_OP_TASK_RET(sch, mask, op, rq, task, args...)                 \
+#define SCX_CALL_OP_TASK_RET(sch, op, rq, task, args...)                       \
 ({                                                                             \
        __typeof__((sch)->ops.op(task, ##args)) __ret;                          \
-       BUILD_BUG_ON((mask) & ~__SCX_KF_TERMINAL);                              \
        current->scx.kf_tasks[0] = task;                                        \
-       __ret = SCX_CALL_OP_RET((sch), mask, op, rq, task, ##args);             \
+       __ret = SCX_CALL_OP_RET((sch), op, rq, task, ##args);                   \
        current->scx.kf_tasks[0] = NULL;                                        \
        __ret;                                                                  \
 })
 
-#define SCX_CALL_OP_2TASKS_RET(sch, mask, op, rq, task0, task1, args...)       \
+#define SCX_CALL_OP_2TASKS_RET(sch, op, rq, task0, task1, args...)             \
 ({                                                                             \
        __typeof__((sch)->ops.op(task0, task1, ##args)) __ret;                  \
-       BUILD_BUG_ON((mask) & ~__SCX_KF_TERMINAL);                              \
        current->scx.kf_tasks[0] = task0;                                       \
        current->scx.kf_tasks[1] = task1;                                       \
-       __ret = SCX_CALL_OP_RET((sch), mask, op, rq, task0, task1, ##args);     \
+       __ret = SCX_CALL_OP_RET((sch), op, rq, task0, task1, ##args);           \
        current->scx.kf_tasks[0] = NULL;                                        \
        current->scx.kf_tasks[1] = NULL;                                        \
        __ret;                                                                  \
 })
 
-/* @mask is constant, always inline to cull unnecessary branches */
-static __always_inline bool scx_kf_allowed(struct scx_sched *sch, u32 mask)
-{
-       if (unlikely(!(current->scx.kf_mask & mask))) {
-               scx_error(sch, "kfunc with mask 0x%x called from an operation only allowing 0x%x",
-                         mask, current->scx.kf_mask);
-               return false;
-       }
-
-       /*
-        * Enforce nesting boundaries. e.g. A kfunc which can be called from
-        * DISPATCH must not be called if we're running DEQUEUE which is nested
-        * inside ops.dispatch(). We don't need to check boundaries for any
-        * blocking kfuncs as the verifier ensures they're only called from
-        * sleepable progs.
-        */
-       if (unlikely(highest_bit(mask) == SCX_KF_CPU_RELEASE &&
-                    (current->scx.kf_mask & higher_bits(SCX_KF_CPU_RELEASE)))) {
-               scx_error(sch, "cpu_release kfunc called from a nested operation");
-               return false;
-       }
-
-       if (unlikely(highest_bit(mask) == SCX_KF_DISPATCH &&
-                    (current->scx.kf_mask & higher_bits(SCX_KF_DISPATCH)))) {
-               scx_error(sch, "dispatch kfunc called from a nested operation");
-               return false;
-       }
-
-       return true;
-}
-
 /* see SCX_CALL_OP_TASK() */
 static __always_inline bool scx_kf_allowed_on_arg_tasks(struct scx_sched *sch,
                                                        struct task_struct *p)
@@ -1461,7 +1378,7 @@ static void call_task_dequeue(struct scx_sched *sch, struct rq *rq,
                return;
 
        if (SCX_HAS_OP(sch, dequeue))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, dequeue, rq, p, deq_flags);
+               SCX_CALL_OP_TASK(sch, dequeue, rq, p, deq_flags);
 
        p->scx.flags &= ~SCX_TASK_IN_CUSTODY;
 }
@@ -1920,7 +1837,7 @@ static void do_enqueue_task(struct rq *rq, struct task_struct *p, u64 enq_flags,
        WARN_ON_ONCE(*ddsp_taskp);
        *ddsp_taskp = p;
 
-       SCX_CALL_OP_TASK(sch, SCX_KF_ENQUEUE, enqueue, rq, p, enq_flags);
+       SCX_CALL_OP_TASK(sch, enqueue, rq, p, enq_flags);
 
        *ddsp_taskp = NULL;
        if (p->scx.ddsp_dsq_id != SCX_DSQ_INVALID)
@@ -2024,7 +1941,7 @@ static void enqueue_task_scx(struct rq *rq, struct task_struct *p, int core_enq_
        add_nr_running(rq, 1);
 
        if (SCX_HAS_OP(sch, runnable) && !task_on_rq_migrating(p))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, runnable, rq, p, enq_flags);
+               SCX_CALL_OP_TASK(sch, runnable, rq, p, enq_flags);
 
        if (enq_flags & SCX_ENQ_WAKEUP)
                touch_core_sched(rq, p);
@@ -2141,11 +2058,11 @@ static bool dequeue_task_scx(struct rq *rq, struct task_struct *p, int core_deq_
         */
        if (SCX_HAS_OP(sch, stopping) && task_current(rq, p)) {
                update_curr_scx(rq);
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, stopping, rq, p, false);
+               SCX_CALL_OP_TASK(sch, stopping, rq, p, false);
        }
 
        if (SCX_HAS_OP(sch, quiescent) && !task_on_rq_migrating(p))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, quiescent, rq, p, deq_flags);
+               SCX_CALL_OP_TASK(sch, quiescent, rq, p, deq_flags);
 
        if (deq_flags & SCX_DEQ_SLEEP)
                p->scx.flags |= SCX_TASK_DEQD_FOR_SLEEP;
@@ -2167,7 +2084,7 @@ static void yield_task_scx(struct rq *rq)
        struct scx_sched *sch = scx_task_sched(p);
 
        if (SCX_HAS_OP(sch, yield))
-               SCX_CALL_OP_2TASKS_RET(sch, SCX_KF_REST, yield, rq, p, NULL);
+               SCX_CALL_OP_2TASKS_RET(sch, yield, rq, p, NULL);
        else
                p->scx.slice = 0;
 }
@@ -2178,8 +2095,7 @@ static bool yield_to_task_scx(struct rq *rq, struct task_struct *to)
        struct scx_sched *sch = scx_task_sched(from);
 
        if (SCX_HAS_OP(sch, yield) && sch == scx_task_sched(to))
-               return SCX_CALL_OP_2TASKS_RET(sch, SCX_KF_REST, yield, rq,
-                                             from, to);
+               return SCX_CALL_OP_2TASKS_RET(sch, yield, rq, from, to);
        else
                return false;
 }
@@ -2799,20 +2715,11 @@ scx_dispatch_sched(struct scx_sched *sch, struct rq *rq,
                dspc->nr_tasks = 0;
 
                if (nested) {
-                       /*
-                        * If nested, don't update kf_mask as the originating
-                        * invocation would already have set it up.
-                        */
-                       SCX_CALL_OP(sch, 0, dispatch, rq, cpu,
-                                   prev_on_sch ? prev : NULL);
+                       SCX_CALL_OP(sch, dispatch, rq, cpu, prev_on_sch ? prev : NULL);
                } else {
-                       /*
-                        * If not nested, stash @prev so that nested invocations
-                        * can access it.
-                        */
+                       /* stash @prev so that nested invocations can access it */
                        rq->scx.sub_dispatch_prev = prev;
-                       SCX_CALL_OP(sch, SCX_KF_DISPATCH, dispatch, rq, cpu,
-                                   prev_on_sch ? prev : NULL);
+                       SCX_CALL_OP(sch, dispatch, rq, cpu, prev_on_sch ? prev : NULL);
                        rq->scx.sub_dispatch_prev = NULL;
                }
 
@@ -2871,7 +2778,7 @@ static int balance_one(struct rq *rq, struct task_struct *prev)
                 * emitted in switch_class().
                 */
                if (SCX_HAS_OP(sch, cpu_acquire))
-                       SCX_CALL_OP(sch, SCX_KF_REST, cpu_acquire, rq, cpu, NULL);
+                       SCX_CALL_OP(sch, cpu_acquire, rq, cpu, NULL);
                rq->scx.cpu_released = false;
        }
 
@@ -2950,7 +2857,7 @@ static void set_next_task_scx(struct rq *rq, struct task_struct *p, bool first)
 
        /* see dequeue_task_scx() on why we skip when !QUEUED */
        if (SCX_HAS_OP(sch, running) && (p->scx.flags & SCX_TASK_QUEUED))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, running, rq, p);
+               SCX_CALL_OP_TASK(sch, running, rq, p);
 
        clr_task_runnable(p, true);
 
@@ -3022,8 +2929,7 @@ static void switch_class(struct rq *rq, struct task_struct *next)
                                .task = next,
                        };
 
-                       SCX_CALL_OP(sch, SCX_KF_CPU_RELEASE, cpu_release, rq,
-                                   cpu_of(rq), &args);
+                       SCX_CALL_OP(sch, cpu_release, rq, cpu_of(rq), &args);
                }
                rq->scx.cpu_released = true;
        }
@@ -3041,7 +2947,7 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p,
 
        /* see dequeue_task_scx() on why we skip when !QUEUED */
        if (SCX_HAS_OP(sch, stopping) && (p->scx.flags & SCX_TASK_QUEUED))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, stopping, rq, p, true);
+               SCX_CALL_OP_TASK(sch, stopping, rq, p, true);
 
        if (p->scx.flags & SCX_TASK_QUEUED) {
                set_task_runnable(rq, p);
@@ -3271,7 +3177,7 @@ bool scx_prio_less(const struct task_struct *a, const struct task_struct *b,
         */
        if (sch_a == sch_b && SCX_HAS_OP(sch_a, core_sched_before) &&
            !scx_bypassing(sch_a, task_cpu(a)))
-               return SCX_CALL_OP_2TASKS_RET(sch_a, SCX_KF_REST, core_sched_before,
+               return SCX_CALL_OP_2TASKS_RET(sch_a, core_sched_before,
                                              NULL,
                                              (struct task_struct *)a,
                                              (struct task_struct *)b);
@@ -3308,10 +3214,7 @@ static int select_task_rq_scx(struct task_struct *p, int prev_cpu, int wake_flag
                *ddsp_taskp = p;
 
                this_rq()->scx.in_select_cpu = true;
-               cpu = SCX_CALL_OP_TASK_RET(sch,
-                                          SCX_KF_ENQUEUE | SCX_KF_SELECT_CPU,
-                                          select_cpu, NULL, p, prev_cpu,
-                                          wake_flags);
+               cpu = SCX_CALL_OP_TASK_RET(sch, select_cpu, NULL, p, prev_cpu, wake_flags);
                this_rq()->scx.in_select_cpu = false;
                p->scx.selected_cpu = cpu;
                *ddsp_taskp = NULL;
@@ -3361,8 +3264,7 @@ static void set_cpus_allowed_scx(struct task_struct *p,
         * designation pointless. Cast it away when calling the operation.
         */
        if (SCX_HAS_OP(sch, set_cpumask))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, set_cpumask, task_rq(p),
-                                p, (struct cpumask *)p->cpus_ptr);
+               SCX_CALL_OP_TASK(sch, set_cpumask, task_rq(p), p, (struct cpumask *)p->cpus_ptr);
 }
 
 static void handle_hotplug(struct rq *rq, bool online)
@@ -3384,9 +3286,9 @@ static void handle_hotplug(struct rq *rq, bool online)
                scx_idle_update_selcpu_topology(&sch->ops);
 
        if (online && SCX_HAS_OP(sch, cpu_online))
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cpu_online, NULL, cpu);
+               SCX_CALL_OP(sch, cpu_online, NULL, cpu);
        else if (!online && SCX_HAS_OP(sch, cpu_offline))
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cpu_offline, NULL, cpu);
+               SCX_CALL_OP(sch, cpu_offline, NULL, cpu);
        else
                scx_exit(sch, SCX_EXIT_UNREG_KERN,
                         SCX_ECODE_ACT_RESTART | SCX_ECODE_RSN_HOTPLUG,
@@ -3504,7 +3406,7 @@ static void task_tick_scx(struct rq *rq, struct task_struct *curr, int queued)
                curr->scx.slice = 0;
                touch_core_sched(rq, curr);
        } else if (SCX_HAS_OP(sch, tick)) {
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, tick, rq, curr);
+               SCX_CALL_OP_TASK(sch, tick, rq, curr);
        }
 
        if (!curr->scx.slice)
@@ -3580,8 +3482,7 @@ static int __scx_init_task(struct scx_sched *sch, struct task_struct *p, bool fo
                        .fork = fork,
                };
 
-               ret = SCX_CALL_OP_RET(sch, SCX_KF_UNLOCKED, init_task, NULL,
-                                     p, &args);
+               ret = SCX_CALL_OP_RET(sch, init_task, NULL, p, &args);
                if (unlikely(ret)) {
                        ret = ops_sanitize_err(sch, "init_task", ret);
                        return ret;
@@ -3662,11 +3563,10 @@ static void __scx_enable_task(struct scx_sched *sch, struct task_struct *p)
        p->scx.weight = sched_weight_to_cgroup(weight);
 
        if (SCX_HAS_OP(sch, enable))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, enable, rq, p);
+               SCX_CALL_OP_TASK(sch, enable, rq, p);
 
        if (SCX_HAS_OP(sch, set_weight))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, set_weight, rq,
-                                p, p->scx.weight);
+               SCX_CALL_OP_TASK(sch, set_weight, rq, p, p->scx.weight);
 }
 
 static void scx_enable_task(struct scx_sched *sch, struct task_struct *p)
@@ -3685,7 +3585,7 @@ static void scx_disable_task(struct scx_sched *sch, struct task_struct *p)
        clear_direct_dispatch(p);
 
        if (SCX_HAS_OP(sch, disable))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, disable, rq, p);
+               SCX_CALL_OP_TASK(sch, disable, rq, p);
        scx_set_task_state(p, SCX_TASK_READY);
 
        /*
@@ -3723,8 +3623,7 @@ static void __scx_disable_and_exit_task(struct scx_sched *sch,
        }
 
        if (SCX_HAS_OP(sch, exit_task))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, exit_task, task_rq(p),
-                                p, &args);
+               SCX_CALL_OP_TASK(sch, exit_task, task_rq(p), p, &args);
 }
 
 static void scx_disable_and_exit_task(struct scx_sched *sch,
@@ -3903,8 +3802,7 @@ static void reweight_task_scx(struct rq *rq, struct task_struct *p,
 
        p->scx.weight = sched_weight_to_cgroup(scale_load_down(lw->weight));
        if (SCX_HAS_OP(sch, set_weight))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, set_weight, rq,
-                                p, p->scx.weight);
+               SCX_CALL_OP_TASK(sch, set_weight, rq, p, p->scx.weight);
 }
 
 static void prio_changed_scx(struct rq *rq, struct task_struct *p, u64 oldprio)
@@ -3925,8 +3823,7 @@ static void switching_to_scx(struct rq *rq, struct task_struct *p)
         * different scheduler class. Keep the BPF scheduler up-to-date.
         */
        if (SCX_HAS_OP(sch, set_cpumask))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, set_cpumask, rq,
-                                p, (struct cpumask *)p->cpus_ptr);
+               SCX_CALL_OP_TASK(sch, set_cpumask, rq, p, (struct cpumask *)p->cpus_ptr);
 }
 
 static void switched_from_scx(struct rq *rq, struct task_struct *p)
@@ -4309,7 +4206,7 @@ int scx_tg_online(struct task_group *tg)
                                  .bw_quota_us = tg->scx.bw_quota_us,
                                  .bw_burst_us = tg->scx.bw_burst_us };
 
-                       ret = SCX_CALL_OP_RET(sch, SCX_KF_UNLOCKED, cgroup_init,
+                       ret = SCX_CALL_OP_RET(sch, cgroup_init,
                                              NULL, tg->css.cgroup, &args);
                        if (ret)
                                ret = ops_sanitize_err(sch, "cgroup_init", ret);
@@ -4331,8 +4228,7 @@ void scx_tg_offline(struct task_group *tg)
 
        if (scx_cgroup_enabled && SCX_HAS_OP(sch, cgroup_exit) &&
            (tg->scx.flags & SCX_TG_INITED))
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_exit, NULL,
-                           tg->css.cgroup);
+               SCX_CALL_OP(sch, cgroup_exit, NULL, tg->css.cgroup);
        tg->scx.flags &= ~(SCX_TG_ONLINE | SCX_TG_INITED);
 }
 
@@ -4361,8 +4257,7 @@ int scx_cgroup_can_attach(struct cgroup_taskset *tset)
                        continue;
 
                if (SCX_HAS_OP(sch, cgroup_prep_move)) {
-                       ret = SCX_CALL_OP_RET(sch, SCX_KF_UNLOCKED,
-                                             cgroup_prep_move, NULL,
+                       ret = SCX_CALL_OP_RET(sch, cgroup_prep_move, NULL,
                                              p, from, css->cgroup);
                        if (ret)
                                goto err;
@@ -4377,7 +4272,7 @@ err:
        cgroup_taskset_for_each(p, css, tset) {
                if (SCX_HAS_OP(sch, cgroup_cancel_move) &&
                    p->scx.cgrp_moving_from)
-                       SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_cancel_move, NULL,
+                       SCX_CALL_OP(sch, cgroup_cancel_move, NULL,
                                    p, p->scx.cgrp_moving_from, css->cgroup);
                p->scx.cgrp_moving_from = NULL;
        }
@@ -4398,7 +4293,7 @@ void scx_cgroup_move_task(struct task_struct *p)
         */
        if (SCX_HAS_OP(sch, cgroup_move) &&
            !WARN_ON_ONCE(!p->scx.cgrp_moving_from))
-               SCX_CALL_OP_TASK(sch, SCX_KF_REST, cgroup_move, task_rq(p),
+               SCX_CALL_OP_TASK(sch, cgroup_move, task_rq(p),
                                 p, p->scx.cgrp_moving_from,
                                 tg_cgrp(task_group(p)));
        p->scx.cgrp_moving_from = NULL;
@@ -4416,7 +4311,7 @@ void scx_cgroup_cancel_attach(struct cgroup_taskset *tset)
        cgroup_taskset_for_each(p, css, tset) {
                if (SCX_HAS_OP(sch, cgroup_cancel_move) &&
                    p->scx.cgrp_moving_from)
-                       SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_cancel_move, NULL,
+                       SCX_CALL_OP(sch, cgroup_cancel_move, NULL,
                                    p, p->scx.cgrp_moving_from, css->cgroup);
                p->scx.cgrp_moving_from = NULL;
        }
@@ -4430,8 +4325,7 @@ void scx_group_set_weight(struct task_group *tg, unsigned long weight)
 
        if (scx_cgroup_enabled && SCX_HAS_OP(sch, cgroup_set_weight) &&
            tg->scx.weight != weight)
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_set_weight, NULL,
-                           tg_cgrp(tg), weight);
+               SCX_CALL_OP(sch, cgroup_set_weight, NULL, tg_cgrp(tg), weight);
 
        tg->scx.weight = weight;
 
@@ -4445,8 +4339,7 @@ void scx_group_set_idle(struct task_group *tg, bool idle)
        percpu_down_read(&scx_cgroup_ops_rwsem);
 
        if (scx_cgroup_enabled && SCX_HAS_OP(sch, cgroup_set_idle))
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_set_idle, NULL,
-                           tg_cgrp(tg), idle);
+               SCX_CALL_OP(sch, cgroup_set_idle, NULL, tg_cgrp(tg), idle);
 
        /* Update the task group's idle state */
        tg->scx.idle = idle;
@@ -4465,7 +4358,7 @@ void scx_group_set_bandwidth(struct task_group *tg,
            (tg->scx.bw_period_us != period_us ||
             tg->scx.bw_quota_us != quota_us ||
             tg->scx.bw_burst_us != burst_us))
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_set_bandwidth, NULL,
+               SCX_CALL_OP(sch, cgroup_set_bandwidth, NULL,
                            tg_cgrp(tg), period_us, quota_us, burst_us);
 
        tg->scx.bw_period_us = period_us;
@@ -4690,8 +4583,7 @@ static void scx_cgroup_exit(struct scx_sched *sch)
                if (!sch->ops.cgroup_exit)
                        continue;
 
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_exit, NULL,
-                           css->cgroup);
+               SCX_CALL_OP(sch, cgroup_exit, NULL, css->cgroup);
        }
 }
 
@@ -4722,7 +4614,7 @@ static int scx_cgroup_init(struct scx_sched *sch)
                        continue;
                }
 
-               ret = SCX_CALL_OP_RET(sch, SCX_KF_UNLOCKED, cgroup_init, NULL,
+               ret = SCX_CALL_OP_RET(sch, cgroup_init, NULL,
                                      css->cgroup, &args);
                if (ret) {
                        scx_error(sch, "ops.cgroup_init() failed (%d)", ret);
@@ -5795,12 +5687,12 @@ static void scx_sub_disable(struct scx_sched *sch)
                        .ops = &sch->ops,
                        .cgroup_path = sch->cgrp_path,
                };
-               SCX_CALL_OP(parent, SCX_KF_UNLOCKED, sub_detach, NULL,
+               SCX_CALL_OP(parent, sub_detach, NULL,
                            &sub_detach_args);
        }
 
        if (sch->ops.exit)
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, exit, NULL, sch->exit_info);
+               SCX_CALL_OP(sch, exit, NULL, sch->exit_info);
        kobject_del(&sch->kobj);
 }
 #else  /* CONFIG_EXT_SUB_SCHED */
@@ -5915,7 +5807,7 @@ static void scx_root_disable(struct scx_sched *sch)
        }
 
        if (sch->ops.exit)
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, exit, NULL, ei);
+               SCX_CALL_OP(sch, exit, NULL, ei);
 
        scx_unlink_sched(sch);
 
@@ -6178,7 +6070,7 @@ static void scx_dump_task(struct scx_sched *sch,
 
        if (SCX_HAS_OP(sch, dump_task)) {
                ops_dump_init(s, "    ");
-               SCX_CALL_OP(sch, SCX_KF_REST, dump_task, NULL, dctx, p);
+               SCX_CALL_OP(sch, dump_task, NULL, dctx, p);
                ops_dump_exit();
        }
 
@@ -6242,7 +6134,7 @@ static void scx_dump_state(struct scx_sched *sch, struct scx_exit_info *ei,
 
        if (SCX_HAS_OP(sch, dump)) {
                ops_dump_init(&s, "");
-               SCX_CALL_OP(sch, SCX_KF_UNLOCKED, dump, NULL, &dctx);
+               SCX_CALL_OP(sch, dump, NULL, &dctx);
                ops_dump_exit();
        }
 
@@ -6302,7 +6194,7 @@ static void scx_dump_state(struct scx_sched *sch, struct scx_exit_info *ei,
                used = seq_buf_used(&ns);
                if (SCX_HAS_OP(sch, dump_cpu)) {
                        ops_dump_init(&ns, "  ");
-                       SCX_CALL_OP(sch, SCX_KF_REST, dump_cpu, NULL,
+                       SCX_CALL_OP(sch, dump_cpu, NULL,
                                    &dctx, cpu, idle);
                        ops_dump_exit();
                }
@@ -6748,7 +6640,7 @@ static void scx_root_enable_workfn(struct kthread_work *work)
        scx_idle_enable(ops);
 
        if (sch->ops.init) {
-               ret = SCX_CALL_OP_RET(sch, SCX_KF_UNLOCKED, init, NULL);
+               ret = SCX_CALL_OP_RET(sch, init, NULL);
                if (ret) {
                        ret = ops_sanitize_err(sch, "init", ret);
                        cpus_read_unlock();
@@ -7020,7 +6912,7 @@ static void scx_sub_enable_workfn(struct kthread_work *work)
        }
 
        if (sch->ops.init) {
-               ret = SCX_CALL_OP_RET(sch, SCX_KF_UNLOCKED, init, NULL);
+               ret = SCX_CALL_OP_RET(sch, init, NULL);
                if (ret) {
                        ret = ops_sanitize_err(sch, "init", ret);
                        scx_error(sch, "ops.init() failed (%d)", ret);
@@ -7037,7 +6929,7 @@ static void scx_sub_enable_workfn(struct kthread_work *work)
                .cgroup_path = sch->cgrp_path,
        };
 
-       ret = SCX_CALL_OP_RET(parent, SCX_KF_UNLOCKED, sub_attach, NULL,
+       ret = SCX_CALL_OP_RET(parent, sub_attach, NULL,
                              &sub_attach_args);
        if (ret) {
                ret = ops_sanitize_err(sch, "sub_attach", ret);
@@ -7891,9 +7783,6 @@ static bool scx_vet_enq_flags(struct scx_sched *sch, u64 dsq_id, u64 *enq_flags)
 static bool scx_dsq_insert_preamble(struct scx_sched *sch, struct task_struct *p,
                                    u64 dsq_id, u64 *enq_flags)
 {
-       if (!scx_kf_allowed(sch, SCX_KF_ENQUEUE | SCX_KF_DISPATCH))
-               return false;
-
        lockdep_assert_irqs_disabled();
 
        if (unlikely(!p)) {
@@ -8146,10 +8035,6 @@ static bool scx_dsq_move(struct bpf_iter_scx_dsq_kern *kit,
        bool in_balance;
        unsigned long flags;
 
-       if ((scx_locked_rq() || this_rq()->scx.in_select_cpu) &&
-           !scx_kf_allowed(sch, SCX_KF_DISPATCH))
-               return false;
-
        if (!scx_vet_enq_flags(sch, dsq_id, &enq_flags))
                return false;
 
@@ -8244,9 +8129,6 @@ __bpf_kfunc u32 scx_bpf_dispatch_nr_slots(const struct bpf_prog_aux *aux)
        if (unlikely(!sch))
                return 0;
 
-       if (!scx_kf_allowed(sch, SCX_KF_DISPATCH))
-               return 0;
-
        return sch->dsp_max_batch - __this_cpu_read(sch->pcpu->dsp_ctx.cursor);
 }
 
@@ -8268,9 +8150,6 @@ __bpf_kfunc void scx_bpf_dispatch_cancel(const struct bpf_prog_aux *aux)
        if (unlikely(!sch))
                return;
 
-       if (!scx_kf_allowed(sch, SCX_KF_DISPATCH))
-               return;
-
        dspc = &this_cpu_ptr(sch->pcpu)->dsp_ctx;
 
        if (dspc->cursor > 0)
@@ -8317,9 +8196,6 @@ __bpf_kfunc bool scx_bpf_dsq_move_to_local___v2(u64 dsq_id, u64 enq_flags,
        if (unlikely(!sch))
                return false;
 
-       if (!scx_kf_allowed(sch, SCX_KF_DISPATCH))
-               return false;
-
        if (!scx_vet_enq_flags(sch, SCX_DSQ_LOCAL, &enq_flags))
                return false;
 
@@ -8473,9 +8349,6 @@ __bpf_kfunc bool scx_bpf_sub_dispatch(u64 cgroup_id, const struct bpf_prog_aux *
        if (unlikely(!parent))
                return false;
 
-       if (!scx_kf_allowed(parent, SCX_KF_DISPATCH))
-               return false;
-
        child = scx_find_sub_sched(cgroup_id);
 
        if (unlikely(!child))
@@ -8535,9 +8408,6 @@ __bpf_kfunc u32 scx_bpf_reenqueue_local(const struct bpf_prog_aux *aux)
        if (unlikely(!sch))
                return 0;
 
-       if (!scx_kf_allowed(sch, SCX_KF_CPU_RELEASE))
-               return 0;
-
        rq = cpu_rq(smp_processor_id());
        lockdep_assert_rq_held(rq);
 

diff --git a/kernel/sched/ext_idle.c b/kernel/sched/ext_idle.c
index ec49e0c9892e6fa96a00e5f12e4eae51967cec2d..443d12a3df67c6e1527381de3f6840ba192fe40c 100644 (file)
--- a/kernel/sched/ext_idle.c
+++ b/kernel/sched/ext_idle.c
@@ -789,7 +789,7 @@ void __scx_update_idle(struct rq *rq, bool idle, bool do_notify)
         */
        if (SCX_HAS_OP(sch, update_idle) && do_notify &&
            !scx_bypassing(sch, cpu_of(rq)))
-               SCX_CALL_OP(sch, SCX_KF_REST, update_idle, rq, cpu_of(rq), idle);
+               SCX_CALL_OP(sch, update_idle, rq, cpu_of(rq), idle);
 }
 
 static void reset_idle_masks(struct sched_ext_ops *ops)
@@ -937,8 +937,6 @@ static s32 select_cpu_from_kfunc(struct scx_sched *sch, struct task_struct *p,
        } else if (!scx_locked_rq()) {
                raw_spin_lock_irqsave(&p->pi_lock, irq_flags);
                we_locked = true;
-       } else if (!scx_kf_allowed(sch, SCX_KF_ENQUEUE)) {
-               return -EPERM;
        }
 
        /*