From 16fc9c600b3caf97f42cdd1e35309b7529a55cfb Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 3 Jul 2018 15:54:39 -0700 Subject: [PATCH] rcu: Remove rcu_state_p pointer to default rcu_state structure The rcu_state_p pointer references the default rcu_state structure, that is, the one that call_rcu() uses, as opposed to call_rcu_bh() and sometimes call_rcu_sched(). But there is now only one rcu_state structure, so that one structure is by definition the default, which means that the rcu_state_p pointer no longer serves any useful purpose. This commit therefore removes it. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 27 ++++++++++++--------------- kernel/rcu/tree_exp.h | 2 +- kernel/rcu/tree_plugin.h | 16 ++++++++-------- 3 files changed, 21 insertions(+), 24 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index e6b0bb0d00b7..e3cdec55ef3c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -85,7 +85,6 @@ struct rcu_state rcu_state = { .ofl_lock = __SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock), }; -static struct rcu_state *const rcu_state_p = &rcu_state; static struct rcu_data __percpu *const rcu_data_p = &rcu_data; LIST_HEAD(rcu_struct_flavors); @@ -491,7 +490,7 @@ static int rcu_pending(void); */ unsigned long rcu_get_gp_seq(void) { - return READ_ONCE(rcu_state_p->gp_seq); + return READ_ONCE(rcu_state.gp_seq); } EXPORT_SYMBOL_GPL(rcu_get_gp_seq); @@ -510,7 +509,7 @@ EXPORT_SYMBOL_GPL(rcu_sched_get_gp_seq); */ unsigned long rcu_bh_get_gp_seq(void) { - return READ_ONCE(rcu_state_p->gp_seq); + return READ_ONCE(rcu_state.gp_seq); } EXPORT_SYMBOL_GPL(rcu_bh_get_gp_seq); @@ -522,7 +521,7 @@ EXPORT_SYMBOL_GPL(rcu_bh_get_gp_seq); */ unsigned long rcu_exp_batches_completed(void) { - return rcu_state_p->expedited_sequence; + return rcu_state.expedited_sequence; } EXPORT_SYMBOL_GPL(rcu_exp_batches_completed); @@ -541,7 +540,7 @@ EXPORT_SYMBOL_GPL(rcu_exp_batches_completed_sched); */ void rcu_force_quiescent_state(void) { - force_quiescent_state(rcu_state_p); + force_quiescent_state(&rcu_state); } EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); @@ -550,7 +549,7 @@ EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); */ void rcu_bh_force_quiescent_state(void) { - force_quiescent_state(rcu_state_p); + force_quiescent_state(&rcu_state); } EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state); @@ -611,7 +610,7 @@ void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags, case RCU_FLAVOR: case RCU_BH_FLAVOR: case RCU_SCHED_FLAVOR: - rsp = rcu_state_p; + rsp = &rcu_state; break; default: break; @@ -2292,7 +2291,6 @@ rcu_report_unblock_qs_rnp(struct rcu_state *rsp, raw_lockdep_assert_held_rcu_node(rnp); if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT)) || - WARN_ON_ONCE(rsp != rcu_state_p) || WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) || rnp->qsmask != 0) { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); @@ -2604,7 +2602,6 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *rsp)) raw_spin_lock_irqsave_rcu_node(rnp, flags); if (rnp->qsmask == 0) { if (!IS_ENABLED(CONFIG_PREEMPT) || - rsp != rcu_state_p || rcu_preempt_blocked_readers_cgp(rnp)) { /* * No point in scanning bits because they @@ -2973,7 +2970,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func, */ void call_rcu(struct rcu_head *head, rcu_callback_t func) { - __call_rcu(head, func, rcu_state_p, -1, 0); + __call_rcu(head, func, &rcu_state, -1, 0); } EXPORT_SYMBOL_GPL(call_rcu); @@ -3000,7 +2997,7 @@ EXPORT_SYMBOL_GPL(call_rcu_sched); void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func) { - __call_rcu(head, func, rcu_state_p, -1, 1); + __call_rcu(head, func, &rcu_state, -1, 1); } EXPORT_SYMBOL_GPL(kfree_call_rcu); @@ -3029,7 +3026,7 @@ unsigned long get_state_synchronize_rcu(void) * before the load from ->gp_seq. */ smp_mb(); /* ^^^ */ - return rcu_seq_snap(&rcu_state_p->gp_seq); + return rcu_seq_snap(&rcu_state.gp_seq); } EXPORT_SYMBOL_GPL(get_state_synchronize_rcu); @@ -3049,7 +3046,7 @@ EXPORT_SYMBOL_GPL(get_state_synchronize_rcu); */ void cond_synchronize_rcu(unsigned long oldstate) { - if (!rcu_seq_done(&rcu_state_p->gp_seq, oldstate)) + if (!rcu_seq_done(&rcu_state.gp_seq, oldstate)) synchronize_rcu(); else smp_mb(); /* Ensure GP ends before subsequent accesses. */ @@ -3308,7 +3305,7 @@ static void _rcu_barrier(struct rcu_state *rsp) */ void rcu_barrier_bh(void) { - _rcu_barrier(rcu_state_p); + _rcu_barrier(&rcu_state); } EXPORT_SYMBOL_GPL(rcu_barrier_bh); @@ -3322,7 +3319,7 @@ EXPORT_SYMBOL_GPL(rcu_barrier_bh); */ void rcu_barrier(void) { - _rcu_barrier(rcu_state_p); + _rcu_barrier(&rcu_state); } EXPORT_SYMBOL_GPL(rcu_barrier); diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 3a8a582d9958..298a6904bbcd 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -756,7 +756,7 @@ static void sync_sched_exp_online_cleanup(int cpu) */ void synchronize_rcu_expedited(void) { - struct rcu_state *rsp = rcu_state_p; + struct rcu_state *rsp = &rcu_state; RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) || lock_is_held(&rcu_lock_map) || diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index b7a99a6e64b6..329d5802d899 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -381,7 +381,7 @@ void rcu_note_context_switch(bool preempt) */ rcu_qs(); if (rdp->deferred_qs) - rcu_report_exp_rdp(rcu_state_p, rdp); + rcu_report_exp_rdp(&rcu_state, rdp); trace_rcu_utilization(TPS("End context switch")); barrier(); /* Avoid RCU read-side critical sections leaking up. */ } @@ -509,7 +509,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) * blocked-tasks list below. */ if (rdp->deferred_qs) { - rcu_report_exp_rdp(rcu_state_p, rdp); + rcu_report_exp_rdp(&rcu_state, rdp); if (!t->rcu_read_unlock_special.s) { local_irq_restore(flags); return; @@ -566,7 +566,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) rnp->grplo, rnp->grphi, !!rnp->gp_tasks); - rcu_report_unblock_qs_rnp(rcu_state_p, rnp, flags); + rcu_report_unblock_qs_rnp(&rcu_state, rnp, flags); } else { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } @@ -580,7 +580,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) * then we need to report up the rcu_node hierarchy. */ if (!empty_exp && empty_exp_now) - rcu_report_exp_rnp(rcu_state_p, rnp, true); + rcu_report_exp_rnp(&rcu_state, rnp, true); } else { local_irq_restore(flags); } @@ -1300,7 +1300,7 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp, struct sched_param sp; struct task_struct *t; - if (rcu_state_p != rsp) + if (&rcu_state != rsp) return 0; if (!rcu_scheduler_fully_active || rcu_rnp_online_cpus(rnp) == 0) @@ -1431,8 +1431,8 @@ static void __init rcu_spawn_boost_kthreads(void) for_each_possible_cpu(cpu) per_cpu(rcu_cpu_has_work, cpu) = 0; BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec)); - rcu_for_each_leaf_node(rcu_state_p, rnp) - (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp); + rcu_for_each_leaf_node(&rcu_state, rnp) + (void)rcu_spawn_one_boost_kthread(&rcu_state, rnp); } static void rcu_prepare_kthreads(int cpu) @@ -1442,7 +1442,7 @@ static void rcu_prepare_kthreads(int cpu) /* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */ if (rcu_scheduler_fully_active) - (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp); + (void)rcu_spawn_one_boost_kthread(&rcu_state, rnp); } #else /* #ifdef CONFIG_RCU_BOOST */