From: Mike Galbraith <[email protected]> 1e64b15a4b10 ("rcu: Fix grace-period hangs due to race with CPU offline") added spinlock_t ofl_lock to the rcu_state structure, then takes it with preemption disabled during CPU offline, which gives the -rt patchset's sleeping spinlock heartburn.
This commit therefore converts ->ofl_lock to raw_spinlock_t. Signed-off-by: Mike Galbraith <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> --- kernel/rcu/tree.c | 12 ++++++------ kernel/rcu/tree.h | 2 +- 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 65b6e03ae6f5..0ce4702ce09f 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -97,7 +97,7 @@ struct rcu_state rcu_state = { .abbr = RCU_ABBR, .exp_mutex = __MUTEX_INITIALIZER(rcu_state.exp_mutex), .exp_wake_mutex = __MUTEX_INITIALIZER(rcu_state.exp_wake_mutex), - .ofl_lock = __SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock), + .ofl_lock = __RAW_SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock), }; /* Dump rcu_node combining tree at boot to verify correct setup. */ @@ -1775,13 +1775,13 @@ static bool rcu_gp_init(void) */ rcu_state.gp_state = RCU_GP_ONOFF; rcu_for_each_leaf_node(rnp) { - spin_lock(&rcu_state.ofl_lock); + raw_spin_lock(&rcu_state.ofl_lock); raw_spin_lock_irq_rcu_node(rnp); if (rnp->qsmaskinit == rnp->qsmaskinitnext && !rnp->wait_blkd_tasks) { /* Nothing to do on this leaf rcu_node structure. */ raw_spin_unlock_irq_rcu_node(rnp); - spin_unlock(&rcu_state.ofl_lock); + raw_spin_unlock(&rcu_state.ofl_lock); continue; } @@ -1817,7 +1817,7 @@ static bool rcu_gp_init(void) } raw_spin_unlock_irq_rcu_node(rnp); - spin_unlock(&rcu_state.ofl_lock); + raw_spin_unlock(&rcu_state.ofl_lock); } rcu_gp_slow(gp_preinit_delay); /* Races with CPU hotplug. */ @@ -3376,7 +3376,7 @@ void rcu_report_dead(unsigned int cpu) /* Remove outgoing CPU from mask in the leaf rcu_node structure. */ mask = rdp->grpmask; - spin_lock(&rcu_state.ofl_lock); + raw_spin_lock(&rcu_state.ofl_lock); raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Enforce GP memory-order guarantee. */ rdp->rcu_ofl_gp_seq = READ_ONCE(rcu_state.gp_seq); rdp->rcu_ofl_gp_flags = READ_ONCE(rcu_state.gp_flags); @@ -3387,7 +3387,7 @@ void rcu_report_dead(unsigned int cpu) } rnp->qsmaskinitnext &= ~mask; raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - spin_unlock(&rcu_state.ofl_lock); + raw_spin_unlock(&rcu_state.ofl_lock); per_cpu(rcu_cpu_started, cpu) = 0; } diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index bfbf97a1c29d..703e19ff532d 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -343,7 +343,7 @@ struct rcu_state { const char *name; /* Name of structure. */ char abbr; /* Abbreviated name. */ - spinlock_t ofl_lock ____cacheline_internodealigned_in_smp; + raw_spinlock_t ofl_lock ____cacheline_internodealigned_in_smp; /* Synchronize offline with */ /* GP pre-initialization. */ }; -- 2.17.1
