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rcu/tree: Move kfree_rcu_cpu locking/unlocking to separate functions 

Introduce helpers to lock and unlock per-cpu "kfree_rcu_cpu"
structures. That will make kfree_call_rcu() more readable
and prevent programming errors.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Uladzislau Rezki (Sony) 2020-05-25 23:47:50 +02:00 committed by Paul E. McKenney
parent 3af8486281
commit 952371d6fc
1 changed files with 23 additions and 8 deletions
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31
kernel/rcu/tree.c
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@ -3035,6 +3035,27 @@ debug_rcu_bhead_unqueue(struct kfree_rcu_bulk_data *bhead)
#endif
}
static inline struct kfree_rcu_cpu *
krc_this_cpu_lock(unsigned long *flags)
{
struct kfree_rcu_cpu *krcp;
local_irq_save(*flags); // For safely calling this_cpu_ptr().
krcp = this_cpu_ptr(&krc);
if (likely(krcp->initialized))
raw_spin_lock(&krcp->lock);
return krcp;
}
static inline void
krc_this_cpu_unlock(struct kfree_rcu_cpu *krcp, unsigned long flags)
{
if (likely(krcp->initialized))
raw_spin_unlock(&krcp->lock);
local_irq_restore(flags);
}
/*
* This function is invoked in workqueue context after a grace period.
* It frees all the objects queued on ->bhead_free or ->head_free.
@ -3260,11 +3281,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
struct kfree_rcu_cpu *krcp;
void *ptr;
local_irq_save(flags); // For safely calling this_cpu_ptr().
krcp = this_cpu_ptr(&krc);
if (krcp->initialized)
raw_spin_lock(&krcp->lock);
krcp = krc_this_cpu_lock(&flags);
ptr = (void *)head - (unsigned long)func;
// Queue the object but don't yet schedule the batch.
@ -3295,9 +3312,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
}
unlock_return:
if (krcp->initialized)
raw_spin_unlock(&krcp->lock);
local_irq_restore(flags);
krc_this_cpu_unlock(krcp, flags);
}
EXPORT_SYMBOL_GPL(kfree_call_rcu);