On Thu, Aug 30, 2012 at 11:56:26AM -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney" <paul.mcken...@linaro.org>
>
> The use of raw_local_irq_save() is unnecessary, given that local_irq_save()
> really does disable interrupts. Also, it appears to interfere with lockdep.
> Therefore, this commit moves to local_irq_save().
It looks like the non-raw versions also include tracing, which typically
has recursive dependency problems with RCU. Can all of these call sites
safely call into tracing without recursing back into RCU?
- Josh Triplett
> Reported-by: Fengguang Wu <fengguang...@intel.com>
> Signed-off-by: Paul E. McKenney <paul.mcken...@linaro.org>
> Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
> Tested-by: Fengguang Wu <fengguang...@intel.com>
> ---
> kernel/rcutiny_plugin.h | 10 +++++-----
> 1 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
> index 918fd1e..3d01902 100644
> --- a/kernel/rcutiny_plugin.h
> +++ b/kernel/rcutiny_plugin.h
> @@ -278,7 +278,7 @@ static int rcu_boost(void)
> rcu_preempt_ctrlblk.exp_tasks == NULL)
> return 0; /* Nothing to boost. */
>
> - raw_local_irq_save(flags);
> + local_irq_save(flags);
>
> /*
> * Recheck with irqs disabled: all tasks in need of boosting
> @@ -287,7 +287,7 @@ static int rcu_boost(void)
> */
> if (rcu_preempt_ctrlblk.boost_tasks == NULL &&
> rcu_preempt_ctrlblk.exp_tasks == NULL) {
> - raw_local_irq_restore(flags);
> + local_irq_restore(flags);
> return 0;
> }
>
> @@ -317,7 +317,7 @@ static int rcu_boost(void)
> t = container_of(tb, struct task_struct, rcu_node_entry);
> rt_mutex_init_proxy_locked(&mtx, t);
> t->rcu_boost_mutex = &mtx;
> - raw_local_irq_restore(flags);
> + local_irq_restore(flags);
> rt_mutex_lock(&mtx);
> rt_mutex_unlock(&mtx); /* Keep lockdep happy. */
>
> @@ -991,9 +991,9 @@ static void rcu_trace_sub_qlen(struct rcu_ctrlblk *rcp,
> int n)
> {
> unsigned long flags;
>
> - raw_local_irq_save(flags);
> + local_irq_save(flags);
> rcp->qlen -= n;
> - raw_local_irq_restore(flags);
> + local_irq_restore(flags);
> }
>
> /*
> --
> 1.7.8
>
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