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Commit 275a89bd authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
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rcu: use irq-safe locks 



Some earlier tip/core/rcu patches caused RCU to incorrectly enable irqs
too early in boot.  This caused Yinghai's repeated-kexec testing to
hit oopses, presumably due to so that device interrupts left over from
the prior kernel instance (which would oops the newly booting kernel
before it got a chance to reset said devices).  This patch therefore
converts all the local_irq_disable()s in rcuclassic.c to local_irq_save().

Besides, I never did like local_irq_disable() anyway.  ;-)

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 0c925d79

kernel/rcuclassic.c

+10 −6
Original line number Diff line number Diff line
@@ -247,6 +247,7 @@ static inline void raise_rcu_softirq(void) 
 */

static void rcu_do_batch(struct rcu_data *rdp)

{

	unsigned long flags;

	struct rcu_head *next, *list;

	int count = 0;
@@ -261,9 +262,9 @@ static void rcu_do_batch(struct rcu_data *rdp) 
	}

	rdp->donelist = list;



	local_irq_disable();

	local_irq_save(flags);

	rdp->qlen -= count;

	local_irq_enable();

	local_irq_restore(flags);

	if (rdp->blimit == INT_MAX && rdp->qlen <= qlowmark)

		rdp->blimit = blimit;
@@ -464,12 +465,14 @@ static void rcu_check_quiescent_state(struct rcu_ctrlblk *rcp, 
static void rcu_move_batch(struct rcu_data *this_rdp, struct rcu_head *list,

				struct rcu_head **tail, long batch)

{

	unsigned long flags;



	if (list) {

		local_irq_disable();

		local_irq_save(flags);

		this_rdp->batch = batch;

		*this_rdp->nxttail[2] = list;

		this_rdp->nxttail[2] = tail;

		local_irq_enable();

		local_irq_restore(flags);

	}

}
@@ -521,10 +524,11 @@ static void rcu_offline_cpu(int cpu) 
static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp,

					struct rcu_data *rdp)

{

	unsigned long flags;

	long completed_snap;



	if (rdp->nxtlist) {

		local_irq_disable();

		local_irq_save(flags);

		completed_snap = ACCESS_ONCE(rcp->completed);



		/*
@@ -554,7 +558,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp, 
			rdp->nxttail[0] = &rdp->nxtlist;

		}



		local_irq_enable();

		local_irq_restore(flags);



		if (rcu_batch_after(rdp->batch, rcp->pending)) {

			unsigned long flags;