From 275a89bdd3868af3008852594d2e169eaf69441b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 21 Aug 2008 06:14:55 -0700 Subject: 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: Paul E. McKenney Signed-off-by: Yinghai Lu Signed-off-by: Ingo Molnar --- kernel/rcuclassic.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c index 01e761a6b38..3f6918966bd 100644 --- a/kernel/rcuclassic.c +++ b/kernel/rcuclassic.c @@ -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; -- cgit v1.2.3-18-g5258