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 <paulmck@linux.vnet.ibm.com>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c
index 01e761a..3f691896 100644
--- a/kernel/rcuclassic.c
+++ b/kernel/rcuclassic.c
@@ -247,6 +247,7 @@
*/
static void rcu_do_batch(struct rcu_data *rdp)
{
+ unsigned long flags;
struct rcu_head *next, *list;
int count = 0;
@@ -261,9 +262,9 @@
}
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_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_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 @@
rdp->nxttail[0] = &rdp->nxtlist;
}
- local_irq_enable();
+ local_irq_restore(flags);
if (rcu_batch_after(rdp->batch, rcp->pending)) {
unsigned long flags;