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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2021-10-06 13:18:50 +0200
committerPeter Zijlstra <peterz@infradead.org>2021-10-15 11:25:17 +0200
commit810979682ccc98dbd83f341c18a2e556c30a7164 (patch)
treea9d692207ee2df66d8292a5fe89ef0440465d419 /kernel/irq_work.c
parentda6ff09943491819e077b94c284bf0a6b751c9b8 (diff)
irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
irq_work() triggers instantly an interrupt if supported by the architecture. Otherwise the work will be processed on the next timer tick. In worst case irq_work_sync() could spin up to a jiffy. irq_work_sync() is usually used in tear down context which is fully preemptible. Based on review irq_work_sync() is invoked from preemptible context and there is one waiter at a time. This qualifies it to use rcuwait for synchronisation. Let irq_work_sync() synchronize with rcuwait if the architecture processes irqwork via the timer tick. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211006111852.1514359-3-bigeasy@linutronix.de
Diffstat (limited to 'kernel/irq_work.c')
-rw-r--r--kernel/irq_work.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index db8c248ebc8c..e789beda8297 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -160,6 +160,9 @@ void irq_work_single(void *arg)
* else claimed it meanwhile.
*/
(void)atomic_cmpxchg(&work->node.a_flags, flags, flags & ~IRQ_WORK_BUSY);
+
+ if (!arch_irq_work_has_interrupt())
+ rcuwait_wake_up(&work->irqwait);
}
static void irq_work_run_list(struct llist_head *list)
@@ -204,6 +207,13 @@ void irq_work_tick(void)
void irq_work_sync(struct irq_work *work)
{
lockdep_assert_irqs_enabled();
+ might_sleep();
+
+ if (!arch_irq_work_has_interrupt()) {
+ rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work),
+ TASK_UNINTERRUPTIBLE);
+ return;
+ }
while (irq_work_is_busy(work))
cpu_relax();