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Diffstat (limited to 'kernel/irq_work.c')
-rw-r--r--kernel/irq_work.c45
1 files changed, 25 insertions, 20 deletions
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index eca83965b631..e8da1e71583a 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -31,10 +31,10 @@ static bool irq_work_claim(struct irq_work *work)
{
int oflags;
- oflags = atomic_fetch_or(IRQ_WORK_CLAIMED | CSD_TYPE_IRQ_WORK, &work->flags);
+ oflags = atomic_fetch_or(IRQ_WORK_CLAIMED | CSD_TYPE_IRQ_WORK, &work->node.a_flags);
/*
* If the work is already pending, no need to raise the IPI.
- * The pairing atomic_fetch_andnot() in irq_work_run() makes sure
+ * The pairing smp_mb() in irq_work_single() makes sure
* everything we did before is visible.
*/
if (oflags & IRQ_WORK_PENDING)
@@ -53,12 +53,12 @@ void __weak arch_irq_work_raise(void)
static void __irq_work_queue_local(struct irq_work *work)
{
/* If the work is "lazy", handle it from next tick if any */
- if (atomic_read(&work->flags) & IRQ_WORK_LAZY) {
- if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) &&
+ if (atomic_read(&work->node.a_flags) & IRQ_WORK_LAZY) {
+ if (llist_add(&work->node.llist, this_cpu_ptr(&lazy_list)) &&
tick_nohz_tick_stopped())
arch_irq_work_raise();
} else {
- if (llist_add(&work->llnode, this_cpu_ptr(&raised_list)))
+ if (llist_add(&work->node.llist, this_cpu_ptr(&raised_list)))
arch_irq_work_raise();
}
}
@@ -102,7 +102,7 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
if (cpu != smp_processor_id()) {
/* Arch remote IPI send/receive backend aren't NMI safe */
WARN_ON_ONCE(in_nmi());
- __smp_call_single_queue(cpu, &work->llnode);
+ __smp_call_single_queue(cpu, &work->node.llist);
} else {
__irq_work_queue_local(work);
}
@@ -136,23 +136,28 @@ void irq_work_single(void *arg)
int flags;
/*
- * Clear the PENDING bit, after this point the @work
- * can be re-used.
- * Make it immediately visible so that other CPUs trying
- * to claim that work don't rely on us to handle their data
- * while we are in the middle of the func.
+ * Clear the PENDING bit, after this point the @work can be re-used.
+ * The PENDING bit acts as a lock, and we own it, so we can clear it
+ * without atomic ops.
*/
- flags = atomic_fetch_andnot(IRQ_WORK_PENDING, &work->flags);
+ flags = atomic_read(&work->node.a_flags);
+ flags &= ~IRQ_WORK_PENDING;
+ atomic_set(&work->node.a_flags, flags);
+
+ /*
+ * See irq_work_claim().
+ */
+ smp_mb();
- lockdep_irq_work_enter(work);
+ lockdep_irq_work_enter(flags);
work->func(work);
- lockdep_irq_work_exit(work);
+ lockdep_irq_work_exit(flags);
+
/*
- * Clear the BUSY bit and return to the free state if
- * no-one else claimed it meanwhile.
+ * Clear the BUSY bit, if set, and return to the free state if no-one
+ * else claimed it meanwhile.
*/
- flags &= ~IRQ_WORK_PENDING;
- (void)atomic_cmpxchg(&work->flags, flags, flags & ~IRQ_WORK_BUSY);
+ (void)atomic_cmpxchg(&work->node.a_flags, flags, flags & ~IRQ_WORK_BUSY);
}
static void irq_work_run_list(struct llist_head *list)
@@ -166,7 +171,7 @@ static void irq_work_run_list(struct llist_head *list)
return;
llnode = llist_del_all(list);
- llist_for_each_entry_safe(work, tmp, llnode, llnode)
+ llist_for_each_entry_safe(work, tmp, llnode, node.llist)
irq_work_single(work);
}
@@ -198,7 +203,7 @@ void irq_work_sync(struct irq_work *work)
{
lockdep_assert_irqs_enabled();
- while (atomic_read(&work->flags) & IRQ_WORK_BUSY)
+ while (irq_work_is_busy(work))
cpu_relax();
}
EXPORT_SYMBOL_GPL(irq_work_sync);