summaryrefslogtreecommitdiff
path: root/drivers/iommu/iova.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/iommu/iova.c')
-rw-r--r--drivers/iommu/iova.c22
1 files changed, 17 insertions, 5 deletions
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 33edfa794ae9..4edf65dbbcab 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -58,9 +58,14 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule,
}
EXPORT_SYMBOL_GPL(init_iova_domain);
+bool has_iova_flush_queue(struct iova_domain *iovad)
+{
+ return !!iovad->fq;
+}
+
static void free_iova_flush_queue(struct iova_domain *iovad)
{
- if (!iovad->fq)
+ if (!has_iova_flush_queue(iovad))
return;
if (timer_pending(&iovad->fq_timer))
@@ -78,13 +83,14 @@ static void free_iova_flush_queue(struct iova_domain *iovad)
int init_iova_flush_queue(struct iova_domain *iovad,
iova_flush_cb flush_cb, iova_entry_dtor entry_dtor)
{
+ struct iova_fq __percpu *queue;
int cpu;
atomic64_set(&iovad->fq_flush_start_cnt, 0);
atomic64_set(&iovad->fq_flush_finish_cnt, 0);
- iovad->fq = alloc_percpu(struct iova_fq);
- if (!iovad->fq)
+ queue = alloc_percpu(struct iova_fq);
+ if (!queue)
return -ENOMEM;
iovad->flush_cb = flush_cb;
@@ -93,13 +99,17 @@ int init_iova_flush_queue(struct iova_domain *iovad,
for_each_possible_cpu(cpu) {
struct iova_fq *fq;
- fq = per_cpu_ptr(iovad->fq, cpu);
+ fq = per_cpu_ptr(queue, cpu);
fq->head = 0;
fq->tail = 0;
spin_lock_init(&fq->lock);
}
+ smp_wmb();
+
+ iovad->fq = queue;
+
setup_timer(&iovad->fq_timer, fq_flush_timeout, (unsigned long)iovad);
atomic_set(&iovad->fq_timer_on, 0);
@@ -597,7 +607,9 @@ void queue_iova(struct iova_domain *iovad,
spin_unlock_irqrestore(&fq->lock, flags);
- if (atomic_cmpxchg(&iovad->fq_timer_on, 0, 1) == 0)
+ /* Avoid false sharing as much as possible. */
+ if (!atomic_read(&iovad->fq_timer_on) &&
+ !atomic_cmpxchg(&iovad->fq_timer_on, 0, 1))
mod_timer(&iovad->fq_timer,
jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT));