iommu: avoid taking iova_rbtree_lock twice

Both find_iova() and __free_iova() take iova_rbtree_lock,
there is no reason to take and release it twice inside
free_iova().

Fold them into one critical section by calling the unlock
versions instead.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1605608734-84416-5-git-send-email-john.garry@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index ea04a88..ff59d8a 100644 (file)
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -402,10 +402,14 @@ EXPORT_SYMBOL_GPL(__free_iova);
 void
 free_iova(struct iova_domain *iovad, unsigned long pfn)
 {
-       struct iova *iova = find_iova(iovad, pfn);
+       unsigned long flags;
+       struct iova *iova;
 
+       spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
+       iova = private_find_iova(iovad, pfn);
        if (iova)
-               __free_iova(iovad, iova);
+               private_free_iova(iovad, iova);
+       spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 
 }
 EXPORT_SYMBOL_GPL(free_iova);